Rotation

src/GameEngine.cpp

@@ -12,6 +12,10 @@
 #include <cmath>
 #include <Python.h>
 
+// Static member definitions for shader intermediate texture (#106)
+std::unique_ptr<sf::RenderTexture> GameEngine::shaderIntermediate;
+bool GameEngine::shaderIntermediateInitialized = false;
+
 // #219 - FrameLock implementation for thread-safe UI updates
 
 void FrameLock::acquire() {
@@ -718,6 +722,37 @@ sf::Vector2f GameEngine::windowToGameCoords(const sf::Vector2f& windowPos) const
     return render_target->mapPixelToCoords(sf::Vector2i(windowPos), gameView);
 }
 
+// #106 - Shader intermediate texture: shared texture for shader rendering
+void GameEngine::initShaderIntermediate(unsigned int width, unsigned int height) {
+    if (!sf::Shader::isAvailable()) {
+        std::cerr << "GameEngine: Shaders not available, skipping intermediate texture init" << std::endl;
+        return;
+    }
+
+    if (!shaderIntermediate) {
+        shaderIntermediate = std::make_unique<sf::RenderTexture>();
+    }
+
+    if (!shaderIntermediate->create(width, height)) {
+        std::cerr << "GameEngine: Failed to create shader intermediate texture ("
+                  << width << "x" << height << ")" << std::endl;
+        shaderIntermediate.reset();
+        shaderIntermediateInitialized = false;
+        return;
+    }
+
+    shaderIntermediate->setSmooth(false);  // Pixel-perfect rendering
+    shaderIntermediateInitialized = true;
+}
+
+sf::RenderTexture& GameEngine::getShaderIntermediate() {
+    if (!shaderIntermediateInitialized) {
+        // Initialize with default resolution if not already done
+        initShaderIntermediate(1024, 768);
+    }
+    return *shaderIntermediate;
+}
+
 // #153 - Headless simulation control: step() advances simulation time
 float GameEngine::step(float dt) {
     // In windowed mode, step() is a no-op

src/GameEngine.h

@@ -185,6 +185,10 @@ private:
     sf::View gameView;                        // View for the game content
     ViewportMode viewportMode = ViewportMode::Fit;
 
+    // Shader intermediate texture (#106) - shared texture for shader rendering
+    static std::unique_ptr<sf::RenderTexture> shaderIntermediate;
+    static bool shaderIntermediateInitialized;
+
     // Profiling overlay
     bool showProfilerOverlay = false;         // F3 key toggles this
     int overlayUpdateCounter = 0;             // Only update overlay every N frames
@@ -257,6 +261,11 @@ public:
     std::string getViewportModeString() const;
     sf::Vector2f windowToGameCoords(const sf::Vector2f& windowPos) const;
 
+    // Shader system (#106) - shared intermediate texture for shader rendering
+    static sf::RenderTexture& getShaderIntermediate();
+    static void initShaderIntermediate(unsigned int width, unsigned int height);
+    static bool isShaderIntermediateReady() { return shaderIntermediateInitialized; }
+
     // #153 - Headless simulation control
     float step(float dt = -1.0f);  // Advance simulation; dt<0 means advance to next event
     int getSimulationTime() const { return simulation_time; }

src/McRFPy_API.cpp

@@ -27,6 +27,9 @@
 #include "PyNoiseSource.h"  // Procedural generation noise (#207-208)
 #include "PyLock.h"  // Thread synchronization (#219)
 #include "PyVector.h"  // For bresenham Vector support (#215)
+#include "PyShader.h"  // Shader support (#106)
+#include "PyUniformBinding.h"  // Shader uniform bindings (#106)
+#include "PyUniformCollection.h"  // Shader uniform collection (#106)
 #include "McRogueFaceVersion.h"
 #include "GameEngine.h"
 #include "ImGuiConsole.h"
@@ -452,6 +455,11 @@ PyObject* PyInit_mcrfpy()
         &mcrfpydef::PyBSPType,
         &mcrfpydef::PyNoiseSourceType,
 
+        /*shaders (#106)*/
+        &mcrfpydef::PyShaderType,
+        &mcrfpydef::PyPropertyBindingType,
+        &mcrfpydef::PyCallableBindingType,
+
         nullptr};
 
     // Types that are used internally but NOT exported to module namespace (#189)
@@ -473,6 +481,9 @@ PyObject* PyInit_mcrfpy()
         &mcrfpydef::PyBSPAdjacencyType,      // #210: BSP.adjacency wrapper
         &mcrfpydef::PyBSPAdjacentTilesType,  // #210: BSPNode.adjacent_tiles wrapper
 
+        /*shader uniform collection - returned by drawable.uniforms but not directly instantiable (#106)*/
+        &mcrfpydef::PyUniformCollectionType,
+
         nullptr};
     
     // Set up PyWindowType methods and getsetters before PyType_Ready
@@ -497,6 +508,17 @@ PyObject* PyInit_mcrfpy()
     mcrfpydef::PyNoiseSourceType.tp_methods = PyNoiseSource::methods;
     mcrfpydef::PyNoiseSourceType.tp_getset = PyNoiseSource::getsetters;
 
+    // Set up PyShaderType methods and getsetters (#106)
+    mcrfpydef::PyShaderType.tp_methods = PyShader::methods;
+    mcrfpydef::PyShaderType.tp_getset = PyShader::getsetters;
+
+    // Set up PyPropertyBindingType and PyCallableBindingType getsetters (#106)
+    mcrfpydef::PyPropertyBindingType.tp_getset = PyPropertyBindingType::getsetters;
+    mcrfpydef::PyCallableBindingType.tp_getset = PyCallableBindingType::getsetters;
+
+    // Set up PyUniformCollectionType methods (#106)
+    mcrfpydef::PyUniformCollectionType.tp_methods = ::PyUniformCollectionType::methods;
+
     // Set up weakref support for all types that need it
     PyTimerType.tp_weaklistoffset = offsetof(PyTimerObject, weakreflist);
     PyUIFrameType.tp_weaklistoffset = offsetof(PyUIFrameObject, weakreflist);

src/PyShader.cpp

@@ -0,0 +1,256 @@
+#include "PyShader.h"
+#include "McRFPy_API.h"
+#include "McRFPy_Doc.h"
+#include "GameEngine.h"
+#include "Resources.h"
+#include <sstream>
+
+// Static clock for time uniform
+static sf::Clock shader_engine_clock;
+static sf::Clock shader_frame_clock;
+
+// Python method and getset definitions
+PyGetSetDef PyShader::getsetters[] = {
+    {"dynamic", (getter)PyShader::get_dynamic, (setter)PyShader::set_dynamic,
+     MCRF_PROPERTY(dynamic,
+         "Whether this shader uses time-varying effects (bool). "
+         "Dynamic shaders invalidate parent caches each frame."), NULL},
+    {"source", (getter)PyShader::get_source, NULL,
+     MCRF_PROPERTY(source,
+         "The GLSL fragment shader source code (str, read-only)."), NULL},
+    {"is_valid", (getter)PyShader::get_is_valid, NULL,
+     MCRF_PROPERTY(is_valid,
+         "True if the shader compiled successfully (bool, read-only)."), NULL},
+    {NULL}
+};
+
+PyMethodDef PyShader::methods[] = {
+    {"set_uniform", (PyCFunction)PyShader::set_uniform, METH_VARARGS | METH_KEYWORDS,
+     MCRF_METHOD(Shader, set_uniform,
+         MCRF_SIG("(name: str, value: float|tuple)", "None"),
+         MCRF_DESC("Set a custom uniform value on this shader."),
+         MCRF_ARGS_START
+         MCRF_ARG("name", "Uniform variable name in the shader")
+         MCRF_ARG("value", "Float, vec2 (2-tuple), vec3 (3-tuple), or vec4 (4-tuple)")
+         MCRF_RAISES("ValueError", "If uniform type cannot be determined")
+         MCRF_NOTE("Engine uniforms (time, resolution, etc.) are set automatically")
+     )},
+    {NULL}
+};
+
+// Constructor
+PyObject* PyShader::pynew(PyTypeObject* type, PyObject* args, PyObject* kwds)
+{
+    PyShaderObject* self = (PyShaderObject*)type->tp_alloc(type, 0);
+    if (self) {
+        self->shader = nullptr;
+        self->dynamic = false;
+        self->weakreflist = NULL;
+        new (&self->fragment_source) std::string();
+    }
+    return (PyObject*)self;
+}
+
+// Destructor
+void PyShader::dealloc(PyShaderObject* self)
+{
+    // Clear weak references
+    if (self->weakreflist) {
+        PyObject_ClearWeakRefs((PyObject*)self);
+    }
+
+    // Destroy C++ objects
+    self->shader.reset();
+    self->fragment_source.~basic_string();
+
+    // Free Python object
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+// Initializer
+int PyShader::init(PyShaderObject* self, PyObject* args, PyObject* kwds)
+{
+    static const char* keywords[] = {"fragment_source", "dynamic", nullptr};
+    const char* source = nullptr;
+    int dynamic = 0;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "s|p", const_cast<char**>(keywords),
+                                     &source, &dynamic)) {
+        return -1;
+    }
+
+    // Check if shaders are available
+    if (!sf::Shader::isAvailable()) {
+        PyErr_SetString(PyExc_RuntimeError,
+            "Shaders are not available on this system (no GPU support or OpenGL too old)");
+        return -1;
+    }
+
+    // Store source and dynamic flag
+    self->fragment_source = source;
+    self->dynamic = (bool)dynamic;
+
+    // Create and compile the shader
+    self->shader = std::make_shared<sf::Shader>();
+
+    // Capture sf::err() output during shader compilation
+    std::streambuf* oldBuf = sf::err().rdbuf();
+    std::ostringstream errStream;
+    sf::err().rdbuf(errStream.rdbuf());
+
+    bool success = self->shader->loadFromMemory(source, sf::Shader::Fragment);
+
+    // Restore sf::err() and check for errors
+    sf::err().rdbuf(oldBuf);
+
+    if (!success) {
+        std::string error_msg = errStream.str();
+        if (error_msg.empty()) {
+            error_msg = "Shader compilation failed (unknown error)";
+        }
+        PyErr_Format(PyExc_ValueError, "Shader compilation failed: %s", error_msg.c_str());
+        self->shader.reset();
+        return -1;
+    }
+
+    return 0;
+}
+
+// Repr
+PyObject* PyShader::repr(PyObject* obj)
+{
+    PyShaderObject* self = (PyShaderObject*)obj;
+    std::ostringstream ss;
+    ss << "<Shader";
+    if (self->shader) {
+        ss << " valid";
+    } else {
+        ss << " invalid";
+    }
+    if (self->dynamic) {
+        ss << " dynamic";
+    }
+    ss << ">";
+    return PyUnicode_FromString(ss.str().c_str());
+}
+
+// Property: dynamic
+PyObject* PyShader::get_dynamic(PyShaderObject* self, void* closure)
+{
+    return PyBool_FromLong(self->dynamic);
+}
+
+int PyShader::set_dynamic(PyShaderObject* self, PyObject* value, void* closure)
+{
+    if (!PyBool_Check(value)) {
+        PyErr_SetString(PyExc_TypeError, "dynamic must be a boolean");
+        return -1;
+    }
+    self->dynamic = PyObject_IsTrue(value);
+    return 0;
+}
+
+// Property: source (read-only)
+PyObject* PyShader::get_source(PyShaderObject* self, void* closure)
+{
+    return PyUnicode_FromString(self->fragment_source.c_str());
+}
+
+// Property: is_valid (read-only)
+PyObject* PyShader::get_is_valid(PyShaderObject* self, void* closure)
+{
+    return PyBool_FromLong(self->shader != nullptr);
+}
+
+// Method: set_uniform
+PyObject* PyShader::set_uniform(PyShaderObject* self, PyObject* args, PyObject* kwds)
+{
+    static const char* keywords[] = {"name", "value", nullptr};
+    const char* name = nullptr;
+    PyObject* value = nullptr;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "sO", const_cast<char**>(keywords),
+                                     &name, &value)) {
+        return NULL;
+    }
+
+    if (!self->shader) {
+        PyErr_SetString(PyExc_RuntimeError, "Shader is not valid");
+        return NULL;
+    }
+
+    // Determine the type and set uniform
+    if (PyFloat_Check(value) || PyLong_Check(value)) {
+        // Single float
+        float f = (float)PyFloat_AsDouble(value);
+        if (PyErr_Occurred()) return NULL;
+        self->shader->setUniform(name, f);
+    }
+    else if (PyTuple_Check(value)) {
+        Py_ssize_t size = PyTuple_Size(value);
+        if (size == 2) {
+            // vec2
+            float x = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 0));
+            float y = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 1));
+            if (PyErr_Occurred()) return NULL;
+            self->shader->setUniform(name, sf::Glsl::Vec2(x, y));
+        }
+        else if (size == 3) {
+            // vec3
+            float x = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 0));
+            float y = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 1));
+            float z = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 2));
+            if (PyErr_Occurred()) return NULL;
+            self->shader->setUniform(name, sf::Glsl::Vec3(x, y, z));
+        }
+        else if (size == 4) {
+            // vec4
+            float x = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 0));
+            float y = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 1));
+            float z = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 2));
+            float w = (float)PyFloat_AsDouble(PyTuple_GetItem(value, 3));
+            if (PyErr_Occurred()) return NULL;
+            self->shader->setUniform(name, sf::Glsl::Vec4(x, y, z, w));
+        }
+        else {
+            PyErr_Format(PyExc_ValueError,
+                "Tuple must have 2, 3, or 4 elements for vec2/vec3/vec4, got %zd", size);
+            return NULL;
+        }
+    }
+    else {
+        PyErr_SetString(PyExc_TypeError,
+            "Uniform value must be a float or tuple of 2-4 floats");
+        return NULL;
+    }
+
+    Py_RETURN_NONE;
+}
+
+// Static helper: apply engine-provided uniforms
+void PyShader::applyEngineUniforms(sf::Shader& shader, sf::Vector2f resolution)
+{
+    // Time uniforms
+    shader.setUniform("time", shader_engine_clock.getElapsedTime().asSeconds());
+    shader.setUniform("delta_time", shader_frame_clock.restart().asSeconds());
+
+    // Resolution
+    shader.setUniform("resolution", resolution);
+
+    // Mouse position - get from GameEngine if available
+    sf::Vector2f mouse(0.f, 0.f);
+    if (Resources::game && !Resources::game->isHeadless()) {
+        sf::Vector2i mousePos = sf::Mouse::getPosition(Resources::game->getWindow());
+        mouse = sf::Vector2f(static_cast<float>(mousePos.x), static_cast<float>(mousePos.y));
+    }
+    shader.setUniform("mouse", mouse);
+
+    // CurrentTexture is handled by SFML automatically when drawing
+    shader.setUniform("texture", sf::Shader::CurrentTexture);
+}
+
+// Static helper: check availability
+bool PyShader::isAvailable()
+{
+    return sf::Shader::isAvailable();
+}

src/PyShader.h

@@ -0,0 +1,94 @@
+#pragma once
+#include "Common.h"
+#include "Python.h"
+
+// Forward declarations
+class UIDrawable;
+
+// Python object structure for Shader
+typedef struct PyShaderObjectStruct {
+    PyObject_HEAD
+    std::shared_ptr<sf::Shader> shader;
+    bool dynamic;                        // Time-varying shader (affects caching)
+    std::string fragment_source;         // Source code for recompilation
+    PyObject* weakreflist;               // Support weak references
+} PyShaderObject;
+
+class PyShader
+{
+public:
+    // Python type methods
+    static PyObject* repr(PyObject* self);
+    static int init(PyShaderObject* self, PyObject* args, PyObject* kwds);
+    static PyObject* pynew(PyTypeObject* type, PyObject* args, PyObject* kwds);
+    static void dealloc(PyShaderObject* self);
+
+    // Property getters/setters
+    static PyObject* get_dynamic(PyShaderObject* self, void* closure);
+    static int set_dynamic(PyShaderObject* self, PyObject* value, void* closure);
+    static PyObject* get_source(PyShaderObject* self, void* closure);
+    static PyObject* get_is_valid(PyShaderObject* self, void* closure);
+
+    // Methods
+    static PyObject* set_uniform(PyShaderObject* self, PyObject* args, PyObject* kwds);
+
+    // Static helper: apply engine-provided uniforms (time, resolution, etc.)
+    static void applyEngineUniforms(sf::Shader& shader, sf::Vector2f resolution);
+
+    // Check if shaders are available on this system
+    static bool isAvailable();
+
+    // Arrays for Python type definition
+    static PyGetSetDef getsetters[];
+    static PyMethodDef methods[];
+};
+
+namespace mcrfpydef {
+    // Using inline to ensure single definition across translation units (C++17)
+    inline PyTypeObject PyShaderType = {
+        .ob_base = {.ob_base = {.ob_refcnt = 1, .ob_type = NULL}, .ob_size = 0},
+        .tp_name = "mcrfpy.Shader",
+        .tp_basicsize = sizeof(PyShaderObject),
+        .tp_itemsize = 0,
+        .tp_dealloc = (destructor)PyShader::dealloc,
+        .tp_repr = PyShader::repr,
+        .tp_flags = Py_TPFLAGS_DEFAULT,
+        .tp_doc = PyDoc_STR(
+            "Shader(fragment_source: str, dynamic: bool = False)\n"
+            "\n"
+            "A GPU shader program for visual effects.\n"
+            "\n"
+            "Args:\n"
+            "    fragment_source: GLSL fragment shader source code\n"
+            "    dynamic: If True, shader uses time-varying effects and will\n"
+            "             invalidate parent caches each frame\n"
+            "\n"
+            "Shaders enable GPU-accelerated visual effects like glow, distortion,\n"
+            "color manipulation, and more. Assign to drawable.shader to apply.\n"
+            "\n"
+            "Engine-provided uniforms (automatically available):\n"
+            "    - float time: Seconds since engine start\n"
+            "    - float delta_time: Seconds since last frame\n"
+            "    - vec2 resolution: Texture size in pixels\n"
+            "    - vec2 mouse: Mouse position in window coordinates\n"
+            "\n"
+            "Example:\n"
+            "    shader = mcrfpy.Shader('''\n"
+            "        uniform sampler2D texture;\n"
+            "        uniform float time;\n"
+            "        void main() {\n"
+            "            vec2 uv = gl_TexCoord[0].xy;\n"
+            "            vec4 color = texture2D(texture, uv);\n"
+            "            color.rgb *= 0.5 + 0.5 * sin(time);\n"
+            "            gl_FragColor = color;\n"
+            "        }\n"
+            "    ''', dynamic=True)\n"
+            "    frame.shader = shader\n"
+        ),
+        .tp_weaklistoffset = offsetof(PyShaderObject, weakreflist),
+        .tp_methods = nullptr,  // Set in McRFPy_API.cpp before PyType_Ready
+        .tp_getset = nullptr,   // Set in McRFPy_API.cpp before PyType_Ready
+        .tp_init = (initproc)PyShader::init,
+        .tp_new = PyShader::pynew,
+    };
+}

