1GLUPROJECT(3G)                                                  GLUPROJECT(3G)
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NAME

6       gluProject - map object coordinates to window coordinates
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C SPECIFICATION

10       GLint gluProject( GLdouble objX,
11                         GLdouble objY,
12                         GLdouble objZ,
13                         const GLdouble *model,
14                         const GLdouble *proj,
15                         const GLint *view,
16                         GLdouble* winX,
17                         GLdouble* winY,
18                         GLdouble* winZ )
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20       delim $$
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PARAMETERS

23       objX, objY, objZ
24                       Specify the object coordinates.
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26       model           Specifies  the  current  modelview  matrix  (as  from a
27                       glGetDoublev call).
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29       proj            Specifies the current  projection  matrix  (as  from  a
30                       glGetDoublev call).
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32       view            Specifies the current viewport (as from a glGetIntegerv
33                       call).
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35       winX, winY, winZ
36                       Return the computed window coordinates.
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DESCRIPTION

39       gluProject transforms the  specified  object  coordinates  into  window
40       coordinates  using model, proj, and view. The result is stored in winX,
41       winY, and winZ. A return value of GL_TRUE indicates success,  a  return
42       value of GL_FALSE indicates failure.
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44       To  compute  the coordinates, let $v ~=~ ("objX", "objY", "objZ", 1.0)$
45       represented as a matrix with 4 rows and 1 column.  Then gluProject com‐
46       putes $v sup prime$ as follows:
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48       v sup prime ~=~ P ~times~ M ~times~ v
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50       where  $P$  is  the  current projection matrix proj, $M$ is the current
51       modelview matrix model (both represented as $4  times  4$  matrices  in
52       column-major order) and '$times$' represents matrix multiplication.
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54       The window coordinates are then computed as follows:
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56       "winX" ~=~ "view" (0) ~+~ "view" (2) ~*~ (v sup prime (0) ~+~ 1)~/~2
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58       "winY" ~=~ "view" (1) ~+~ "view" (3)~*~(v sup prime (1) ~+~ 1)~/~2
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60       "winZ" ~=~ (v sup prime (2)  ~+~ 1)~/~ 2
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SEE ALSO

64       glGet(3G), gluUnProject(3G)
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69                                                                GLUPROJECT(3G)