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Thread: Dependent texture reads

  1. #1
    Senior Member OpenGL Guru Humus's Avatar
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    Dependent texture reads

    I'd like to see dependent texture reads implemented in hw and accessible from OpenGL.
    I don't know if anything like this is planned but Carmack has talked a little about it. Like you use (red, green) from the previous texture pass as texture coordinates in the next texture pass, or (red,green,blue) for 3d textures. This way you could implement almost any function you'd like. Sure, it'll be a little slow (very non-linear texture memory reads), but very useful.

  2. #2
    Junior Member Regular Contributor
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    Re: Dependent texture reads

    Originally posted by Humus:
    I'd like to see dependent texture reads implemented in hw and accessible from OpenGL.
    I don't know if anything like this is planned but Carmack has talked a little about it. Like you use (red, green) from the previous texture pass as texture coordinates in the next texture pass, or (red,green,blue) for 3d textures. This way you could implement almost any function you'd like. Sure, it'll be a little slow (very non-linear texture memory reads), but very useful.
    I was under the impression that Matrox' Environment-Mapped Bump-Mapping used DTR, can anybody confirm that?

    Furthermore the rumors about NV20 include DTR, so we'll just have to wait a little and see.

    DTR really is a very powerful tool, and I'd expect it to appear pretty soon.

  3. #3
    Senior Member OpenGL Guru Humus's Avatar
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    Re: Dependent texture reads

    EMBM is a sort of special case of Dependent Texture Reads. You get texture coords for the next pass from the bumpmap. But I'd like to see the general solution in hw.

  4. #4
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    Re: Dependent texture reads

    Where to get any rumours about nv20?
    - Michael Steinberg

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