src/PyUniformBinding.cpp

@@ -0,0 +1,341 @@
+#include "PyUniformBinding.h"
+#include "UIDrawable.h"
+#include "UIFrame.h"
+#include "UICaption.h"
+#include "UISprite.h"
+#include "UIGrid.h"
+#include "UILine.h"
+#include "UICircle.h"
+#include "UIArc.h"
+#include "McRFPy_API.h"
+#include "McRFPy_Doc.h"
+#include <sstream>
+#include <cstring>
+
+// ============================================================================
+// PropertyBinding Implementation
+// ============================================================================
+
+PropertyBinding::PropertyBinding(std::weak_ptr<UIDrawable> target, const std::string& property)
+    : target(target), property_name(property) {}
+
+std::optional<float> PropertyBinding::evaluate() const {
+    auto ptr = target.lock();
+    if (!ptr) return std::nullopt;
+
+    float value = 0.0f;
+    if (ptr->getProperty(property_name, value)) {
+        return value;
+    }
+    return std::nullopt;
+}
+
+bool PropertyBinding::isValid() const {
+    auto ptr = target.lock();
+    if (!ptr) return false;
+    return ptr->hasProperty(property_name);
+}
+
+// ============================================================================
+// CallableBinding Implementation
+// ============================================================================
+
+CallableBinding::CallableBinding(PyObject* callable)
+    : callable(callable) {
+    if (callable) {
+        Py_INCREF(callable);
+    }
+}
+
+CallableBinding::~CallableBinding() {
+    if (callable) {
+        Py_DECREF(callable);
+    }
+}
+
+CallableBinding::CallableBinding(CallableBinding&& other) noexcept
+    : callable(other.callable) {
+    other.callable = nullptr;
+}
+
+CallableBinding& CallableBinding::operator=(CallableBinding&& other) noexcept {
+    if (this != &other) {
+        if (callable) {
+            Py_DECREF(callable);
+        }
+        callable = other.callable;
+        other.callable = nullptr;
+    }
+    return *this;
+}
+
+std::optional<float> CallableBinding::evaluate() const {
+    if (!callable || !PyCallable_Check(callable)) {
+        return std::nullopt;
+    }
+
+    PyObject* result = PyObject_CallNoArgs(callable);
+    if (!result) {
+        // Python exception occurred - print and clear it
+        PyErr_Print();
+        return std::nullopt;
+    }
+
+    float value = 0.0f;
+    if (PyFloat_Check(result)) {
+        value = static_cast<float>(PyFloat_AsDouble(result));
+    } else if (PyLong_Check(result)) {
+        value = static_cast<float>(PyLong_AsDouble(result));
+    } else {
+        // Try to convert to float
+        PyObject* float_result = PyNumber_Float(result);
+        if (float_result) {
+            value = static_cast<float>(PyFloat_AsDouble(float_result));
+            Py_DECREF(float_result);
+        } else {
+            PyErr_Clear();
+            Py_DECREF(result);
+            return std::nullopt;
+        }
+    }
+
+    Py_DECREF(result);
+    return value;
+}
+
+bool CallableBinding::isValid() const {
+    return callable && PyCallable_Check(callable);
+}
+
+// ============================================================================
+// PyPropertyBindingType Python Interface
+// ============================================================================
+
+PyGetSetDef PyPropertyBindingType::getsetters[] = {
+    {"target", (getter)PyPropertyBindingType::get_target, NULL,
+     MCRF_PROPERTY(target, "The drawable this binding reads from (read-only)."), NULL},
+    {"property", (getter)PyPropertyBindingType::get_property, NULL,
+     MCRF_PROPERTY(property, "The property name being read (str, read-only)."), NULL},
+    {"value", (getter)PyPropertyBindingType::get_value, NULL,
+     MCRF_PROPERTY(value, "Current value of the binding (float, read-only). Returns None if invalid."), NULL},
+    {"is_valid", (getter)PyPropertyBindingType::is_valid, NULL,
+     MCRF_PROPERTY(is_valid, "True if the binding target still exists and property is valid (bool, read-only)."), NULL},
+    {NULL}
+};
+
+PyObject* PyPropertyBindingType::pynew(PyTypeObject* type, PyObject* args, PyObject* kwds) {
+    PyPropertyBindingObject* self = (PyPropertyBindingObject*)type->tp_alloc(type, 0);
+    if (self) {
+        self->binding = nullptr;
+        self->weakreflist = NULL;
+    }
+    return (PyObject*)self;
+}
+
+void PyPropertyBindingType::dealloc(PyPropertyBindingObject* self) {
+    if (self->weakreflist) {
+        PyObject_ClearWeakRefs((PyObject*)self);
+    }
+    self->binding.reset();
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+int PyPropertyBindingType::init(PyPropertyBindingObject* self, PyObject* args, PyObject* kwds) {
+    static const char* keywords[] = {"target", "property", nullptr};
+    PyObject* target_obj = nullptr;
+    const char* property = nullptr;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "Os", const_cast<char**>(keywords),
+                                     &target_obj, &property)) {
+        return -1;
+    }
+
+    // Get the shared_ptr from the target drawable by checking the type name
+    // We can't use PyObject_IsInstance with static type objects from other translation units
+    // So we check the type name string instead
+    std::shared_ptr<UIDrawable> target_ptr;
+    const char* type_name = Py_TYPE(target_obj)->tp_name;
+
+    if (strcmp(type_name, "mcrfpy.Frame") == 0) {
+        target_ptr = ((PyUIFrameObject*)target_obj)->data;
+    } else if (strcmp(type_name, "mcrfpy.Caption") == 0) {
+        target_ptr = ((PyUICaptionObject*)target_obj)->data;
+    } else if (strcmp(type_name, "mcrfpy.Sprite") == 0) {
+        target_ptr = ((PyUISpriteObject*)target_obj)->data;
+    } else if (strcmp(type_name, "mcrfpy.Grid") == 0) {
+        target_ptr = ((PyUIGridObject*)target_obj)->data;
+    } else if (strcmp(type_name, "mcrfpy.Line") == 0) {
+        target_ptr = ((PyUILineObject*)target_obj)->data;
+    } else if (strcmp(type_name, "mcrfpy.Circle") == 0) {
+        target_ptr = ((PyUICircleObject*)target_obj)->data;
+    } else if (strcmp(type_name, "mcrfpy.Arc") == 0) {
+        target_ptr = ((PyUIArcObject*)target_obj)->data;
+    }
+
+    if (!target_ptr) {
+        PyErr_SetString(PyExc_TypeError,
+            "PropertyBinding requires a UIDrawable (Frame, Sprite, Caption, Grid, Line, Circle, or Arc)");
+        return -1;
+    }
+
+    // Validate that the property exists
+    if (!target_ptr->hasProperty(property)) {
+        PyErr_Format(PyExc_ValueError,
+            "Property '%s' is not a valid animatable property on this drawable", property);
+        return -1;
+    }
+
+    self->binding = std::make_shared<PropertyBinding>(target_ptr, property);
+    return 0;
+}
+
+PyObject* PyPropertyBindingType::repr(PyObject* obj) {
+    PyPropertyBindingObject* self = (PyPropertyBindingObject*)obj;
+    std::ostringstream ss;
+    ss << "<PropertyBinding";
+    if (self->binding) {
+        ss << " property='" << self->binding->getPropertyName() << "'";
+        if (self->binding->isValid()) {
+            auto val = self->binding->evaluate();
+            if (val) {
+                ss << " value=" << *val;
+            }
+        } else {
+            ss << " (invalid)";
+        }
+    }
+    ss << ">";
+    return PyUnicode_FromString(ss.str().c_str());
+}
+
+PyObject* PyPropertyBindingType::get_target(PyPropertyBindingObject* self, void* closure) {
+    if (!self->binding) {
+        Py_RETURN_NONE;
+    }
+    auto ptr = self->binding->getTarget().lock();
+    if (!ptr) {
+        Py_RETURN_NONE;
+    }
+    // TODO: Return the actual Python object for the drawable
+    Py_RETURN_NONE;
+}
+
+PyObject* PyPropertyBindingType::get_property(PyPropertyBindingObject* self, void* closure) {
+    if (!self->binding) {
+        Py_RETURN_NONE;
+    }
+    return PyUnicode_FromString(self->binding->getPropertyName().c_str());
+}
+
+PyObject* PyPropertyBindingType::get_value(PyPropertyBindingObject* self, void* closure) {
+    if (!self->binding) {
+        Py_RETURN_NONE;
+    }
+    auto val = self->binding->evaluate();
+    if (!val) {
+        Py_RETURN_NONE;
+    }
+    return PyFloat_FromDouble(*val);
+}
+
+PyObject* PyPropertyBindingType::is_valid(PyPropertyBindingObject* self, void* closure) {
+    if (!self->binding) {
+        Py_RETURN_FALSE;
+    }
+    return PyBool_FromLong(self->binding->isValid());
+}
+
+// ============================================================================
+// PyCallableBindingType Python Interface
+// ============================================================================
+
+PyGetSetDef PyCallableBindingType::getsetters[] = {
+    {"callable", (getter)PyCallableBindingType::get_callable, NULL,
+     MCRF_PROPERTY(callable, "The Python callable (read-only)."), NULL},
+    {"value", (getter)PyCallableBindingType::get_value, NULL,
+     MCRF_PROPERTY(value, "Current value from calling the callable (float, read-only). Returns None on error."), NULL},
+    {"is_valid", (getter)PyCallableBindingType::is_valid, NULL,
+     MCRF_PROPERTY(is_valid, "True if the callable is still valid (bool, read-only)."), NULL},
+    {NULL}
+};
+
+PyObject* PyCallableBindingType::pynew(PyTypeObject* type, PyObject* args, PyObject* kwds) {
+    PyCallableBindingObject* self = (PyCallableBindingObject*)type->tp_alloc(type, 0);
+    if (self) {
+        self->binding = nullptr;
+        self->weakreflist = NULL;
+    }
+    return (PyObject*)self;
+}
+
+void PyCallableBindingType::dealloc(PyCallableBindingObject* self) {
+    if (self->weakreflist) {
+        PyObject_ClearWeakRefs((PyObject*)self);
+    }
+    self->binding.reset();
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+int PyCallableBindingType::init(PyCallableBindingObject* self, PyObject* args, PyObject* kwds) {
+    static const char* keywords[] = {"callable", nullptr};
+    PyObject* callable = nullptr;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O", const_cast<char**>(keywords),
+                                     &callable)) {
+        return -1;
+    }
+
+    if (!PyCallable_Check(callable)) {
+        PyErr_SetString(PyExc_TypeError, "Argument must be callable");
+        return -1;
+    }
+
+    self->binding = std::make_shared<CallableBinding>(callable);
+    return 0;
+}
+
+PyObject* PyCallableBindingType::repr(PyObject* obj) {
+    PyCallableBindingObject* self = (PyCallableBindingObject*)obj;
+    std::ostringstream ss;
+    ss << "<CallableBinding";
+    if (self->binding && self->binding->isValid()) {
+        auto val = self->binding->evaluate();
+        if (val) {
+            ss << " value=" << *val;
+        }
+    } else {
+        ss << " (invalid)";
+    }
+    ss << ">";
+    return PyUnicode_FromString(ss.str().c_str());
+}
+
+PyObject* PyCallableBindingType::get_callable(PyCallableBindingObject* self, void* closure) {
+    if (!self->binding) {
+        Py_RETURN_NONE;
+    }
+    PyObject* callable = self->binding->getCallable();
+    if (!callable) {
+        Py_RETURN_NONE;
+    }
+    Py_INCREF(callable);
+    return callable;
+}
+
+PyObject* PyCallableBindingType::get_value(PyCallableBindingObject* self, void* closure) {
+    if (!self->binding) {
+        Py_RETURN_NONE;
+    }
+    auto val = self->binding->evaluate();
+    if (!val) {
+        Py_RETURN_NONE;
+    }
+    return PyFloat_FromDouble(*val);
+}
+
+PyObject* PyCallableBindingType::is_valid(PyCallableBindingObject* self, void* closure) {
+    if (!self->binding) {
+        Py_RETURN_FALSE;
+    }
+    return PyBool_FromLong(self->binding->isValid());
+}

src/PyUniformBinding.h

@@ -0,0 +1,201 @@
+#pragma once
+#include "Common.h"
+#include "Python.h"
+#include <variant>
+#include <map>
+#include <memory>
+#include <optional>
+
+// Forward declarations
+class UIDrawable;
+
+/**
+ * @brief Variant type for uniform values
+ *
+ * Supports float, vec2, vec3, and vec4 uniform types.
+ */
+using UniformValue = std::variant<
+    float,
+    sf::Glsl::Vec2,
+    sf::Glsl::Vec3,
+    sf::Glsl::Vec4
+>;
+
+/**
+ * @brief Base class for uniform bindings
+ *
+ * Bindings provide dynamic uniform values that are evaluated each frame.
+ */
+class UniformBinding {
+public:
+    virtual ~UniformBinding() = default;
+
+    /**
+     * @brief Evaluate the binding and return its current value
+     * @return The current uniform value, or std::nullopt if binding is invalid
+     */
+    virtual std::optional<float> evaluate() const = 0;
+
+    /**
+     * @brief Check if the binding is still valid
+     */
+    virtual bool isValid() const = 0;
+};
+
+/**
+ * @brief Binding that reads a property from a UIDrawable
+ *
+ * Uses a weak_ptr to prevent dangling references if the target is destroyed.
+ */
+class PropertyBinding : public UniformBinding {
+public:
+    PropertyBinding(std::weak_ptr<UIDrawable> target, const std::string& property);
+
+    std::optional<float> evaluate() const override;
+    bool isValid() const override;
+
+    // Accessors for Python
+    std::weak_ptr<UIDrawable> getTarget() const { return target; }
+    const std::string& getPropertyName() const { return property_name; }
+
+private:
+    std::weak_ptr<UIDrawable> target;
+    std::string property_name;
+};
+
+/**
+ * @brief Binding that calls a Python callable to get the value
+ *
+ * The callable should return a float value.
+ */
+class CallableBinding : public UniformBinding {
+public:
+    explicit CallableBinding(PyObject* callable);
+    ~CallableBinding();
+
+    // Non-copyable due to PyObject reference management
+    CallableBinding(const CallableBinding&) = delete;
+    CallableBinding& operator=(const CallableBinding&) = delete;
+
+    // Move semantics
+    CallableBinding(CallableBinding&& other) noexcept;
+    CallableBinding& operator=(CallableBinding&& other) noexcept;
+
+    std::optional<float> evaluate() const override;
+    bool isValid() const override;
+
+    // Accessor for Python
+    PyObject* getCallable() const { return callable; }
+
+private:
+    PyObject* callable;  // Owned reference
+};
+
+// Python object structures for bindings
+typedef struct {
+    PyObject_HEAD
+    std::shared_ptr<PropertyBinding> binding;
+    PyObject* weakreflist;
+} PyPropertyBindingObject;
+
+typedef struct {
+    PyObject_HEAD
+    std::shared_ptr<CallableBinding> binding;
+    PyObject* weakreflist;
+} PyCallableBindingObject;
+
+// Python type class for PropertyBinding
+class PyPropertyBindingType {
+public:
+    static PyObject* repr(PyObject* self);
+    static int init(PyPropertyBindingObject* self, PyObject* args, PyObject* kwds);
+    static PyObject* pynew(PyTypeObject* type, PyObject* args, PyObject* kwds);
+    static void dealloc(PyPropertyBindingObject* self);
+
+    static PyObject* get_target(PyPropertyBindingObject* self, void* closure);
+    static PyObject* get_property(PyPropertyBindingObject* self, void* closure);
+    static PyObject* get_value(PyPropertyBindingObject* self, void* closure);
+    static PyObject* is_valid(PyPropertyBindingObject* self, void* closure);
+
+    static PyGetSetDef getsetters[];
+};
+
+// Python type class for CallableBinding
+class PyCallableBindingType {
+public:
+    static PyObject* repr(PyObject* self);
+    static int init(PyCallableBindingObject* self, PyObject* args, PyObject* kwds);
+    static PyObject* pynew(PyTypeObject* type, PyObject* args, PyObject* kwds);
+    static void dealloc(PyCallableBindingObject* self);
+
+    static PyObject* get_callable(PyCallableBindingObject* self, void* closure);
+    static PyObject* get_value(PyCallableBindingObject* self, void* closure);
+    static PyObject* is_valid(PyCallableBindingObject* self, void* closure);
+
+    static PyGetSetDef getsetters[];
+};
+
+namespace mcrfpydef {
+    // Using inline to ensure single definition across translation units (C++17)
+    inline PyTypeObject PyPropertyBindingType = {
+        .ob_base = {.ob_base = {.ob_refcnt = 1, .ob_type = NULL}, .ob_size = 0},
+        .tp_name = "mcrfpy.PropertyBinding",
+        .tp_basicsize = sizeof(PyPropertyBindingObject),
+        .tp_itemsize = 0,
+        .tp_dealloc = (destructor)::PyPropertyBindingType::dealloc,
+        .tp_repr = ::PyPropertyBindingType::repr,
+        .tp_flags = Py_TPFLAGS_DEFAULT,
+        .tp_doc = PyDoc_STR(
+            "PropertyBinding(target: UIDrawable, property: str)\n"
+            "\n"
+            "A binding that reads a property value from a UI drawable.\n"
+            "\n"
+            "Args:\n"
+            "    target: The drawable to read the property from\n"
+            "    property: Name of the property to read (e.g., 'x', 'opacity')\n"
+            "\n"
+            "Use this to create dynamic shader uniforms that follow a drawable's\n"
+            "properties. The binding automatically handles cases where the target\n"
+            "is destroyed.\n"
+            "\n"
+            "Example:\n"
+            "    other_frame = mcrfpy.Frame(pos=(100, 100))\n"
+            "    frame.uniforms['offset_x'] = mcrfpy.PropertyBinding(other_frame, 'x')\n"
+        ),
+        .tp_weaklistoffset = offsetof(PyPropertyBindingObject, weakreflist),
+        .tp_getset = nullptr,  // Set in McRFPy_API.cpp before PyType_Ready
+        .tp_init = (initproc)::PyPropertyBindingType::init,
+        .tp_new = ::PyPropertyBindingType::pynew,
+    };
+
+    inline PyTypeObject PyCallableBindingType = {
+        .ob_base = {.ob_base = {.ob_refcnt = 1, .ob_type = NULL}, .ob_size = 0},
+        .tp_name = "mcrfpy.CallableBinding",
+        .tp_basicsize = sizeof(PyCallableBindingObject),
+        .tp_itemsize = 0,
+        .tp_dealloc = (destructor)::PyCallableBindingType::dealloc,
+        .tp_repr = ::PyCallableBindingType::repr,
+        .tp_flags = Py_TPFLAGS_DEFAULT,
+        .tp_doc = PyDoc_STR(
+            "CallableBinding(callable: Callable[[], float])\n"
+            "\n"
+            "A binding that calls a Python function to get its value.\n"
+            "\n"
+            "Args:\n"
+            "    callable: A function that takes no arguments and returns a float\n"
+            "\n"
+            "The callable is invoked every frame when the shader is rendered.\n"
+            "Keep the callable lightweight to avoid performance issues.\n"
+            "\n"
+            "Example:\n"
+            "    player_health = 100\n"
+            "    frame.uniforms['health_pct'] = mcrfpy.CallableBinding(\n"
+            "        lambda: player_health / 100.0\n"
+            "    )\n"
+        ),
+        .tp_weaklistoffset = offsetof(PyCallableBindingObject, weakreflist),
+        .tp_getset = nullptr,  // Set in McRFPy_API.cpp before PyType_Ready
+        .tp_init = (initproc)::PyCallableBindingType::init,
+        .tp_new = ::PyCallableBindingType::pynew,
+    };
+}

