1GLUUNPROJECT4(3G)                                            GLUUNPROJECT4(3G)
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NAME

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

10       GLint gluUnProject4( GLdouble winX,
11                            GLdouble winY,
12                            GLdouble winZ,
13                            GLdouble clipW,
14                            const GLdouble *model,
15                            const GLdouble *proj,
16                            const GLint *view,
17                            GLdouble near,
18                            GLdouble far,
19                            GLdouble* objX,
20                            GLdouble* objY,
21                            GLdouble* objZ,
22                            GLdouble* objW )
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PARAMETERS

26       winX, winY, winZ
27                       Specify the window coordinates to be mapped.
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29       clipW           Specify the clip w coordinate to be mapped.
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31       model           Specifies  the modelview matrix (as from a glGetDoublev
32                       call).
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34       proj            Specifies the projection matrix (as from a glGetDoublev
35                       call).
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37       view            Specifies the viewport (as from a glGetIntegerv call).
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39       near, far       Specifies  the near and far planes (as from a glGetDou‐
40                       blev call).
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42       objX, objY, objZ, objW
43                       Returns the computed object coordinates.
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DESCRIPTION

46       gluUnProject4 maps the specified window coordinates winX, winY and winZ
47       and  its  clip  w coordinate clipW into object coordinates (objX, objY,
48       objZ, objW) using model, proj and view. clipW can be other  than  1  as
49       for  vertices in glFeedbackBuffer when data type GL_4D_COLOR_TEXTURE is
50       returned.  This also handles the case where the near and far planes are
51       different  from  the default, 0 and 1, respectively.  A return value of
52       GL_TRUE indicates success; a return value of GL_FALSE  indicates  fail‐
53       ure.
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55       To  compute  the coordinates (objX, objY, objZ and objW), gluUnProject4
56       multiplies  the  normalized  device  coordinates  by  the  inverse   of
57       model*proj as follows:
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60                           objX
61                          ⎛⎝objY⎞⎠=INV(PM)⎛⎝2_(_w_i_nv_Xi_−e_vw_i[_e2_w]_[_0_]_)_−1⎞⎠
62                           objZ          2_(_w_i_nv_Yi_−e_vw_i[_e3_w]_[_1_]_)_−1
63                           objW           2_((_wf_ia_nr_Z−_−n_ne_ea_ar_r)_)_−1
64                                               clipW
65       INV() denotes matrix inversion.
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67       gluUnProject4  is equivalent to gluUnProject when clipW is 1, near is 0
68       and far is 1.
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NOTES

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

74       glGet(3G), glFeedbackBuffer(3G), gluProject(3G), gluUnProject(3G)
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78                                                             GLUUNPROJECT4(3G)
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