GLUUNPROJECT(3G) GLUUNPROJECT(3G)
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 )
delim $$
PARAMETERS
w'winX winY winZ  'u 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)