glDepthRange

GLDEPTHRANGE(3G)					     GLDEPTHRANGE(3G)



NAME
       glDepthRange  - specify mapping of depth values from normalized device
       coordinates to window coordinates


C SPECIFICATION
       void glDepthRange( GLclampd near_val,
			  GLclampd far_val )


PARAMETERS
       near_val	 Specifies the mapping of the near clipping plane  to  window
		 coordinates.  The initial value is 0.

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

DESCRIPTION
       After clipping and division by w, depth coordinates range from  -1  to
       1,  corresponding  to  the near and far clipping planes.	 glDepthRange
       specifies a linear mapping of the normalized depth coordinates in this
       range  to  window  depth	 coordinates.  Regardless of the actual depth
       buffer implementation, window coordinate depth values are  treated  as
       though they range from 0 through 1 (like color components).  Thus, the
       values accepted by glDepthRange are both clamped to this range  before
       they are accepted.

       The  setting 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_val be less than far_val.	Reverse	 map-
       pings such as near_val=1, and far_val=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(3G), glPolygonOffset(3G), glViewport(3G)



							     GLDEPTHRANGE(3G)