glXChooseFBConfig not giving me what I want

andrew rader andrew.r.rader at
Fri Mar 28 16:10:15 PDT 2008

Hi again,

to repeat my earlier mail, I'm working on a small compositing wm for
funsies, and I've again run into an issue. I'm using as my guide
what's in compiz as well as the usage example near the bottom of this

First problem: the below snippit returns 0 configurations:

    const int fb_attrs[] = { GLX_DRAWABLE, GLX_PIXMAP_BIT, None };
    fb_configs = glXChooseFBConfig(dpy, screen_num, fb_attrs, &n_configs);
    // n_configs now equals 0 :(

Does that mean I'm somehow missing GLX Pixmap support? do I need it?
(I notice compiz doesn't appear to check for it)

Next problem: If instead of the above I just iterate through all of
the configs using glXGetFBConfigs, none of the configurations support
GLX_BIND_TO_TEXTURE_TARGETS_EXT (glXGetFBConfigAttrib returns 0 for
all of the configs). Is this needed? I tried ignoring this and used
GL_TEXTURE_2D rather than GLX_TEXTURE_2D_EXT (and
GLX_TEXTURE_RECTANGLE_BIT_EXT) but I end up with just a white
texture... If I do try and use either of the EXT targets my machine
hardlocks :(

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