GLUUNPROJECT

Section: Misc. Reference Manual Pages (3G)
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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 )

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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:


left ( down 70 {cpile { ~"objX" above ~"objY" above ~"objZ" above ~W}} ~~ right ) ~=~ INV(P M) left ( down 140 {cpile { { {2("winX" ~-~ "view"[0])} over {"view" [2]} ~-~ 1 } above { {2("winY" ~-~ "view"[1])} over {"view"[3]} ~-~ 1 } above { 2("winZ") ~-~ 1 } above 1}} ~~ right ) $INV()$ denotes matrix inversion. W is an unused variable, included for consistent matrix notation.  

SEE ALSO

glGet(3G), gluProject(3G)