HP Workstation zx2000 OpenGL 1.1 Reference for HP-UX 11.x - Page 189

Chapter 7 G glXGetConfig GLX_AUX_BUFFERS Number of auxiliary color buffers that are available. Zero indicates that no auxiliary color buffers exist. GLX_RED_SIZE Number of bits of red stored in each color buffer. Undefined if GLX_RGBA is False. GLX_GREEN_SIZE Number of bits of green stored in each color buffer. Undefined if GLX_RGBA is False. GLX_BLUE_SIZE Number of bits of blue stored in each color buffer. Undefined if GLX_RGBA is False. GLX_ALPHA_SIZE Number of bits of alpha stored in each color buffer. Undefined if GLX_RGBA is False. GLX_DEPTH_SIZE Number of bits in the depth buffer. GLX_STENCIL_SIZE Number of bits in the stencil buffer. GLX_ACCUM_RED_SIZE Number of bits of red stored in the accumulation buffer. GLX_ACCUM_GREEN_SIZE Number of bits of green stored in the accumulation buffer. GLX_ACCUM_BLUE_SIZE Number of bits of blue stored in the accumulation buffer. GLX_ACCUM_ALPHA_SIZE Number of bits of alpha stored in the accumulation buffer. The X protocol allows a single visual ID to be instantiated with different numbers of bits per pixel. Windows or GLX pixmaps that will be rendered with OpenGL, however, must be instantiated with a color buffer depth of GLX_BUFFER_SIZE. Although a GLX implementation can export many visuals that support GL rendering, it must support at least one RGBA visual. This visual must have at least one color buffer, a stencil buffer of at least 1 bit, a depth buffer of at least 12 bits, and an accumulation buffer. Alpha bitplanes are optional in this visual. However, its color buffer size must be as great as that of the deepest TrueColor, DirectColor, PseudoColor, or StaticColor visual supported on level zero, and it must itself be made available on level zero. In addition, if the X server exports a PseudoColor or StaticColor visual on frame buffer level 0, a color index visual is also required on that level. It must have at least one color buffer, a stencil buffer of at least 1 bit, and depth buffer of at least 12 bits. This visual must have as many color bitplanes as the deepest PseudoColor or StaticColor visual supported on level 0. Applications are best written to select the visual that most closely meets their requirements. Creating windows or GLX pixmaps with unnecessary buffers can result in reduced rendering performance as well as poor resource allocation. 189