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Thread: fglrx 13.20.5 OGL 4.3 CORE: glDrawElements causes Segmentation fault

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  1. #1
    Junior Member Newbie
    Join Date
    Oct 2013
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    7

    fglrx 13.20.5 OGL 4.3 CORE: glDrawElements causes Segmentation fault

    Using glDrawElements with the draw mode GL_PATCHES for a shader without tessellation-evaluation or geometry shader causes a SEGV:

    Code :
    #0  0x00007f1325cb4d7d in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so
    #1  0x00007f1325d1aaa2 in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so
    #2  0x00007f1325cf90e0 in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so
    #3  0x00007f1325cf9533 in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so
    #4  0x00007f1324dd127b in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so
    #5  0x00007f1324ffffc4 in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so
    #6  0x00007f132500024b in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so
    #7  0x00007f13255940ac in ?? () from /usr/lib/fglrx/dri/fglrx_dri.so

    Example (with drawMode = GL_PATCHES):
    Code :
    glDrawElementsInstanced(drawMode, patcheCount * patchSize, GL_UNSIGNED_INT, 0, instances);

  2. #2
    Senior Member OpenGL Pro
    Join Date
    Jan 2007
    Posts
    1,201
    Have you an attrib array enabled but no pointer set for it?

    Alternatively - what is "instances" in your code? A syster-memory pointer? An offset into a buffer? Have you got things set up correctly for whichever it is?

  3. #3
    Junior Member Newbie
    Join Date
    Oct 2013
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    7
    Quote Originally Posted by mhagain View Post
    Have you an attrib array enabled but no pointer set for it?
    I checked my log:

    Code :
    [YATessellationModel] Patches: 14280
    [YATessellationModel] attribVertexLocation 0 enabled

    Alternatively - what is "instances" in your code? A syster-memory pointer? An offset into a buffer? Have you got things set up correctly for whichever it is?
    Instances is defined as:
    Code :
        uint instances;

    I accidentally activated my old shadow-map rendering, where several default shader programs are used. These are simple depth map renderer without GS or TS stages. In these cases the fglrx driver crashes with a buffer overrun. In my opinion this is an indication for an unhanded exception and at least annoying.

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