Index for Section 3

Alphabetical listing for G

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glXGetConfig()
NAME
  glXGetConfig - return information about GLX visuals

SYNOPSIS
  int glXGetConfig(
	  Display *dpy,
	  XVisualInfo *vis,
	  int attrib,
	  int *value );

PARAMETERS
  dpy Specifies the connection to the X server.

  vis Specifies the visual to be queried. It is a pointer to an XVisualInfo
      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 visuals, GLX_BUFFER_SIZE is
      the sum of GLX_RED_SIZE, GLX_GREEN_SIZE, GLX_BLUE_SIZE, and
      GLX_ALPHA_SIZE. For color index visuals, GLX_BUFFER_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 correspond 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 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
  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 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.

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(3), glXCreateContext(3)

Index for Section 3

Alphabetical listing for G

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