MTXFrustum

Syntax

#include <revolution/mtx.h>

void MTXFrustum (
    Mtx44 m,
    f32   t,
    f32   b,
    f32   l,
    f32   r,
    f32   n,
    f32   f );

Arguments

m	New 4x4 projection matrix. The type of m may be either `Mtx44` or `Mtx44Ptr`.
t	Top edge of view volume at the near clipping plane.
b	Bottom edge of view volume at the near clipping plane.
l	Left edge of view volume at the near clipping plane.
r	Right edge of view volume at the near clipping plane.
n	Positive distance to the near clipping plane.
f	Positive distance to the far clipping plane.

Return Values

None.

Description

Sets a 4×4 perspective projection matrix based on the dimensions of the viewing volume. This matrix is used by the GX API to transform points to screen space.

For normal perspective projection, the axis of projection is the -Z axis, so t = positive, b = -t, r = positive, and l = -r. Both n and f must be positive distances.

Note: m negates a point's Z values, so pre-transformed points should have negative Z values in eye space in order to be visible after projection.

Revision History

2006/03/01 Initial version.