HP Workstation zx2000 OpenGL 1.1 Reference for HP-UX 11.x - Page 46

C glXChooseVisual glXChooseVisual glXChooseVisual: return a visual that matches specified attributes. C Specification XVisualInfo *glXChooseVisual( Display *dpy, int screen, int *attribList) Parameters dpy screen attribList Specifies the connection to the X server. Specifies the screen number. Specifies a list of boolean attributes and integer attribute/value pairs. The last attribute must be None. Description glXChooseVisual returns a pointer to an XVisualInfo structure describing the visual that best meets a minimum specification. The boolean GLX attributes of the visual that is returned will match the specified values, and the integer GLX attributes will meet or exceed the specified minimum values. If all other attributes are equivalent, then TrueColor and PseudoColor visuals have priority over DirectColor and StaticColor visuals, respectively. If no conforming visual exists, NULL is returned. To free the data returned by this function, use XFree. All boolean GLX attributes default to False except GLX_USE_GL, which defaults to True. All integer GLX attributes default to zero. Default specifications are superseded by attributes included in attribList. Boolean attributes included in attribList are understood to be True. Integer attributes and enumerated type attributes are followed immediately by the corresponding desired or minimum value. The list must be terminated with None. The interpretations of the various GLX visual attributes are as follows: GLX_USE_GL Ignored. Only visuals that can be rendered with GLX are considered. GLX_BUFFER_SIZE Must be followed by a non-negative integer that indicates the desired color index buffer size. The smallest index buffer of at least the specified size is preferred. Ignored if GLX_RGBA is asserted. GLX_LEVEL Must be followed by an integer buffer-level specification. This specification is honored exactly. Buffer level zero corresponds to the main frame buffer of the display. Buffer level one is the first overlay frame buffer, level two the second overlay frame buffer, and so on. Negative buffer levels correspond to underlay frame buffers. 46 Chapter 3