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View Full Version : texture vs. register combiners



quynh-clone
07-22-2003, 06:13 AM
Hello,

What are the advantages or disadvantages of using NV_register_combiners over ARB_texture_env_combine? What are the situations where one would decide to use one over the other? Is it that register combiners allow you to do the combining before it is bound to a texture unit? I'm confused about which to use. Thanks.
- Q.

jra101
07-22-2003, 07:41 AM
Register combiners allow you to do more operations per pixel as well as do basic if statements (using the mux).

[This message has been edited by jra101 (edited 07-22-2003).]

marcus256
07-23-2003, 05:31 AM
And of course, NV_xyz only works on NVIDIA hardware. Otherwise I think it's more general than texture environments (though in most cases you can do the same thing with both).

Jan
07-23-2003, 11:07 AM
I think stuff like bumpmapping is not possible with texture combiners.
Well, at least i never tried it (and i am quite sure the reason was, that itīs not possible).

However, if you understand the one, than you also will understand the other extension. And then you will know, what is possible with each one.

Jan.

Mazy
07-23-2003, 11:27 AM
Env_combine and dot3 extension allows bumpmapping with just opengl1.4 or any open with those extensions.

dorbie
07-23-2003, 11:41 AM
Incase there's any lingering doubt here is a detailed tutorial on doing this:
http://users.ox.ac.uk/~univ1234/tutorials/simplebump/simplebump.htm

Obli
07-23-2003, 11:42 AM
Originally posted by Jan2000:
I think stuff like bumpmapping is not possible with texture combiners...
Uh-oh, I always though reg combs were **designed** to do bumpmapping.

gator
07-23-2003, 01:28 PM
Aren't OpenGL "combiners" equivalent to DirectX texture stage operations?

It gives you greater control how textures are blended at each texture unit?

dorbie
07-26-2003, 03:58 PM
It is possible, there is code, it has been posted, move along there's nothing to see.