int fps_calc() {
double cur_time = sys_float_time();
if(_num_frames_drawn == 0) {
_prev_fps_frame = 0;
_prev_fps_time = sys_float_time();
return _fps;
}
size_t delta_frames = _num_frames_drawn - _prev_fps_frame;
if(delta_frames < _fps_frame_interval)
return _fps;
float delta_time = cur_time - _prev_fps_time;
if(delta_time <= 0)
return _fps;
// calc new fps
_prev_fps_time = cur_time;
_prev_fps_frame = _num_frames_drawn;
_fps = (int) (((float)delta_frames) / delta_time);
return _fps;
}
static void report_fps() {
static float _prev_report_time = -1;
float now = sys_float_time();
if(_prev_report_time == -1)
_prev_report_time = now;
if(now - _prev_report_time < 1)
return;
_prev_report_time = now;
int fps = fps_calc();
printf("fps: % 3d\n", fps);
}
int
main(int argc, char const *argv[]) {
if(argc < 2) return 1; // TODO: Show usage.
puts("Chipmunk: CHIP-8 Emulator");
// NOTE: Chip8 initialization.
struct chip8 c8 = {0};
if(!chipmunk_init(&c8, argv[1])) return 1;
// NOTE: SDL setup.
SDL_Window *w = NULL;
SDL_Renderer *r = NULL;
SDL_Texture *t = NULL;
// NOTE: SDL initialization.
if(!sdl_init("chipmunk", 64 * 14, 32 * 14, &w, &r)) goto escape;
t = SDL_CreateTexture(r, SDL_PIXELFORMAT_RGB332, SDL_TEXTUREACCESS_STREAMING, 64, 32);
// NOTE: Timer and frame rate set up.
double seconds_per_tick = 1.0 / (double)SDL_GetPerformanceFrequency();
double newtime = 0.0, oldtime = 0.0, time_accumulated = 0.0;
double target_fps = 1.0 / 60.0;
u64 time_count = SDL_GetPerformanceCounter();
for(;;) {
// NOTE: SDL event processing
SDL_Event event;
sdl_pump_events();
if(sdl_event_exists(&event, SDL_QUIT)) goto escape;
sdl_flush_events();
// NOTE: Run the emulator.
chipmunk_run(&c8, 2000);
// NOTE: Timing update
newtime = sys_float_time(&time_count, seconds_per_tick);
time_accumulated += newtime - oldtime;
oldtime = newtime;
// NOTE: Do sound and rendering every 60th of a second.
if(time_accumulated > target_fps) {
if(c8.beep) {
puts("BEEP");
c8.beep = false;
}
// TODO: Has to be a better way to do this...
for(u32 i = sizeof(c8.display); i--;) {
if(c8.display[i]) c8.display[i] = 255;
}
SDL_UpdateTexture(t, NULL, c8.display, 64 * sizeof(u8));
SDL_RenderClear(r);
SDL_RenderCopy(r, t, NULL, NULL);
SDL_RenderPresent(r);
time_accumulated -= target_fps;
}
}
escape:
if(t) SDL_DestroyTexture(t);
if(r) SDL_DestroyRenderer(r);
if(w) SDL_DestroyWindow(w);
SDL_Quit();
return 0;
}
