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Type: Posts; User: Bruce Wheaton

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    No, if your texture is being read properly, then...

    No, if your texture is being read properly, then your target format should be irrelevant.

    Run a color bars still through your pipeline and post a picture.
  2. Side note - pulling the pixels to the CPU and...

    Side note - pulling the pixels to the CPU and doing the work then pushing it back is a really poor idea. Use a fragment shader instead.

    Bruce
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    If your texture format isn't natively supported...

    If your texture format isn't natively supported on a platform you're targeting (as your weird colors indicate) then yes, you'd need to write a shader. It isn't just a colorspace problem? For...
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    Yes, the number of textures shouldn't be a...

    Yes, the number of textures shouldn't be a problem - the memory used is the same, and as long as you don't expect to draw all those videos in one shader pass (probably can't anyway), binding the...
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    The black and white levels are a separate issue...

    The black and white levels are a separate issue from prohibited values in an SDI signal. I would hazard a guess that there's a bug in the Nvidia driver, and it's disallowing invalid SDI values at the...
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    Are you outputting SDI? Some values are illegal...

    Are you outputting SDI? Some values are illegal in SDI, in which case you are seeing the correct result.

    In fact, 'black' and 'white' values have special definitions in a video signal, and your...
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    Generally what people miss with PBOs is that they...

    Generally what people miss with PBOs is that they free up the CPU to do extra work. If you don't do any extra work, then you won't get the benefit - you're just using a different transfer mechanism....
  8. I tried a few different Matrix orders, and was...

    I tried a few different Matrix orders, and was getting close, but in the end I did mvp * vertex, then did a multiply by a vec4 bias and added an offset. Those numbers seemed arbitrary, like they were...
  9. I'm not sure. I have the 0,0 - 1,1 tex coords: I...

    I'm not sure. I have the 0,0 - 1,1 tex coords: I had thought I was going to multiply those, but you're saying use the vertex and a bias? The bias being to deal with the vertices being -1 - +1 instead...
  10. A picture expresses it better. In the diagram...

    A picture expresses it better. In the diagram below, it's clear that multiplying the vertices by the MVP matrix gives me the viewport coords. But what do I transform the tex-cords by so that 0,0, -...
  11. Modifying Texture Coordinates to represent visible area

    I have a rectangular mesh, where the height ranges from +1 to -1, and the the sides are at +Aspect Ratio, - Aspect ratio. Texture coordinates [0] range from 0,0 to 1,1

    In my vertex shader, I...
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    Umer, you're mishearing. You do not want to use...

    Umer, you're mishearing. You do not want to use glTexCoord. You have drawn a flat quad, on one plane, and you want it to act like it's in a 3D space. Adjust the vertices - not the texture coordinates...
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    Re: What is a scene graph?

    You seem to be saying:

    I can put all my drawing into a simple scene graph and render that.

    Why would I need a scene graph then?

    Good question.

    Bruce
  14. Re: how to put a 3D object at fixed screen location ?

    Generally, you would draw your fixed item separately. Draw your 3D scene with whatever orientation you need, then set things up again, and draw your locked object on top.

    Bruce
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    Re: Texture disappears!

    Your code for the texture setup and clean-up and also mouse actions would be more relevant.

    Bruce

    (and this probably isn't an 'advanced' topic, btw)
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    Re: Offscreen rendering ?

    AFAIK, Windows is the only platform that requires you to make an actual 'window'. Mac and iOS just needs a context, Linux and derivatives can use pbuffers (including Android, apparently).

    So in...
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    Re: Alternative to glXWaitVideoSyncSGI

    I was wondering.... so in this case, where I've managed to move most of my main work to a single thread/context, and the thread is for this one job, blocking the CPU to wait for the frame to complete...
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    Re: Alpha Channel of texture

    OpenGL doesn't have any functions to load textures from compressed formats. You could in theory open a raw RGBA type format - look for the NeHe tutorials, I think one does that.

    For something like...
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    Alternative to glXWaitVideoSyncSGI

    I'm having a problem with glXWaitVideoSyncSGI, probably driver related.

    http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=308282#Post308282

    What's a good alternative?...
  20. glXWaitVideoSyncSGI hangs in Nvidia 290.10 Linux

    glXWaitVideoSyncSGI started to hang on me with a new GTX 520 card.

    I have:
    2 X screens in Twinview, each with their own display connection and context, both Nvidia GPUs (a 275 and a 520).

    The...
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    Re: Nvidia Dual Copy Engines

    Sorry, trying to work this out. I'm using the 'traditional' PBO method now - I render to an FBO and glReadPixels to a PBO set up as GL_READ_ONLY. It sounds like you are saying that a two step process...
  22. Effect of swap-buffers on the GL Command Queue?

    If I draw a frame, put in a query end, call swapbuffers, and then when pulling the query find that I still have time before the swap actually happens, can I use that time within the same frame?
    ...
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    Re: Texure mapping anti-alias

    Actually, the edges and the jaggies inside the image will need different solutions.

    Turning on hardware anti-aliasing will help with your edges. But your OpenGL-ES (iPhone?) hardware may not...
  24. Re: async glReadPixels on HD3000 stalls the pipeline

    Are you doing a glFlush after the read pixels call?

    Otherwise your GL commands could be just sitting in the queue, and then when you map the PBO, all the work is being done at once.

    Bruce
  25. Re: Tranlsating Texture Channels (R,G,B,A separately)

    You have a film scan with an alpha channel? That's quite a trick.

    Anyway, yes, use a fragment shader and sample in a slightly different place for each color component as needed, then combine.
    ...
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