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<STRONG>NAME</STRONG>
<STRONG>gluUnProject</STRONG> - map window coordinates to object coordinates
<STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>
GLint <STRONG>gluUnProject</STRONG>( GLdouble <EM>winX</EM>,
GLdouble <EM>winY</EM>,
GLdouble <EM>winZ</EM>,
const GLdouble *<EM>model</EM>,
const GLdouble *<EM>proj</EM>,
const GLint *<EM>view</EM>,
GLdouble* <EM>objX</EM>,
GLdouble* <EM>objY</EM>,
GLdouble* <EM>objZ</EM> )
<STRONG>PARAMETERS</STRONG>
<EM>winX</EM>, <EM>winY</EM>, <EM>winZ</EM>
Specify the window coordinates to be mapped.
<EM>model</EM> Specifies the modelview matrix (as from a
<STRONG>glGetDoublev</STRONG> call).
<EM>proj</EM> Specifies the projection matrix (as from a
<STRONG>glGetDoublev</STRONG> call).
<EM>view</EM> Specifies the viewport (as from a
<STRONG>glGetIntegerv</STRONG> call).
<EM>objX</EM>, <EM>objY</EM>, <EM>objZ</EM>
Returns the computed object coordinates.
<STRONG>DESCRIPTION</STRONG>
<STRONG>gluUnProject</STRONG> maps the specified window coordinates into
object coordinates using <EM>model</EM>, <EM>proj</EM>, and <EM>view</EM>. The result
is stored in <EM>objX</EM>, <EM>objY</EM>, and <EM>objZ</EM>. A return value of <STRONG>GL_TRUE</STRONG>
indicates success; a return value of <STRONG>GL_FALSE</STRONG> indicates
failure.
To compute the coordinates (<EM>objX</EM>, <EM>objY</EM>, and <EM>objZ</EM>),
<STRONG>gluUnProject</STRONG> multiplies the normalized device coordinates by
the inverse of <EM>model</EM>*<EM>proj</EM> as follows:
| |
|<STRONG>______</STRONG>_<STRONG>_</STRONG>_<STRONG>________</STRONG> |
( ) | view[2] - 1 |
| objX | | |
| objY | = INV(PM)|<STRONG>______</STRONG>_<STRONG>_</STRONG>_<STRONG>________</STRONG> - 1 |
| | | view[3] |
| objZ | | 2(winZ) - 1 |
( W ) | |
( 1 )
INV() denotes matrix inversion. W is an unused variable,
included for consistent matrix notation.
<STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>
<STRONG>glGet</STRONG>, <STRONG>gluProject</STRONG>
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