src/PyUniformCollection.cpp

@@ -0,0 +1,405 @@
+#include "PyUniformCollection.h"
+#include "UIDrawable.h"
+#include "McRFPy_API.h"
+#include "McRFPy_Doc.h"
+#include <sstream>
+
+// ============================================================================
+// UniformCollection Implementation
+// ============================================================================
+
+void UniformCollection::setFloat(const std::string& name, float value) {
+    entries[name] = UniformValue(value);
+}
+
+void UniformCollection::setVec2(const std::string& name, float x, float y) {
+    entries[name] = UniformValue(sf::Glsl::Vec2(x, y));
+}
+
+void UniformCollection::setVec3(const std::string& name, float x, float y, float z) {
+    entries[name] = UniformValue(sf::Glsl::Vec3(x, y, z));
+}
+
+void UniformCollection::setVec4(const std::string& name, float x, float y, float z, float w) {
+    entries[name] = UniformValue(sf::Glsl::Vec4(x, y, z, w));
+}
+
+void UniformCollection::setPropertyBinding(const std::string& name, std::shared_ptr<PropertyBinding> binding) {
+    entries[name] = binding;
+}
+
+void UniformCollection::setCallableBinding(const std::string& name, std::shared_ptr<CallableBinding> binding) {
+    entries[name] = binding;
+}
+
+void UniformCollection::remove(const std::string& name) {
+    entries.erase(name);
+}
+
+bool UniformCollection::contains(const std::string& name) const {
+    return entries.find(name) != entries.end();
+}
+
+std::vector<std::string> UniformCollection::getNames() const {
+    std::vector<std::string> names;
+    names.reserve(entries.size());
+    for (const auto& [name, _] : entries) {
+        names.push_back(name);
+    }
+    return names;
+}
+
+void UniformCollection::applyTo(sf::Shader& shader) const {
+    for (const auto& [name, entry] : entries) {
+        std::visit([&shader, &name](auto&& arg) {
+            using T = std::decay_t<decltype(arg)>;
+
+            if constexpr (std::is_same_v<T, UniformValue>) {
+                // Static value
+                std::visit([&shader, &name](auto&& val) {
+                    using V = std::decay_t<decltype(val)>;
+                    if constexpr (std::is_same_v<V, float>) {
+                        shader.setUniform(name, val);
+                    } else if constexpr (std::is_same_v<V, sf::Glsl::Vec2>) {
+                        shader.setUniform(name, val);
+                    } else if constexpr (std::is_same_v<V, sf::Glsl::Vec3>) {
+                        shader.setUniform(name, val);
+                    } else if constexpr (std::is_same_v<V, sf::Glsl::Vec4>) {
+                        shader.setUniform(name, val);
+                    }
+                }, arg);
+            }
+            else if constexpr (std::is_same_v<T, std::shared_ptr<PropertyBinding>>) {
+                // Property binding - evaluate and apply
+                if (arg && arg->isValid()) {
+                    auto val = arg->evaluate();
+                    if (val) {
+                        shader.setUniform(name, *val);
+                    }
+                }
+            }
+            else if constexpr (std::is_same_v<T, std::shared_ptr<CallableBinding>>) {
+                // Callable binding - evaluate and apply
+                if (arg && arg->isValid()) {
+                    auto val = arg->evaluate();
+                    if (val) {
+                        shader.setUniform(name, *val);
+                    }
+                }
+            }
+        }, entry);
+    }
+}
+
+bool UniformCollection::hasDynamicBindings() const {
+    for (const auto& [_, entry] : entries) {
+        if (std::holds_alternative<std::shared_ptr<CallableBinding>>(entry)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+const UniformEntry* UniformCollection::getEntry(const std::string& name) const {
+    auto it = entries.find(name);
+    if (it == entries.end()) return nullptr;
+    return &it->second;
+}
+
+// ============================================================================
+// PyUniformCollectionType Python Interface
+// ============================================================================
+
+PyMethodDef PyUniformCollectionType::methods[] = {
+    {"keys", (PyCFunction)PyUniformCollectionType::keys, METH_NOARGS,
+     "Return list of uniform names"},
+    {"values", (PyCFunction)PyUniformCollectionType::values, METH_NOARGS,
+     "Return list of uniform values"},
+    {"items", (PyCFunction)PyUniformCollectionType::items, METH_NOARGS,
+     "Return list of (name, value) tuples"},
+    {"clear", (PyCFunction)PyUniformCollectionType::clear, METH_NOARGS,
+     "Remove all uniforms"},
+    {NULL}
+};
+
+PyMappingMethods PyUniformCollectionType::mapping_methods = {
+    .mp_length = PyUniformCollectionType::mp_length,
+    .mp_subscript = PyUniformCollectionType::mp_subscript,
+    .mp_ass_subscript = PyUniformCollectionType::mp_ass_subscript,
+};
+
+PySequenceMethods PyUniformCollectionType::sequence_methods = {
+    .sq_length = nullptr,
+    .sq_concat = nullptr,
+    .sq_repeat = nullptr,
+    .sq_item = nullptr,
+    .was_sq_slice = nullptr,
+    .sq_ass_item = nullptr,
+    .was_sq_ass_slice = nullptr,
+    .sq_contains = PyUniformCollectionType::sq_contains,
+};
+
+void PyUniformCollectionType::dealloc(PyUniformCollectionObject* self) {
+    if (self->weakreflist) {
+        PyObject_ClearWeakRefs((PyObject*)self);
+    }
+    // Don't delete collection - it's owned by UIDrawable
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+PyObject* PyUniformCollectionType::repr(PyObject* obj) {
+    PyUniformCollectionObject* self = (PyUniformCollectionObject*)obj;
+    std::ostringstream ss;
+    ss << "<UniformCollection";
+    if (self->collection) {
+        auto names = self->collection->getNames();
+        ss << " [";
+        for (size_t i = 0; i < names.size(); ++i) {
+            if (i > 0) ss << ", ";
+            ss << "'" << names[i] << "'";
+        }
+        ss << "]";
+    }
+    ss << ">";
+    return PyUnicode_FromString(ss.str().c_str());
+}
+
+Py_ssize_t PyUniformCollectionType::mp_length(PyObject* obj) {
+    PyUniformCollectionObject* self = (PyUniformCollectionObject*)obj;
+    if (!self->collection) return 0;
+    return static_cast<Py_ssize_t>(self->collection->getNames().size());
+}
+
+PyObject* PyUniformCollectionType::mp_subscript(PyObject* obj, PyObject* key) {
+    PyUniformCollectionObject* self = (PyUniformCollectionObject*)obj;
+
+    if (!self->collection) {
+        PyErr_SetString(PyExc_RuntimeError, "UniformCollection is not valid");
+        return NULL;
+    }
+
+    if (!PyUnicode_Check(key)) {
+        PyErr_SetString(PyExc_TypeError, "Uniform name must be a string");
+        return NULL;
+    }
+
+    const char* name = PyUnicode_AsUTF8(key);
+    const UniformEntry* entry = self->collection->getEntry(name);
+
+    if (!entry) {
+        PyErr_Format(PyExc_KeyError, "'%s'", name);
+        return NULL;
+    }
+
+    // Convert entry to Python object
+    return std::visit([](auto&& arg) -> PyObject* {
+        using T = std::decay_t<decltype(arg)>;
+
+        if constexpr (std::is_same_v<T, UniformValue>) {
+            return std::visit([](auto&& val) -> PyObject* {
+                using V = std::decay_t<decltype(val)>;
+                if constexpr (std::is_same_v<V, float>) {
+                    return PyFloat_FromDouble(val);
+                } else if constexpr (std::is_same_v<V, sf::Glsl::Vec2>) {
+                    return Py_BuildValue("(ff)", val.x, val.y);
+                } else if constexpr (std::is_same_v<V, sf::Glsl::Vec3>) {
+                    return Py_BuildValue("(fff)", val.x, val.y, val.z);
+                } else if constexpr (std::is_same_v<V, sf::Glsl::Vec4>) {
+                    return Py_BuildValue("(ffff)", val.x, val.y, val.z, val.w);
+                }
+                Py_RETURN_NONE;
+            }, arg);
+        }
+        else if constexpr (std::is_same_v<T, std::shared_ptr<PropertyBinding>>) {
+            // Return the current value for now
+            // TODO: Return the actual PropertyBinding object
+            if (arg && arg->isValid()) {
+                auto val = arg->evaluate();
+                if (val) {
+                    return PyFloat_FromDouble(*val);
+                }
+            }
+            Py_RETURN_NONE;
+        }
+        else if constexpr (std::is_same_v<T, std::shared_ptr<CallableBinding>>) {
+            // Return the current value for now
+            // TODO: Return the actual CallableBinding object
+            if (arg && arg->isValid()) {
+                auto val = arg->evaluate();
+                if (val) {
+                    return PyFloat_FromDouble(*val);
+                }
+            }
+            Py_RETURN_NONE;
+        }
+        Py_RETURN_NONE;
+    }, *entry);
+}
+
+int PyUniformCollectionType::mp_ass_subscript(PyObject* obj, PyObject* key, PyObject* value) {
+    PyUniformCollectionObject* self = (PyUniformCollectionObject*)obj;
+
+    if (!self->collection) {
+        PyErr_SetString(PyExc_RuntimeError, "UniformCollection is not valid");
+        return -1;
+    }
+
+    if (!PyUnicode_Check(key)) {
+        PyErr_SetString(PyExc_TypeError, "Uniform name must be a string");
+        return -1;
+    }
+
+    const char* name = PyUnicode_AsUTF8(key);
+
+    // Delete operation
+    if (value == NULL) {
+        self->collection->remove(name);
+        return 0;
+    }
+
+    // Check for binding types first
+    // PropertyBinding
+    if (PyObject_IsInstance(value, (PyObject*)&mcrfpydef::PyPropertyBindingType)) {
+        PyPropertyBindingObject* binding = (PyPropertyBindingObject*)value;
+        if (binding->binding) {
+            self->collection->setPropertyBinding(name, binding->binding);
+            return 0;
+        }
+        PyErr_SetString(PyExc_ValueError, "PropertyBinding is not valid");
+        return -1;
+    }
+
+    // CallableBinding
+    if (PyObject_IsInstance(value, (PyObject*)&mcrfpydef::PyCallableBindingType)) {
+        PyCallableBindingObject* binding = (PyCallableBindingObject*)value;
+        if (binding->binding) {
+            self->collection->setCallableBinding(name, binding->binding);
+            return 0;
+        }
+        PyErr_SetString(PyExc_ValueError, "CallableBinding is not valid");
+        return -1;
+    }
+
+    // Float value
+    if (PyFloat_Check(value) || PyLong_Check(value)) {
+        float f = static_cast<float>(PyFloat_AsDouble(value));
+        if (PyErr_Occurred()) return -1;
+        self->collection->setFloat(name, f);
+        return 0;
+    }
+
+    // Tuple for vec2/vec3/vec4
+    if (PyTuple_Check(value)) {
+        Py_ssize_t size = PyTuple_Size(value);
+        if (size == 2) {
+            float x = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 0)));
+            float y = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 1)));
+            if (PyErr_Occurred()) return -1;
+            self->collection->setVec2(name, x, y);
+            return 0;
+        }
+        else if (size == 3) {
+            float x = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 0)));
+            float y = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 1)));
+            float z = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 2)));
+            if (PyErr_Occurred()) return -1;
+            self->collection->setVec3(name, x, y, z);
+            return 0;
+        }
+        else if (size == 4) {
+            float x = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 0)));
+            float y = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 1)));
+            float z = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 2)));
+            float w = static_cast<float>(PyFloat_AsDouble(PyTuple_GetItem(value, 3)));
+            if (PyErr_Occurred()) return -1;
+            self->collection->setVec4(name, x, y, z, w);
+            return 0;
+        }
+        else {
+            PyErr_Format(PyExc_ValueError,
+                "Tuple must have 2, 3, or 4 elements for vec2/vec3/vec4, got %zd", size);
+            return -1;
+        }
+    }
+
+    PyErr_SetString(PyExc_TypeError,
+        "Uniform value must be a float, tuple (vec2/vec3/vec4), PropertyBinding, or CallableBinding");
+    return -1;
+}
+
+int PyUniformCollectionType::sq_contains(PyObject* obj, PyObject* key) {
+    PyUniformCollectionObject* self = (PyUniformCollectionObject*)obj;
+
+    if (!self->collection) return 0;
+
+    if (!PyUnicode_Check(key)) return 0;
+
+    const char* name = PyUnicode_AsUTF8(key);
+    return self->collection->contains(name) ? 1 : 0;
+}
+
+PyObject* PyUniformCollectionType::keys(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored)) {
+    if (!self->collection) {
+        return PyList_New(0);
+    }
+
+    auto names = self->collection->getNames();
+    PyObject* list = PyList_New(names.size());
+    for (size_t i = 0; i < names.size(); ++i) {
+        PyList_SetItem(list, i, PyUnicode_FromString(names[i].c_str()));
+    }
+    return list;
+}
+
+PyObject* PyUniformCollectionType::values(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored)) {
+    if (!self->collection) {
+        return PyList_New(0);
+    }
+
+    auto names = self->collection->getNames();
+    PyObject* list = PyList_New(names.size());
+    for (size_t i = 0; i < names.size(); ++i) {
+        PyObject* key = PyUnicode_FromString(names[i].c_str());
+        PyObject* val = mp_subscript((PyObject*)self, key);
+        Py_DECREF(key);
+        if (!val) {
+            Py_DECREF(list);
+            return NULL;
+        }
+        PyList_SetItem(list, i, val);
+    }
+    return list;
+}
+
+PyObject* PyUniformCollectionType::items(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored)) {
+    if (!self->collection) {
+        return PyList_New(0);
+    }
+
+    auto names = self->collection->getNames();
+    PyObject* list = PyList_New(names.size());
+    for (size_t i = 0; i < names.size(); ++i) {
+        PyObject* key = PyUnicode_FromString(names[i].c_str());
+        PyObject* val = mp_subscript((PyObject*)self, key);
+        if (!val) {
+            Py_DECREF(key);
+            Py_DECREF(list);
+            return NULL;
+        }
+        PyObject* tuple = PyTuple_Pack(2, key, val);
+        Py_DECREF(key);
+        Py_DECREF(val);
+        PyList_SetItem(list, i, tuple);
+    }
+    return list;
+}
+
+PyObject* PyUniformCollectionType::clear(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored)) {
+    if (self->collection) {
+        auto names = self->collection->getNames();
+        for (const auto& name : names) {
+            self->collection->remove(name);
+        }
+    }
+    Py_RETURN_NONE;
+}

src/PyUniformCollection.h

@@ -0,0 +1,157 @@
+#pragma once
+#include "Common.h"
+#include "Python.h"
+#include "PyUniformBinding.h"
+#include <map>
+#include <variant>
+
+// Forward declarations
+class UIDrawable;
+
+/**
+ * @brief Entry in UniformCollection - can be static value or binding
+ */
+using UniformEntry = std::variant<
+    UniformValue,                           // Static value (float, vec2, vec3, vec4)
+    std::shared_ptr<PropertyBinding>,       // Property binding
+    std::shared_ptr<CallableBinding>        // Callable binding
+>;
+
+/**
+ * @brief Collection of shader uniforms for a UIDrawable
+ *
+ * Stores both static uniform values and dynamic bindings. When applying
+ * uniforms to a shader, static values are used directly while bindings
+ * are evaluated each frame.
+ */
+class UniformCollection {
+public:
+    UniformCollection() = default;
+
+    /**
+     * @brief Set a static uniform value
+     */
+    void setFloat(const std::string& name, float value);
+    void setVec2(const std::string& name, float x, float y);
+    void setVec3(const std::string& name, float x, float y, float z);
+    void setVec4(const std::string& name, float x, float y, float z, float w);
+
+    /**
+     * @brief Set a property binding
+     */
+    void setPropertyBinding(const std::string& name, std::shared_ptr<PropertyBinding> binding);
+
+    /**
+     * @brief Set a callable binding
+     */
+    void setCallableBinding(const std::string& name, std::shared_ptr<CallableBinding> binding);
+
+    /**
+     * @brief Remove a uniform
+     */
+    void remove(const std::string& name);
+
+    /**
+     * @brief Check if a uniform exists
+     */
+    bool contains(const std::string& name) const;
+
+    /**
+     * @brief Get all uniform names
+     */
+    std::vector<std::string> getNames() const;
+
+    /**
+     * @brief Apply all uniforms to a shader
+     */
+    void applyTo(sf::Shader& shader) const;
+
+    /**
+     * @brief Check if any binding is dynamic (callable)
+     */
+    bool hasDynamicBindings() const;
+
+    /**
+     * @brief Get the entry for a uniform (for Python access)
+     */
+    const UniformEntry* getEntry(const std::string& name) const;
+
+private:
+    std::map<std::string, UniformEntry> entries;
+};
+
+// Python object structure for UniformCollection
+typedef struct {
+    PyObject_HEAD
+    UniformCollection* collection;  // Owned by UIDrawable, not by this object
+    std::weak_ptr<UIDrawable> owner;  // For checking validity
+    PyObject* weakreflist;
+} PyUniformCollectionObject;
+
+/**
+ * @brief Python type for UniformCollection
+ *
+ * Supports dict-like access: collection["name"] = value
+ */
+class PyUniformCollectionType {
+public:
+    static PyObject* repr(PyObject* self);
+    static void dealloc(PyUniformCollectionObject* self);
+
+    // Mapping protocol (dict-like access)
+    static Py_ssize_t mp_length(PyObject* self);
+    static PyObject* mp_subscript(PyObject* self, PyObject* key);
+    static int mp_ass_subscript(PyObject* self, PyObject* key, PyObject* value);
+
+    // Sequence protocol for 'in' operator
+    static int sq_contains(PyObject* self, PyObject* key);
+
+    // Methods
+    static PyObject* keys(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored));
+    static PyObject* values(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored));
+    static PyObject* items(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored));
+    static PyObject* clear(PyUniformCollectionObject* self, PyObject* Py_UNUSED(ignored));
+
+    static PyMethodDef methods[];
+    static PyMappingMethods mapping_methods;
+    static PySequenceMethods sequence_methods;
+};
+
+namespace mcrfpydef {
+    // Using inline to ensure single definition across translation units (C++17)
+    inline PyTypeObject PyUniformCollectionType = {
+        .ob_base = {.ob_base = {.ob_refcnt = 1, .ob_type = NULL}, .ob_size = 0},
+        .tp_name = "mcrfpy.UniformCollection",
+        .tp_basicsize = sizeof(PyUniformCollectionObject),
+        .tp_itemsize = 0,
+        .tp_dealloc = (destructor)::PyUniformCollectionType::dealloc,
+        .tp_repr = ::PyUniformCollectionType::repr,
+        .tp_as_sequence = &::PyUniformCollectionType::sequence_methods,
+        .tp_as_mapping = &::PyUniformCollectionType::mapping_methods,
+        .tp_flags = Py_TPFLAGS_DEFAULT,
+        .tp_doc = PyDoc_STR(
+            "UniformCollection - dict-like container for shader uniforms.\n"
+            "\n"
+            "This object is accessed via drawable.uniforms and supports:\n"
+            "- Getting: value = uniforms['name']\n"
+            "- Setting: uniforms['name'] = value\n"
+            "- Deleting: del uniforms['name']\n"
+            "- Checking: 'name' in uniforms\n"
+            "- Iterating: for name in uniforms.keys()\n"
+            "\n"
+            "Values can be:\n"
+            "- float: Single value uniform\n"
+            "- tuple: vec2 (2-tuple), vec3 (3-tuple), or vec4 (4-tuple)\n"
+            "- PropertyBinding: Dynamic value from another drawable's property\n"
+            "- CallableBinding: Dynamic value from a Python function\n"
+            "\n"
+            "Example:\n"
+            "    frame.uniforms['intensity'] = 0.5\n"
+            "    frame.uniforms['color'] = (1.0, 0.5, 0.0, 1.0)\n"
+            "    frame.uniforms['offset'] = mcrfpy.PropertyBinding(other, 'x')\n"
+            "    del frame.uniforms['intensity']\n"
+        ),
+        .tp_weaklistoffset = offsetof(PyUniformCollectionObject, weakreflist),
+        .tp_methods = nullptr,  // Set in McRFPy_API.cpp
+    };
+}

src/UIArc.cpp

@@ -134,9 +134,13 @@ void UIArc::render(sf::Vector2f offset, sf::RenderTarget& target) {
         rebuildVertices();
     }
 
-    // Apply offset by creating a transformed copy
+    // Apply offset and rotation by creating a transform
     sf::Transform transform;
     transform.translate(offset);
+    // Apply rotation around origin
+    transform.translate(origin);
+    transform.rotate(rotation);
+    transform.translate(-origin);
     target.draw(vertices, transform);
 }
 
@@ -146,9 +150,25 @@ UIDrawable* UIArc::click_at(sf::Vector2f point) {
     // #184: Also check for Python subclass (might have on_click method)
     if (!click_callable && !is_python_subclass) return nullptr;
 
-    // Calculate distance from center
+    // Transform click point to local coordinates accounting for rotation
-    float dx = point.x - center.x;
+    sf::Vector2f localPoint;
-    float dy = point.y - center.y;
+    if (rotation != 0.0f) {
+        // Build transform: rotate around origin (matches render transform)
+        sf::Transform transform;
+        transform.translate(origin);
+        transform.rotate(rotation);
+        transform.translate(-origin);
+
+        // Apply inverse transform to get local coordinates
+        sf::Transform inverse = transform.getInverse();
+        localPoint = inverse.transformPoint(point);
+    } else {
+        localPoint = point;
+    }
+
+    // Calculate distance from center in local (unrotated) space
+    float dx = localPoint.x - center.x;
+    float dy = localPoint.y - center.y;
     float dist = std::sqrt(dx * dx + dy * dy);
 
     // Check if within the arc's radial range
@@ -249,6 +269,21 @@ bool UIArc::setProperty(const std::string& name, float value) {
         markCompositeDirty();  // #144 - Position change, texture still valid
         return true;
     }
+    else if (name == "rotation") {
+        rotation = value;
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_x") {
+        origin.x = value;
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_y") {
+        origin.y = value;
+        markDirty();
+        return true;
+    }
     return false;
 }
 
@@ -295,6 +330,18 @@ bool UIArc::getProperty(const std::string& name, float& value) const {
         value = center.y;
         return true;
     }
+    else if (name == "rotation") {
+        value = rotation;
+        return true;
+    }
+    else if (name == "origin_x") {
+        value = origin.x;
+        return true;
+    }
+    else if (name == "origin_y") {
+        value = origin.y;
+        return true;
+    }
     return false;
 }
 
