VG_STATIC void render_world_depth( world_instance *world, camera *cam );
VG_STATIC void render_world( world_instance *world, camera *cam,
int layer_depth );
VG_STATIC void render_world_depth( world_instance *world, camera *cam );
VG_STATIC void render_world( world_instance *world, camera *cam,
int layer_depth );