gluUnProject4

Nom

gluUnProject4 - map window and clip coordinates to object coordinates.

Prototype

GLint gluUnProject4 (GLdouble winX,
                     GLdouble winY,
                     GLdouble winZ,
                     GLdouble clipW,
                     const GLdouble *model,
                     const GLdouble *proj,
                     const GLint *view,
                     GLdouble near,
                     GLdouble far,
                     GLdouble* objX,
                     GLdouble* objY,
                     GLdouble* objZ,
                     GLdouble* objW);

Paramètres

winX, winY, winZ

Specify the window coordinates to be mapped.

clipW

Specify the clip w coordinate to be mapped.

model

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

proj

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

view

Specifies the viewport (as from a glGetIntegerv call).

near, far

Specifies the near and far planes (as from a glGetDoublev call).

objX, objY, objZ, objW

Returns the computed object coordinates.

Description

gluUnProject4 maps the specified window coordinates winX, winY and winZ and its clip w coordinate clipW into object coordinates (objX, objY, objZ, objW) using model, proj and view. clipW can be other than 1 as for vertices in glFeedbackBuffer when data type GL_4D_COLOR_TEXTURE is returned. This also handles the case where the near and far planes are different from the default, 0 and 1, respectively. A return value of GL_TRUE indicates success; a return value of GL_FALSE indicates failure.

To compute the coordinates (objX, objY, objZ and objW), gluUnProject4 multiplies the normalized device coordinates by the inverse of model*proj as follows:

                                2(winX - view[0])
                                -----------------  - 1
                                     view[2]

           objX                 2(winY - view[1])
           objY   =  INV(PM)    -----------------  - 1
           objZ                      view[3]
            W
                                  2(winZ - near)
                                -----------------  - 1
                                    (far - near)

                                      clipW


       INV() denotes matrix inversion.

gluUnProject4 is equivalent to gluUnProject when clipW is 1, near is 0 and far is 1.

Notes

gluUnProject4 n'est disponible qu'à partir de la version 1.3 de GLU.

Voir aussi

glGet, glFeedbackBuffer, gluProject, gluUnProject.