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Thread: Fixing backprojection

  1. #1
    Junior Member Newbie
    Join Date
    Oct 2011
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    7

    Fixing backprojection

    Well this'll be an old timer question, I'm doing this on fixed function because the base I'm working on is quite old, and I don't want to recode almost all of it.

    I'm trying to add shadow mapping to my projective light, it works fine on the depth map side, but I get the well expected back projection problem, and I'm having trouble solving that. I know that my blending and all other texture units are set up fine, I'm just having trouble with the 1x2 pixel 1D clipper texture, that's explained here:
    http://www.cbloom.com/3d/techdocs/sh...p_advanced.txt

    My problem is, I have no clue how I should set projection up for the clipper texture. I'm not very good when it comes to any kind of projection or matrix work. I was wondering if anybody could help me on this matter. I'm totally lost here. From what I understand I need the Z coord to be mapped to the S texture coordinate, but any of my attempts didn't work. Does anyone have an example of this working, at all?

    Thanks.

  2. #2
    Senior Member OpenGL Guru Dark Photon's Avatar
    Join Date
    Oct 2004
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    Druidia
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    2,894

    Re: Fixing backprojection

    You might check out this thread. Particularly the last few posts:

    * GLSL - cube shadows - projecting (opengl.org thread, 3/31/11)

  3. #3
    Junior Member Newbie
    Join Date
    Oct 2011
    Posts
    7

    Re: Fixing backprojection

    This problem was actually "fixed", it wasn't the problem I had haha. Thanks for replying though, the problem was something else that I had gotten through.

    The real problems are being discussed in the "Shadow mapping problem" thread.

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