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GLXGETCONFIG()							GLXGETCONFIG()

NAME
       glXGetConfig - return information about GLX visuals

C SPECIFICATION
       int glXGetConfig( Display *dpy,
			 XVisualInfo *vis,
			 int attrib,
			 int *value )

       delim $$

PARAMETERS
       dpy     Specifies the connection	to the X server.

       vis     Specifies the visual to be queried.  It is a pointer to an XVi-
	       sualInfo	structure, not a visual	ID or a	pointer	to a Visual.

       attrib  Specifies the visual attribute to be returned.

       value   Returns the requested value.

DESCRIPTION
       glXGetConfig sets value to the attrib value of windows or  GLX  pixmaps
       created	with respect to	vis.  glXGetConfig returns an error code if it
       fails for any reason.  Otherwise, zero is returned.

       attrib is one of	the following:

       GLX_USE_GL	     True if OpenGL rendering  is  supported  by  this
			     visual, False otherwise.

       GLX_BUFFER_SIZE	     Number  of	bits per color buffer.	For RGBA visu-
			     als, GLX_BUFFER_SIZE is the sum of	 GLX_RED_SIZE,
			     GLX_GREEN_SIZE,	GLX_BLUE_SIZE,	 and   GLX_AL-
			     PHA_SIZE.	 For  color  index  visuals,  GLX_BUF-
			     FER_SIZE is the size of the color indexes.

       GLX_LEVEL	     Frame  buffer level of the	visual.	 Level zero is
			     the default frame buffer.	Positive levels	corre-
			     spond  to	frame buffers that overlay the default
			     buffer, and negative levels correspond  to	 frame
			     buffers that underlay the default buffer.

       GLX_RGBA		     True if color buffers store red, green, blue, and
			     alpha values.  False if they store	color indexes.

       GLX_DOUBLEBUFFER	     True if color buffers exist in  front/back	 pairs
			     that can be swapped, False	otherwise.

       GLX_STEREO	     True  if color buffers exist in left/right	pairs,
			     False otherwise.

       GLX_AUX_BUFFERS	     Number of auxiliary color buffers that are	avail-
			     able.   Zero  indicates  that  no auxiliary color
			     buffers exist.

       GLX_RED_SIZE	     Number of bits of red stored in each  color  buf-
			     fer.  Undefined if	GLX_RGBA is False.

       GLX_GREEN_SIZE	     Number of bits of green stored in each color buf-
			     fer.  Undefined if	GLX_RGBA is False.

       GLX_BLUE_SIZE	     Number of bits of blue stored in each color  buf-
			     fer.  Undefined if	GLX_RGBA is False.

       GLX_ALPHA_SIZE	     Number of bits of alpha stored in each color buf-
			     fer.  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 accumula-
			     tion 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 accumula-
			     tion buffer.

       The X protocol allows a single visual ID	to be instantiated  with  dif-
       ferent  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, Pseudo-
       Color,  or  StaticColor visual supported	on level zero, and it must it-
       self be made available on level zero.

       In addition, if the X server exports a PseudoColor or StaticColor  vis-
       ual  on	framebuffer  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 a	depth buffer of	at least 12 bits.  This	visual
       must have as many color bitplanes as the	deepest	PseudoColor or Static-
       Color 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	unnec-
       essary  buffers	can result in reduced rendering	performance as well as
       poor resource allocation.

NOTES
       XVisualInfo is defined in Xutil.h.  It is  a  structure	that  includes
       visual, visualID, screen, and depth elements.

ERRORS
       GLX_NO_EXTENSION	is returned if dpy does	not support the	GLX extension.

       GLX_BAD_SCREEN  is returned if the screen of vis	does not correspond to
       a screen.

       GLX_BAD_ATTRIBUTE is returned if	attrib is not a	valid GLX attribute.

       GLX_BAD_VISUAL is returned if vis doesn't support GLX and an  attribute
       other than GLX_USE_GL is	requested.

SEE ALSO
       glXChooseVisual,	glXCreateContext

								GLXGETCONFIG()

NAME | C SPECIFICATION | PARAMETERS | DESCRIPTION | NOTES | ERRORS | SEE ALSO

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