From fa25646f8092dc6fe38ecf6d1293e9123a2f3fd1 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Sun, 15 Aug 2010 16:56:07 +0000
Subject: [PATCH] Improve the timer accuracy even more.
---
src/timer.cpp | 38 +++++++++++++++++---------------------
1 file changed, 17 insertions(+), 21 deletions(-)
diff --git a/src/timer.cpp b/src/timer.cpp
index 4d1c1f82..9037cf54 100644
--- a/src/timer.cpp
+++ b/src/timer.cpp
@@ -48,42 +48,40 @@ private:
#endif
}
- float GetSeconds(bool update)
+ float GetOrWait(float seconds)
{
- float ret;
+ float ret, delta_time;
#if defined __linux__
struct timeval tv;
gettimeofday(&tv, NULL);
ret = 1e-6f * (tv.tv_usec - tv0.tv_usec) + (tv.tv_sec - tv0.tv_sec);
- if (update)
+ delta_time = seconds - ret;
+ if (!seconds)
tv0 = tv;
+ else if (delta_time > 0.0f)
+ usleep((int)(delta_time * 1e6f));
#elif defined _WIN32
LARGE_INTEGER cycles;
QueryPerformanceCounter(&cycles);
ret = seconds_per_cycle * (cycles.QuadPart - cycles0.QuadPart);
- if (update)
+ delta_time = seconds - ret;
+ if (!seconds)
cycles0 = cycles;
+ else if (delta_time > 5e-4f) // FIXME: use native Win32 stuff
+ SDL_Delay((int)(delta_time * 1e3f + 0.5f));
#else
+ /* The crappy SDL fallback */
Uint32 ticks = SDL_GetTicks();
ret = 1e-3f * (ticks - ticks0);
- if (update)
+ delta_time = seconds - ret;
+ if (!seconds)
ticks0 = ticks;
+ else if (delta_time > 5e-4f)
+ SDL_Delay((int)(delta_time * 1e3f + 0.5f));
#endif
return ret;
}
- void WaitSeconds(float seconds)
- {
-#if defined __linux__
- usleep((int)(seconds * 1000000.0f));
-#elif defined _WIN32
- /* FIXME: use native Win32 stuff */
- SDL_Delay((int)(seconds * 1000.0f + 0.5f));
-#else
- SDL_Delay((int)(seconds * 1000.0f + 0.5f));
-#endif
- }
-
#if defined __linux__
struct timeval tv0;
#elif defined _WIN32
@@ -110,13 +108,11 @@ Timer::~Timer()
float Timer::GetSeconds()
{
- return data->GetSeconds(true);
+ return data->GetOrWait(0.0f);
}
void Timer::WaitSeconds(float seconds)
{
- float sleep = seconds - data->GetSeconds(false);
- if (sleep > 1e-4f)
- data->WaitSeconds(sleep);
+ (void)data->GetOrWait(seconds);
}