xfree86 man page for gluunproject

GLUUNPROJECT(3G)														  GLUUNPROJECT(3G)

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:

							     objX
							    (objY)=INV(PM)(_______________-1)
							     objZ	   _______________-1
							      W 	       2(winZ)-1
										   1
       INV() denotes matrix inversion.	W is an unused variable, included for consistent matrix notation.

SEE ALSO
       glGet(3G), gluProject(3G)

																  GLUUNPROJECT(3G)