10 virtual void display(float d) = 0;
11 virtual void timer() = 0;
12 virtual void motion(int x, int y, int dx, int dy) = 0;
13 virtual void passiveMotion(int x, int y, int dx, int dy) = 0;
14 virtual void mouse(int button, int state, int x, int y) = 0;
15 std::vector<Light> getLights(float d) { return {}; }