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Type: Posts; User: fred_em

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  1. MemoryBarrier doesn't work on AMD hardware

    Hi,

    I have a fragment shader that does some heavy work using image load/store operations. memoryBarrier() is called inside the shader (and inbetween shader executions) to make sure the...
  2. Replies
    2
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    454

    Nevermind I figured it out....

    Nevermind I figured it out. glGetIntegerv(GL_MAX_TEXTURE_BUFFER_SIZE, &i); gives me 134M texels, that is, 512MB. It is weird glBufferData does not raise an error.
  3. Replies
    2
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    454

    512MB buffer size limitation and GLSL

    Hi,

    It seems there is a limitation in terms of buffer memory size with the nVidia drivers, in that although I can successfully allocate more than 512MB for a buffer object, running my shaders will...
  4. I figured it out. As things weren't working, I...

    I figured it out. As things weren't working, I switched to a smaller prototype application that we are using. I changed the value of layered to GL_TRUE in this prototype, and things were still not...
  5. Hi Dan, Yes it is a forum post typo, I'm doing...

    Hi Dan,

    Yes it is a forum post typo, I'm doing result = glGetUniformLocationARB(prog, "tex"); then glUniform1iARB(result, SLOT);
    result is valid and no GL error.
  6. Hi Ilian, I did try layered=GL_TRUE already,...

    Hi Ilian,

    I did try layered=GL_TRUE already, and it doesn't work. All read values are 0.0f.
    Also MIN and MAG FILTER are at GL_NEAREST.

    Tried to generate mipmaps - same result. Tried setting...
  7. Can't make imageLoad(image3D) to work (texture(sampler3D) or imageLoad(image2D) OK)

    Hi,

    I am trying to make my shader work with a read-only image3D uniform.

    This is the way I create my image:


    // Creation
    glGenTextures(1, &tex);
    glBindTexture(GL_TEXTURE_3D, tex);
  8. Coherent GLSL 420 imageBuffer access in single-stage, single-pass scenario

    Sorry if this question has been asked before, but I find lots of confusing information in the forums. Sometimes this information is (I believe) contradicting the specification of OpenGL.

    When...
  9. Thanks for your reply. This makes sense. One...

    Thanks for your reply. This makes sense.


    One last question, if my shader has to perform multiple atomicMin's at the same memory location, but without ever having the need to read any old value...
  10. imageAtomicMin(), memoryBarrier() and coherent uniform qualifier

    Hi,

    I have a shader that pokes into a framebuffer-sized image (uimage2D) when rendering fragments.
    Eg. everytime a fragment shader invocation is run, the following happens:


    uniform uimage2D...
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    1,209

    Kepler GK110 - using atomicMin64 from GLSL?

    Hi,

    According to the following document (*), GK110 GPUs (eg. GTX 780) offer atomicMin/Max/And/Or/Xor operations on 64-bit unsigned integers.

    How can I access this functionality through GLSL? It...
  12. Unable to attach separate stencil buffer to FBO (packed depth+stencil is fine)

    Hi,

    I can use a packed depth stencil with my FBO just fine using the following code (color buffer construction code omitted):


    glBindTexture(target = GL_TEXTURE_2D, texture = 17)...
  13. It seems early stencil cull is completely...

    It seems early stencil cull is completely disabled as soon as discard is being used in the shader.
    I don't understand why, as the stencil test should be done before the depth test and rasterization....
  14. Can't manage to get early stencil culling to work...

    Can't manage to get early stencil culling to work :(

    From what I can see, nVidia has a patent on stencil-based culling, but how I can enable it?
    http://www.freepatentsonline.com/7184040.html

    I...
  15. Early fragment culling using the stencil buffe

    Hi,

    I have a fragment shader that writes to the depth buffer (gl_FragDepth) and does some pretty expensive work. This shader only needs to run on a few screen pixels (maybe a thousand or more)....
  16. Replies
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    2,744

    This makes sense. I tried with a regular...

    This makes sense.


    I tried with a regular GL_RGBA pixel format and get the following:

    1085

    So it's better, but it isn't perfect. I verified the values in the depth buffer and the missing...
  17. Replies
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    2,744

    Ouch. I believe you, but I am just very...

    Ouch. I believe you, but I am just very surprised. I thought that, say, one-pixel sized triangles would always get rendered as a single fragment, but according to what you say, very often, they won't...
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    2,744

    Have a look at the following image: 1084 ...

    When a group of triangles cover a fragment, the fragment's centre will lie within one of the triangles, and thus be rendered. OpenGL's rasterisation rules require that, in this situation, the...
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    2,744

    [/LIST] Does this mean most fragments don't...

    [/LIST]
    Does this mean most fragments don't actually get rendered in my situation?
    This rule makes sense but sounds a bit odd to me. Afterall, fragments at triangle endpoints usually do not lie in...
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    2,744

    This is what I am surprised with. And I do render...

    This is what I am surprised with. And I do render every single fragment (gl_FragColor = vec4(1,0,0,1)).


    I don't have antialiasing enabled.
  21. Replies
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    2,744

    Unexpected GPU triangle rasterization output

    Hi,

    I'm trying to render the geometry that is shown in the following screenshot (wireframe mode):

    1081

    This geometry is issued from dynamic tessellation, with fixed tessellation factors. As...
  22. Very weird spec... Also, in the code above...

    Very weird spec...

    Also, in the code above with the teapot, does it mean the driver doesn't do any form of Early-Z test when I'm not using layout(early_fragment_tests)?
    What about Early-Z/Hyper-Z...
  23. early_fragment_tests doesn't work with discard,...

    early_fragment_tests doesn't work with discard, period.

    With early_fragment_tests disabled:

    1061

    And now with early_fragment_tests enabled:

    1062
  24. Given that all threads always branch the same...

    Given that all threads always branch the same way, how come the GPU tries to execute both branches?

    You know what... don't feel obliged to answer here ;) I am on the brink of drawing the...
  25. Same result with the latest 320.18 drivers. ...

    Same result with the latest 320.18 drivers.

    I'm using FBO attachments, COLOR0 + DEPTH. Surely early_fragment_tests works correctly with these in place, I don't see any reason why it wouldn't?
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