gluPerspective — set up a perspective projection matrix
Specifies the field of view angle, in degrees, in the y direction.
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).
Specifies the distance from the viewer to the near clipping plane (always positive).
Specifies the distance from the viewer to the far clipping plane (always positive).
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,
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:
The generated matrix is
Depth buffer precision is affected by the values specified for
The greater the ratio of
the less effective the depth buffer will be at distinguishing between
surfaces that are near each other.
bits of depth buffer precision are lost.
approaches infinity as
zNear approaches 0,
zNear must never be set to 0.
Copyright © 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/.