gluUnProject

gluUnProject: map window coordinates to object coordinates.

C Specification | Parameters | Description | See Also

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.

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, objZ), gluUnProject multiplies the normalized device coordinates by the inverse of modelproj as follows:

objX

objY

objZ

= INV(PM )

2 (winX

view[0] ) / view[2]

2 (winY

view[1] ) / view[3]

2 winZ

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