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GLUPERSPECTIVE(3G)			  OpenGL Manual 		       GLUPERSPECTIVE(3G)

NAME
       gluPerspective - set up a perspective projection matrix

C SPECIFICATION
       void gluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar);

PARAMETERS
       fovy
	   Specifies the field of view angle, in degrees, in the y direction.

       aspect
	   Specifies the aspect ratio that determines the field of view in the x direction. The
	   aspect ratio is the ratio of x (width) to y (height).

       zNear
	   Specifies the distance from the viewer to the near clipping plane (always positive).

       zFar
	   Specifies the distance from the viewer to the far clipping plane (always positive).

DESCRIPTION
       gluPerspective specifies a viewing frustum into the world coordinate system. In general,
       the aspect ratio in gluPerspective should match the aspect ratio of the associated
       viewport. For example, aspect = 2.0 means the viewer's angle of view is twice as wide in x
       as it is in y. If the viewport is twice as wide as it is tall, it displays the image
       without distortion.

       The matrix generated by gluPerspective is multipled by the current matrix, just as if
       glMultMatrix() were called with the generated matrix. To load the perspective matrix onto
       the current matrix stack instead, precede the call to gluPerspective with a call to
       glLoadIdentity().

       Given f defined as follows:

       f = cotangent  fovy 2 The generated matrix is

       f aspect 0 0 0 0 f 0 0 0 0 zFar + zNear zNear - zFar 2 x zFar x zNear zNear - zFar 0 0 -1
       0

NOTES
       Depth buffer precision is affected by the values specified for zNear and zFar. The greater
       the ratio of zFar to zNear is, the less effective the depth buffer will be at
       distinguishing between surfaces that are near each other. If

       r = zFar zNear

       roughly log 2  r bits of depth buffer precision are lost. Because r approaches infinity as
       zNear approaches 0, zNear must never be set to 0.

SEE ALSO
       gluOrtho2D(), glFrustum(), glLoadIdentity(), glMultMatrix()

COPYRIGHT
       Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI
       Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.

AUTHORS
       opengl.org

opengl.org				    06/10/2014			       GLUPERSPECTIVE(3G)
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