Another checkpoint. Compiling/building/running - Python API tests from in-engine REPL are not passing, though

src/IndexSprite.cpp

@@ -0,0 +1,16 @@
+#include "IndexSprite.h"
+#include "GameEngine.h"
+
+//int texture_index, sprite_index, x, y;
+
+GameEngine* IndexSprite::game;
+
+sf::Sprite IndexSprite::drawable()
+{
+    sf::Sprite s;
+    auto& tex = IndexSprite::game->textures[texture_index];
+    s.setTexture(tex.texture);
+    s.setPosition(sf::Vector2f(x, y));
+    s.setTextureRect(tex.spriteCoordinates(sprite_index));
+    return s;
+}