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

6       gluLookAt - define a viewing transformation
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C SPECIFICATION

9       void gluLookAt(GLdouble eyeX, GLdouble eyeY, GLdouble eyeZ,
10                      GLdouble centerX, GLdouble centerY, GLdouble centerZ,
11                      GLdouble upX, GLdouble upY, GLdouble upZ);
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PARAMETERS

14       eyeX, eyeY, eyeZ
15           Specifies the position of the eye point.
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17       centerX, centerY, centerZ
18           Specifies the position of the reference point.
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20       upX, upY, upZ
21           Specifies the direction of the up vector.
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DESCRIPTION

24       gluLookAt creates a viewing matrix derived from an eye point, a
25       reference point indicating the center of the scene, and an UP vector.
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27       The matrix maps the reference point to the negative z axis and the eye
28       point to the origin. When a typical projection matrix is used, the
29       center of the scene therefore maps to the center of the viewport.
30       Similarly, the direction described by the UP vector projected onto the
31       viewing plane is mapped to the positive y axis so that it points upward
32       in the viewport. The UP vector must not be parallel to the line of
33       sight from the eye point to the reference point.
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35       Let
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37       F = centerX - eyeX centerY - eyeY centerZ - eyeZ
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39       Let UP be the vector upX upY upZ.
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41       Then normalize as follows: f = F F
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43       UP ″ = UP UP
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45       Finally, let s = f × UP ″, and u = s s × f.
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47       M is then constructed as follows: M = s ⁡ 0 s ⁡ 1 s ⁡ 2 0 u ⁡ 0 u ⁡ 1 u
48       ⁡ 2 0 - f ⁡ 0 - f ⁡ 1 - f ⁡ 2 0 0 0 0 1
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50       and gluLookAt is equivalent to
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52           glMultMatrixf(M);
53           glTranslated(-eyex, -eyey, -eyez);
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SEE ALSO

58       gluPerspective(), glFrustum()
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61       Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed
62       under the SGI Free Software B License. For details, see
63       http://oss.sgi.com/projects/FreeB/.
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AUTHORS

66       opengl.org
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70opengl.org                        07/13/2018                     GLULOOKAT(3G)
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