@@ -317,7 +364,8 @@ bool UIArc::getProperty(const std::string& name, sf::Vector2f& value) const {
 bool UIArc::hasProperty(const std::string& name) const {
     // Float properties
     if (name == "radius" || name == "start_angle" || name == "end_angle" ||
-        name == "thickness" || name == "x" || name == "y") {
+        name == "thickness" || name == "x" || name == "y" ||
+        name == "rotation" || name == "origin_x" || name == "origin_y") {
         return true;
     }
     // Color properties
@@ -453,6 +501,7 @@ PyGetSetDef UIArc::getsetters[] = {
     UIDRAWABLE_GETSETTERS,
     UIDRAWABLE_PARENT_GETSETTERS(PyObjectsEnum::UIARC),
     UIDRAWABLE_ALIGNMENT_GETSETTERS(PyObjectsEnum::UIARC),
+    UIDRAWABLE_ROTATION_GETSETTERS(PyObjectsEnum::UIARC),
     {NULL}
 };
 

src/UIBase.h

@@ -282,4 +282,38 @@ static int UIDrawable_set_opacity(T* self, PyObject* value, void* closure)
          "Invalid for horizontally-centered alignments (CENTER_LEFT, CENTER_RIGHT, CENTER)." \
      ), (void*)type_enum}
 
+// Rotation support - rotation angle and transform origin
+#define UIDRAWABLE_ROTATION_GETSETTERS(type_enum) \
+    {"rotation", (getter)UIDrawable::get_rotation, (setter)UIDrawable::set_rotation, \
+     MCRF_PROPERTY(rotation, \
+         "Rotation angle in degrees (clockwise around origin). " \
+         "Animatable property." \
+     ), (void*)type_enum}, \
+    {"origin", (getter)UIDrawable::get_origin, (setter)UIDrawable::set_origin, \
+     MCRF_PROPERTY(origin, \
+         "Transform origin as Vector (pivot point for rotation). " \
+         "Default (0,0) is top-left; set to (w/2, h/2) to rotate around center." \
+     ), (void*)type_enum}, \
+    {"rotate_with_camera", (getter)UIDrawable::get_rotate_with_camera, (setter)UIDrawable::set_rotate_with_camera, \
+     MCRF_PROPERTY(rotate_with_camera, \
+         "Whether to rotate visually with parent Grid's camera_rotation (bool). " \
+         "False (default): stay screen-aligned. True: tilt with camera. " \
+         "Only affects children of UIGrid; ignored for other parents." \
+     ), (void*)type_enum}
+
+// #106: Shader support - GPU-accelerated visual effects
+#define UIDRAWABLE_SHADER_GETSETTERS(type_enum) \
+    {"shader", (getter)UIDrawable::get_shader, (setter)UIDrawable::set_shader, \
+     MCRF_PROPERTY(shader, \
+         "Shader for GPU visual effects (Shader or None). " \
+         "When set, the drawable is rendered through the shader program. " \
+         "Set to None to disable shader effects." \
+     ), (void*)type_enum}, \
+    {"uniforms", (getter)UIDrawable::get_uniforms, NULL, \
+     MCRF_PROPERTY(uniforms, \
+         "Collection of shader uniforms (read-only access to collection). " \
+         "Set uniforms via dict-like syntax: drawable.uniforms['name'] = value. " \
+         "Supports float, vec2/3/4 tuples, PropertyBinding, and CallableBinding." \
+     ), (void*)type_enum}
+
 // UIEntity specializations are defined in UIEntity.cpp after UIEntity class is complete

src/UICaption.cpp

@@ -5,6 +5,8 @@
 #include "PyFont.h"
 #include "PythonObjectCache.h"
 #include "PyAlignment.h"
+#include "PyShader.h"  // #106: Shader support
+#include "PyUniformCollection.h"  // #106: Uniform collection support
 // UIDrawable methods now in UIBase.h
 #include <algorithm>
 
@@ -23,11 +25,40 @@ UICaption::UICaption()
 UIDrawable* UICaption::click_at(sf::Vector2f point)
 {
     // #184: Also check for Python subclass (might have on_click method)
-    if (click_callable || is_python_subclass)
+    if (!click_callable && !is_python_subclass) return nullptr;
-    {
+
-        if (text.getGlobalBounds().contains(point)) return this;
+    // Get text dimensions from local bounds
+    sf::FloatRect localBounds = text.getLocalBounds();
+    float w = localBounds.width;
+    float h = localBounds.height;
+    // Account for text origin offset (SFML text has non-zero left/top in local bounds)
+    float textOffsetX = localBounds.left;
+    float textOffsetY = localBounds.top;
+
+    // Transform click point to local coordinates accounting for rotation
+    sf::Vector2f localPoint;
+    if (rotation != 0.0f) {
+        // Build transform: translate to position, then rotate around origin
+        sf::Transform transform;
+        transform.translate(position);
+        transform.translate(origin);
+        transform.rotate(rotation);
+        transform.translate(-origin);
+
+        // Apply inverse transform to get local coordinates
+        sf::Transform inverse = transform.getInverse();
+        localPoint = inverse.transformPoint(point);
+    } else {
+        // No rotation - simple subtraction
+        localPoint = point - position;
     }
-    return NULL;
+
+    // Check if local point is within bounds (accounting for text offset)
+    if (localPoint.x >= textOffsetX && localPoint.y >= textOffsetY &&
+        localPoint.x < textOffsetX + w && localPoint.y < textOffsetY + h) {
+        return this;
+    }
+    return nullptr;
 }
 
 void UICaption::render(sf::Vector2f offset, sf::RenderTarget& target)
@@ -40,10 +71,47 @@ void UICaption::render(sf::Vector2f offset, sf::RenderTarget& target)
     color.a = static_cast<sf::Uint8>(255 * opacity);
     text.setFillColor(color);
 
-    text.move(offset);
+    // Apply rotation and origin
-    //Resources::game->getWindow().draw(text);
+    text.setOrigin(origin);
-    target.draw(text);
+    text.setRotation(rotation);
-    text.move(-offset);
+
+    // #106: Shader rendering path
+    if (shader && shader->shader) {
+        // Get the text bounds for rendering
+        auto bounds = text.getGlobalBounds();
+        sf::Vector2f screen_pos = offset + position;
+
+        // Get or create intermediate texture
+        auto& intermediate = GameEngine::getShaderIntermediate();
+        intermediate.clear(sf::Color::Transparent);
+
+        // Render text at origin in intermediate texture
+        sf::Text temp_text = text;
+        temp_text.setPosition(0, 0);  // Render at origin of intermediate texture
+        intermediate.draw(temp_text);
+        intermediate.display();
+
+        // Create result sprite from intermediate texture
+        sf::Sprite result_sprite(intermediate.getTexture());
+        result_sprite.setPosition(screen_pos);
+
+        // Apply engine uniforms
+        sf::Vector2f resolution(bounds.width, bounds.height);
+        PyShader::applyEngineUniforms(*shader->shader, resolution);
+
+        // Apply user uniforms
+        if (uniforms) {
+            uniforms->applyTo(*shader->shader);
+        }
+
+        // Draw with shader
+        target.draw(result_sprite, shader->shader.get());
+    } else {
+        // Standard rendering path (no shader)
+        text.move(offset);
+        target.draw(text);
+        text.move(-offset);
+    }
 
     // Restore original alpha
     color.a = 255;
@@ -314,6 +382,8 @@ PyGetSetDef UICaption::getsetters[] = {
     UIDRAWABLE_GETSETTERS,
     UIDRAWABLE_PARENT_GETSETTERS(PyObjectsEnum::UICAPTION),
     UIDRAWABLE_ALIGNMENT_GETSETTERS(PyObjectsEnum::UICAPTION),
+    UIDRAWABLE_SHADER_GETSETTERS(PyObjectsEnum::UICAPTION),
+    UIDRAWABLE_ROTATION_GETSETTERS(PyObjectsEnum::UICAPTION),
     {NULL}
 };
 
@@ -595,6 +665,28 @@ bool UICaption::setProperty(const std::string& name, float value) {
         markDirty();  // #144 - Z-order change affects parent
         return true;
     }
+    else if (name == "rotation") {
+        rotation = value;
+        text.setRotation(rotation);
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_x") {
+        origin.x = value;
+        text.setOrigin(origin);
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_y") {
+        origin.y = value;
+        text.setOrigin(origin);
+        markDirty();
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (setShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -674,6 +766,22 @@ bool UICaption::getProperty(const std::string& name, float& value) const {
         value = static_cast<float>(z_index);
         return true;
     }
+    else if (name == "rotation") {
+        value = rotation;
+        return true;
+    }
+    else if (name == "origin_x") {
+        value = origin.x;
+        return true;
+    }
+    else if (name == "origin_y") {
+        value = origin.y;
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (getShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -704,7 +812,8 @@ bool UICaption::hasProperty(const std::string& name) const {
         name == "fill_color.r" || name == "fill_color.g" ||
         name == "fill_color.b" || name == "fill_color.a" ||
         name == "outline_color.r" || name == "outline_color.g" ||
-        name == "outline_color.b" || name == "outline_color.a") {
+        name == "outline_color.b" || name == "outline_color.a" ||
+        name == "rotation" || name == "origin_x" || name == "origin_y") {
         return true;
     }
     // Color properties
@@ -715,6 +824,14 @@ bool UICaption::hasProperty(const std::string& name) const {
     if (name == "text") {
         return true;
     }
+    // Vector2f properties
+    if (name == "origin") {
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (hasShaderProperty(name)) {
+        return true;
+    }
     return false;
 }
 

src/UICircle.cpp

@@ -115,6 +115,12 @@ void UICircle::render(sf::Vector2f offset, sf::RenderTarget& target) {
     // Apply position and offset
     shape.setPosition(position + offset);
 
+    // Apply rotation (using UIDrawable::origin as offset from circle center)
+    // The shape already has its origin at center (radius, radius)
+    // UIDrawable::origin provides additional offset from that center
+    shape.setOrigin(radius + origin.x, radius + origin.y);
+    shape.setRotation(rotation);
+
     // Apply opacity to colors
     sf::Color render_fill = fill_color;
     render_fill.a = static_cast<sf::Uint8>(fill_color.a * opacity);
@@ -131,9 +137,30 @@ UIDrawable* UICircle::click_at(sf::Vector2f point) {
     // #184: Also check for Python subclass (might have on_click method)
     if (!click_callable && !is_python_subclass) return nullptr;
 
+    // Calculate the actual circle center accounting for rotation around origin
+    // In render(), the circle is drawn at position with origin offset (radius + origin.x/y)
+    // So the visual center moves when rotated around a non-default origin
+    sf::Vector2f circleCenter = position;
+
+    if (rotation != 0.0f && (origin.x != 0.0f || origin.y != 0.0f)) {
+        // The circle center in local space (relative to position) is at (0, 0)
+        // With rotation around (origin.x, origin.y), the center moves
+        float rad = rotation * 3.14159265f / 180.0f;
+        float cos_r = std::cos(rad);
+        float sin_r = std::sin(rad);
+
+        // Rotate (0,0) around origin
+        float dx = -origin.x;
+        float dy = -origin.y;
+        float rotatedX = dx * cos_r - dy * sin_r + origin.x;
+        float rotatedY = dx * sin_r + dy * cos_r + origin.y;
+
+        circleCenter = position + sf::Vector2f(rotatedX, rotatedY);
+    }
+
     // Check if point is within the circle (including outline)
-    float dx = point.x - position.x;
+    float dx = point.x - circleCenter.x;
-    float dy = point.y - position.y;
+    float dy = point.y - circleCenter.y;
     float distance = std::sqrt(dx * dx + dy * dy);
 
     float effective_radius = radius + outline_thickness;
@@ -188,6 +215,21 @@ bool UICircle::setProperty(const std::string& name, float value) {
         position.y = value;
         markCompositeDirty();  // #144 - Position change, texture still valid
         return true;
+    } else if (name == "rotation") {
+        rotation = value;
+        shape.setRotation(rotation);
+        markDirty();
+        return true;
+    } else if (name == "origin_x") {
+        origin.x = value;
+        shape.setOrigin(radius + origin.x, radius + origin.y);
+        markDirty();
+        return true;
+    } else if (name == "origin_y") {
+        origin.y = value;
+        shape.setOrigin(radius + origin.x, radius + origin.y);
+        markDirty();
+        return true;
     }
     return false;
 }
@@ -227,6 +269,15 @@ bool UICircle::getProperty(const std::string& name, float& value) const {
     } else if (name == "y") {
         value = position.y;
         return true;
+    } else if (name == "rotation") {
+        value = rotation;
+        return true;
+    } else if (name == "origin_x") {
+        value = origin.x;
+        return true;
+    } else if (name == "origin_y") {
+        value = origin.y;
+        return true;
     }
     return false;
 }
@@ -253,7 +304,8 @@ bool UICircle::getProperty(const std::string& name, sf::Vector2f& value) const {
 bool UICircle::hasProperty(const std::string& name) const {
     // Float properties
     if (name == "radius" || name == "outline" ||
-        name == "x" || name == "y") {
+        name == "x" || name == "y" ||
+        name == "rotation" || name == "origin_x" || name == "origin_y") {
         return true;
     }
     // Color properties
@@ -261,7 +313,7 @@ bool UICircle::hasProperty(const std::string& name) const {
         return true;
     }
     // Vector2f properties
-    if (name == "center" || name == "position") {
+    if (name == "center" || name == "position" || name == "origin") {
         return true;
     }
     return false;
@@ -399,6 +451,7 @@ PyGetSetDef UICircle::getsetters[] = {
     UIDRAWABLE_GETSETTERS,
     UIDRAWABLE_PARENT_GETSETTERS(PyObjectsEnum::UICIRCLE),
     UIDRAWABLE_ALIGNMENT_GETSETTERS(PyObjectsEnum::UICIRCLE),
+    UIDRAWABLE_ROTATION_GETSETTERS(PyObjectsEnum::UICIRCLE),
     {NULL}
 };
 

src/UIDrawable.cpp

@@ -13,6 +13,8 @@
 #include "PyAnimation.h"
 #include "PyEasing.h"
 #include "PySceneObject.h"  // #183: For scene parent lookup
+#include "PyShader.h"  // #106: Shader support
+#include "PyUniformCollection.h"  // #106: Uniform collection support
 
 // Helper function to extract UIDrawable* from any Python UI object
 // Returns nullptr and sets Python error on failure
@@ -44,6 +46,9 @@ UIDrawable::UIDrawable(const UIDrawable& other)
     : z_index(other.z_index),
       name(other.name),
       position(other.position),
+      rotation(other.rotation),
+      origin(other.origin),
+      rotate_with_camera(other.rotate_with_camera),
       visible(other.visible),
       opacity(other.opacity),
       hovered(false),  // Don't copy hover state
@@ -80,6 +85,9 @@ UIDrawable& UIDrawable::operator=(const UIDrawable& other) {
         z_index = other.z_index;
         name = other.name;
         position = other.position;
+        rotation = other.rotation;
+        origin = other.origin;
+        rotate_with_camera = other.rotate_with_camera;
         visible = other.visible;
         opacity = other.opacity;
         hovered = false;  // Don't copy hover state
@@ -126,6 +134,9 @@ UIDrawable::UIDrawable(UIDrawable&& other) noexcept
     : z_index(other.z_index),
       name(std::move(other.name)),
       position(other.position),
+      rotation(other.rotation),
+      origin(other.origin),
+      rotate_with_camera(other.rotate_with_camera),
       visible(other.visible),
       opacity(other.opacity),
       hovered(other.hovered),
@@ -155,6 +166,9 @@ UIDrawable& UIDrawable::operator=(UIDrawable&& other) noexcept {
         z_index = other.z_index;
         name = std::move(other.name);
         position = other.position;
+        rotation = other.rotation;
+        origin = other.origin;
+        rotate_with_camera = other.rotate_with_camera;
         visible = other.visible;
         opacity = other.opacity;
         hovered = other.hovered;  // #140
@@ -587,6 +601,132 @@ int UIDrawable::set_pos(PyObject* self, PyObject* value, void* closure) {
     return 0;
 }
 
+// Rotation property getter/setter
+PyObject* UIDrawable::get_rotation(PyObject* self, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return NULL;
+
+    return PyFloat_FromDouble(drawable->rotation);
+}
+
+int UIDrawable::set_rotation(PyObject* self, PyObject* value, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return -1;
+
+    float val = 0.0f;
+    if (PyFloat_Check(value)) {
+        val = PyFloat_AsDouble(value);
+    } else if (PyLong_Check(value)) {
+        val = static_cast<float>(PyLong_AsLong(value));
+    } else {
+        PyErr_SetString(PyExc_TypeError, "rotation must be a number (int or float)");
+        return -1;
+    }
+
+    drawable->rotation = val;
+    drawable->markDirty();
+    return 0;
+}
+
+// Origin property getter/setter
+PyObject* UIDrawable::get_origin(PyObject* self, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return NULL;
+
+    // Create a Python Vector object from origin
+    PyObject* module = PyImport_ImportModule("mcrfpy");
+    if (!module) return NULL;
+
+    PyObject* vector_type = PyObject_GetAttrString(module, "Vector");
+    Py_DECREF(module);
+    if (!vector_type) return NULL;
+
+    PyObject* args = Py_BuildValue("(ff)", drawable->origin.x, drawable->origin.y);
+    PyObject* result = PyObject_CallObject(vector_type, args);
+    Py_DECREF(vector_type);
+    Py_DECREF(args);
+
+    return result;
+}
+
+int UIDrawable::set_origin(PyObject* self, PyObject* value, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return -1;
+
+    // Accept tuple or Vector
+    float x, y;
+    if (PyTuple_Check(value) && PyTuple_Size(value) == 2) {
+        PyObject* x_obj = PyTuple_GetItem(value, 0);
+        PyObject* y_obj = PyTuple_GetItem(value, 1);
+
+        if (PyFloat_Check(x_obj) || PyLong_Check(x_obj)) {
+            x = PyFloat_Check(x_obj) ? PyFloat_AsDouble(x_obj) : static_cast<float>(PyLong_AsLong(x_obj));
+        } else {
+            PyErr_SetString(PyExc_TypeError, "origin x must be a number");
+            return -1;
+        }
+
+        if (PyFloat_Check(y_obj) || PyLong_Check(y_obj)) {
+            y = PyFloat_Check(y_obj) ? PyFloat_AsDouble(y_obj) : static_cast<float>(PyLong_AsLong(y_obj));
+        } else {
+            PyErr_SetString(PyExc_TypeError, "origin y must be a number");
+            return -1;
+        }
+    } else {
+        // Try to get as Vector
+        PyObject* module = PyImport_ImportModule("mcrfpy");
+        if (!module) return -1;
+
+        PyObject* vector_type = PyObject_GetAttrString(module, "Vector");
+        Py_DECREF(module);
+        if (!vector_type) return -1;
+
+        int is_vector = PyObject_IsInstance(value, vector_type);
+        Py_DECREF(vector_type);
+
+        if (is_vector) {
+            PyVectorObject* vec = (PyVectorObject*)value;
+            x = vec->data.x;
+            y = vec->data.y;
+        } else {
+            PyErr_SetString(PyExc_TypeError, "origin must be a tuple (x, y) or Vector");
+            return -1;
+        }
+    }
+
+    drawable->origin = sf::Vector2f(x, y);
+    drawable->markDirty();
+    return 0;
+}
+
+// rotate_with_camera property getter/setter
+PyObject* UIDrawable::get_rotate_with_camera(PyObject* self, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return NULL;
+
+    return PyBool_FromLong(drawable->rotate_with_camera);
+}
+
+int UIDrawable::set_rotate_with_camera(PyObject* self, PyObject* value, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return -1;
+
+    if (!PyBool_Check(value)) {
+        PyErr_SetString(PyExc_TypeError, "rotate_with_camera must be a boolean");
+        return -1;
+    }
+
+    drawable->rotate_with_camera = PyObject_IsTrue(value);
+    drawable->markDirty();
+    return 0;
+}
+
 // #221 - Grid coordinate properties (only valid when parent is UIGrid)
 PyObject* UIDrawable::get_grid_pos(PyObject* self, void* closure) {
     PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
@@ -947,6 +1087,195 @@ void UIDrawable::markDirty() {
     markContentDirty();
 }
 
