McRogueFace/CLAUDE.md

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Build Commands

# Build the project (compiles to ./build directory)
make

# Or use the build script directly
./build.sh

# Run the game
make run

# Clean build artifacts
make clean

# The executable and all assets are in ./build/
cd build
./mcrogueface

Project Architecture

McRogueFace is a C++ game engine with Python scripting support, designed for creating roguelike games. The architecture consists of:

Core Engine (C++)

• Entry Point: src/main.cpp initializes the game engine
• Scene System: Scene.h/cpp manages game states
• Entity System: UIEntity.h/cpp provides game objects
• Python Integration: McRFPy_API.h/cpp exposes engine functionality to Python
• UI Components: UIFrame, UICaption, UISprite, UIGrid for rendering

Game Logic (Python)

• Main Script: src/scripts/game.py contains game initialization and scene setup
• Entity System: src/scripts/cos_entities.py implements game entities (Player, Enemy, Boulder, etc.)
• Level Generation: src/scripts/cos_level.py uses BSP for procedural dungeon generation
• Tile System: src/scripts/cos_tiles.py implements Wave Function Collapse for tile placement

Key Python API (mcrfpy module)

The C++ engine exposes these primary functions to Python:

• Scene Management: createScene(), setScene(), sceneUI()
• Entity Creation: Entity() with position and sprite properties
• Grid Management: Grid() for tilemap rendering
• Input Handling: keypressScene() for keyboard events
• Audio: createSoundBuffer(), playSound(), setVolume()
• Timers: setTimer(), delTimer() for event scheduling

Development Workflow

Running the Game

After building, the executable expects:

• assets/ directory with sprites, fonts, and audio
• scripts/ directory with Python game files
• Python 3.12 shared libraries in ./lib/

Modifying Game Logic

• Game scripts are in src/scripts/
• Main game entry is game.py
• Entity behavior in cos_entities.py
• Level generation in cos_level.py

Adding New Features

1. C++ API additions go in src/McRFPy_API.cpp
2. Expose to Python using the existing binding pattern
3. Update Python scripts to use new functionality

Testing Game Changes

Currently no automated test suite. Manual testing workflow:

1. Build with make
2. Run make run or cd build && ./mcrogueface
3. Test specific features through gameplay
4. Check console output for Python errors

Quick Testing Commands

# Test basic functionality
make test

# Run in Python interactive mode
make python

# Test headless mode
cd build
./mcrogueface --headless -c "import mcrfpy; print('Headless test')"

Common Development Tasks

Compiling McRogueFace

# Standard build (to ./build directory)
make

# Full rebuild
make clean && make

# Manual CMake build
mkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make -j$(nproc)

# The library path issue: if linking fails, check that libraries are in __lib/
# CMakeLists.txt expects: link_directories(${CMAKE_SOURCE_DIR}/__lib)

Running and Capturing Output

# Run with timeout and capture output
cd build
timeout 5 ./mcrogueface 2>&1 | tee output.log

# Run in background and kill after delay
./mcrogueface > output.txt 2>&1 & PID=$!; sleep 3; kill $PID 2>/dev/null

# Just capture first N lines (useful for crashes)
./mcrogueface 2>&1 | head -50

Debugging with GDB

# Interactive debugging
gdb ./mcrogueface
(gdb) run
(gdb) bt  # backtrace after crash

# Batch mode debugging (non-interactive)
gdb -batch -ex run -ex where -ex quit ./mcrogueface 2>&1

# Get just the backtrace after a crash
gdb -batch -ex "run" -ex "bt" ./mcrogueface 2>&1 | head -50

# Debug with specific commands
echo -e "run\nbt 5\nquit\ny" | gdb ./mcrogueface 2>&1

Testing Different Python Scripts

# The game automatically runs build/scripts/game.py on startup
# To test different behavior:

# Option 1: Replace game.py temporarily
cd build
cp scripts/my_test_script.py scripts/game.py
./mcrogueface

# Option 2: Backup original and test
mv scripts/game.py scripts/game.py.bak
cp my_test.py scripts/game.py
./mcrogueface
mv scripts/game.py.bak scripts/game.py

