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Thread: constructing triangle faces from an unindexed VBO

  1. #1
    Intern Contributor
    Join Date
    Oct 2012

    constructing triangle faces from an unindexed VBO


    I need to generate trianlges from a VBO that is filled with normal,position and colour from EmitVertex() calls. Since no indexing ( such as glBindBuffer(GL_ELEMENT_ARRAY_BUFFER_ARB,eb); /* index data */ ) was associated with the VBO in question and although i know that the EmitVertex() was done traingle by triangle in a shader , I feel it's not safe to say that the traingle faces come in consecutive tuples from the VBO since shader launches are asynchronous.

    Is there a way to construct triangle faces from a VBO that contains position,normal but has no indexing associated with it?


  2. #2
    Advanced Member Frequent Contributor
    Join Date
    Apr 2010
    But that would render transform feedback nearly useless, no? I haven't checked, but it seems to me the spec has to make some guarantee between the order you feed vertices into the pipeline and the the order they come out after all the vertex/geometry processing stages - just like the way that primitives have to rasterized in the order they are submitted, otherwise things like sorting by depth to get correct blending could not work.

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