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Type: Posts; User: malexander

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  1. You can use the glXSwapInterval(0) function...

    You can use the glXSwapInterval(0) function defined by the GLX_SGI_swap_control extension to disable vsync for your application.
  2. You can use glScissor with an area of 1 pixel at...

    You can use glScissor with an area of 1 pixel at the specified mouse coords. That will crop the render to a single pixel. While this will save on fragment writes, you'll still pay for all vertex...
  3. I ran into an AMD driver bug where -1 for the...

    I ran into an AMD driver bug where -1 for the string length was being rejected as an invalid value, instead of indicating a NULL-terminated string. Passing strlen(msg) worked around the issue. Not...
  4. If you print the result of...

    If you print the result of glGetString(GL_RENDERER) in your app, do you get the nvidia or MESA driver?
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    There's no standard gl call to query memory or...

    There's no standard gl call to query memory or memory use, but you can try the AMD and Nvidia specific extensions:

    http://www.opengl.org/registry/specs/ATI/meminfo.txt...
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    Try reading this tutorial on drawing with VBOs: ...

    Try reading this tutorial on drawing with VBOs:

    http://www.arcsynthesis.org/gltut/Basics/Tutorial%2001.html

    It draws a single triangle, and is quite good at introducing the concept of drawing...
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    It looks from your code like you're rebuilding...

    It looks from your code like you're rebuilding the model every time you move it. You don't need to do this unless the model itself is deforming, and this is the source of your performance loss....
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    The only way I know of doing this in unextended...

    The only way I know of doing this in unextended GL is to use a geometry shader in conjuntion with a texture buffer object containing the UV coords. It requires that your model be all triangles, or...
  9. That's probably the bug then, in the first...

    That's probably the bug then, in the first example v3.w would be 2 and not 1, messing up any perspective divide.
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    This is especially true for AMD cards. While they...

    This is especially true for AMD cards. While they report a GL_MAX_VERTICES of 2^32-1, and GL_MAX_ELEMENTS_VERTICES of 2^24-1 (16M), if you use multiple vertex buffers with sizes greater than roughly...
  11. That's a good point, you do have to check the...

    That's a good point, you do have to check the GL_LINE_WIDTH_RANGE (or GL_SMOOTH_LINE_WIDTH_RANGE, if you are using smooth lines). Both AMD and Nvidia drivers on Linux and Windows support the same...
  12. Again, wide lines are deprecated but not removed...

    Again, wide lines are deprecated but not removed in the Core GL contexts. The GL ARB specifically mentions this in the GL 3.1 spec (Appendix G). Since the ARB went to the trouble of specifically...
  13. You can still use line widths > 1.0 in the core...

    You can still use line widths > 1.0 in the core profile, and render to a multisample render target. That looks pretty decent for 4x multisample and above. The old smooth lines are pretty slow for a...
  14. You can definitely use multiple TBOs in a shader...

    You can definitely use multiple TBOs in a shader stage. The setup code looks fine, though I don't have my code that does TBOs in front of me. Most of your drawing code isn't necessary, you only need...
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    Looking back at your OP, I see that the Intel GL...

    Looking back at your OP, I see that the Intel GL implementation only supports GLSL 1.40. So, you'll need to do:



    #version 140
    #extension GL_ARB_explicit_attrib_location : require
    ...
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    Try: Using version 130 will not work at...

    Try:



    Using version 130 will not work at all as layout(location) is a GLSL 330 feature. I'd expect a syntax error in that case.
  17. Ah, I was thinking you were blending a diffuse...

    Ah, I was thinking you were blending a diffuse decal.

    In that case, you might draw glBlendFuncSeparate(), where you could blend the RGB components using (Sa, 1-Sa) and A using either (0, 1) or (1,...
  18. You don't have to have diffuse.a in all 4...

    You don't have to have diffuse.a in all 4 textures' Alpha component. I have a deferred renderer where the alpha channels store other data, like your second setup. All you need to do is draw to...
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    If you're using the Compatibility profile,...

    If you're using the Compatibility profile, GL_POINT_SPRITE still exists and must be explicitly enabled. GL_POINT_SPRITE is only removed in the Core profile, and gl_PointCoord should always be...
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    Try putting more newlines at the end of each line...

    Try putting more newlines at the end of each line in the string. If that doesn't work, fetch the compile logs for each of the shaders with



    int log_len = 0;
    glGetShaderiv(vertShader,...
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    It's very likely the alpha test, then. It's a...

    It's very likely the alpha test, then. It's a compatiblity mode test, and likely works off the first buffer, not the union of all of them. Try:

    glDisable(GL_ALPHA_TEST);

    before you render to...
  22. In the first case, you're drawing 1 million...

    In the first case, you're drawing 1 million fragments. In the second, you're drawing 100 million fragments (and change). Since neither case is likely to be vertex processing bound, how you're drawing...
  23. Are you somehow generating negative color values...

    Are you somehow generating negative color values for light 0? Try clamping it to zero (lightval = max(vec3(0.0), lightval)). The RGBA8888 textures will implicitly clamp negative values to zero,...
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    If that is the case, then you should at least...

    If that is the case, then you should at least recommend 2G. If your textures are larger than the installed VRAM, it'll still work, just slower. There is nothing you can do about how the driver...
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    The specified min/max of the aliased and smooth...

    The specified min/max of the aliased and smooth line width range is 1,1. So it's perfectly valid for an implementation to not support wide or thin lines at all, which is why you need to check the...
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