# Option 3: For quick tests, create minimal game.py
echo 'import mcrfpy; print("Test"); mcrfpy.createScene("test")' > scripts/game.py

Understanding Key Macros and Patterns

RET_PY_INSTANCE Macro (UIDrawable.h)

This macro handles converting C++ UI objects to their Python equivalents:

RET_PY_INSTANCE(target);
// Expands to a switch on target->derived_type() that:
// 1. Allocates the correct Python object type (Frame, Caption, Sprite, Grid)
// 2. Sets the shared_ptr data member
// 3. Returns the PyObject*

Collection Patterns

• UICollection wraps std::vector<std::shared_ptr<UIDrawable>>
• UIEntityCollection wraps std::list<std::shared_ptr<UIEntity>>
• Different containers require different iteration code (vector vs list)

Python Object Creation Patterns

// Pattern 1: Using tp_alloc (most common)
auto o = (PyUIFrameObject*)type->tp_alloc(type, 0);
o->data = std::make_shared<UIFrame>();

// Pattern 2: Getting type from module
auto type = (PyTypeObject*)PyObject_GetAttrString(McRFPy_API::mcrf_module, "Entity");
auto o = (PyUIEntityObject*)type->tp_alloc(type, 0);

// Pattern 3: Direct shared_ptr assignment
iterObj->data = self->data;  // Shares the C++ object

Working Directory Structure

build/
├── mcrogueface          # The executable
├── scripts/            
│   └── game.py         # Auto-loaded Python script
├── assets/             # Copied from source during build
└── lib/                # Python libraries (copied from __lib/)

Quick Iteration Tips

• Keep a test script ready for quick experiments
• Use timeout to auto-kill hanging processes
• The game expects a window manager; use Xvfb for headless testing
• Python errors go to stderr, game output to stdout
• Segfaults usually mean Python type initialization issues

Important Notes

• The project uses SFML for graphics/audio and libtcod for roguelike utilities
• Python scripts are loaded at runtime from the scripts/ directory
• Asset loading expects specific paths relative to the executable
• The game was created for 7DRL 2025 as "Crypt of Sokoban"
• Iterator implementations require careful handling of C++/Python boundaries

Testing Guidelines

Test-Driven Development

• Always write tests first: Create automation tests in ./tests/ for all bugs and new features
• Practice TDD: Write tests that fail to demonstrate the issue, then pass after the fix is applied
• Close the loop: Reproduce issue → change code → recompile → verify behavior change

Two Types of Tests

1. Direct Execution Tests (No Game Loop)

For tests that only need class initialization or direct code execution:

# These tests can treat McRogueFace like a Python interpreter
import mcrfpy

# Test code here
result = mcrfpy.some_function()
assert result == expected_value
print("PASS" if condition else "FAIL")

2. Game Loop Tests (Timer-Based)

For tests requiring rendering, game state, or elapsed time:

import mcrfpy
from mcrfpy import automation
import sys

def run_test(runtime):
    """Timer callback - runs after game loop starts"""
    # Now rendering is active, screenshots will work
    automation.screenshot("test_result.png")
    
    # Run your tests here
    automation.click(100, 100)
    
    # Always exit at the end
    print("PASS" if success else "FAIL")
    sys.exit(0)

# Set up the test scene
mcrfpy.createScene("test")
# ... add UI elements ...

# Schedule test to run after game loop starts
mcrfpy.setTimer("test", run_test, 100)  # 0.1 seconds

Key Testing Principles

• Timer callbacks are essential: Screenshots and UI interactions only work after the render loop starts
• Use automation API: Always create and examine screenshots when visual feedback is required
• Exit properly: Call sys.exit() at the end of timer-based tests to prevent hanging
• Headless mode: Use --exec flag for automated testing: ./mcrogueface --headless --exec tests/my_test.py

Example Test Pattern

# Run a test that requires game loop
./build/mcrogueface --headless --exec tests/issue_78_middle_click_test.py

# The test will:
# 1. Set up the scene during script execution
# 2. Register a timer callback
# 3. Game loop starts
# 4. Timer fires after 100ms
# 5. Test runs with full rendering available
# 6. Test takes screenshots and validates behavior
# 7. Test calls sys.exit() to terminate