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)