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Thread: Can I use the costomized rasterization algorithm by GLSL?

  1. #1
    Junior Member Newbie
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    Feb 2013
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    Question Can I use the costomized rasterization algorithm by GLSL?

    Hi.

    I'm not good at English well, so please understand me.

    I am beginer, study OpenGL for studying graphics performances.
    OpenGL Architecture has the Vertex Processor and Fragment Processor. So, we can program in the two cases.
    Then, I would like to use the customized rasterization algorithm. But, I don't know how to do it.

    Just assume that have some rasterization algorithms.

  2. #2
    Senior Member OpenGL Guru
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    May 2009
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    You can, but only by co-opting a fragment shader for that purpose. Basically, you draw a screen-space polygon over the area where the rasterized primitive will appear, then use `discard` and other fragment shader mechanisms to "rasterize" your actual primitive.

    But in general, it'll probably be faster to just render a triangular mesh that approximates your surface.

  3. #3
    Junior Member Newbie
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    Feb 2013
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    Thanks a lot, Reinheart!
    You give me the answer

  4. #4
    Senior Member OpenGL Pro
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    Just out of curiosity, why would you want to use your own rasterization algorithm? Do you have high-performance needs or simply want something rendered on the screen? Before perverting fragment shaders in that fashion, wouldn't a CPU implementation do as well?

  5. #5
    Intern Newbie
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    Jan 2013
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    I wonder why you would want your own rasterization . I do think it would be cool to do ray tracing with 'real' ambient occlusion algorithms on the fragment shaders, by defining your inworld objects using mathematical surfaces etc.... I wonder what kind of permormance you could get... with a limited amount of objects maybe even real time?

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