NAME
	  gluUnProject - map window coordinates	to object coordinates


     C SPECIFICATION
	  GLint	gluUnProject( GLdouble winX,
			      GLdouble winY,
			      GLdouble winZ,
			      const GLdouble *model,
			      const GLdouble *proj,
			      const GLint *view,
			      GLdouble*	objX,
			      GLdouble*	objY,
			      GLdouble*	objZ )


     PARAMETERS
	  winX,	winY, winZ
			  Specify the window coordinates to be mapped.

	  model		  Specifies the	modelview matrix (as from a
			  glGetDoublev call).

	  proj		  Specifies the	projection matrix (as from a
			  glGetDoublev call).

	  view		  Specifies the	viewport (as from a
			  glGetIntegerv	call).

	  objX,	objY, objZ
			  Returns the computed object coordinates.

     DESCRIPTION
	  gluUnProject maps the	specified window coordinates into
	  object coordinates using model, proj,	and view.  The result
	  is stored in objX, objY, and objZ. A return value of GL_TRUE
	  indicates success; a return value of GL_FALSE	indicates
	  failure.

	  To compute the coordinates (objX, objY, and objZ),
	  gluUnProject multiplies the normalized device	coordinates by
	  the inverse of model*proj as follows:










				     |			     |
				     |_________________	     |
		  (	  )	     |	   view[2]	- 1  |
		  | objX  |	     |			     |
		  | objY  | = INV(PM)|_________________	- 1  |
		  |	  |	     |	   view[3]	     |
		  | objZ  |	     |	   2(winZ) - 1	     |
		  (  W	  )	     |			     |
				     (		1	     )

	  INV()	denotes	matrix inversion. W is an unused variable,
	  included for consistent matrix notation.

     SEE ALSO
	  glGet, gluProject