gluPerspective

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⁡fovy2

The generated matrix is

 

faspect0000f0000zFar+zNearzNear-zFar2×zFar×zNearzNear-zFar00-10