Reorganize files and remove unused code

src/gpu_and_windowing.h

@@ -0,0 +1,49 @@
+#include <stdint.h>
+#include "vector.h"
+
+typedef struct {
+	uint8_t *data[6];
+	int w, h, chan;
+} Cubemap;
+
+typedef enum {
+	CF_FRONT,
+	CF_BACK,
+	CF_LEFT,
+	CF_RIGHT,
+	CF_TOP,
+	CF_BOTTOM,
+} CubeFace;
+
+enum {
+	EVENT_EMPTY = 0,
+	EVENT_CLOSE,
+	EVENT_PRESS_SPACE,
+	EVENT_PRESS_ESC,
+	EVENT_PRESS_W,
+	EVENT_PRESS_A,
+	EVENT_PRESS_S,
+	EVENT_PRESS_D,
+	EVENT_AGAIN_SPACE,
+	EVENT_AGAIN_ESC,
+	EVENT_AGAIN_W,
+	EVENT_AGAIN_A,
+	EVENT_AGAIN_S,
+	EVENT_AGAIN_D,
+	EVENT_MOVE_MOUSE,
+};
+
+int pop_event(double *mouse_x, double *mouse_y);
+
+void startup_window_and_opengl_context_or_exit(int window_w, int window_h, const char *title);
+void cleanup_window_and_opengl_context(void);
+
+int get_screen_w(void);
+int get_screen_h(void);
+
+void move_frame_to_the_gpu(int w, int h, Vector3 *data);
+void draw_frame(void);
+
+void    load_cubemap(Cubemap *c, const char *files[6]);
+void    free_cubemap(Cubemap *c);
+Vector3 sample_cubemap(Cubemap *c, Vector3 dir);