void app_resize(int x, int y);
void app_fullscreen(int fs);
void app_vsync(int vsync);
void app_resize(int x, int y);
void app_fullscreen(int fs);
void app_vsync(int vsync);
/* defined in scr_mod.c for convenience */
void primray(cgm_ray *ray, int x, int y);
/* defined in scr_mod.c for convenience */
void primray(cgm_ray *ray, int x, int y);