Re: [Pysdl-devel] A little trivia

[Mark B. <mb...@0x...>]

On Wed, 19 Apr 2000, "David Clark wrote:
> I was doing a little video testing, profiling large numbers of blits
> to the framebuffer, and noticed a few interesting facts...
> 
> A blit of a 7k bmp from one SWSURFACE to another took less than a
> millisecond. Woohoo!
> 
> update_rect((0,0,0,0)) is expensive, but not prohibitivly so. Updating
> a 640 x 480 surface all at once only took about 20 times longer than
> updating a 64 x 48 rectangle, in spite of the fact that the surface is
> 100 times bigger than the rectangle.

Well this is good. SDL is fairly speedy, all things considered, and I've heard
good things about the V3 X server.
It's my hope we won't get too much in the way, with PySDL.

 
> Blitting a png takes about 50% longer than an identical bmp. (Of
> course, the png is compressed to 5% of the bmp's size :)

Are you including the loading time? PNGs are decompressed on load, like all
other image types, so after the load, it should blit at the same rate as a BMP.

 
> Out of curiousity, is anyone able to create a HWSURFACE? I'm simply
> unable, using the setup below. I realize this is kind of off topic, so
> feel free to ignore this question :)

SDL doesn't allow for hardware surfaces in X. The only exception I can think
of, is DGA, and only the main surface is in video memory.