[SDL] Flickering and division by zero in Windows

[Ryan C. Gordon]

>> I'm writing an SDL application but am having trouble with flickering. 
>> I tried all combinations of flags (SDL_SWSURFACE, SDL_HWSURFACE, 
>> SDL_DOUBLEBUF, SDL_NOFRAME, SDL_FULLSCREEN etc.) but with no luck.
>>
> What about this one, any thoughts?

Is it possible that you're drawing to one buffer and SDL_gfx is drawing 
to the other? Try removing SDL_DOUBLEBUF and see if it makes a difference.

Also, if you need to touch pixels directly, SDL_HWSURFACE is probably 
going to slow you down...that's meant to be a speed boost if you're just 
doing SDL_FillRect() and SDL_BlitSurface() and the hardware supports it, 
but if you have to access the framebuffer directly (like SDL_gfx 
probably does), you're probably taking a speed hit here as it has to 
keep locking and unlocking the surface.

--ryan.