[SDL] Re: sdl GL with stencil buffer

Oliver Batchelor shadows at ihug.co.nz
Thu Apr 27 00:41:23 PDT 2000

Would a two passes algorithm be twice as slow ?
I am trying to make this quite fast for use in flying over a
landscape type thing ... 
I have display lists for all the objects
and to do that I would need to stop using them...

To do the shadow and reflection I would still need stencil buffer or
it would go there no matter what even if nothing was there wouldnt it

so basically it would be better to do a double rendering rather than
use the gl multi texture ARB thing's.

Oliver Batchelor

On Thu, 27 Apr 2000, you wrote:
> Oliver Batchelor wrote:
> > 
> > Damn that means I cant use shadows/reflection  or anything !! ugg ! I
> > was looking foward to doing that.
> > 
> > Voodoo banshee cards do do multi texture dont  they ??  I tried that
> > out and it went awful slow ....   if they dont then how does quake3
> > do its multi texture on the voodoo ?
> > 
>    You can use projected texture to do this. Using a two passes
> algorithm.
>  First pass, draw your scene
>  Calculate shadow and reflexion texture 
>  Second pass, render (over the first) scene with shadow & reflection
> textures, blending enabled.
>   You'll find source code for this in the mesa distrib and the glut
> distrib.
>                        Franck.

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