How a GLXFBConfig Is Selected

• Preference is given to GLXFBConfigs with the largest GLX_RED_SIZE, GLX_GREEN_SIZE, and GLX_BLUE_SIZE.

• If the requested GLX_ALPHA_SIZE is zero, preference is given to GLXFBConfigs that have GLX_ALPHA_SIZE set to zero; otherwise preference is given to GLXFBConfigs that have the largest GLX_ALPHA_SIZE value.

• If the requested number of GLX_AUX_BUFFERS is zero, preference is given to GLXFBConfigs that have GLX_AUX_BUFFERS set to zero; otherwise preference is given to GLXFBConfigs that have the smallest GLX_AUX_BUFFERS value.

• If the requested size of a particular ancillary buffer is zero (for example, GLX_DEPTH_BUFFER is zero), preference is given to GLXFBConfigs that also have that size set to zero; otherwise preference is given to GLXFBConfigs that have the largest size.

• If the requested value of either GLX_SAMPLE_BUFFERS_SGIS or GLX_SAMPLES_SGIS is zero, preference is given to GLXFBConfigs that also have these attributes set to zero; otherwise preference is given to GLXFBConfigs that have the smallest size.

• If GLX_X_VISUAL_TYPE_EXT is not specified but there is an X visual associated with the GLXFBConfig, the visual type is used to prioritize the GLXFBConfig.

• If GLX_RENDER_TYPE_SGIX has GLX_RGBA_BIT_SGIX set, the visual types are prioritized as follows: TrueColor, DirectColor, PseudoColor, StaticColor, GrayScale, and StaticGray.

• If only the GLX_COLOR_INDEX_SGIX is set in GLX_RENDER_TYPE_SGIX, visual types are prioritized as PseudoColor, StaticColor, GrayScale, and StaticGray.

• If GLX_VISUAL_CAVEAT_EXT is set, the implementation for the particular system on which you run determines which visuals are returned. See "The Visual Rating Extension" for more information.