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Wait for remaining time in interval rather than busy looping

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Camden Dixie O'Brien 2025-01-02 16:15:18 +00:00
parent 178d6a23d3
commit cda484c9ab
1 changed files with 38 additions and 40 deletions
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78
engine/engine.c
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@ -37,54 +37,52 @@ int main(int argc, char *argv[])
void *gamemem = calloc(1, game_conf.memsize); void *gamemem = calloc(1, game_conf.memsize);
game_init(argc, argv, gamemem, renderer); game_init(argc, argv, gamemem, renderer);
perf_t perf = { .freq = SDL_GetPerformanceFrequency() / 1000000.0 }; const uint64_t perfhz = SDL_GetPerformanceFrequency();
uint64_t frame = 0, prevt = SDL_GetTicks64(); const uint64_t intervalperf = (INTERVAL * perfhz) / 1000;
perf_t perf = { .freq = perfhz / 1000000.0 };
uint64_t frame = 0;
while (1) { while (1) {
const uint64_t t = SDL_GetTicks64(); perf.start = SDL_GetPerformanceCounter();
const uint64_t dt = t - prevt;
if (dt >= INTERVAL) {
perf.start = SDL_GetPerformanceCounter();
// Handle all events currently in queue // Handle all events currently in queue
SDL_Event evt; SDL_Event evt;
while (SDL_PollEvent(&evt)) { while (SDL_PollEvent(&evt)) {
if (game_evthandle(gamemem, &evt) != GAMESTATUS_OK) if (game_evthandle(gamemem, &evt) != GAMESTATUS_OK)
goto quit;
}
perf.evt = SDL_GetPerformanceCounter();
// Update game state
if (game_update(gamemem, INTERVAL) != GAMESTATUS_OK)
goto quit; goto quit;
perf.update = SDL_GetPerformanceCounter(); }
perf.evt = SDL_GetPerformanceCounter();
// Render frame // Update game state
SDL_RenderClear(renderer); if (game_update(gamemem, INTERVAL) != GAMESTATUS_OK)
game_render(gamemem, renderer, t); goto quit;
SDL_RenderPresent(renderer); perf.update = SDL_GetPerformanceCounter();
perf.render = SDL_GetPerformanceCounter();
// Print performance analysis every 16 frames // Render frame
if ((frame & 15) == 0) { SDL_RenderClear(renderer);
const double evt = (perf.evt - perf.start) / perf.freq; game_render(gamemem, renderer, SDL_GetTicks64());
const double update = (perf.update - perf.evt) / perf.freq; SDL_RenderPresent(renderer);
const double render perf.render = SDL_GetPerformanceCounter();
= (perf.render - perf.update) / perf.freq;
const double total = (perf.render - perf.start) / perf.freq;
const double total_pc = (100 * total / (1000 * INTERVAL));
printf(
VT100_CLEAR VT100_CURSORTOPLEFT
"evt\t%10.3f μs\nupdate\t%10.3f μs\nrender\t"
"%10.3f μs\ntotal\t%10.3f μs (%05.2f%%)\n",
evt, update, render, total, total_pc);
}
// Increment frame counter and update time // Print performance analysis every 16 frames
++frame; if ((frame & 15) == 0) {
prevt = t; const double evt = (perf.evt - perf.start) / perf.freq;
const double update = (perf.update - perf.evt) / perf.freq;
const double render
= (perf.render - perf.update) / perf.freq;
const double total = (perf.render - perf.start) / perf.freq;
const double total_pc = (100 * total / (1000 * INTERVAL));
printf(
VT100_CLEAR VT100_CURSORTOPLEFT
"evt\t%10.3f μs\nupdate\t%10.3f μs\nrender\t"
"%10.3f μs\ntotal\t%10.3f μs (%05.2f%%)\n",
evt, update, render, total, total_pc);
} }
SDL_Delay(INTERVAL / 8); // Increment frame counter and wait until next interval
++frame;
const uint64_t elapsed = SDL_GetPerformanceCounter() - perf.start;
assert(elapsed < intervalperf);
SDL_Delay((1000 * (intervalperf - elapsed)) / perfhz);
} }
quit: quit: