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Manual Reference Pages  - GLUUNPROJECT (3G)

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gluUnProject - map window coordinates to object coordinates

CONTENTS

C Specification
Parameters
Description
See Also

GLint gluUnProject( GLdouble winX,

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

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.

 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:

(down70 cpile objX objY objZ W ) = INV(PM)(down140 cpile 2(winX - view[0]) / view[2] - 1 2(winY - view[1]) / view[3] - 1 2(winZ) - 1 1 ) INV() denotes matrix inversion. W is an unused variable, included for consistent matrix notation.

glGet(3G),  gluProject(3G)

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