SDL_UpdateRect: why is it so slow?

SDL Development
1

hi,

I’m pretty new to SDL and I have a problem with speed concerning all SDL
applications. I wrote a simple test program to measure the speed of
SDL_UpdateRect(screen, 0, 0, 0, 0) and it took awful 30 ms at a resolution
of 1024x768 with 16 bpp. This leads to about 33 frames per second with a
blank screen!!! I have a AMD Athlon 800 MHz with 128 MB ram and a voodoo 5
graphics board, SDL-1.2.0, Mandrake 8.0, 2.4.3 kernel. Normally I get about
<100 fps with this computer (in games for example). Did anyone have the
same problem and was able to fix it?

Thanks in advance!
greetings
X3N3X

2

hi,

I’m pretty new to SDL and I have a problem with speed concerning all SDL
applications. I wrote a simple test program to measure the speed of
SDL_UpdateRect(screen, 0, 0, 0, 0) and it took awful 30 ms at a resolution
of 1024x768 with 16 bpp. This leads to about 33 frames per second with a
blank screen!!! I have a AMD Athlon 800 MHz with 128 MB ram and a voodoo 5
graphics board, SDL-1.2.0, Mandrake 8.0, 2.4.3 kernel. Normally I get about
<100 fps with this computer (in games for example). Did anyone have the
same problem and was able to fix it?

Thanks in advance!
greetings
X3N3X

3

Look for the recent thread “Scrolling background” (posted 2 days ago)
for suggestions and tips. You can find the mailing list archive from
www.libsdl.org or by searching for “SDL” with Google…–

Olivier A. Dagenais - Software Architect and Developer

“X3N3X” wrote in message
news:9ga5v7$td0$1 at ftp.lokigames.com…

hi,

I’m pretty new to SDL and I have a problem with speed concerning all
SDL
applications. I wrote a simple test program to measure the speed of
SDL_UpdateRect(screen, 0, 0, 0, 0) and it took awful 30 ms at a
resolution
of 1024x768 with 16 bpp. This leads to about 33 frames per second
with a
blank screen!!! I have a AMD Athlon 800 MHz with 128 MB ram and a
voodoo 5
graphics board, SDL-1.2.0, Mandrake 8.0, 2.4.3 kernel. Normally I
get about
<100 fps with this computer (in games for example). Did anyone have
the
same problem and was able to fix it?

Thanks in advance!
greetings
X3N3X

4

Note that this is mere software rendering we’re talking about here… Unless
you are using the OpenGL extensions, you aren’t using your voodoo 5’s hardware
acceleration.

Blitting surfaces that big without hardware acceleration is inherently slow.

I think there has been some discussions on this list recently about this very
thing (I think in respect to scrolling). I’d recommend going and looking
through them.On Thu, 14 Jun 2001, you wrote:

hi,

I’m pretty new to SDL and I have a problem with speed concerning all SDL
applications. I wrote a simple test program to measure the speed of
SDL_UpdateRect(screen, 0, 0, 0, 0) and it took awful 30 ms at a resolution
of 1024x768 with 16 bpp. This leads to about 33 frames per second with a
blank screen!!! I have a AMD Athlon 800 MHz with 128 MB ram and a voodoo 5
graphics board, SDL-1.2.0, Mandrake 8.0, 2.4.3 kernel. Normally I get about
<100 fps with this computer (in games for example). Did anyone have the
same problem and was able to fix it?

–
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