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Thread: [NV305.67] compute shader texture sampling reads zero

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  1. #1
    Junior Member Newbie
    Join Date
    Feb 2012
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    Germany
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    [NV305.67 & NV306.63] compute shader texture sampling reads zero

    Hi there,

    I stumbled upon this bug(?) a couple of times by now:
    1. create a texture, make it immutable
    2. upload data from cpu to the texture
    3. bind texture to some texture unit (not image unit - actually, I haven't tested that)
    4. run compute shader
    -> read some data from that texture
    Result: read is always 0.
    If I use the same texture in some program in an old compute shader fashion (quad; vertex/fragment shader), it works.
    If - between step 2 and 4 - the texture is read by some fragment shader, the compute program IS able to read data from the texture.

    Some more hints about my application (although it shouldn't matter)
    - I have a small OpenGL library, which wraps most of the OpenGL "objects"... so no code here.
    - I use DSA (I just like OOP thinking)
    - Am I correct that the 305.67 is still the only driver supporting OpenGL 4.3? I tried the others and (although the nvidia page partially says differently) they do not give me an 4.3 context (card: 560ti).

    Best

    Update:
    I just tried the new driver 306.63 and it behaves the same .
    Furthermore I ran into an example, where even the trick with first using the texture in a fragment shader does not help, the compute shader always reads 0. I tried the "same" shader as a fragment shader with framebuffers etc. and it there it works as expected.
    Last edited by Ambator; 09-26-2012 at 05:52 AM.

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