1GLUUNPROJECT4(3G)                OpenGL Manual               GLUUNPROJECT4(3G)
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NAME

6       gluUnProject4 - map window and clip coordinates to object coordinates
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C SPECIFICATION

9       GLint gluUnProject4(GLdouble winX, GLdouble winY, GLdouble winZ,
10                           GLdouble clipW, const GLdouble * model,
11                           const GLdouble * proj, const GLint * view,
12                           GLdouble nearVal, GLdouble farVal, GLdouble* objX,
13                           GLdouble* objY, GLdouble* objZ, GLdouble* objW);
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PARAMETERS

16       winX, winY, winZ
17           Specify the window coordinates to be mapped.
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19       clipW
20           Specify the clip w coordinate to be mapped.
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22       model
23           Specifies the modelview matrix (as from a glGetDoublev() call).
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25       proj
26           Specifies the projection matrix (as from a glGetDoublev() call).
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28       view
29           Specifies the viewport (as from a glGetIntegerv() call).
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31       nearVal, farVal
32           Specifies the near and far planes (as from a glGetDoublev() call).
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34       objX, objY, objZ, objW
35           Returns the computed object coordinates.
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DESCRIPTION

38       gluUnProject4 maps the specified window coordinatesi: winX, winY, and
39       winZ and its clip w coordinate clipW into object coordinates objX objY
40       objZ objW using model, proj, and view.  clipW can be other than 1 as
41       for vertices in glFeedbackBuffer() when data type GLU_4D_COLOR_TEXTURE
42       is returned. This also handles the case where the nearVal and farVal
43       planes are different from the default, 0 and 1, respectively. A return
44       value of GLU_TRUE indicates success; a return value of GLU_FALSE
45       indicates failure.
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47       To compute the coordinates objX objY objZ objW, gluUnProject4
48       multiplies the normalized device coordinates by the inverse of model *
49       proj as follows:
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51       objX objY objZ objW = INV ⁡ P ⁢ M ⁢ 2 ⁡ winX - view ⁡ 0 view ⁡ 2 - 1 2
52       ⁡ winY - view ⁡ 1 view ⁡ 3 - 1 2 ⁡ winZ - nearVal farVal - nearVal - 1
53       clipW
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55       INV denotes matrix inversion.
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57       gluUnProject4 is equivalent to gluUnProject() when clipW is 1, nearVal
58       is 0, and farVal is 1.
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NOTES

61       gluUnProject4 is available only if the GLU version is 1.3 or greater.
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SEE ALSO

64       gluProject(), gluUnProject(), glFeedbackBuffer(), glGet()
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67       Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed
68       under the SGI Free Software B License. For details, see
69       http://oss.sgi.com/projects/FreeB/.
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AUTHORS

72       opengl.org
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76opengl.org                        06/10/2014                 GLUUNPROJECT4(3G)
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