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

6       gluPerspective - set up a perspective projection matrix
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C SPECIFICATION

9       void gluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear,
10                           GLdouble zFar);
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PARAMETERS

13       fovy
14           Specifies the field of view angle, in degrees, in the y direction.
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16       aspect
17           Specifies the aspect ratio that determines the field of view in the
18           x direction. The aspect ratio is the ratio of x (width) to y
19           (height).
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21       zNear
22           Specifies the distance from the viewer to the near clipping plane
23           (always positive).
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25       zFar
26           Specifies the distance from the viewer to the far clipping plane
27           (always positive).
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DESCRIPTION

30       gluPerspective specifies a viewing frustum into the world coordinate
31       system. In general, the aspect ratio in gluPerspective should match the
32       aspect ratio of the associated viewport. For example, aspect = 2.0
33       means the viewer's angle of view is twice as wide in x as it is in y.
34       If the viewport is twice as wide as it is tall, it displays the image
35       without distortion.
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37       The matrix generated by gluPerspective is multipled by the current
38       matrix, just as if glMultMatrix() were called with the generated
39       matrix. To load the perspective matrix onto the current matrix stack
40       instead, precede the call to gluPerspective with a call to
41       glLoadIdentity().
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43       Given f defined as follows:
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45       f = cotangent ⁡ fovy 2 The generated matrix is
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47       f aspect 0 0 0 0 f 0 0 0 0 zFar + zNear zNear - zFar 2 × zFar × zNear
48       zNear - zFar 0 0 -1 0
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NOTES

51       Depth buffer precision is affected by the values specified for zNear
52       and zFar. The greater the ratio of zFar to zNear is, the less effective
53       the depth buffer will be at distinguishing between surfaces that are
54       near each other. If
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56       r = zFar zNear
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58       roughly log 2 ⁡ r bits of depth buffer precision are lost. Because r
59       approaches infinity as zNear approaches 0, zNear must never be set to
60       0.
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SEE ALSO

63       gluOrtho2D(), glFrustum(), glLoadIdentity(), glMultMatrix()
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66       Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed
67       under the SGI Free Software B License. For details, see
68       http://oss.sgi.com/projects/FreeB/.
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AUTHORS

71       opengl.org
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75opengl.org                        07/13/2018                GLUPERSPECTIVE(3G)
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