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HLSL written SV_VertexID works different in opengl after automatic compile

Discussion in 'Shaders' started by segant, Jun 29, 2020.

  1. segant

    segant

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    May 3, 2017
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    196
    Shader is different from directx. I used hlsl in shader. I think unity converts it wrong.
     
    Last edited: Jun 29, 2020
    segant, Jun 29, 2020
    #1

  2. aleksandrk

    aleksandrk

    Unity Technologies

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    If you think shader compilation is incorrect, please submit a bug report.
     
    aleksandrk, Jun 30, 2020
    #2

  3. segant

    segant

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    Allright, I'll upload it today.
     
    segant, Jun 30, 2020
    #3
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  4. segant

    segant

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    @aleksandrk I have uploaded it but forgot to tell. May I take some of your time ? Case 1259743
     
    segant, Jul 7, 2020
    #4

  5. aleksandrk

    aleksandrk

    Unity Technologies

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    The bug will get processed by QA first, I'll take a look afterwards :)
     
    aleksandrk, Jul 7, 2020
    #5
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  6. aleksandrk

    aleksandrk

    Unity Technologies

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    @segant Hi! I finally managed to take a look at your bug report. This is caused by OpenGL and other APIs having different rules for selecting a provoking vertex (the vertex that defines the value for fragment shading when this value is not interpolated). For GL it's the last vertex, all other APIs use the first.
    You can just change your geometry shader to output the ID of the first vertex for all three vertices you output there (e.g. 
    o.vertexIdPassed=i[0].id;
    ).
     
    aleksandrk, Sep 22, 2020
    #6