gluUnProject(3) gluUnProject(3)
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 )
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 coordi-
nates 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 multi-
plies the normalized device coordinates by the inverse of model*proj as
follows:
2(winX - view[0])
----------------- - 1
view[2]
objX 2(winY - view[1])
objY = INV(PM) ----------------- - 1
objZ view[3]
W
2(winZ) - 1
1
INV() denotes matrix inversion. W is an unused variable, included for
consistent matrix notation.
SEE ALSO
glGet(3), gluProject(3)
gluUnProject(3)
Mac OS X 10.6 - Generated Thu Sep 17 20:20:37 CDT 2009