#include <revolution/mtx.h>
void MTXLightFrustum(
Mtx m,
f32 t,
f32 b,
f32 l,
f32 r,
f32 n,
f32 scaleS,
f32 scaleT,
f32 transS,
f32 transT );m |
New 3x4 projection matrix. m may be either a Mtx or a MtxPtr.. |
t |
Top edge of view volume at the near clipping plane. |
|
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 near clipping plane. |
scaleS |
Scale in the S direction for projected coordinates (usually 0.5). |
scaleT |
Scale in the T direction for projected coordinates (usually 0.5). |
transS |
Translate in the S direction for projected coordinates (usually 0.5). |
transT |
Translate in the T direction for projected coordinates (usually 0.5). |
None.
Sets a 3x4 perspective projection matrix from viewing volume dimensions, two scale values, and two translation values. This matrix is used to project points into texture space and yield texture coordinates.
For normal perspective projections, the axis of projection is the -z axis, so t = positive, b = -t, r = positive, and l = -r. n must be given as a positive distance.
Standard projection yields values ranging from -1.0 to 1.0 in both dimensions of the front clipping plane. Since texture coordinates should usually be within the range of 0.0 to 1.0, we have added a scale and translation value for both S and T. The most common way to use these values is to set all of them to 0.5 (so that points in the range of -1.0 to 1.0 are first scaled by 0.5) to be in the range of -0.5 to 0.5. Then they are translated by 0.5 to be in the range of 0.0 to 1.0. Other values can be used for translation and scale to yield different effects.
Mtx, MtxPtr, MTXLightOrtho, MtxLightPerspective
03/01/2006 Initial version.