## Name

gluProject — map object coordinates to window coordinates

## C Specification

`GLint `**gluProject**( | GLdouble `objX`, |

| GLdouble `objY`, |

| GLdouble `objZ`, |

| const GLdouble * `model`, |

| const GLdouble * `proj`, |

| const GLint * `view`, |

| GLdouble* `winX`, |

| GLdouble* `winY`, |

| GLdouble* `winZ``)` ; |

## Parameters

`objX`

, `objY`

, `objZ`

Specify the object coordinates.

`model`

Specifies the current modelview matrix (as from a glGetDoublev call).

`proj`

Specifies the current projection matrix (as from a glGetDoublev call).

`view`

Specifies the current viewport (as from a glGetIntegerv call).

`winX`

, `winY`

, `winZ`

Return the computed window coordinates.

## Description

`gluProject`

transforms the specified object coordinates into window coordinates
using `model`

, `proj`

, and `view`

. The result is stored
in `winX`

, `winY`

, and `winZ`

. A return value of
`GLU_TRUE`

indicates success, a return value of `GLU_FALSE`

indicates failure.

To compute the coordinates,
let
v
=
objX
objY
objZ
1.0
represented as a matrix with 4 rows and 1 column.
Then `gluProject`

computes
v
″
as follows:

v
″
=
P
×
M
×
v

where
P
is the current projection matrix `proj`

and
M
is the current
modelview matrix `model`

(both represented as
4
×
4
matrices in column-major order).

The window coordinates are then computed as follows:

winX
=
view
0
+
view
2
×
v
″
0
+
1
2

winY
=
view
1
+
view
3
×
v
″
1
+
1
2

winZ
=
v
″
2
+
1
2

## Copyright

Copyright © 1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.