View Full Version : Fast shadow casting
11-23-2001, 12:48 AM
Is there anyone who can tell me how can i make fast shadows without stencil buffer. Because i'm working on an old computer (PMMX 233MHz with RIVA 128ZX(Viper V330)) the stencil buffer algorithm is a little slow on shadows and reflections. I had read a way of making the illusion of shadow with a "shadowMatrix" in OpenGL Super Bible but the code specific for flat surfaces. If there is a way of getting the same result as stencil buffer without stencil buffer please inform me.
yes, but the shadow matrix is used for the stencil buffer.
If you have a directional light as far away light (sun), you could just make projection onto your ground.
11-23-2001, 05:48 AM
The best way to do (dynamic) shadows on your system would probably be projected shadow textures, i.e. Render the shadow caster from the vew of the light in all black, and then render the receiver(s) with that texture blended over them. It isn't as correct as stencil shadows and you don't get any self shadowing, but it looks pretty good.
11-26-2001, 12:08 AM
The thought about shadow textures had crossed my mind but i can't figure out how to project the shadow texture on the ground. If it needs multitexturing, i think the idea is not good for my card. It doesn't support multitexturing and i can't think of a way to project the shadow texture ON the ground texture.
If i haven't understood what you are saying please send a message and be more specific.
And forgive my terrible English.
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