gluProject(3G)		       OpenGL Reference			gluProject(3G)

NAME    [Toc]    [Back]

     gluProject	- map object coordinates to window coordinates

C SPECIFICATION    [Toc]    [Back]

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

PARAMETERS    [Toc]    [Back]

     objX, objY, objZ
		     Specify the object	coordinates.

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

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

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

     winX, winY, winZ
		     Return the	computed window	coordinates.

DESCRIPTION    [Toc]    [Back]

     gluProject	transforms the specified object	coordinates into window
     coordinates using model, proj, and	view. The result is stored in winX,
     winY, and winZ. A return value of GL_TRUE indicates success, a return
     value of GL_FALSE indicates failure.

     To	compute	the coordinates, let v = (objX,objY,objZ,1.0) represented as a
     matrix with 4 rows	and 1 column.  Then gluProject computes	v' as follows:

     v'	= P x M	x v

     where P is	the current projection matrix proj, M is the current modelview
     matrix model (both	represented as 4x4 matrices in column-major order) and
     'x' represents matrix multiplication.

     The window	coordinates are	then computed as follows:

     winX = view(0) + view(2) *	(v'(0) + 1) / 2





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gluProject(3G)		       OpenGL Reference			gluProject(3G)



     winY = view(1) + view(3) *	(v'(1) + 1) / 2

     winZ = (v'(2) + 1)	/ 2

SEE ALSO    [Toc]    [Back]

     glGet, gluUnProject


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