[SDL] Windows XP speed problems

[Martin Konrad]

> Martin Konrad wrote:
> 
> > t0 = SDL_GetTicks();
> > SDL_BlitSurface(...)...
> > t1 = SDL_GetTicks();
> 
> GetTicks precision is about +-10msec, so using it for a benchmark is not 
> correct for calls fast as SDL_BlitSurface!
> 
> Try something like:
> 
> t0 = SDL_GetTicks();
> for(i=0; i<100; i++ )
> 	SDL_BlitSurface(...)...
> t1 = SDL_GetTicks();
> 
> t2 = SDL_GetTicks();
> for(i=0; i<100; i++ )
> 	SDL_Flip...)
> t3 = SDL_GetTicks();
> 
> In this way you SHOULD be able to understand in a more reliable way 
> where your time is lost (and probably it is in SDL_Flip for the hw 
> refresh sync).

The precision is not the problem.
For 1/60 second I get a value between 16 and 17, and it's definately lost
with the first blit or fill. So, I get either 0 or 16/17.

Testing the time with 100x SDL_Flip() and nothing else doesn't help. The
time is only lost when there are about 20 or more blits in the main loop with
both blits and SDL_Flip().

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