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Thread: vs texelFetch

  1. #1
    Junior Member Newbie
    Join Date
    Jun 2012

    vs texelFetch


    I'm having trouble making sense of an issue I have.
    I'm trying to store vertex positions in a texture and pass indices to the shader in the vbo.

    Now texelFetch returns complete garbage, although the texture seems to be okay (here's what apitrace is showing)

    this is how i try to get the position from the texture in the vertex shader:
    Code :
    void main()
        indOut.m = indIn[0];
        indOut.n1 = indIn[1];
        indOut.n2 = indIn[2];
        indOut.debugVert = vec4(floor(indOut.m%11)*1.0f/11, 1.0f-floor(indOut.m%11)*1.0f/11, 0.0f, 1.0f);
        ivec2 indices = ivec2(floor(indOut.m % 11), floor(indOut.m / 11));
        vec4 position = texelFetch(hvt, indices, 0);
        indOut.debugVert += position*0.01f;
        if(position.length() == 4.0f)
            indOut.debugVert += vec4(0.0,0.0,1.0,0.0);
        gl_Position = position;
    the debugVert is just a color I use to identify issues in the Vertex Shader and to ensure that the texture changes the color (else it gets optimized out). Only the m component of indOut is used, although three indices are passed per vertex. strangely the if statement is always true.

    Here's what's inside the texture

    I have no Idea what I'm doing wrong :/

  2. #2
    Junior Member Newbie
    Join Date
    Jun 2012
    nevermind, figured it out - regular textures aren't really good at saving arbitrary float data. I'm using a buffer texture now. Also - position.length() should have been length(position)

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