+// #106 - Shader support
+void UIDrawable::markShaderDynamic() {
+    shader_dynamic = true;
+
+    // Propagate to parent to invalidate caches
+    auto p = parent.lock();
+    if (p) {
+        p->markShaderDynamic();
+    }
+}
+
+// #106: Shader uniform property helpers for animation support
+bool UIDrawable::setShaderProperty(const std::string& name, float value) {
+    // Check if name starts with "shader."
+    if (name.compare(0, 7, "shader.") != 0) {
+        return false;
+    }
+
+    // Extract the uniform name after "shader."
+    std::string uniform_name = name.substr(7);
+    if (uniform_name.empty()) {
+        return false;
+    }
+
+    // Initialize uniforms collection if needed
+    if (!uniforms) {
+        uniforms = std::make_unique<UniformCollection>();
+    }
+
+    // Set the uniform value
+    uniforms->setFloat(uniform_name, value);
+    markDirty();
+    return true;
+}
+
+bool UIDrawable::getShaderProperty(const std::string& name, float& value) const {
+    // Check if name starts with "shader."
+    if (name.compare(0, 7, "shader.") != 0) {
+        return false;
+    }
+
+    // Extract the uniform name after "shader."
+    std::string uniform_name = name.substr(7);
+    if (uniform_name.empty() || !uniforms) {
+        return false;
+    }
+
+    // Try to get the value from uniforms
+    const auto* entry = uniforms->getEntry(uniform_name);
+    if (!entry) {
+        return false;
+    }
+
+    // UniformEntry is variant<UniformValue, shared_ptr<PropertyBinding>, shared_ptr<CallableBinding>>
+    // UniformValue is variant<float, vec2, vec3, vec4>
+    // So we need to check for UniformValue first, then extract the float from it
+
+    // Try to extract static UniformValue from the entry
+    if (const auto* uval = std::get_if<UniformValue>(entry)) {
+        // Now try to extract float from UniformValue
+        if (const float* fval = std::get_if<float>(uval)) {
+            value = *fval;
+            return true;
+        }
+        // Could be vec2/vec3/vec4 - not a float, return false
+        return false;
+    }
+
+    // For bindings, evaluate and return
+    if (const auto* prop_binding = std::get_if<std::shared_ptr<PropertyBinding>>(entry)) {
+        auto opt_val = (*prop_binding)->evaluate();
+        if (opt_val) {
+            value = *opt_val;
+            return true;
+        }
+    } else if (const auto* call_binding = std::get_if<std::shared_ptr<CallableBinding>>(entry)) {
+        auto opt_val = (*call_binding)->evaluate();
+        if (opt_val) {
+            value = *opt_val;
+            return true;
+        }
+    }
+
+    return false;
+}
+
+bool UIDrawable::hasShaderProperty(const std::string& name) const {
+    // Check if name starts with "shader."
+    if (name.compare(0, 7, "shader.") != 0) {
+        return false;
+    }
+
+    // Shader uniforms are always valid property names (they'll be created on set)
+    return true;
+}
+
+// Python API for shader property
+PyObject* UIDrawable::get_shader(PyObject* self, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return NULL;
+
+    if (!drawable->shader) {
+        Py_RETURN_NONE;
+    }
+
+    // Return the shader object (increment reference)
+    Py_INCREF(drawable->shader.get());
+    return (PyObject*)drawable->shader.get();
+}
+
+int UIDrawable::set_shader(PyObject* self, PyObject* value, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return -1;
+
+    if (value == Py_None) {
+        // Clear shader
+        drawable->shader.reset();
+        drawable->shader_dynamic = false;
+        drawable->markDirty();
+        return 0;
+    }
+
+    // Check if it's a Shader object
+    if (!PyObject_IsInstance(value, (PyObject*)&mcrfpydef::PyShaderType)) {
+        PyErr_SetString(PyExc_TypeError, "shader must be a Shader object or None");
+        return -1;
+    }
+
+    PyShaderObject* shader_obj = (PyShaderObject*)value;
+    if (!shader_obj->shader) {
+        PyErr_SetString(PyExc_ValueError, "Shader is not valid (compilation failed?)");
+        return -1;
+    }
+
+    // Store the shader
+    drawable->shader = std::shared_ptr<PyShaderObject>(shader_obj, [](PyShaderObject* p) {
+        // Custom deleter that doesn't delete the Python object
+        // The Python reference counting handles that
+    });
+    Py_INCREF(shader_obj);  // Keep the Python object alive
+
+    // Create uniforms collection if needed
+    if (!drawable->uniforms) {
+        drawable->uniforms = std::make_unique<UniformCollection>();
+    }
+
+    // Set dynamic flag if shader is dynamic
+    if (shader_obj->dynamic) {
+        drawable->markShaderDynamic();
+    }
+
+    // Enable RenderTexture for shader rendering (if not already enabled)
+    auto bounds = drawable->get_bounds();
+    if (bounds.width > 0 && bounds.height > 0) {
+        drawable->enableRenderTexture(
+            static_cast<unsigned int>(bounds.width),
+            static_cast<unsigned int>(bounds.height)
+        );
+    }
+
+    drawable->markDirty();
+    return 0;
+}
+
+PyObject* UIDrawable::get_uniforms(PyObject* self, void* closure) {
+    PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
+    UIDrawable* drawable = extractDrawable(self, objtype);
+    if (!drawable) return NULL;
+
+    // Create uniforms collection if needed
+    if (!drawable->uniforms) {
+        drawable->uniforms = std::make_unique<UniformCollection>();
+    }
+
+    // Create and return a Python wrapper for the collection
+    PyUniformCollectionObject* collection = (PyUniformCollectionObject*)
+        mcrfpydef::PyUniformCollectionType.tp_alloc(&mcrfpydef::PyUniformCollectionType, 0);
+
+    if (!collection) return NULL;
+
+    collection->collection = drawable->uniforms.get();
+    collection->weakreflist = NULL;
+    // Note: owner weak_ptr could be set here if we had access to shared_ptr
+
+    return (PyObject*)collection;
+}
+
 // Python API - get parent drawable
 PyObject* UIDrawable::get_parent(PyObject* self, void* closure) {
     PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));

src/UIDrawable.h

@@ -16,6 +16,12 @@
 
 #include "Resources.h"
 #include "UIBase.h"
+
+// Forward declarations for shader support (#106)
+class UniformCollection;
+// PyShaderObject is a typedef, forward declare as a struct with explicit typedef
+typedef struct PyShaderObjectStruct PyShaderObject;
+
 class UIFrame; class UICaption; class UISprite; class UIEntity; class UIGrid;
 
 enum PyObjectsEnum : int
@@ -93,6 +99,14 @@ public:
     static PyObject* get_pos(PyObject* self, void* closure);
     static int set_pos(PyObject* self, PyObject* value, void* closure);
 
+    // Rotation getters/setters for Python API
+    static PyObject* get_rotation(PyObject* self, void* closure);
+    static int set_rotation(PyObject* self, PyObject* value, void* closure);
+    static PyObject* get_origin(PyObject* self, void* closure);
+    static int set_origin(PyObject* self, PyObject* value, void* closure);
+    static PyObject* get_rotate_with_camera(PyObject* self, void* closure);
+    static int set_rotate_with_camera(PyObject* self, PyObject* value, void* closure);
+
     // #221 - Grid coordinate properties (only valid when parent is UIGrid)
     static PyObject* get_grid_pos(PyObject* self, void* closure);
     static int set_grid_pos(PyObject* self, PyObject* value, void* closure);
@@ -111,6 +125,16 @@ public:
     // Position in pixel coordinates (moved from derived classes)
     sf::Vector2f position;
 
+    // Rotation in degrees (clockwise around origin)
+    float rotation = 0.0f;
+
+    // Transform origin point (relative to position, pivot for rotation/scale)
+    sf::Vector2f origin;
+
+    // Whether to rotate visually with parent Grid's camera_rotation
+    // Only affects children of UIGrid; ignored for other parents
+    bool rotate_with_camera = false;
+
     // Parent-child hierarchy (#122)
     std::weak_ptr<UIDrawable> parent;
 
@@ -205,6 +229,12 @@ public:
     // Check if a property name is valid for animation on this drawable type
     virtual bool hasProperty(const std::string& name) const { return false; }
 
+    // #106: Shader uniform property helpers for animation support
+    // These methods handle "shader.uniform_name" property paths
+    bool setShaderProperty(const std::string& name, float value);
+    bool getShaderProperty(const std::string& name, float& value) const;
+    bool hasShaderProperty(const std::string& name) const;
+
     // Note: animate_helper is now a free function (UIDrawable_animate_impl) declared in UIBase.h
     // to avoid incomplete type issues with template instantiation.
 
@@ -253,6 +283,20 @@ protected:
 public:
     void disableRenderTexture();
 
+    // Shader support (#106)
+    std::shared_ptr<PyShaderObject> shader;
+    std::unique_ptr<UniformCollection> uniforms;
+    bool shader_dynamic = false;  // True if shader uses time-varying effects
+
+    // Mark this drawable as having dynamic shader effects
+    // Propagates up to parent to invalidate caches
+    void markShaderDynamic();
+
+    // Python API for shader properties
+    static PyObject* get_shader(PyObject* self, void* closure);
+    static int set_shader(PyObject* self, PyObject* value, void* closure);
+    static PyObject* get_uniforms(PyObject* self, void* closure);
+
 protected:
 
 public:

src/UIEntity.cpp

@@ -12,6 +12,8 @@
 #include "PyAnimation.h"
 #include "PyEasing.h"
 #include "PyPositionHelper.h"
+#include "PyShader.h"  // #106: Shader support
+#include "PyUniformCollection.h"  // #106: Uniform collection support
 // UIDrawable methods now in UIBase.h
 #include "UIEntityPyMethods.h"
 
@@ -1035,6 +1037,14 @@ PyGetSetDef UIEntity::getsetters[] = {
     {"visible", (getter)UIEntity_get_visible, (setter)UIEntity_set_visible, "Visibility flag", NULL},
     {"opacity", (getter)UIEntity_get_opacity, (setter)UIEntity_set_opacity, "Opacity (0.0 = transparent, 1.0 = opaque)", NULL},
     {"name", (getter)UIEntity_get_name, (setter)UIEntity_set_name, "Name for finding elements", NULL},
+    {"shader", (getter)UIEntity_get_shader, (setter)UIEntity_set_shader,
+     "Shader for GPU visual effects (Shader or None). "
+     "When set, the entity is rendered through the shader program. "
+     "Set to None to disable shader effects.", NULL},
+    {"uniforms", (getter)UIEntity_get_uniforms, NULL,
+     "Collection of shader uniforms (read-only access to collection). "
+     "Set uniforms via dict-like syntax: entity.uniforms['name'] = value. "
+     "Supports float, vec2/3/4 tuples, PropertyBinding, and CallableBinding.", NULL},
     {NULL}  /* Sentinel */
 };
 
@@ -1073,6 +1083,10 @@ bool UIEntity::setProperty(const std::string& name, float value) {
         if (grid) grid->markDirty();  // #144 - Content change
         return true;
     }
+    // #106: Shader uniform properties - delegate to sprite
+    if (sprite.setShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -1098,6 +1112,10 @@ bool UIEntity::getProperty(const std::string& name, float& value) const {
         value = sprite.getScale().x;  // Assuming uniform scale
         return true;
     }
+    // #106: Shader uniform properties - delegate to sprite
+    if (sprite.getShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -1110,6 +1128,10 @@ bool UIEntity::hasProperty(const std::string& name) const {
     if (name == "sprite_index" || name == "sprite_number") {
         return true;
     }
+    // #106: Shader uniform properties - delegate to sprite
+    if (sprite.hasShaderProperty(name)) {
+        return true;
+    }
     return false;
 }
 

src/UIEntityPyMethods.h

@@ -1,6 +1,8 @@
 #pragma once
 #include "UIEntity.h"
 #include "UIBase.h"
+#include "PyShader.h"  // #106: Shader support
+#include "PyUniformCollection.h"  // #106: Uniform collection support
 
 // UIEntity-specific property implementations
 // These delegate to the wrapped sprite member
@@ -73,3 +75,72 @@ static int UIEntity_set_name(PyUIEntityObject* self, PyObject* value, void* clos
     self->data->sprite.name = name_str;
     return 0;
 }
+
+// #106: Shader property - delegate to sprite
+static PyObject* UIEntity_get_shader(PyUIEntityObject* self, void* closure)
+{
+    auto& shader_ptr = self->data->sprite.shader;
+    if (!shader_ptr) {
+        Py_RETURN_NONE;
+    }
+    // Return the PyShaderObject (which is also a PyObject)
+    Py_INCREF((PyObject*)shader_ptr.get());
+    return (PyObject*)shader_ptr.get();
+}
+
+static int UIEntity_set_shader(PyUIEntityObject* self, PyObject* value, void* closure)
+{
+    if (value == Py_None || value == NULL) {
+        self->data->sprite.shader.reset();
+        self->data->sprite.shader_dynamic = false;
+        return 0;
+    }
+
+    // Check if value is a Shader object
+    if (!PyObject_IsInstance(value, (PyObject*)&mcrfpydef::PyShaderType)) {
+        PyErr_SetString(PyExc_TypeError, "shader must be a Shader object or None");
+        return -1;
+    }
+
+    PyShaderObject* shader_obj = (PyShaderObject*)value;
+
+    // Store a shared_ptr to the PyShaderObject
+    // We need to increment the refcount since we're storing a reference
+    Py_INCREF(value);
+    self->data->sprite.shader = std::shared_ptr<PyShaderObject>(shader_obj, [](PyShaderObject* p) {
+        Py_DECREF((PyObject*)p);
+    });
+
+    // Initialize uniforms collection if needed
+    if (!self->data->sprite.uniforms) {
+        self->data->sprite.uniforms = std::make_unique<UniformCollection>();
+    }
+
+    // Propagate dynamic flag
+    if (shader_obj->dynamic) {
+        self->data->sprite.markShaderDynamic();
+    }
+
+    return 0;
+}
+
+// #106: Uniforms property - delegate to sprite's uniforms collection
+static PyObject* UIEntity_get_uniforms(PyUIEntityObject* self, void* closure)
+{
+    // Initialize uniforms collection if needed
+    if (!self->data->sprite.uniforms) {
+        self->data->sprite.uniforms = std::make_unique<UniformCollection>();
+    }
+
+    // Create a Python wrapper for the uniforms collection
+    PyUniformCollectionObject* uniforms_obj = (PyUniformCollectionObject*)mcrfpydef::PyUniformCollectionType.tp_alloc(&mcrfpydef::PyUniformCollectionType, 0);
+    if (!uniforms_obj) {
+        return NULL;
+    }
+
+    // The collection is owned by the sprite, we just provide a view
+    uniforms_obj->collection = self->data->sprite.uniforms.get();
+    uniforms_obj->weakreflist = NULL;
+
+    return (PyObject*)uniforms_obj;
+}

src/UIFrame.cpp

@@ -8,19 +8,37 @@
 #include "McRFPy_API.h"
 #include "PythonObjectCache.h"
 #include "PyAlignment.h"
+#include "PyShader.h"  // #106: Shader support
+#include "PyUniformCollection.h"  // #106: Uniform collection
 #include <iostream>  // #106: for shader error output
 // UIDrawable methods now in UIBase.h
 
 UIDrawable* UIFrame::click_at(sf::Vector2f point)
 {
-    // Check bounds first (optimization)
+    float w = box.getSize().x, h = box.getSize().y;
-    float x = position.x, y = position.y, w = box.getSize().x, h = box.getSize().y;
+
-    if (point.x < x || point.y < y || point.x >= x+w || point.y >= y+h) {
+    // Transform click point to local coordinates accounting for rotation
-        return nullptr;
+    sf::Vector2f localPoint;
+    if (rotation != 0.0f) {
+        // Build transform: translate to position, then rotate around origin
+        sf::Transform transform;
+        transform.translate(position);
+        transform.translate(origin);
+        transform.rotate(rotation);
+        transform.translate(-origin);
+
+        // Apply inverse transform to get local coordinates
+        sf::Transform inverse = transform.getInverse();
+        localPoint = inverse.transformPoint(point);
+    } else {
+        // No rotation - simple subtraction
+        localPoint = point - position;
     }
 
-    // Transform to local coordinates for children
+    // Check if local point is within bounds (0,0 to w,h in local space)
-    sf::Vector2f localPoint = point - position;
+    if (localPoint.x < 0 || localPoint.y < 0 || localPoint.x >= w || localPoint.y >= h) {
+        return nullptr;
+    }
 
     // Check children in reverse order (top to bottom, highest z-index first)
     for (auto it = children->rbegin(); it != children->rend(); ++it) {
@@ -110,11 +128,11 @@ void UIFrame::render(sf::Vector2f offset, sf::RenderTarget& target)
 
     // TODO: Apply opacity when SFML supports it on shapes
 
-    // #144: Use RenderTexture for clipping OR texture caching OR shaders
+    // #144: Use RenderTexture for clipping OR texture caching OR shaders (#106)
     // clip_children: requires texture for clipping effect (only when has children)
     // cache_subtree: uses texture for performance (always, even without children)
-    // shader_enabled: requires texture for shader post-processing
+    // shader: requires texture for shader post-processing
-    bool use_texture = (clip_children && !children->empty()) || cache_subtree || shader_enabled;
+    bool use_texture = (clip_children && !children->empty()) || cache_subtree || (shader && shader->shader);
 
     if (use_texture) {
         // Enable RenderTexture if not already enabled
@@ -138,8 +156,10 @@ void UIFrame::render(sf::Vector2f offset, sf::RenderTarget& target)
             // Clear the RenderTexture
             render_texture->clear(sf::Color::Transparent);
 
-            // Draw the frame box to RenderTexture
+            // Draw the frame box to RenderTexture (without rotation - that's applied to the final sprite)
             box.setPosition(0, 0);  // Render at origin in texture
+            box.setOrigin(0, 0);    // No origin offset in texture
+            box.setRotation(0);     // No rotation in texture
             render_texture->draw(box);
 
             // Sort children by z_index if needed
@@ -170,13 +190,23 @@ void UIFrame::render(sf::Vector2f offset, sf::RenderTarget& target)
             // Use `position` instead of box.getPosition() - box was set to (0,0) for texture rendering
             render_sprite.setPosition(offset + position);
 
-            // #106 POC: Apply shader if enabled
+            // Apply rotation to the rendered sprite (children rotate with parent)
-            if (shader_enabled && shader) {
+            render_sprite.setOrigin(origin);
-                // Update time uniform for animated effects
+            render_sprite.setRotation(rotation);
-                static sf::Clock shader_clock;
+
-                shader->setUniform("time", shader_clock.getElapsedTime().asSeconds());
+            // #106: Apply shader if set
-                shader->setUniform("texture", sf::Shader::CurrentTexture);
+            if (shader && shader->shader) {
-                target.draw(render_sprite, shader.get());
+                // Apply engine uniforms (time, resolution, mouse, texture)
+                sf::Vector2f resolution(render_sprite.getLocalBounds().width,
+                                        render_sprite.getLocalBounds().height);
+                PyShader::applyEngineUniforms(*shader->shader, resolution);
+
+                // Apply user-defined uniforms
+                if (uniforms) {
+                    uniforms->applyTo(*shader->shader);
+                }
+
+                target.draw(render_sprite, shader->shader.get());
             } else {
                 target.draw(render_sprite);
             }
@@ -185,6 +215,8 @@ void UIFrame::render(sf::Vector2f offset, sf::RenderTarget& target)
         // Standard rendering without caching
         // Restore box position from `position` - may have been set to (0,0) by previous texture render
         box.setPosition(offset + position);
+        box.setOrigin(origin);
+        box.setRotation(rotation);
         target.draw(box);
         box.setPosition(position);  // Restore to canonical position
 
@@ -197,6 +229,9 @@ void UIFrame::render(sf::Vector2f offset, sf::RenderTarget& target)
             children_need_sort = false;
         }
 
+        // Render children - note: in non-texture mode, children don't automatically
+        // rotate with parent. Use clip_children=True or cache_subtree=True if you need
+        // children to rotate with the frame.
         for (auto drawable : *children) {
             drawable->render(offset + position, target);  // Use `position` as source of truth
         }
@@ -462,87 +497,6 @@ int UIFrame::set_cache_subtree(PyUIFrameObject* self, PyObject* value, void* clo
 }
 
