GLdoubleaspect, GLdoublezNear, GLdoublezFar)

**eqn not supported**

*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).

The matrix
generated by **gluPerspective** is multiplied 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:

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