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• Author : matthieu
  Date : 2006-11-29 17:01:51
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  Message : GLU manual pages from monolithic tree

• doc/gl-docs/GLU/unproject.3gl

• '\" e
  '\"! eqn | mmdoc
  '\"macro stdmacro
  .ds Vn Version 1.2
  .ds Dt 6 March 1997
  .ds Re Release 1.2.0
  .ds Dp May 02 11:53
  .ds Dm 37 unproject
  .ds Xs 63442 4 unproject.gl
  .TH GLUUNPROJECT 3G
  .SH NAME
  .B "gluUnProject
  \- map window coordinates to object coordinates
  
  .SH C SPECIFICATION
  GLint \f3gluUnProject\fP(
  GLdouble \fIwinX\fP,
  .nf
  .ta \w'\f3GLint \fPgluUnProject( 'u
  	GLdouble \fIwinY\fP,
  	GLdouble \fIwinZ\fP,
  	const GLdouble \fI*model\fP,
  	const GLdouble \fI*proj\fP,
  	const GLint \fI*view\fP,
  	GLdouble* \fIobjX\fP,
  	GLdouble* \fIobjY\fP,
  	GLdouble* \fIobjZ\fP )
  .fi
  
  .EQ
  delim $$
  .EN
  .SH PARAMETERS
  .TP \w'\f2winX\fP\ \f2winY\fP\ \f2winZ\fP\ \ 'u 
  \f2winX\fP, \f2winY\fP, \f2winZ\fP
  Specify the window coordinates to be mapped.
  .TP
  \f2model\fP
  Specifies the modelview matrix (as from a \f3glGetDoublev\fP call).
  .TP
  \f2proj\fP
  Specifies the projection matrix (as from a \f3glGetDoublev\fP call).
  .TP
  \f2view\fP
  Specifies the viewport (as from a \f3glGetIntegerv\fP call).
  .TP
  \f2objX\fP, \f2objY\fP, \f2objZ\fP
  Returns the computed object coordinates.
  .SH DESCRIPTION
  \%\f3gluUnProject\fP maps the specified window coordinates into object 
  coordinates using \f2model\fP, \f2proj\fP, and \f2view\fP.
  The result is stored in \f2objX\fP, \f2objY\fP, and \f2objZ\fP. A return value of 
  \%\f3GL_TRUE\fP indicates success; a return value of \%\f3GL_FALSE\fP
  indicates failure.
  .P
  To compute the coordinates (\f2objX\fP, \f2objY\fP, and \f2objZ\fP),
  \%\f3gluUnProject\fP multiplies the normalized device coordinates by the inverse of
  \f2model\fP*\f2proj\fP as follows:
  
  .P
  .ce
  .EQ
  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 )
  .EN
  .bp
  $INV()$ denotes matrix inversion. 
  W is an unused variable, included for consistent matrix notation.
  .SH SEE ALSO
  \f3glGet(3G)\fP, \%\f3gluProject(3G)\fP