 // #106 - Shader POC: shader_enabled property
-PyObject* UIFrame::get_shader_enabled(PyUIFrameObject* self, void* closure)
-{
-    return PyBool_FromLong(self->data->shader_enabled);
-}
-
-int UIFrame::set_shader_enabled(PyUIFrameObject* self, PyObject* value, void* closure)
-{
-    if (!PyBool_Check(value)) {
-        PyErr_SetString(PyExc_TypeError, "shader_enabled must be a boolean");
-        return -1;
-    }
-
-    bool new_shader = PyObject_IsTrue(value);
-    if (new_shader != self->data->shader_enabled) {
-        self->data->shader_enabled = new_shader;
-
-        if (new_shader) {
-            // Initialize the test shader if not already done
-            if (!self->data->shader) {
-                self->data->initializeTestShader();
-            }
-            // Shader requires RenderTexture - enable it
-            auto size = self->data->box.getSize();
-            if (size.x > 0 && size.y > 0) {
-                self->data->enableRenderTexture(static_cast<unsigned int>(size.x),
-                                                static_cast<unsigned int>(size.y));
-            }
-        }
-        // Note: we don't disable RenderTexture when shader disabled -
-        // clip_children or cache_subtree may still need it
-
-        self->data->markDirty();
-    }
-
-    return 0;
-}
-
-// #106 - Initialize test shader (hardcoded glow/brightness effect)
-void UIFrame::initializeTestShader()
-{
-    // Check if shaders are available
-    if (!sf::Shader::isAvailable()) {
-        std::cerr << "Shaders are not available on this system!" << std::endl;
-        return;
-    }
-
-    shader = std::make_unique<sf::Shader>();
-
-    // Simple color inversion + wave distortion shader for POC
-    // This makes it obvious the shader is working
-    const std::string fragmentShader = R"(
-        uniform sampler2D texture;
-        uniform float time;
-
-        void main() {
-            vec2 uv = gl_TexCoord[0].xy;
-
-            // Subtle wave distortion based on time
-            uv.x += sin(uv.y * 10.0 + time * 2.0) * 0.01;
-            uv.y += cos(uv.x * 10.0 + time * 2.0) * 0.01;
-
-            vec4 color = texture2D(texture, uv);
-
-            // Glow effect: boost brightness and add slight color shift
-            float glow = 0.2 + 0.1 * sin(time * 3.0);
-            color.rgb = color.rgb * (1.0 + glow);
-
-            // Slight hue shift for visual interest
-            color.r += 0.1 * sin(time);
-            color.b += 0.1 * cos(time);
-
-            gl_FragColor = color;
-        }
-    )";
-
-    if (!shader->loadFromMemory(fragmentShader, sf::Shader::Fragment)) {
-        std::cerr << "Failed to load test shader!" << std::endl;
-        shader.reset();
-    }
-}
-
 // Define the PyObjectType alias for the macros
 typedef PyUIFrameObject PyObjectType;
 
@@ -581,10 +535,11 @@ PyGetSetDef UIFrame::getsetters[] = {
     {"grid_size", (getter)UIDrawable::get_grid_size, (setter)UIDrawable::set_grid_size, "Size in grid tile coordinates (only when parent is Grid)", (void*)PyObjectsEnum::UIFRAME},
     {"clip_children", (getter)UIFrame::get_clip_children, (setter)UIFrame::set_clip_children, "Whether to clip children to frame bounds", NULL},
     {"cache_subtree", (getter)UIFrame::get_cache_subtree, (setter)UIFrame::set_cache_subtree, "#144: Cache subtree rendering to texture for performance", NULL},
-    {"shader_enabled", (getter)UIFrame::get_shader_enabled, (setter)UIFrame::set_shader_enabled, "#106 POC: Enable test shader effect", NULL},
     UIDRAWABLE_GETSETTERS,
     UIDRAWABLE_PARENT_GETSETTERS(PyObjectsEnum::UIFRAME),
     UIDRAWABLE_ALIGNMENT_GETSETTERS(PyObjectsEnum::UIFRAME),
+    UIDRAWABLE_SHADER_GETSETTERS(PyObjectsEnum::UIFRAME),
+    UIDRAWABLE_ROTATION_GETSETTERS(PyObjectsEnum::UIFRAME),
     {NULL}
 };
 
@@ -929,6 +884,25 @@ bool UIFrame::setProperty(const std::string& name, float value) {
         box.setOutlineColor(color);
         markDirty();
         return true;
+    } else if (name == "rotation") {
+        rotation = value;
+        box.setRotation(rotation);
+        markDirty();
+        return true;
+    } else if (name == "origin_x") {
+        origin.x = value;
+        box.setOrigin(origin);
+        markDirty();
+        return true;
+    } else if (name == "origin_y") {
+        origin.y = value;
+        box.setOrigin(origin);
+        markDirty();
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (setShaderProperty(name, value)) {
+        return true;
     }
     return false;
 }
@@ -961,6 +935,11 @@ bool UIFrame::setProperty(const std::string& name, const sf::Vector2f& value) {
         }
         markDirty();
         return true;
+    } else if (name == "origin") {
+        origin = value;
+        box.setOrigin(origin);
+        markDirty();
+        return true;
     }
     return false;
 }
@@ -1005,6 +984,19 @@ bool UIFrame::getProperty(const std::string& name, float& value) const {
     } else if (name == "outline_color.a") {
         value = box.getOutlineColor().a;
         return true;
+    } else if (name == "rotation") {
+        value = rotation;
+        return true;
+    } else if (name == "origin_x") {
+        value = origin.x;
+        return true;
+    } else if (name == "origin_y") {
+        value = origin.y;
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (getShaderProperty(name, value)) {
+        return true;
     }
     return false;
 }
@@ -1027,6 +1019,9 @@ bool UIFrame::getProperty(const std::string& name, sf::Vector2f& value) const {
     } else if (name == "size") {
         value = box.getSize();
         return true;
+    } else if (name == "origin") {
+        value = origin;
+        return true;
     }
     return false;
 }
@@ -1038,7 +1033,8 @@ bool UIFrame::hasProperty(const std::string& name) const {
         name == "fill_color.r" || name == "fill_color.g" ||
         name == "fill_color.b" || name == "fill_color.a" ||
         name == "outline_color.r" || name == "outline_color.g" ||
-        name == "outline_color.b" || name == "outline_color.a") {
+        name == "outline_color.b" || name == "outline_color.a" ||
+        name == "rotation" || name == "origin_x" || name == "origin_y") {
         return true;
     }
     // Color properties
@@ -1046,7 +1042,11 @@ bool UIFrame::hasProperty(const std::string& name) const {
         return true;
     }
     // Vector2f properties
-    if (name == "position" || name == "size") {
+    if (name == "position" || name == "size" || name == "origin") {
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (hasShaderProperty(name)) {
         return true;
     }
     return false;

src/UIFrame.h

@@ -33,10 +33,6 @@ public:
     bool clip_children = false;  // Whether to clip children to frame bounds
     bool cache_subtree = false;  // #144: Whether to cache subtree rendering to texture
 
-    // Shader POC (#106)
-    std::unique_ptr<sf::Shader> shader;
-    bool shader_enabled = false;
-    void initializeTestShader();  // Load hardcoded test shader
     void render(sf::Vector2f, sf::RenderTarget&) override final;
     void move(sf::Vector2f);
     PyObjectsEnum derived_type() override final;
@@ -60,8 +56,6 @@ public:
     static int set_clip_children(PyUIFrameObject* self, PyObject* value, void* closure);
     static PyObject* get_cache_subtree(PyUIFrameObject* self, void* closure);
     static int set_cache_subtree(PyUIFrameObject* self, PyObject* value, void* closure);
-    static PyObject* get_shader_enabled(PyUIFrameObject* self, void* closure);
-    static int set_shader_enabled(PyUIFrameObject* self, PyObject* value, void* closure);
     static PyGetSetDef getsetters[];
     static PyObject* repr(PyUIFrameObject* self);
     static int init(PyUIFrameObject* self, PyObject* args, PyObject* kwds);

src/UIGrid.cpp

@@ -11,6 +11,8 @@
 #include "PyPositionHelper.h"  // For standardized position argument parsing
 #include "PyVector.h"  // #179, #181 - For Vector return types
 #include "PyHeightMap.h"  // #199 - HeightMap application methods
+#include "PyShader.h"  // #106: Shader support
+#include "PyUniformCollection.h"  // #106: Uniform collection support
 #include <algorithm>
 #include <cmath>    // #142 - for std::floor, std::isnan
 #include <cstring>  // #150 - for strcmp
@@ -143,28 +145,59 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
 
     // TODO: Apply opacity to output sprite
 
-    output.setPosition(box.getPosition() + offset); // output sprite can move; update position when drawing
-    // output size can change; update size when drawing
-    output.setTextureRect(
-         sf::IntRect(0, 0,
-         box.getSize().x, box.getSize().y));
-    renderTexture.clear(fill_color);
-    
     // Get cell dimensions - use texture if available, otherwise defaults
     int cell_width = ptex ? ptex->sprite_width : DEFAULT_CELL_WIDTH;
     int cell_height = ptex ? ptex->sprite_height : DEFAULT_CELL_HEIGHT;
 
-    // sprites that are visible according to zoom, center_x, center_y, and box width
+    // Determine if we need camera rotation handling
+    bool has_camera_rotation = (camera_rotation != 0.0f);
+    float grid_w_px = box.getSize().x;
+    float grid_h_px = box.getSize().y;
+
+    // Calculate AABB for rotated view (if camera rotation is active)
+    float rad = camera_rotation * (M_PI / 180.0f);
+    float cos_r = std::cos(rad);
+    float sin_r = std::sin(rad);
+    float abs_cos = std::abs(cos_r);
+    float abs_sin = std::abs(sin_r);
+
+    // AABB dimensions of the rotated viewport
+    float aabb_w = grid_w_px * abs_cos + grid_h_px * abs_sin;
+    float aabb_h = grid_w_px * abs_sin + grid_h_px * abs_cos;
+
+    // Choose which texture to render to
+    sf::RenderTexture* activeTexture = &renderTexture;
+
+    if (has_camera_rotation) {
+        // Ensure rotation texture is large enough
+        unsigned int needed_size = static_cast<unsigned int>(std::max(aabb_w, aabb_h) + 1);
+        if (rotationTextureSize < needed_size) {
+            rotationTexture.create(needed_size, needed_size);
+            rotationTextureSize = needed_size;
+        }
+        activeTexture = &rotationTexture;
+        activeTexture->clear(fill_color);
+    } else {
+        output.setPosition(box.getPosition() + offset);
+        output.setTextureRect(sf::IntRect(0, 0, grid_w_px, grid_h_px));
+        renderTexture.clear(fill_color);
+    }
+
+    // Calculate visible tile range
+    // For camera rotation, use AABB dimensions; otherwise use grid dimensions
+    float render_w = has_camera_rotation ? aabb_w : grid_w_px;
+    float render_h = has_camera_rotation ? aabb_h : grid_h_px;
+
     float center_x_sq = center_x / cell_width;
     float center_y_sq = center_y / cell_height;
 
-    float width_sq = box.getSize().x / (cell_width * zoom);
+    float width_sq = render_w / (cell_width * zoom);
-    float height_sq = box.getSize().y / (cell_height * zoom);
+    float height_sq = render_h / (cell_height * zoom);
     float left_edge = center_x_sq - (width_sq / 2.0);
     float top_edge = center_y_sq - (height_sq / 2.0);
 
-    int left_spritepixels = center_x - (box.getSize().x / 2.0 / zoom);
+    int left_spritepixels = center_x - (render_w / 2.0 / zoom);
-    int top_spritepixels = center_y - (box.getSize().y / 2.0 / zoom);
+    int top_spritepixels = center_y - (render_h / 2.0 / zoom);
 
     int x_limit = left_edge + width_sq + 2;
     if (x_limit > grid_w) x_limit = grid_w;
@@ -177,7 +210,7 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
     sortLayers();
     for (auto& layer : layers) {
         if (layer->z_index >= 0) break;  // Stop at layers that go above entities
-        layer->render(renderTexture, left_spritepixels, top_spritepixels,
+        layer->render(*activeTexture, left_spritepixels, top_spritepixels,
                      left_edge, top_edge, x_limit, y_limit, zoom, cell_width, cell_height);
     }
 
@@ -203,9 +236,7 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
             auto pixel_pos = sf::Vector2f(
                 (e->position.x*cell_width - left_spritepixels) * zoom,
                 (e->position.y*cell_height - top_spritepixels) * zoom );
-            //drawent.setPosition(pixel_pos);
+            drawent.render(pixel_pos, *activeTexture);
-            //renderTexture.draw(drawent);
-            drawent.render(pixel_pos, renderTexture);
 
             entitiesRendered++;
         }
@@ -218,7 +249,7 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
     // #147 - Render dynamic layers with z_index >= 0 (above entities)
     for (auto& layer : layers) {
         if (layer->z_index < 0) continue;  // Skip layers below entities
-        layer->render(renderTexture, left_spritepixels, top_spritepixels,
+        layer->render(*activeTexture, left_spritepixels, top_spritepixels,
                      left_edge, top_edge, x_limit, y_limit, zoom, cell_width, cell_height);
     }
 
@@ -250,7 +281,7 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
                 (child->position.y - top_spritepixels) * zoom
             );
 
-            child->render(pixel_pos, renderTexture);
+            child->render(pixel_pos, *activeTexture);
         }
     }
 
@@ -292,11 +323,11 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
                         if (!state.discovered) {
                             // Never seen - black
                             overlay.setFillColor(sf::Color(0, 0, 0, 255));
-                            renderTexture.draw(overlay);
+                            activeTexture->draw(overlay);
                         } else if (!state.visible) {
                             // Discovered but not currently visible - dark gray
                             overlay.setFillColor(sf::Color(32, 32, 40, 192));
-                            renderTexture.draw(overlay);
+                            activeTexture->draw(overlay);
                         }
                         // If visible and discovered, no overlay (fully visible)
                     }
@@ -322,7 +353,7 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
                     
                     overlay.setPosition(pixel_pos);
                     overlay.setFillColor(sf::Color(0, 0, 0, 255));
-                    renderTexture.draw(overlay);
+                    activeTexture->draw(overlay);
                 }
             }
         }
@@ -349,11 +380,66 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
     renderTexture.draw(lineb, 2, sf::Lines);
     */
 
-    // render to window
+    // Finalize the active texture
-    renderTexture.display();
+    activeTexture->display();
-    //Resources::game->getWindow().draw(output);
-    target.draw(output);
 
+    // If camera rotation was used, rotate and blit to the grid's renderTexture
+    if (has_camera_rotation) {
+        // Clear the final renderTexture with fill color
+        renderTexture.clear(fill_color);
+
+        // Create sprite from the larger rotated texture
+        sf::Sprite rotatedSprite(rotationTexture.getTexture());
+
+        // Set origin to center of the rendered content
+        float tex_center_x = aabb_w / 2.0f;
+        float tex_center_y = aabb_h / 2.0f;
+        rotatedSprite.setOrigin(tex_center_x, tex_center_y);
+
+        // Apply rotation
+        rotatedSprite.setRotation(camera_rotation);
+
+        // Position so the rotated center lands at the viewport center
+        rotatedSprite.setPosition(grid_w_px / 2.0f, grid_h_px / 2.0f);
+
+        // Set texture rect to only use the AABB portion (texture may be larger)
+        rotatedSprite.setTextureRect(sf::IntRect(0, 0, static_cast<int>(aabb_w), static_cast<int>(aabb_h)));
+
+        // Draw to the grid's renderTexture (which clips to grid bounds)
+        renderTexture.draw(rotatedSprite);
+        renderTexture.display();
+
+        // Set up output sprite
+        output.setPosition(box.getPosition() + offset);
+        output.setTextureRect(sf::IntRect(0, 0, grid_w_px, grid_h_px));
+    }
+
+    // Apply viewport rotation (UIDrawable::rotation) to the entire grid widget
+    if (rotation != 0.0f) {
+        output.setOrigin(origin);
+        output.setRotation(rotation);
+        // Adjust position to account for origin offset
+        output.setPosition(box.getPosition() + offset + origin);
+    } else {
+        output.setOrigin(0, 0);
+        output.setRotation(0);
+        // Position already set above
+    }
+
+    // #106: Apply shader if set
+    if (shader && shader->shader) {
+        sf::Vector2f resolution(box.getSize().x, box.getSize().y);
+        PyShader::applyEngineUniforms(*shader->shader, resolution);
+
+        // Apply user uniforms
+        if (uniforms) {
+            uniforms->applyTo(*shader->shader);
+        }
+
+        target.draw(output, shader->shader.get());
+    } else {
+        target.draw(output);
+    }
 }
 
 UIGridPoint& UIGrid::at(int x, int y)
@@ -1032,6 +1118,8 @@ PyObject* UIGrid::get_float_member(PyUIGridObject* self, void* closure)
         return PyFloat_FromDouble(self->data->center_y);
     else if (member_ptr == 6) // zoom
         return PyFloat_FromDouble(self->data->zoom);
+    else if (member_ptr == 7) // camera_rotation
+        return PyFloat_FromDouble(self->data->camera_rotation);
     else
     {
         PyErr_SetString(PyExc_AttributeError, "Invalid attribute");
@@ -1086,6 +1174,8 @@ int UIGrid::set_float_member(PyUIGridObject* self, PyObject* value, void* closur
         self->data->center_y = val;
     else if (member_ptr == 6) // zoom
         self->data->zoom = val;
+    else if (member_ptr == 7) // camera_rotation
+        self->data->camera_rotation = val;
     return 0;
 }
 // TODO (7DRL Day 2, item 5.) return Texture object
@@ -2192,6 +2282,7 @@ PyGetSetDef UIGrid::getsetters[] = {
     {"center_x", (getter)UIGrid::get_float_member, (setter)UIGrid::set_float_member, "center of the view X-coordinate", (void*)4},
     {"center_y", (getter)UIGrid::get_float_member, (setter)UIGrid::set_float_member, "center of the view Y-coordinate", (void*)5},
     {"zoom", (getter)UIGrid::get_float_member, (setter)UIGrid::set_float_member, "zoom factor for displaying the Grid", (void*)6},
+    {"camera_rotation", (getter)UIGrid::get_float_member, (setter)UIGrid::set_float_member, "Rotation of grid contents around camera center (degrees). The grid widget stays axis-aligned; only the view into the world rotates.", (void*)7},
 
     {"on_click", (getter)UIDrawable::get_click, (setter)UIDrawable::set_click,
      MCRF_PROPERTY(on_click,
@@ -2223,6 +2314,7 @@ PyGetSetDef UIGrid::getsetters[] = {
     UIDRAWABLE_GETSETTERS,
     UIDRAWABLE_PARENT_GETSETTERS(PyObjectsEnum::UIGRID),
     UIDRAWABLE_ALIGNMENT_GETSETTERS(PyObjectsEnum::UIGRID),
+    UIDRAWABLE_ROTATION_GETSETTERS(PyObjectsEnum::UIGRID),
     // #142 - Grid cell mouse events
     {"on_cell_enter", (getter)UIGrid::get_on_cell_enter, (setter)UIGrid::set_on_cell_enter,
      "Callback when mouse enters a grid cell. Called with (cell_pos: Vector).", NULL},
@@ -2232,6 +2324,7 @@ PyGetSetDef UIGrid::getsetters[] = {
      "Callback when a grid cell is clicked. Called with (cell_pos: Vector).", NULL},
     {"hovered_cell", (getter)UIGrid::get_hovered_cell, NULL,
      "Currently hovered cell as (x, y) tuple, or None if not hovering.", NULL},
+    UIDRAWABLE_SHADER_GETSETTERS(PyObjectsEnum::UIGRID),
     {NULL}  /* Sentinel */
 };
 
@@ -2492,6 +2585,26 @@ bool UIGrid::setProperty(const std::string& name, float value) {
         markDirty();  // #144 - View change affects content
         return true;
     }
+    else if (name == "camera_rotation") {
+        camera_rotation = value;
+        markDirty();  // View rotation affects content
+        return true;
+    }
+    else if (name == "rotation") {
+        rotation = value;
+        markCompositeDirty();  // Viewport rotation doesn't affect internal content
+        return true;
+    }
+    else if (name == "origin_x") {
+        origin.x = value;
+        markCompositeDirty();
+        return true;
+    }
+    else if (name == "origin_y") {
+        origin.y = value;
+        markCompositeDirty();
+        return true;
+    }
     else if (name == "z_index") {
         z_index = static_cast<int>(value);
         markDirty();  // #144 - Z-order change affects parent
@@ -2517,6 +2630,10 @@ bool UIGrid::setProperty(const std::string& name, float value) {
         markDirty();  // #144 - Content change
         return true;
     }
+    // #106: Shader uniform properties
+    if (setShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -2540,6 +2657,11 @@ bool UIGrid::setProperty(const std::string& name, const sf::Vector2f& value) {
         markDirty();  // #144 - View change affects content
         return true;
     }
+    else if (name == "origin") {
+        origin = value;
+        markCompositeDirty();
+        return true;
+    }
     return false;
 }
 
