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Type: Posts; User: Serge K

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    Re: glPointParamter coefficients

    glPointParams[3] = { a, b, c };
    // distance in eye coordinates
    size = point_size / sqrt(a + b·distance + c·distance²)
    GL_EXT_point_parameters
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    Re: GL_POLYGON_SMOOTH and quads

    Just make sure that all primitives drawn with this blend function are sorted front to back.
    Since it uses alpha channel to calculate uncovered part of the pixel, fully covered pixel will prevent...
  3. Re: GL_SEPARATE_SPECULAR_COLOR not working on Bitmap context.

    Apparently, Vista is supposed to have OpenGL 1.4 by default, so both separate specular & secondary color should be available.
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    Re: How to set Texture Border's Color?

    ZbuffeR, do you understand that this extension (GL_ARB_texture_border_clamp) has nothing to do with the presence of hardware support for textures with border?
    It simply allows to clamp any texture...
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    Re: How to use glColorTable(attach code)

    Are you sure that your 3D card actually has GL_EXT_paletted_texture extension?
    It wasn't that widely supported, and even NVIDIA dropped it.
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    Re: glTexImage2D causes problem to opengl color

    What about this line of your code?

    glBindTexture(GL_TEXTURE_2D, texture[2]);

    To create the texture you have to bind it...
  7. Re: LuminaceAlpha vs Luminace+Alpha_lookuptable

    Yes.
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    Re: Texture and Transparencies

    Lots of advices, I see... :rolleyes:

    Why do you set texture function to GL_DECAL?
    It uses texture alpha to blend the texture with fragment color.
    Try GL_REPLACE.

    Texture Environments and...
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    Re: How to use glColorTable(attach code)

    Shouldn't it be glColorTable( GL_TEXTURE_3D, ... ) ?
    Or is it GL_TEXTURE_2D?
    It seems that you found a way to mix them freely... :rolleyes:

    GL_EXT_paletted_texture
  10. Re: glEnableVertexAttribArrayARB: global or per program?

    Globally.
    http://developer.3dlabs.com/documents/GLmanpages/glEnableVertexAttribArray.htm
  11. Thread: faster

    by Serge K
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    Re: faster

    Another point to consider:
    Antialiasing may not be available for rendering to the texture.
  12. Thread: Gl_POLYGON

    by Serge K
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    Re: Gl_POLYGON

    ...but watch out for T-junctions...
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    Re: dynamic alpha textures

    Does that mean that you have 2 textures (1st - Alpha, 2nd - RGB) of different size?
    And how exactly do you want to "apply" them?
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    Re: Multi-texturing equation question.

    So, you want this function:

    Arg0 + Arg0·2·(Arg1-0.5) // (Arg1-0.5) => [-0.5, 0.5]

    // simple math:
    Arg0 + Arg0·2·(Arg1-0.5) = 2·Arg1·Arg0

    Can be done with 2 texture units (OpenGL >=1.3...
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    Re: Sand pixels on ATI

    Do you mean "the triangle will change its orientation (frontfacing<=>backfacing)"?
    Is culling enabled in your code?


    Well, since the results of both operations are rounded to 32bit precision in...
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    Re: Purpose of .tga

    DDS - DirectDraw Surface, can store compressed and uncompressed pixel formats.

    NVIDIA Texture Tools
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    Re: Purpose of .tga

    In case of BMP it's only for 4 & 8bpp indexed images, and the kind of RLE it uses is not good...
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    Re: Rubber-band selection

    The simplest way to get acceptable result is to draw the rectangle with inversion:

    glLogicOp( GL_XOR );
    glEnable( GL_COLOR_LOGIC_OP );
    // xor-ing with grey produce visible changes on any color...
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    Re: multitexturing and alpha channel

    Why do you call glEnable(GL_BLEND) in the set-up of each texture unit? Blending has nothing to do with textures, it only controls how the resulting fragment color is combined with frame buffer.
    ...
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    Re: Multitexturing with multiple passes

    Well, it sort of can be done by rendering previous pass to the texture, then binding this texture to the first unit. Otherwise the target color buffer is available only for the blending stage.
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    Re: Help with Textured Heightfield Terrain

    > fread(bitmapInfoHeader, sizeof(BITMAPFILEHEADER), 1, filePtr);
    > ...
    > bitmapImage = (unsigned char*)malloc(bitmapInfoHeader->biSizeImage);

    Is it a typo? (shouldn't it be BITMAPINFOHEADER?)...
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    Re: XOR effect to show object selection?

    True. ...for OpenGL 1.0 http://www.opengl.org/discussion_boards/ubb/rolleyes.gif

    Logical Operation
    glEnable(GL_COLOR_LOGIC_OP);
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    Re: texture registering

    GL_TEXTURE_MIN_FILTER must be GL_LINEAR or GL_NEAREST.
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    Re: Error running example code of RED BOOK!!

    Actually, much more often it's a result of a stack corruption - out of range access, incorrect poiter math, etc.
  25. Thread: Color Space

    by Serge K
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    Re: Color Space

    how about glBlendFunc( GL_ONE, GL_ONE ) ?
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