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Type: Posts; User: Nicolas Lelong

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  1. Replies

    Thanks for this !! I was about to write yet...

    Thanks for this !!

    I was about to write yet another parser for gles headers, I'm happy not to have to :)
  2. Re: Bad scope in ConvertLocalReferences()

    I also saw this as a driver bug in 2007/2008, at that time, a workaround was possible :

    Don't know if the problem is now...
  3. Re: Creating vertice and index arrays for VBO

    I believe your problem is mostly related to the complexity of the algorithm you're using.

    If for every vertex you do a lookup in an array, you're doing about N*N lookups (N is the number of...
  4. Re: Asynchronous transfer between CPU and GPU

    For the sake of completeness, the answer is hardware dependent : NVidia advertises that Quadro hardware can do some actual parallel transfers while rendering is performing. See :...
  5. Replies

    Re: texture atlas , adapt UV

    Sure you can could this way, this is called 'texture baking'.

    Drawing the texture in the framebuffer is the easy part, what's more difficult is to create a set of UV coordinates to allow to do so....
  6. Replies

    Re: texture atlas , adapt UV

    You're welcome !

    For more involved information, you could take a look at this whitepaper :

  7. Replies

    Re: texture atlas , adapt UV

    Your atlas can described in two ways : either in UV space (ranging from 0 to 1 in both coordinates) or in texel space (ranging from 0 to 1024 in width (x) and from 0 to 512 in height (y)).

  8. AMD Radeon HD 5770 + GL_SAMPLE_ALPHA_TO_ONE


    I'm using Catalyst 11.2 under Win7-64, and I'm trying to create 'imposters' with proper alpha channel by using render to texture and alpha-to-coverage.

    To have a proper alpha channel value,...
  9. Experience with NVidia Optimus and OpenGL ?

    Hi everyone,

    I happened to have my hands for the first time on an NVidia Optimus 'enabled' laptop yesterday.

    It happened that our OpenGL applications did not automatically trigger the switch to...
  10. Replies

    State of Windows Intel OpenGL drivers

    Hi everyone,

    as I don't have available hardware to make tests, I was wondering if anyone around here has experience with OpenGL applications on Windows with Intel graphics chips ?

    From what I...
  11. Re: glClearColor with HDR values (>1) on RGBA16F FBO

    Ahf, ok... I'll keep another driver bug unit test under my belt then...

    It might end like this, I wanted to check to normal road first

  12. Re: glClearColor with HDR values (>1) on RGBA16F FBO

    Thanks for the suggestion ! Alas, the behaviour is the same using :

    glClearBufferfv(GL_COLOR, 0, (1.0, 2.0, 0.0, 1.0))

    The same clamping happens.
  13. glClearColor with HDR values (>1) on RGBA16F FBO


    I have an FBO with a single color attachment, which is a GL_RGBA16F texture.

    Whevener I call glClearColor with values > 1, I get the good result on NVidia boards, clearing with the HDR...
  14. Replies

    Re: How to measure timing in OpenGL?

    FWIW so late after this post, from memory, yes, querying the result also forces a sync on ATI.
  15. Re: 3x NVidia Quadro NVS 450 => 12 screens

    It helps ! On XP32, we're now able to run a simple GL window on all the 12 screens, running a smooth 60Hz white quad moving above a green background...

    Now, I got to display more real things.
  16. Re: 3x NVidia Quadro NVS 450 => 12 screens

    No, no multisampling, no depth buffer, no stencil buffer.

    Tried to see if WGL_NV_gpu_affinity could help, but the boards does not support this extension.

    Trying to setup a WinXP instead of Win7...
  17. Re: 3x NVidia Quadro NVS 450 => 12 screens

    Yep, I did not expect stellar performance, but even with only a glClear, it can't sustain 60Hz, or even 30Hz... I did not bother to measure the actual framerate as the refresh is really perceived as...
  18. 3x NVidia Quadro NVS 450 => 12 screens

    I have a machine at hand, with a Core i7 CPU, and 3 NVidia Quadro NVS 450 cards, each connected to 4 1920x1080 LCD displays.

    I need to run a simple but smooth 60Hz OpenGL animation on this system....
  19. Re: Geometry shader massive slowdown / ATI Radeon 5770

    David, thanks for your reply.

    I'm aware of the GL pipelining, and pipeline balancing according to performance bottlenecks : my aim with this synthetic test was to put some numbers in front of...
  20. Replies

    Re: A fast and actual and beautiful ocean

    Note that you can store your 2D noise data in bitmap textures, and start from there. You then only have to generate your noise once.

    You could then combine multiple scrolling noise textures, at...
  21. Geometry shader massive slowdown / ATI Radeon 5770

    Hi everyone !

    I'm not used to work with geometry shaders, and I set up a small synthetic benchmark to check peak performances on triangles throughput using VBOs and geometry shaders.

    I do this...
  22. Replies

    Re: texture loading with alpha

    This has _nothing_ to do with alpha channel... This is a basic C programming problem: you have to explicitly convert the types you're using, or change them.

    You could try to change your 'data'...
  23. ATI, glGetTexImage + GL_PIXEL_PACK_BUFFER problem

    Hi everyone,

    I'm currently trying to read the contents of textures to dump their raw contents on disk.

    I'm trying to use PBOs (GL_PIXEL_PACK_BUFFER) as glGetTexImage is supposed to raise a...
  24. Re: Per-pixel shading, but still artifacts

    Do your normals look discontinuous if you display them in false colors ?

    gl_FragColor = vec4( normal*0.5+vec3(0.5), 1.0 );
  25. Re: Windows 7 + fullscreen OpenGL + Modal dialogs pb

    Thanks for the tip, but I did know it : I was looking at it closely yesterday and tried various combinations of PFD_ flags, and WS_ styles without much success.

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