@@ -2572,6 +2694,22 @@ bool UIGrid::getProperty(const std::string& name, float& value) const {
         value = zoom;
         return true;
     }
+    else if (name == "camera_rotation") {
+        value = camera_rotation;
+        return true;
+    }
+    else if (name == "rotation") {
+        value = rotation;
+        return true;
+    }
+    else if (name == "origin_x") {
+        value = origin.x;
+        return true;
+    }
+    else if (name == "origin_y") {
+        value = origin.y;
+        return true;
+    }
     else if (name == "z_index") {
         value = static_cast<float>(z_index);
         return true;
@@ -2592,6 +2730,10 @@ bool UIGrid::getProperty(const std::string& name, float& value) const {
         value = static_cast<float>(fill_color.a);
         return true;
     }
+    // #106: Shader uniform properties
+    if (getShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -2608,6 +2750,10 @@ bool UIGrid::getProperty(const std::string& name, sf::Vector2f& value) const {
         value = sf::Vector2f(center_x, center_y);
         return true;
     }
+    else if (name == "origin") {
+        value = origin;
+        return true;
+    }
     return false;
 }
 
@@ -2616,13 +2762,18 @@ bool UIGrid::hasProperty(const std::string& name) const {
     if (name == "x" || name == "y" ||
         name == "w" || name == "h" || name == "width" || name == "height" ||
         name == "center_x" || name == "center_y" || name == "zoom" ||
-        name == "z_index" ||
+        name == "camera_rotation" || name == "rotation" ||
+        name == "origin_x" || name == "origin_y" || name == "z_index" ||
         name == "fill_color.r" || name == "fill_color.g" ||
         name == "fill_color.b" || name == "fill_color.a") {
         return true;
     }
     // Vector2f properties
-    if (name == "position" || name == "size" || name == "center") {
+    if (name == "position" || name == "size" || name == "center" || name == "origin") {
+        return true;
+    }
+    // #106: Shader uniform properties
+    if (hasShaderProperty(name)) {
         return true;
     }
     return false;

src/UIGrid.h

@@ -79,11 +79,16 @@ public:
     //int grid_size; // grid sizes are implied by IndexTexture now
     sf::RectangleShape box;
     float center_x, center_y, zoom;
+    float camera_rotation = 0.0f;  // Rotation of grid contents around camera center (degrees)
     //IndexTexture* itex;
     std::shared_ptr<PyTexture> getTexture();
     sf::Sprite sprite, output;
     sf::RenderTexture renderTexture;
 
+    // Intermediate texture for camera_rotation (larger than viewport to hold rotated content)
+    sf::RenderTexture rotationTexture;
+    unsigned int rotationTextureSize = 0;  // Track current allocation size
+
     // #123 - Chunk-based storage for large grid support
     std::unique_ptr<ChunkManager> chunk_manager;
     // Legacy flat storage (kept for small grids or compatibility)
@@ -181,6 +186,8 @@ public:
     // py_clear_dijkstra_maps -> UIGridPathfinding::Grid_clear_dijkstra_maps
     static PyObject* py_entities_in_radius(PyUIGridObject* self, PyObject* args, PyObject* kwds);  // #115
     static PyObject* py_center_camera(PyUIGridObject* self, PyObject* args);  // #169
+    static PyObject* get_camera_rotation(PyUIGridObject* self, void* closure);
+    static int set_camera_rotation(PyUIGridObject* self, PyObject* value, void* closure);
 
     // #199 - HeightMap application methods
     static PyObject* py_apply_threshold(PyUIGridObject* self, PyObject* args, PyObject* kwds);

src/UILine.cpp

@@ -134,6 +134,10 @@ void UILine::render(sf::Vector2f offset, sf::RenderTarget& target) {
     line_shape.setFillColor(render_color);
     line_shape.setOutlineThickness(0);
 
+    // Apply rotation around origin
+    line_shape.setOrigin(origin);
+    line_shape.setRotation(rotation);
+
     target.draw(line_shape);
 }
 
@@ -141,6 +145,22 @@ UIDrawable* UILine::click_at(sf::Vector2f point) {
     // #184: Also check for Python subclass (might have on_click method)
     if (!click_callable && !is_python_subclass) return nullptr;
 
+    // Transform click point to local coordinates accounting for rotation
+    sf::Vector2f localPoint;
+    if (rotation != 0.0f) {
+        // Build transform: rotate around origin
+        sf::Transform transform;
+        transform.translate(origin);
+        transform.rotate(rotation);
+        transform.translate(-origin);
+
+        // Apply inverse transform to get local coordinates
+        sf::Transform inverse = transform.getInverse();
+        localPoint = inverse.transformPoint(point);
+    } else {
+        localPoint = point;
+    }
+
     // Check if point is close enough to the line
     // Using a simple bounding box check plus distance-to-line calculation
     sf::FloatRect bounds = get_bounds();
@@ -149,11 +169,12 @@ UIDrawable* UILine::click_at(sf::Vector2f point) {
     bounds.width += thickness * 2;
     bounds.height += thickness * 2;
 
-    if (!bounds.contains(point)) return nullptr;
+    // For rotated lines, skip the bounds check (it's an optimization, not required)
+    if (rotation == 0.0f && !bounds.contains(localPoint)) return nullptr;
 
     // Calculate distance from point to line segment
     sf::Vector2f line_vec = end_pos - start_pos;
-    sf::Vector2f point_vec = point - start_pos;
+    sf::Vector2f point_vec = localPoint - start_pos;
 
     float line_len_sq = line_vec.x * line_vec.x + line_vec.y * line_vec.y;
     float t = 0.0f;
@@ -164,7 +185,7 @@ UIDrawable* UILine::click_at(sf::Vector2f point) {
     }
 
     sf::Vector2f closest = start_pos + t * line_vec;
-    sf::Vector2f diff = point - closest;
+    sf::Vector2f diff = localPoint - closest;
     float distance = std::sqrt(diff.x * diff.x + diff.y * diff.y);
 
     // Click is valid if within thickness + some margin
@@ -248,6 +269,21 @@ bool UILine::setProperty(const std::string& name, float value) {
         markDirty();  // #144 - Content change
         return true;
     }
+    else if (name == "rotation") {
+        rotation = value;
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_x") {
+        origin.x = value;
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_y") {
+        origin.y = value;
+        markDirty();
+        return true;
+    }
     return false;
 }
 
@@ -306,6 +342,18 @@ bool UILine::getProperty(const std::string& name, float& value) const {
         value = end_pos.y;
         return true;
     }
+    else if (name == "rotation") {
+        value = rotation;
+        return true;
+    }
+    else if (name == "origin_x") {
+        value = origin.x;
+        return true;
+    }
+    else if (name == "origin_y") {
+        value = origin.y;
+        return true;
+    }
     return false;
 }
 
@@ -333,7 +381,8 @@ bool UILine::hasProperty(const std::string& name) const {
     // Float properties
     if (name == "thickness" || name == "x" || name == "y" ||
         name == "start_x" || name == "start_y" ||
-        name == "end_x" || name == "end_y") {
+        name == "end_x" || name == "end_y" ||
+        name == "rotation" || name == "origin_x" || name == "origin_y") {
         return true;
     }
     // Color properties
@@ -341,7 +390,7 @@ bool UILine::hasProperty(const std::string& name) const {
         return true;
     }
     // Vector2f properties
-    if (name == "start" || name == "end") {
+    if (name == "start" || name == "end" || name == "origin") {
         return true;
     }
     return false;
@@ -469,6 +518,7 @@ PyGetSetDef UILine::getsetters[] = {
     UIDRAWABLE_GETSETTERS,
     UIDRAWABLE_PARENT_GETSETTERS(PyObjectsEnum::UILINE),
     UIDRAWABLE_ALIGNMENT_GETSETTERS(PyObjectsEnum::UILINE),
+    UIDRAWABLE_ROTATION_GETSETTERS(PyObjectsEnum::UILINE),
     {NULL}
 };
 

src/UISprite.cpp

@@ -4,16 +4,43 @@
 #include "PythonObjectCache.h"
 #include "UIFrame.h"  // #144: For snapshot= parameter
 #include "PyAlignment.h"
+#include "PyShader.h"  // #106: Shader support
+#include "PyUniformCollection.h"  // #106: Uniform collection support
 // UIDrawable methods now in UIBase.h
 
 UIDrawable* UISprite::click_at(sf::Vector2f point)
 {
     // #184: Also check for Python subclass (might have on_click method)
-    if (click_callable || is_python_subclass)
+    if (!click_callable && !is_python_subclass) return nullptr;
-    {
+
-        if(sprite.getGlobalBounds().contains(point)) return this;
+    // Get sprite dimensions from local bounds
+    sf::FloatRect localBounds = sprite.getLocalBounds();
+    float w = localBounds.width * sprite.getScale().x;
+    float h = localBounds.height * sprite.getScale().y;
+
+    // Transform click point to local coordinates accounting for rotation
+    sf::Vector2f localPoint;
+    if (rotation != 0.0f) {
+        // Build transform: translate to position, then rotate around origin
+        sf::Transform transform;
+        transform.translate(position);
+        transform.translate(origin);
+        transform.rotate(rotation);
+        transform.translate(-origin);
+
+        // Apply inverse transform to get local coordinates
+        sf::Transform inverse = transform.getInverse();
+        localPoint = inverse.transformPoint(point);
+    } else {
+        // No rotation - simple subtraction
+        localPoint = point - position;
     }
-    return NULL;
+
+    // Check if local point is within bounds (0,0 to w,h in local space)
+    if (localPoint.x >= 0 && localPoint.y >= 0 && localPoint.x < w && localPoint.y < h) {
+        return this;
+    }
+    return nullptr;
 }
 
 UISprite::UISprite() 
@@ -87,9 +114,47 @@ void UISprite::render(sf::Vector2f offset, sf::RenderTarget& target)
     color.a = static_cast<sf::Uint8>(255 * opacity);
     sprite.setColor(color);
 
-    sprite.move(offset);
+    // Apply rotation and origin
-    target.draw(sprite);
+    sprite.setOrigin(origin);
-    sprite.move(-offset);
+    sprite.setRotation(rotation);
+
+    // #106: Shader rendering path
+    if (shader && shader->shader) {
+        // Get the sprite bounds for rendering
+        auto bounds = sprite.getGlobalBounds();
+        sf::Vector2f screen_pos = offset + position;
+
+        // Get or create intermediate texture
+        auto& intermediate = GameEngine::getShaderIntermediate();
+        intermediate.clear(sf::Color::Transparent);
+
+        // Render sprite at origin in intermediate texture
+        sf::Sprite temp_sprite = sprite;
+        temp_sprite.setPosition(0, 0);  // Render at origin of intermediate texture
+        intermediate.draw(temp_sprite);
+        intermediate.display();
+
+        // Create result sprite from intermediate texture
+        sf::Sprite result_sprite(intermediate.getTexture());
+        result_sprite.setPosition(screen_pos);
+
+        // Apply engine uniforms
+        sf::Vector2f resolution(bounds.width, bounds.height);
+        PyShader::applyEngineUniforms(*shader->shader, resolution);
+
+        // Apply user uniforms
+        if (uniforms) {
+            uniforms->applyTo(*shader->shader);
+        }
+
+        // Draw with shader
+        target.draw(result_sprite, shader->shader.get());
+    } else {
+        // Standard rendering path (no shader)
+        sprite.move(offset);
+        target.draw(sprite);
+        sprite.move(-offset);
+    }
 
     // Restore original alpha
     color.a = 255;
@@ -359,6 +424,8 @@ PyGetSetDef UISprite::getsetters[] = {
     UIDRAWABLE_GETSETTERS,
     UIDRAWABLE_PARENT_GETSETTERS(PyObjectsEnum::UISPRITE),
     UIDRAWABLE_ALIGNMENT_GETSETTERS(PyObjectsEnum::UISPRITE),
+    UIDRAWABLE_SHADER_GETSETTERS(PyObjectsEnum::UISPRITE),
+    UIDRAWABLE_ROTATION_GETSETTERS(PyObjectsEnum::UISPRITE),
     {NULL}
 };
 
@@ -591,6 +658,28 @@ bool UISprite::setProperty(const std::string& name, float value) {
         markDirty();  // #144 - Z-order change affects parent
         return true;
     }
+    else if (name == "rotation") {
+        rotation = value;
+        sprite.setRotation(rotation);
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_x") {
+        origin.x = value;
+        sprite.setOrigin(origin);
+        markDirty();
+        return true;
+    }
+    else if (name == "origin_y") {
+        origin.y = value;
+        sprite.setOrigin(origin);
+        markDirty();
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (setShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -633,6 +722,22 @@ bool UISprite::getProperty(const std::string& name, float& value) const {
         value = static_cast<float>(z_index);
         return true;
     }
+    else if (name == "rotation") {
+        value = rotation;
+        return true;
+    }
+    else if (name == "origin_x") {
+        value = origin.x;
+        return true;
+    }
+    else if (name == "origin_y") {
+        value = origin.y;
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (getShaderProperty(name, value)) {
+        return true;
+    }
     return false;
 }
 
@@ -652,12 +757,21 @@ bool UISprite::hasProperty(const std::string& name) const {
     // Float properties
     if (name == "x" || name == "y" ||
         name == "scale" || name == "scale_x" || name == "scale_y" ||
-        name == "z_index") {
+        name == "z_index" ||
+        name == "rotation" || name == "origin_x" || name == "origin_y") {
         return true;
     }
     // Int properties
     if (name == "sprite_index" || name == "sprite_number") {
         return true;
     }
+    // Vector2f properties
+    if (name == "origin") {
+        return true;
+    }
+    // #106: Check for shader uniform properties
+    if (hasShaderProperty(name)) {
+        return true;
+    }
     return false;
 }

tests/unit/grid_camera_rotation_test.py

@@ -0,0 +1,86 @@
+#!/usr/bin/env python3
+"""Test UIGrid camera_rotation functionality"""
+import mcrfpy
+from mcrfpy import automation
+import sys
+
+# Create test scene
+test_scene = mcrfpy.Scene("grid_rotation_test")
+ui = test_scene.children
+
+# Create background
+bg = mcrfpy.Frame(pos=(0, 0), size=(800, 600), fill_color=mcrfpy.Color(30, 30, 40))
+ui.append(bg)
+
+# Create a grid with entities to visualize rotation
+grid = mcrfpy.Grid(grid_size=(8, 8), pos=(50, 50), size=(300, 300))
+grid.fill_color = mcrfpy.Color(60, 60, 80)
+
+# Add some entities to visualize the rotation
+for i in range(8):
+    entity = mcrfpy.Entity((i, 0))  # Top row
+    grid.entities.append(entity)
+
+for i in range(1, 8):
+    entity = mcrfpy.Entity((0, i))  # Left column
+    grid.entities.append(entity)
+
+# Apply camera rotation
+grid.camera_rotation = 30.0  # 30 degree rotation
+grid.center_camera((4, 4))   # Center on middle of grid
+
+ui.append(grid)
+
+# Create a second grid without rotation for comparison
+grid2 = mcrfpy.Grid(grid_size=(8, 8), pos=(400, 50), size=(300, 300))
+grid2.fill_color = mcrfpy.Color(60, 60, 80)
+
+# Add same entities pattern
+for i in range(8):
+    entity = mcrfpy.Entity((i, 0))
+    grid2.entities.append(entity)
+
+for i in range(1, 8):
+    entity = mcrfpy.Entity((0, i))
+    grid2.entities.append(entity)
+
+grid2.camera_rotation = 0.0  # No rotation
+grid2.center_camera((4, 4))
+
+ui.append(grid2)
+
+# Labels
+label1 = mcrfpy.Caption(text="Grid with camera_rotation=30", pos=(50, 20))
+ui.append(label1)
+
+label2 = mcrfpy.Caption(text="Grid with camera_rotation=0", pos=(400, 20))
+ui.append(label2)
+
+# Create a third grid with viewport rotation (different from camera rotation)
+grid3 = mcrfpy.Grid(grid_size=(6, 6), pos=(175, 400), size=(200, 150))
+grid3.fill_color = mcrfpy.Color(80, 60, 60)
+
+# Add entities
+for i in range(6):
+    entity = mcrfpy.Entity((i, 0))
+    grid3.entities.append(entity)
+
+# Apply viewport rotation (entire grid rotates)
+grid3.rotation = 15.0
+grid3.origin = (100, 75)  # Center origin for rotation
+grid3.center_camera((3, 3))
+
+ui.append(grid3)
+
+label3 = mcrfpy.Caption(text="Grid with viewport rotation=15 (rotates entire widget)", pos=(100, 560))
+ui.append(label3)
+
+# Activate scene
+mcrfpy.current_scene = test_scene
+
+# Advance the game loop to render, then take screenshot
+mcrfpy.step(0.1)
+automation.screenshot("grid_camera_rotation_test.png")
+print("Screenshot saved as grid_camera_rotation_test.png")
+print("PASS")
+sys.exit(0)

tests/unit/rotation_test.py

@@ -0,0 +1,163 @@
+#!/usr/bin/env python3
+"""Test rotation support for UIDrawable subclasses"""
+import mcrfpy
+import sys
+
+def test_rotation_properties():
+    """Test rotation, origin, rotate_with_camera properties on all UIDrawable types"""
+    print("Testing rotation properties on all UIDrawable types...")
+
+    # Test UIFrame
+    frame = mcrfpy.Frame(pos=(100, 100), size=(50, 50))
+    assert frame.rotation == 0.0, f"Frame default rotation should be 0, got {frame.rotation}"
+    frame.rotation = 45.0
+    assert frame.rotation == 45.0, f"Frame rotation should be 45, got {frame.rotation}"
+
+    # Test origin as Vector
+    frame.origin = (25, 25)
+    assert frame.origin.x == 25.0, f"Frame origin.x should be 25, got {frame.origin.x}"
+    assert frame.origin.y == 25.0, f"Frame origin.y should be 25, got {frame.origin.y}"
+
+    # Test rotate_with_camera
+    assert frame.rotate_with_camera == False, "Default rotate_with_camera should be False"
+    frame.rotate_with_camera = True
+    assert frame.rotate_with_camera == True, "rotate_with_camera should be True after setting"
+    print("  Frame: PASS")
+
+    # Test UISprite
+    sprite = mcrfpy.Sprite(pos=(100, 100))
+    assert sprite.rotation == 0.0, f"Sprite default rotation should be 0, got {sprite.rotation}"
+    sprite.rotation = 90.0
+    assert sprite.rotation == 90.0, f"Sprite rotation should be 90, got {sprite.rotation}"
+    sprite.origin = (8, 8)
+    assert sprite.origin.x == 8.0, f"Sprite origin.x should be 8, got {sprite.origin.x}"
+    print("  Sprite: PASS")
+
+    # Test UICaption
+    caption = mcrfpy.Caption(text="Test", pos=(100, 100))
+    assert caption.rotation == 0.0, f"Caption default rotation should be 0, got {caption.rotation}"
+    caption.rotation = -30.0
+    assert caption.rotation == -30.0, f"Caption rotation should be -30, got {caption.rotation}"
+    caption.origin = (0, 0)
+    assert caption.origin.x == 0.0, f"Caption origin.x should be 0, got {caption.origin.x}"
+    print("  Caption: PASS")
+
+    # Test UICircle
+    circle = mcrfpy.Circle(center=(100, 100), radius=25)
+    assert circle.rotation == 0.0, f"Circle default rotation should be 0, got {circle.rotation}"
+    circle.rotation = 180.0
+    assert circle.rotation == 180.0, f"Circle rotation should be 180, got {circle.rotation}"
+    print("  Circle: PASS")
+
+    # Test UILine
+    line = mcrfpy.Line(start=(0, 0), end=(100, 100))
+    assert line.rotation == 0.0, f"Line default rotation should be 0, got {line.rotation}"
+    line.rotation = 45.0
+    assert line.rotation == 45.0, f"Line rotation should be 45, got {line.rotation}"
+    print("  Line: PASS")
+
+    # Test UIArc
+    arc = mcrfpy.Arc(center=(100, 100), radius=50, start_angle=0, end_angle=90)
+    assert arc.rotation == 0.0, f"Arc default rotation should be 0, got {arc.rotation}"
+    arc.rotation = 270.0
+    assert arc.rotation == 270.0, f"Arc rotation should be 270, got {arc.rotation}"
+    print("  Arc: PASS")
+
+    print("All rotation property tests passed!")
+    return True
+
+def test_rotation_animation():
+    """Test that rotation can be animated"""
+    print("\nTesting rotation animation...")
+
+    frame = mcrfpy.Frame(pos=(100, 100), size=(50, 50))
+    frame.rotation = 0.0
+
+    # Test that animate method exists and accepts rotation
+    try:
+        frame.animate("rotation", 360.0, 1.0, mcrfpy.Easing.LINEAR)
+        print("  Animation started successfully")
+    except Exception as e:
+        print(f"  Animation failed: {e}")
+        return False
+
+    # Test origin animation
+    try:
+        frame.animate("origin_x", 25.0, 0.5, mcrfpy.Easing.LINEAR)
+        frame.animate("origin_y", 25.0, 0.5, mcrfpy.Easing.LINEAR)
+        print("  Origin animation started successfully")
+    except Exception as e:
+        print(f"  Origin animation failed: {e}")
+        return False
+
+    print("Rotation animation tests passed!")
+    return True
+
+def test_grid_camera_rotation():
+    """Test UIGrid camera_rotation property"""
+    print("\nTesting Grid camera_rotation...")
+
+    grid = mcrfpy.Grid(grid_size=(10, 10), pos=(50, 50), size=(200, 200))
+
+    # Test default camera_rotation
+    assert grid.camera_rotation == 0.0, f"Grid default camera_rotation should be 0, got {grid.camera_rotation}"
+
+    # Test setting camera_rotation
+    grid.camera_rotation = 45.0
+    assert grid.camera_rotation == 45.0, f"Grid camera_rotation should be 45, got {grid.camera_rotation}"
+
+    # Test negative rotation
+    grid.camera_rotation = -90.0
+    assert grid.camera_rotation == -90.0, f"Grid camera_rotation should be -90, got {grid.camera_rotation}"
+
+    # Test full rotation
+    grid.camera_rotation = 360.0
+    assert grid.camera_rotation == 360.0, f"Grid camera_rotation should be 360, got {grid.camera_rotation}"
+
+    # Grid also has regular rotation (viewport rotation)
+    assert grid.rotation == 0.0, f"Grid viewport rotation should default to 0, got {grid.rotation}"
+    grid.rotation = 15.0
+    assert grid.rotation == 15.0, f"Grid viewport rotation should be 15, got {grid.rotation}"
+
+    # Test camera_rotation animation
+    try:
+        grid.animate("camera_rotation", 90.0, 1.0, mcrfpy.Easing.EASE_IN_OUT)
+        print("  Camera rotation animation started successfully")
+    except Exception as e:
+        print(f"  Camera rotation animation failed: {e}")
+        return False
+
+    print("Grid camera_rotation tests passed!")
+    return True
+
+def run_all_tests():
+    """Run all rotation tests"""
+    print("=" * 50)
+    print("UIDrawable Rotation Tests")
+    print("=" * 50)
+
+    results = []
+    results.append(("Rotation Properties", test_rotation_properties()))
+    results.append(("Rotation Animation", test_rotation_animation()))
+    results.append(("Grid Camera Rotation", test_grid_camera_rotation()))
+
+    print("\n" + "=" * 50)
+    print("Test Results Summary")
+    print("=" * 50)
+
+    all_passed = True
+    for name, passed in results:
+        status = "PASS" if passed else "FAIL"
+        print(f"  {name}: {status}")
+        if not passed:
+            all_passed = False
+
+    if all_passed:
+        print("\nAll tests PASSED!")
+        return 0
+    else:
+        print("\nSome tests FAILED!")
+        return 1
+
+if __name__ == "__main__":
+    sys.exit(run_all_tests())

