glDepthRange(3G)	       OpenGL Reference		      glDepthRange(3G)



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 possible.

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


MACHINE	DEPENDENCIES
     Although it is possible to	reverse	the depth mapping so that near is 1
     and far is	0, doing so may	cause severe depth-buffering artifacts on
     InfiniteReality systems.  (This is	particularly true for 16-bit depth
     buffers.)	Therefore this practice	is strongly discouraged.







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glDepthRange(3G)	       OpenGL Reference		      glDepthRange(3G)



SEE ALSO
     glDepthFunc, glViewport





















































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