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/**
* @(#) MatrixFuncs.java
* @(#) author: Ronald B. Cemer
* @(#) version: 1.0
*/
import java.io.*;
public class MatrixFuncs
{
public static final float M_PI = 3.14159265359f;
// Given the angle in degs, create a 4x4 matrix
// in mtx which rotates around the X axis.
public void rotateAroundX(float degs, float mtx[])
{
float rads, rsin, rcos;
rads = degs*(M_PI/180.0f);
rsin = (float)Math.sin(rads);
rcos = (float)Math.cos(rads);
mtx[0] = 1.0f;
mtx[1] = 0.0f;
mtx[2] = 0.0f;
mtx[3] = 0.0f;
mtx[4] = 0.0f;
mtx[5] = rcos;
mtx[6] = rsin;
mtx[7] = 0.0f;
mtx[8] = 0.0f;
mtx[9] = -rsin;
mtx[10] = rcos;
mtx[11] = 0.0f;
mtx[12] = 0.0f;
mtx[13] = 0.0f;
mtx[14] = 0.0f;
mtx[15] = 1.0f;
}
// Given the angle in degs, create a 4x4 matrix
// in mtx which rotates around the Y axis.
public void rotateAroundY(float degs, float mtx[])
{
float rads, rsin, rcos;
rads = degs*(M_PI/180.0f);
rsin = (float)Math.sin(rads);
rcos = (float)Math.cos(rads);
mtx[0] = rcos;
mtx[1] = 0.0f;
mtx[2] = -rsin;
mtx[3] = 0.0f;
mtx[4] = 0.0f;
mtx[5] = 1.0f;
mtx[6] = 0.0f;
mtx[7] = 0.0f;
mtx[8] = rsin;
mtx[9] = 0.0f;
mtx[10] = rcos;
mtx[11] = 0.0f;
mtx[12] = 0.0f;
mtx[13] = 0.0f;
mtx[14] = 0.0f;
mtx[15] = 1.0f;
}
// Given the angle in degs, create a 4x4 matrix
// in mtx which rotates around the Z axis.
public void rotateAroundZ(float degs, float mtx[])
{
float rads, rsin, rcos;
rads = degs*(M_PI/180.0f);
rsin = (float)Math.sin(rads);
rcos = (float)Math.cos(rads);
mtx[0] = rcos;
mtx[1] = rsin;
mtx[2] = 0.0f;
mtx[3] = 0.0f;
mtx[4] = -rsin;
mtx[5] = rcos;
mtx[6] = 0.0f;
mtx[7] = 0.0f;
mtx[8] = 0.0f;
mtx[9] = 0.0f;
mtx[10] = 1.0f;
mtx[11] = 0.0f;
mtx[12] = 0.0f;
mtx[13] = 0.0f;
mtx[14] = 0.0f;
mtx[15] = 1.0f;
}
// Given two 4x4 matrices in mtx1 and mtx2, multiply
// them and put the result in dest.
// This routine uses a temporary buffer for the result,
// so if dest is the same as mtx1 or mtx2, it will still
// work properly.
public void multiplyMatrices(float mtx1[], float mtx2[], float dest[])
{
float nmtx[] = new float[16];
nmtx[0] =
(mtx1[0]*mtx2[0]) +
(mtx1[1]*mtx2[4]) +
(mtx1[2]*mtx2[8]) +
(mtx1[3]*mtx2[12]);
nmtx[1] =
(mtx1[0]*mtx2[1]) +
(mtx1[1]*mtx2[5]) +
(mtx1[2]*mtx2[9]) +
(mtx1[3]*mtx2[13]);
nmtx[2] =
(mtx1[0]*mtx2[2]) +
(mtx1[1]*mtx2[6]) +
(mtx1[2]*mtx2[10]) +
(mtx1[3]*mtx2[14]);
nmtx[3] =
(mtx1[0]*mtx2[3]) +
(mtx1[1]*mtx2[7]) +
(mtx1[2]*mtx2[11]) +
(mtx1[3]*mtx2[15]);
nmtx[4] =
(mtx1[4]*mtx2[0]) +
(mtx1[5]*mtx2[4]) +
(mtx1[6]*mtx2[8]) +
(mtx1[7]*mtx2[12]);
nmtx[5] =
(mtx1[4]*mtx2[1]) +
(mtx1[5]*mtx2[5]) +
(mtx1[6]*mtx2[9]) +
(mtx1[7]*mtx2[13]);
nmtx[6] =
(mtx1[4]*mtx2[2]) +
(mtx1[5]*mtx2[6]) +
(mtx1[6]*mtx2[10]) +
(mtx1[7]*mtx2[14]);
nmtx[7] =
(mtx1[4]*mtx2[3]) +
(mtx1[5]*mtx2[7]) +
(mtx1[6]*mtx2[11]) +
(mtx1[7]*mtx2[15]);
nmtx[8] =
(mtx1[8]*mtx2[0]) +
(mtx1[9]*mtx2[4]) +
(mtx1[10]*mtx2[8]) +
(mtx1[11]*mtx2[12]);
nmtx[9] =
(mtx1[8]*mtx2[1]) +
(mtx1[9]*mtx2[5]) +
(mtx1[10]*mtx2[9]) +
(mtx1[11]*mtx2[13]);
nmtx[10] =
(mtx1[8]*mtx2[2]) +
(mtx1[9]*mtx2[6]) +
(mtx1[10]*mtx2[10]) +
(mtx1[11]*mtx2[14]);
nmtx[11] =
(mtx1[8]*mtx2[3]) +
(mtx1[9]*mtx2[7]) +
(mtx1[10]*mtx2[11]) +
(mtx1[11]*mtx2[15]);
nmtx[12] =
(mtx1[12]*mtx2[0]) +
(mtx1[13]*mtx2[4]) +
(mtx1[14]*mtx2[8]) +
(mtx1[15]*mtx2[12]);
nmtx[13] =
(mtx1[12]*mtx2[1]) +
(mtx1[13]*mtx2[5]) +
(mtx1[14]*mtx2[9]) +
(mtx1[15]*mtx2[13]);
nmtx[14] =
(mtx1[12]*mtx2[2]) +
(mtx1[13]*mtx2[6]) +
(mtx1[14]*mtx2[10]) +
(mtx1[15]*mtx2[14]);
nmtx[15] =
(mtx1[12]*mtx2[3]) +
(mtx1[13]*mtx2[7]) +
(mtx1[14]*mtx2[11]) +
(mtx1[15]*mtx2[15]);
dest[0] = nmtx[0];
dest[1] = nmtx[1];
dest[2] = nmtx[2];
dest[3] = nmtx[3];
dest[4] = nmtx[4];
dest[5] = nmtx[5];
dest[6] = nmtx[6];
dest[7] = nmtx[7];
dest[8] = nmtx[8];
dest[9] = nmtx[9];
dest[10] = nmtx[10];
dest[11] = nmtx[11];
dest[12] = nmtx[12];
dest[13] = nmtx[13];
dest[14] = nmtx[14];
dest[15] = nmtx[15];
}
}
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