tests/unit/rotation_visual_test.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+"""Visual test for rotation support - uses direct screenshot"""
+import mcrfpy
+from mcrfpy import automation
+import sys
+
+# Create test scene
+test_scene = mcrfpy.Scene("rotation_test")
+ui = test_scene.children
+
+# Create background
+bg = mcrfpy.Frame(pos=(0, 0), size=(800, 600), fill_color=mcrfpy.Color(40, 40, 50))
+ui.append(bg)
+
+# Row 1: Frames with different rotations
+# Frame at 0 degrees
+frame1 = mcrfpy.Frame(pos=(100, 100), size=(60, 60), fill_color=mcrfpy.Color(200, 50, 50))
+frame1.rotation = 0.0
+frame1.origin = (30, 30)  # Center origin
+ui.append(frame1)
+
+# Frame at 45 degrees
+frame2 = mcrfpy.Frame(pos=(250, 100), size=(60, 60), fill_color=mcrfpy.Color(50, 200, 50))
+frame2.rotation = 45.0
+frame2.origin = (30, 30)
+ui.append(frame2)
+
+# Frame at 90 degrees
+frame3 = mcrfpy.Frame(pos=(400, 100), size=(60, 60), fill_color=mcrfpy.Color(50, 50, 200))
+frame3.rotation = 90.0
+frame3.origin = (30, 30)
+ui.append(frame3)
+
+# Label for row 1
+label1 = mcrfpy.Caption(text="Frames: 0, 45, 90 degrees", pos=(100, 50))
+ui.append(label1)
+
+# Row 2: Captions with rotation
+caption1 = mcrfpy.Caption(text="Rotated Text", pos=(100, 250))
+caption1.rotation = 0.0
+ui.append(caption1)
+
+caption2 = mcrfpy.Caption(text="Rotated Text", pos=(300, 250))
+caption2.rotation = -15.0
+ui.append(caption2)
+
+caption3 = mcrfpy.Caption(text="Rotated Text", pos=(500, 250))
+caption3.rotation = 30.0
+ui.append(caption3)
+
+# Label for row 2
+label2 = mcrfpy.Caption(text="Captions: 0, -15, 30 degrees", pos=(100, 200))
+ui.append(label2)
+
+# Row 3: Circles (rotation with offset origin causes orbiting)
+circle1 = mcrfpy.Circle(center=(100, 400), radius=25, fill_color=mcrfpy.Color(200, 200, 50))
+circle1.rotation = 0.0
+ui.append(circle1)
+
+circle2 = mcrfpy.Circle(center=(250, 400), radius=25, fill_color=mcrfpy.Color(200, 50, 200))
+circle2.rotation = 45.0
+circle2.origin = (20, 0)  # Offset origin to show orbiting effect
+ui.append(circle2)
+
+circle3 = mcrfpy.Circle(center=(400, 400), radius=25, fill_color=mcrfpy.Color(50, 200, 200))
+circle3.rotation = 90.0
+circle3.origin = (20, 0)  # Same offset
+ui.append(circle3)
+
+# Label for row 3
+label3 = mcrfpy.Caption(text="Circles with offset origin: 0, 45, 90 degrees", pos=(100, 350))
+ui.append(label3)
+
+# Row 4: Lines with rotation
+line1 = mcrfpy.Line(start=(100, 500), end=(150, 500), thickness=3, color=mcrfpy.Color(255, 255, 255))
+line1.rotation = 0.0
+ui.append(line1)
+
+line2 = mcrfpy.Line(start=(250, 500), end=(300, 500), thickness=3, color=mcrfpy.Color(255, 200, 200))
+line2.rotation = 45.0
+line2.origin = (125, 500)  # Rotate around line center
+ui.append(line2)
+
+line3 = mcrfpy.Line(start=(400, 500), end=(450, 500), thickness=3, color=mcrfpy.Color(200, 255, 200))
+line3.rotation = -45.0
+line3.origin = (200, 500)
+ui.append(line3)
+
+# Label for row 4
+label4 = mcrfpy.Caption(text="Lines: 0, 45, -45 degrees", pos=(100, 470))
+ui.append(label4)
+
+# Arcs with rotation
+arc1 = mcrfpy.Arc(center=(600, 100), radius=40, start_angle=0, end_angle=90, thickness=5)
+arc1.rotation = 0.0
+ui.append(arc1)
+
+arc2 = mcrfpy.Arc(center=(700, 100), radius=40, start_angle=0, end_angle=90, thickness=5)
+arc2.rotation = 45.0
+ui.append(arc2)
+
+# Label for arcs
+label5 = mcrfpy.Caption(text="Arcs: 0, 45 degrees", pos=(550, 50))
+ui.append(label5)
+
+# Activate scene
+mcrfpy.current_scene = test_scene
+
+# Advance the game loop to render, then take screenshot
+mcrfpy.step(0.1)
+automation.screenshot("rotation_visual_test.png")
+print("Screenshot saved as rotation_visual_test.png")
+print("PASS")
+sys.exit(0)

tests/unit/shader_test.py

@@ -0,0 +1,422 @@
+#!/usr/bin/env python3
+"""Unit tests for the Shader system (Issue #106)
+
+Tests cover:
+- Shader creation and compilation
+- Static uniforms (float, vec2, vec3, vec4)
+- PropertyBinding for dynamic uniform values
+- CallableBinding for computed uniform values
+- Shader assignment to various drawable types
+- Dynamic flag propagation
+"""
+
+import mcrfpy
+import sys
+
+
+def test_shader_creation():
+    """Test basic shader creation"""
+    print("Testing shader creation...")
+
+    # Valid shader
+    shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        void main() {
+            gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);
+        }
+    ''')
+    assert shader is not None, "Shader should be created"
+    assert shader.is_valid, "Shader should be valid"
+    assert shader.dynamic == False, "Shader should not be dynamic by default"
+
+    # Dynamic shader
+    dynamic_shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        uniform float time;
+        void main() {
+            gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);
+        }
+    ''', dynamic=True)
+    assert dynamic_shader.dynamic == True, "Shader should be dynamic when specified"
+
+    print("  PASS: Basic shader creation works")
+
+
+def test_shader_source():
+    """Test that shader source is stored correctly"""
+    print("Testing shader source storage...")
+
+    source = '''uniform sampler2D texture;
+void main() {
+    gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);
+}'''
+    shader = mcrfpy.Shader(source)
+    assert source in shader.source, "Shader source should be stored"
+
+    print("  PASS: Shader source is stored")
+
+
+def test_static_uniforms():
+    """Test static uniform values"""
+    print("Testing static uniforms...")
+
+    frame = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+
+    # Test float uniform
+    frame.uniforms['intensity'] = 0.5
+    assert abs(frame.uniforms['intensity'] - 0.5) < 0.001, "Float uniform should match"
+
+    # Test vec2 uniform
+    frame.uniforms['offset'] = (10.0, 20.0)
+    val = frame.uniforms['offset']
+    assert len(val) == 2, "Vec2 should have 2 components"
+    assert abs(val[0] - 10.0) < 0.001, "Vec2.x should match"
+    assert abs(val[1] - 20.0) < 0.001, "Vec2.y should match"
+
+    # Test vec3 uniform
+    frame.uniforms['color_rgb'] = (1.0, 0.5, 0.0)
+    val = frame.uniforms['color_rgb']
+    assert len(val) == 3, "Vec3 should have 3 components"
+
+    # Test vec4 uniform
+    frame.uniforms['color'] = (1.0, 0.5, 0.0, 1.0)
+    val = frame.uniforms['color']
+    assert len(val) == 4, "Vec4 should have 4 components"
+
+    print("  PASS: Static uniforms work")
+
+
+def test_uniform_keys():
+    """Test uniform collection keys/values/items"""
+    print("Testing uniform collection methods...")
+
+    frame = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+    frame.uniforms['a'] = 1.0
+    frame.uniforms['b'] = 2.0
+    frame.uniforms['c'] = 3.0
+
+    keys = frame.uniforms.keys()
+    assert 'a' in keys, "Key 'a' should be present"
+    assert 'b' in keys, "Key 'b' should be present"
+    assert 'c' in keys, "Key 'c' should be present"
+    assert len(keys) == 3, "Should have 3 keys"
+
+    # Test 'in' operator
+    assert 'a' in frame.uniforms, "'in' operator should work"
+    assert 'nonexistent' not in frame.uniforms, "'not in' should work"
+
+    # Test deletion
+    del frame.uniforms['b']
+    assert 'b' not in frame.uniforms, "Deleted key should be gone"
+    assert len(frame.uniforms.keys()) == 2, "Should have 2 keys after deletion"
+
+    print("  PASS: Uniform collection methods work")
+
+
+def test_property_binding():
+    """Test PropertyBinding for dynamic uniform values"""
+    print("Testing PropertyBinding...")
+
+    # Create source and target frames
+    source_frame = mcrfpy.Frame(pos=(100, 200), size=(50, 50))
+    target_frame = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+
+    # Create binding to source frame's x position
+    binding = mcrfpy.PropertyBinding(source_frame, 'x')
+    assert binding is not None, "PropertyBinding should be created"
+    assert binding.property == 'x', "Property name should be stored"
+    assert abs(binding.value - 100.0) < 0.001, "Initial value should be 100"
+    assert binding.is_valid == True, "Binding should be valid"
+
+    # Assign binding to uniform
+    target_frame.uniforms['source_x'] = binding
+
+    # Check that value tracks changes
+    source_frame.x = 300
+    assert abs(binding.value - 300.0) < 0.001, "Binding should track changes"
+
+    print("  PASS: PropertyBinding works")
+
+
+def test_callable_binding():
+    """Test CallableBinding for computed uniform values"""
+    print("Testing CallableBinding...")
+
+    counter = [0]  # Use list for closure
+
+    def compute_value():
+        counter[0] += 1
+        return counter[0] * 0.1
+
+    binding = mcrfpy.CallableBinding(compute_value)
+    assert binding is not None, "CallableBinding should be created"
+    assert binding.is_valid == True, "Binding should be valid"
+
+    # Each access should call the function
+    v1 = binding.value
+    v2 = binding.value
+    v3 = binding.value
+
+    assert abs(v1 - 0.1) < 0.001, "First call should return 0.1"
+    assert abs(v2 - 0.2) < 0.001, "Second call should return 0.2"
+    assert abs(v3 - 0.3) < 0.001, "Third call should return 0.3"
+
+    # Assign to uniform
+    frame = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+    frame.uniforms['computed'] = binding
+
+    print("  PASS: CallableBinding works")
+
+
+def test_shader_on_frame():
+    """Test shader assignment to Frame"""
+    print("Testing shader on Frame...")
+
+    shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        uniform float intensity;
+        void main() {
+            vec4 color = texture2D(texture, gl_TexCoord[0].xy);
+            color.rgb *= intensity;
+            gl_FragColor = color;
+        }
+    ''')
+
+    frame = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+    assert frame.shader is None, "Shader should be None initially"
+
+    frame.shader = shader
+    assert frame.shader is not None, "Shader should be assigned"
+
+    frame.uniforms['intensity'] = 0.8
+    assert abs(frame.uniforms['intensity'] - 0.8) < 0.001, "Uniform should be set"
+
+    # Test shader removal
+    frame.shader = None
+    assert frame.shader is None, "Shader should be removable"
+
+    print("  PASS: Shader on Frame works")
+
+
+def test_shader_on_sprite():
+    """Test shader assignment to Sprite"""
+    print("Testing shader on Sprite...")
+
+    shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        void main() {
+            gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);
+        }
+    ''')
+
+    sprite = mcrfpy.Sprite(pos=(0, 0))
+    assert sprite.shader is None, "Shader should be None initially"
+
+    sprite.shader = shader
+    assert sprite.shader is not None, "Shader should be assigned"
+
+    sprite.uniforms['test'] = 1.0
+    assert abs(sprite.uniforms['test'] - 1.0) < 0.001, "Uniform should be set"
+
+    print("  PASS: Shader on Sprite works")
+
+
+def test_shader_on_caption():
+    """Test shader assignment to Caption"""
+    print("Testing shader on Caption...")
+
+    shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        void main() {
+            gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);
+        }
+    ''')
+
+    caption = mcrfpy.Caption(text="Test", pos=(0, 0))
+    assert caption.shader is None, "Shader should be None initially"
+
+    caption.shader = shader
+    assert caption.shader is not None, "Shader should be assigned"
+
+    caption.uniforms['test'] = 1.0
+    assert abs(caption.uniforms['test'] - 1.0) < 0.001, "Uniform should be set"
+
+    print("  PASS: Shader on Caption works")
+
+
+def test_shader_on_grid():
+    """Test shader assignment to Grid"""
+    print("Testing shader on Grid...")
+
+    shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        void main() {
+            gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);
+        }
+    ''')
+
+    grid = mcrfpy.Grid(grid_size=(10, 10), pos=(0, 0), size=(200, 200))
+    assert grid.shader is None, "Shader should be None initially"
+
+    grid.shader = shader
+    assert grid.shader is not None, "Shader should be assigned"
+
+    grid.uniforms['test'] = 1.0
+    assert abs(grid.uniforms['test'] - 1.0) < 0.001, "Uniform should be set"
+
+    print("  PASS: Shader on Grid works")
+
+
+def test_shader_on_entity():
+    """Test shader assignment to Entity"""
+    print("Testing shader on Entity...")
+
+    shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        void main() {
+            gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);
+        }
+    ''')
+
+    entity = mcrfpy.Entity()
+    assert entity.shader is None, "Shader should be None initially"
+
+    entity.shader = shader
+    assert entity.shader is not None, "Shader should be assigned"
+
+    entity.uniforms['test'] = 1.0
+    assert abs(entity.uniforms['test'] - 1.0) < 0.001, "Uniform should be set"
+
+    print("  PASS: Shader on Entity works")
+
+
+def test_shared_shader():
+    """Test that multiple drawables can share the same shader"""
+    print("Testing shared shader...")
+
+    shader = mcrfpy.Shader('''
+        uniform sampler2D texture;
+        uniform float intensity;
+        void main() {
+            vec4 color = texture2D(texture, gl_TexCoord[0].xy);
+            color.rgb *= intensity;
+            gl_FragColor = color;
+        }
+    ''')
+
+    frame1 = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+    frame2 = mcrfpy.Frame(pos=(100, 0), size=(100, 100))
+
+    # Assign same shader to both
+    frame1.shader = shader
+    frame2.shader = shader
+
+    # But different uniform values
+    frame1.uniforms['intensity'] = 0.5
+    frame2.uniforms['intensity'] = 1.0
+
+    assert abs(frame1.uniforms['intensity'] - 0.5) < 0.001, "Frame1 intensity should be 0.5"
+    assert abs(frame2.uniforms['intensity'] - 1.0) < 0.001, "Frame2 intensity should be 1.0"
+
+    print("  PASS: Shared shader with different uniforms works")
+
+
+def test_shader_animation_properties():
+    """Test that shader uniforms can be animated via the animation system"""
+    print("Testing shader animation properties...")
+
+    frame = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+
+    # Set initial uniform value
+    frame.uniforms['intensity'] = 0.0
+
+    # Test animate() method with shader.X property syntax
+    # This uses hasProperty/setProperty internally
+    try:
+        frame.animate('shader.intensity', 1.0, 0.5, mcrfpy.Easing.LINEAR)
+        animation_works = True
+    except Exception as e:
+        animation_works = False
+        print(f"    Animation error: {e}")
+
+    assert animation_works, "Animating shader uniforms should work"
+
+    # Test with different drawable types
+    sprite = mcrfpy.Sprite(pos=(0, 0))
+    sprite.uniforms['glow'] = 0.0
+    try:
+        sprite.animate('shader.glow', 2.0, 1.0, mcrfpy.Easing.EASE_IN)
+        sprite_animation_works = True
+    except Exception as e:
+        sprite_animation_works = False
+        print(f"    Sprite animation error: {e}")
+
+    assert sprite_animation_works, "Animating Sprite shader uniforms should work"
+
+    # Test Caption
+    caption = mcrfpy.Caption(text="Test", pos=(0, 0))
+    caption.uniforms['alpha'] = 1.0
+    try:
+        caption.animate('shader.alpha', 0.0, 0.5, mcrfpy.Easing.EASE_OUT)
+        caption_animation_works = True
+    except Exception as e:
+        caption_animation_works = False
+        print(f"    Caption animation error: {e}")
+
+    assert caption_animation_works, "Animating Caption shader uniforms should work"
+
+    # Test Grid
+    grid = mcrfpy.Grid(grid_size=(5, 5), pos=(0, 0), size=(100, 100))
+    grid.uniforms['zoom_effect'] = 1.0
+    try:
+        grid.animate('shader.zoom_effect', 2.0, 1.0, mcrfpy.Easing.LINEAR)
+        grid_animation_works = True
+    except Exception as e:
+        grid_animation_works = False
+        print(f"    Grid animation error: {e}")
+
+    assert grid_animation_works, "Animating Grid shader uniforms should work"
+
+    print("  PASS: Shader animation properties work")
+
+
+def run_all_tests():
+    """Run all shader tests"""
+    print("=" * 50)
+    print("Shader System Unit Tests")
+    print("=" * 50)
+    print()
+
+    try:
+        test_shader_creation()
+        test_shader_source()
+        test_static_uniforms()
+        test_uniform_keys()
+        test_property_binding()
+        test_callable_binding()
+        test_shader_on_frame()
+        test_shader_on_sprite()
+        test_shader_on_caption()
+        test_shader_on_grid()
+        test_shader_on_entity()
+        test_shared_shader()
+        test_shader_animation_properties()
+
+        print()
+        print("=" * 50)
+        print("ALL TESTS PASSED")
+        print("=" * 50)
+        sys.exit(0)
+
+    except AssertionError as e:
+        print(f"  FAIL: {e}")
+        sys.exit(1)
+    except Exception as e:
+        print(f"  ERROR: {e}")
+        import traceback
+        traceback.print_exc()
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    run_all_tests()