54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
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internal b32
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W32_TimerInit(W32_Timer *timer)
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{
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b32 result = 0;
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if(QueryPerformanceFrequency(&timer->counts_per_second))
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{
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result = 1;
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}
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timer->sleep_is_granular = (timeBeginPeriod(1) == TIMERR_NOERROR);
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return result;
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}
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internal void
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W32_TimerBeginFrame(W32_Timer *timer)
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{
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QueryPerformanceCounter(&timer->begin_frame);
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}
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internal void
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W32_TimerEndFrame(W32_Timer *timer, f64 milliseconds_per_frame)
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{
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LARGE_INTEGER end_frame;
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QueryPerformanceCounter(&end_frame);
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f64 desired_seconds_per_frame = (milliseconds_per_frame / 1000.0);
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i64 elapsed_counts = end_frame.QuadPart - timer->begin_frame.QuadPart;
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i64 desired_counts = (i64)(desired_seconds_per_frame * timer->counts_per_second.QuadPart);
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i64 counts_to_wait = desired_counts - elapsed_counts;
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LARGE_INTEGER start_wait;
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LARGE_INTEGER end_wait;
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QueryPerformanceCounter(&start_wait);
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while(counts_to_wait > 0)
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{
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if(timer->sleep_is_granular)
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{
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DWORD milliseconds_to_sleep = (DWORD)(1000.0 * ((f64)(counts_to_wait) / timer->counts_per_second.QuadPart));
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if(milliseconds_to_sleep > 0)
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{
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Sleep(milliseconds_to_sleep);
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}
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}
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QueryPerformanceCounter(&end_wait);
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counts_to_wait -= end_wait.QuadPart - start_wait.QuadPart;
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start_wait = end_wait;
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}
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}
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