Perspective
The Perspective function sets up a perspective projection matrix.
Perspective( fovy, aspect, zNear, zFar );
Arguments
fovy
The field of view angle, in degrees, in the y-direction.
aspect
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
The distance from the viewer to the near clipping plane (always positive).
zFar
The distance from the viewer to the far clipping plane (always positive).
Remarks
The Perspective function specifies a viewing frustum into the world coordinate system. In general, the aspect ratio in Perspective 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 Perspective 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 Perspective with a call to LoadIdentity.
See Also