glDepthRange.3gl

Name

  glDepthRange - specify the mapping of	z values from normalized device
  coordinates to window	coordinates

C Specification

  void glDepthRange( GLclampd near,
		     GLclampd far )

Parameters

  near	Specifies the mapping of the near clipping plane to window
	coordinates.  The default value	is 0.

  far	Specifies the mapping of the far clipping plane	to window
	coordinates.  The default value	is 1.

Description

  After	clipping and division by w, z coordinates range	from -1.0 to 1.0,
  corresponding	to the near and	far clipping planes.  glDepthRange specifies
  a linear mapping of the normalized z coordinates in this range to window z
  coordinates.	Regardless of the actual depth buffer implementation, window
  coordinate depth values are treated as though	they range from	0.0 through
  1.0 (like color components).	Thus, the values accepted by glDepthRange are
  both clamped to this range before they are accepted.

  The default mapping of 0,1 maps the near plane to 0 and the far plane	to 1.
  With this mapping, the depth buffer range is fully utilized.

Notes

  It is	not necessary that near	be less	than far.  Reverse mappings such as
  1,0 are acceptable.

Errors

  GL_INVALID_OPERATION is generated if glDepthRange is executed	between	the
  execution of glBegin and the corresponding execution of glEnd.

Associated Gets

  glGet	with argument GL_DEPTH_RANGE

See Also

  glDepthFunc, glViewport

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Last Edited: Fri Dec 6 11:18:03 EST 1996 by AFV
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