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



C SPECIFICATION


PARAMETERS

       _param1  Specifies the mapping of the near clipping  plane
                to window coordinates.  The initial value is 0.

       _param2  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 imple-
       mentation,  window  coordinate depth values are treated as
       though they range from 0  through  1  (like  color  compo-
       nents).   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 _param1  be  less  than  _param2.
       Reverse  mappings  such  as _eqnparam1=1, and _eqnparam2=0
       are acceptable.


ERRORS

       GL_INVALID_OPERATION is generated if glDepthRange is  exe-
       cuted between the execution of glBegin and the correspond-
       ing execution of glEnd.


ASSOCIATED GETS

       glGet with argument GL_DEPTH_RANGE


SEE ALSO

       glDepthFunc, glPolygonOffset, glViewport



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