NAME

C SPECIFICATION

	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

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

$\left(\begin{array}{c}\mathrm{objX}\\ \mathrm{objY}\\ \mathrm{objZ}\\ W\end{array}\right)=\mathrm{INV}\left(PM\right)\left(\begin{array}{c}\frac{2(\mathrm{winX}-\mathrm{view}[0])}{\mathrm{view}\left[2\right]}-1\\ \frac{2(\mathrm{winY}-\mathrm{view}[1])}{\mathrm{view}\left[3\right]}-1\\ 2\left(\mathrm{winZ}\right)-1\\ 1\end{array}\right)$

$\mathrm{INV}()$ denotes matrix inversion. W is an unused variable, included for consistent matrix notation.

SEE ALSO