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  1. Replies
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    Re: OpenGL prerequiisite?

    OpenGL does not require a GPU. You can use Mesa to run on the CPU:

    http://www.mesa3d.org/

    However, it will be way slower than if you have a GPU.
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    Re: Texture mapping distortion :(

    Depending on how old is the OpenGL implementation you have available on your machine you may solve this issue with:

    glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);

    This is deprecated since...
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    Re: Regarding GL_EXT_framebuffer_object

    Note that GL_ARB_framebuffer_object is a core extension of GL3.0, not GL_EXT_framebuffer_object.

    Both extensions differ slightly. This is an exert of the "Overview" section of...
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    Re: OpenGL / Direct3D projection matrices

    Check Mark Kilgard's presentation "OpenGL 3.2 and More":

    http://www.slideshare.net/Mark_Kilgard/opengl-32-and-more

    see slides 13 to 31 "Direct3Disms"

    notably:
    slide 17 "OpenGL & Direct3D...
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    Re: Loading Bmp file problem

    glaux is really, really old. And was already old at the end of the 90's.

    The glaux library is no longer supported since the Vista SDK (v6.0). You have to find another library to load your bmp...
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    Re: how the matrix of glOrtho is derived?

    Here is a reference:

    http://www.songho.ca/opengl/gl_projectionmatrix.html#ortho
  7. Re: Cube shape appears distorted at edge of viewport

    what is value of the ratio width/height?

    25 degrees can be pretty high.

    Imaging you are taking a picture of somebody very close to the camera with extreme zoom out (fovy is big), you have a...
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    Re: Capture OpenGL stream

    BuGLE is capturing the OpenGL commands with the trace filter:
    http://www.opengl.org/sdk/tools/BuGLe/documentation/trace.7.php

    BuGLE is a free software under the GPL, so you can get the source...
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    Re: How do I get/restore the current shader

    GLint id;
    glGetIntegerv(GL_CURRENT_PROGRAM,&id);


    Make sure that you are not in a section that builds a display list in compile mode only because this state is not part of it. To test that you...
  10. Re: Why are extensions available as function pointers?

    Because the availability of the extensions depends on the combination of the driver version and GPU capabilities.

    They have to be discovered *dynamically* (ie at runtime) by any program that wants...
  11. Thread: Type aliases

    by overlay
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    Re: Type aliases

    McLeary is right.

    You are looking for sizeof(GLuint) and sizeof(GLushort).

    Just read through GL/gl.h. It's that simple.
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    Re: Regarding the MSAA algorithm

    Slide 26/34 of the following lecture has nice pictures to explain the mechanism:

    http://www.cs.cmu.edu/afs/cs/academic/class/15869-f11/www/lectures/12_deferred_shading.pdf


    Actually the whole...
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    Re: OpenGL Profiling

    On Linux, I use BuGLe with the stats_calltimes filter:

    http://www.opengl.org/sdk/tools/BuGLe/documentation/stats_calltimes.7.php
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    Re: Rendering order within a single draw call

    1. OpenGL does NOT draw many triangles in parallel:

    See Spec 2.1 for example, page 4, section 2.1 OpenGL Fundamentals:

    "Commands are always processed in the order in which they are received"...
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    Re: Bad scope in ConvertLocalReferences()

    Last time I saw that was with a driver bug (around 2008):

    ref: google this "C9999: Bad scope in ConvertLocalReferences()".

    It sounds it's back. Maybe some other developers reported the same...
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    Re: Accuracy at large translations

    read the "Floating point precision and accuracy" section here:

    http://www.opensg.org/wiki/HDI/HugeScenes

    www.floatingorigin.com/pubs/thorneC-FloatingOrigin.pdf

    As well as this detailed blog...
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    Re: 3d maze is moving too slow!

    glTexImage2D() only needs to be called once. (I mean not even once per frame, only once in the whole application). It triggers a memory transfer from the RAM to the VRAM.

    You are calling it each...
  18. Re: Help with worms Ultimate Mayhem - framebuffer

    Apparently, it does not support this extension for the most recent version of the driver (assuming you are using Windows):
    ...
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    Re: Help with openGL and Maya...

    You have to draw your transparent polygons back-to-front by first sorting them according to the camera transform.
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    Re: Display List usage

    This is old (GeForce 6) but this is based on benchmarks/measurement:

    http://www.sci.utah.edu/~bavoil/opengl/bavoil_trimeshes_2005.pdf
    slide 29/35 "What about display lists?" shows that for...
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    Re: glXMakeContextCurrent fails with BadMatch

    Is it only your software?

    What happen if you run glxinfo or glxgears? Do they work correctly?
  22. Thread: Display NDC

    by overlay
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    Re: Display NDC

    Normalized Device Coordinates: the coordinates system right after the perspective division.

    That's said, I don't understand much dzk87's question.

    dzk87: Are you looking for displaying the...
  23. Re: rotating a point by x-axis is the formula valid fo

    This is the output of the following test program (Linux x86_64 and gcc):

    6.28319 radians: -2.44929e-16
    6.28319f radians: 1.74846e-07
    passing 360.0 by mistake: 0.958916
    passing 360.0f by...
  24. Re: Can depth value be rendered into texture (Solved)

    Yes you can attach a texture object (TO) as the depth buffer of an FBO.

    Depending on the generation/capabilities of the OpenGL implementation () on your system, it might be possible or not.
    ...
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    Re: Direct State Access

    EXT_texture_compression_s3tc will never be in the core OpenGL spec because of some patent issue.

    Maybe there is an IP issue with Direct State Access too. I don't know, just speculating here.
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