Re: Scene antialiasing

[Al Riddoch <ajr@ecs.soton.ac.uk>]

On Wed, Oct 23, 2002 at 01:55:43AM -0200, Miguel A. Osorio wrote:
> Hey people,
> 
> 
> 
> 	I'm having a strange problem doing scene antialiasing using OpenGL
> (with SDL). Thing is, my code works just fine without the antialiasing
> code. Then, I add the code to use the accumulation buffer, something
> like:
> 
> // Main loop
> while(true) {
> 
>   // Get input //
>   ...
> 
>   // Update scene //
>   ...
> 
>   // Render scene
>   for(i = 0; i < samples; ++i) {
> 
>     // Clear depth buffer (my skybox "clears" the color buffer)
>     ...
> 
>     // Jitter projection matrix
>     jitter_projection();
> 
>     if(!i)
>       glAccum(GL_LOAD, 1.0 / samples);
> 
>     else
>       glAccum(GL_ACCUM, 1.0 / samples);
> 
>     // Render stuff //
>     ...
> 
>     }
> 
>   glAccum(GL_RETURN, 1.0);
>   SDL_GL_SwapBuffers();
> 
>   }
> 
> 	The problem I'm having is that my frame rate drops from an average of
> 100 FPS to *1.2* FPS! This problem arises both on Linux and Windows2000,
> and I tested this on my computer, using an ATI Rage Fury PRO 128, and on
> a friend's machine, using an GeForce4 MX400. Any clues on this one?
> 

I have had similar experiences with trying to use the accumulation buffer.
It seems that it is very slow on most hardware I have available.

Al

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