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View Full Version : What is multitexturing?



Questions Burner
12-12-2001, 08:32 PM
Actually what is multitexturing, what effect can it create? An example and short description will be great. Thanks.

Platinum
12-12-2001, 09:21 PM
When your card has more than one texturing unit, each unit can work separately. You can make effects achievable by multipass rendering, but in much shorter time.

For example all Quake games (and many other 3D FPS) use multitexturing for "lightmaps". It means that there are two textures for any wall. One is a texture such as bricks and the other texture has only information about the light. It means that if the lightmap is black, the wall is rendered black. If the lightmap is white, the wall is rendered with full intensity brick.

Hope it helps
Platinum

Questions Burner
12-13-2001, 05:34 AM
Wait a minute. Are you mean switch to different texture?

Spiral Man
12-13-2001, 09:36 AM
multitexturing means you can apply more than one texture to each primitive.

its often use to have lightmaps. one texture is what people comonly think of the texture as, and the other texture is a grayscale image that is a precalculation of the lighting on each polygon. its faster to use that instead of actually calculating the lighting each frame. but that isnt the only thing it can be used for...

dorbie
12-13-2001, 01:58 PM
Texture is a fundamental rendering element in OpenGL, most effects you see include the use of texture in some way. The more textures you can apply simultaneously, and the more ways you can apply and mix them the more effects are possible. Multitexture encompasses almost any effect you can think of, but the term really only means simultaneously applying more than one texture to a graphics primitive while you draw it. At first you could only do a few basic things with multitexture, like the early light effects in QuakeII, now with newer hardware you can do incredible things simply because of the way hardware lets you flexibly combine the textures.
http://www.bigpanda.com/trinity/article1.html
http://www.berkelium.com/OpenGL/GDC99/multitexture.html

[This message has been edited by dorbie (edited 12-13-2001).]