[SDL] Re: sdl GL with stencil buffer
fguillaud at mailivs.ivs.fr
Thu Apr 27 04:48:41 PDT 2000
Oliver Batchelor wrote:
> 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...
If display list are correctly managed by the driver (cached), you can
second pass at virtually no cost. The algorithm would be :
1) Calculate shadow texture
2) first Pass : render scene
3) second pass : render scene with projected shadow texture
However, if you first rendering is fill rate limited, the second
pass may have a non negligeable cost.
> 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.
I'm surprised that Voodoo 3 doesn't support multitexture.
Did you try to run the Mesa multi-texture demo ? Which GL driver are
you using ?
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