[SDL] Frame rate

[pvwradtke at sympatico.ca]

> screen -> 640x480x32
> the first one is the screen (640x480x32) and the second, virtual screen, 
> is 1280x1024x32
...
> GNU/Linux or Windows (in GNU/Linux is worse than Windows does)
> CPU: 2.8Ghz P4, ATI Mobility Radeon 9000 IGP 32 Mb, 512MB DDR

   Are you by chance using a laptop computer? (your video card hints me that) Usually laptop computers works with fixed resolution, which causes the driver to resize the image to show it correctly - usually you notice that as the image not being as sharp as if it was rendered in the usual desktop resolution. This may be one source of problem, as the resizing requires some time to process and may reduce you frame rate. 

   I use an G3 iBook with a Radeon 7500 Mobility, with resolution fixed at 1024x768. My game was running at about 30fps when using SDL surfaces thanks to the image resizing done by the system. Changing my renderer to OpenGL made all the difference in the world, as the game can run as fast as 300fps on the same machine if I don't keep track of the vertical retrace (sad that it's a TFT screen, which sucks for 2D scrolling games).

   There are other issues that other people already discussed, but this one is something nobody mentioned so far, so it's worth a look :).

   Best regards,

   Paulo