[SDL] Windows XP speed problems
kylotan at kylotan.eidosnet.co.uk
Wed Nov 13 12:49:01 PST 2002
Martin Konrad wrote:
> The strange thing is that when I only
> use about 5 blits, everything is fine, ie. the blits take almost no
> time at all, and SDL_Flip() is waiting about 1/60 second for sync.
> But when I do about 20 blits, the first blit takes 1/60 second, the
> other blits and SDL_Flip() take almost no time. When I use fills
> instead of blits, the same problem happens.
Maybe you're reaching a driver or hardware-specific limit on the number
of blits or operations that can be queued for asynchronous execution?
Have you tried doing 40 blits, or 60, to see if the performance degrades
further? It might be a one-time penalty that you pay for more than N
blits that won't prove significant when a lot more blits are being done.
The weird part of what you've said is that you've implied that the 1st
blit can take longer in the 20-blit version even before the code 'knows'
that there are more than 5 blits in total. If it only applies to the 2nd
frame and so on, it would make more sense.
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