+
+ public Matrix preMultiplyTranslationalComponentBy(Matrix mm) {
+ Vec v = mm.times(getTranslationalComponent());
+ return new Matrix(a, b, c, v.x,
+ e, f, g, v.y,
+ i, j, k, v.z,
+ m, n, o, 1);
+ }
+
+ /** multiply by another matrix */
+ public Matrix times(Matrix z) {
+ float t00 = a;
+ float t01 = b;
+ float t02 = c;
+ float t03 = d;
+ float t10 = e;
+ float t11 = f;
+ float t12 = g;
+ float t13 = h;
+ float t20 = i;
+ float t21 = j;
+ float t22 = k;
+ float t23 = l;
+ float t30 = m;
+ float t31 = n;
+ float t32 = o;
+ float t33 = p;
+ float m00 = z.a;
+ float m01 = z.b;
+ float m02 = z.c;
+ float m03 = z.d;
+ float m10 = z.e;
+ float m11 = z.f;
+ float m12 = z.g;
+ float m13 = z.h;
+ float m20 = z.i;
+ float m21 = z.j;
+ float m22 = z.k;
+ float m23 = z.l;
+ float m30 = z.m;
+ float m31 = z.n;
+ float m32 = z.o;
+ float m33 = z.p;
+ return new Matrix(t00*m00 + t01*m10 + t02*m20 + t03*m30,
+ t00*m01 + t01*m11 + t02*m21 + t03*m31,
+ t00*m02 + t01*m12 + t02*m22 + t03*m32,
+ t00*m03 + t01*m13 + t02*m23 + t03*m33,
+ t10*m00 + t11*m10 + t12*m20 + t13*m30,
+ t10*m01 + t11*m11 + t12*m21 + t13*m31,
+ t10*m02 + t11*m12 + t12*m22 + t13*m32,
+ t10*m03 + t11*m13 + t12*m23 + t13*m33,
+ t20*m00 + t21*m10 + t22*m20 + t23*m30,
+ t20*m01 + t21*m11 + t22*m21 + t23*m31,
+ t20*m02 + t21*m12 + t22*m22 + t23*m32,
+ t20*m03 + t21*m13 + t22*m23 + t23*m33,
+ t30*m00 + t31*m10 + t32*m20 + t33*m30,
+ t30*m01 + t31*m11 + t32*m21 + t33*m31,
+ t30*m02 + t31*m12 + t32*m22 + t33*m32,
+ t30*m03 + t31*m13 + t32*m23 + t33*m33);
+ }
+
+ /** compute the determinant of the matrix */
+ public float determinant() {
+ float m00 = a;
+ float m01 = b;
+ float m02 = c;
+ float m03 = d;
+ float m10 = e;
+ float m11 = f;
+ float m12 = g;
+ float m13 = h;
+ float m20 = i;
+ float m21 = j;
+ float m22 = k;
+ float m23 = l;
+ float m30 = m;
+ float m31 = n;
+ float m32 = o;
+ float m33 = p;
+ return
+ m03 * m12 * m21 * m30-m02 * m13 * m21 * m30-m03 * m11 * m22 * m30+m01 * m13 * m22 * m30+
+ m02 * m11 * m23 * m30-m01 * m12 * m23 * m30-m03 * m12 * m20 * m31+m02 * m13 * m20 * m31+
+ m03 * m10 * m22 * m31-m00 * m13 * m22 * m31-m02 * m10 * m23 * m31+m00 * m12 * m23 * m31+
+ m03 * m11 * m20 * m32-m01 * m13 * m20 * m32-m03 * m10 * m21 * m32+m00 * m13 * m21 * m32+
+ m01 * m10 * m23 * m32-m00 * m11 * m23 * m32-m02 * m11 * m20 * m33+m01 * m12 * m20 * m33+
+ m02 * m10 * m21 * m33-m00 * m12 * m21 * m33-m01 * m10 * m22 * m33+m00 * m11 * m22 * m33;
+ }
+
+ /** compute the inverse of the matrix, returns null if not invertible */
+ public Matrix inverse() {
+ float determinant = determinant();
+ if (determinant==0) return null;
+ float m00 = a;
+ float m01 = b;
+ float m02 = c;
+ float m03 = d;
+ float m10 = e;
+ float m11 = f;
+ float m12 = g;
+ float m13 = h;
+ float m20 = i;
+ float m21 = j;
+ float m22 = k;
+ float m23 = l;
+ float m30 = m;
+ float m31 = n;
+ float m32 = o;
+ float m33 = p;
+ return
+ new Matrix(m12*m23*m31 - m13*m22*m31 + m13*m21*m32 - m11*m23*m32 - m12*m21*m33 + m11*m22*m33,
+ m03*m22*m31 - m02*m23*m31 - m03*m21*m32 + m01*m23*m32 + m02*m21*m33 - m01*m22*m33,
+ m02*m13*m31 - m03*m12*m31 + m03*m11*m32 - m01*m13*m32 - m02*m11*m33 + m01*m12*m33,
+ m03*m12*m21 - m02*m13*m21 - m03*m11*m22 + m01*m13*m22 + m02*m11*m23 - m01*m12*m23,
+ m13*m22*m30 - m12*m23*m30 - m13*m20*m32 + m10*m23*m32 + m12*m20*m33 - m10*m22*m33,
+ m02*m23*m30 - m03*m22*m30 + m03*m20*m32 - m00*m23*m32 - m02*m20*m33 + m00*m22*m33,
+ m03*m12*m30 - m02*m13*m30 - m03*m10*m32 + m00*m13*m32 + m02*m10*m33 - m00*m12*m33,
+ m02*m13*m20 - m03*m12*m20 + m03*m10*m22 - m00*m13*m22 - m02*m10*m23 + m00*m12*m23,
+ m11*m23*m30 - m13*m21*m30 + m13*m20*m31 - m10*m23*m31 - m11*m20*m33 + m10*m21*m33,
+ m03*m21*m30 - m01*m23*m30 - m03*m20*m31 + m00*m23*m31 + m01*m20*m33 - m00*m21*m33,
+ m01*m13*m30 - m03*m11*m30 + m03*m10*m31 - m00*m13*m31 - m01*m10*m33 + m00*m11*m33,
+ m03*m11*m20 - m01*m13*m20 - m03*m10*m21 + m00*m13*m21 + m01*m10*m23 - m00*m11*m23,
+ m12*m21*m30 - m11*m22*m30 - m12*m20*m31 + m10*m22*m31 + m11*m20*m32 - m10*m21*m32,
+ m01*m22*m30 - m02*m21*m30 + m02*m20*m31 - m00*m22*m31 - m01*m20*m32 + m00*m21*m32,
+ m02*m11*m30 - m01*m12*m30 - m02*m10*m31 + m00*m12*m31 + m01*m10*m32 - m00*m11*m32,
+ m01*m12*m20 - m02*m11*m20 + m02*m10*m21 - m00*m12*m21 - m01*m10*m22 + m00*m11*m22)
+ .times(1/determinant);
+ }
+
+ public String toString() {
+ return
+ "\n [ " + a + "\t" + b + "\t" + c + "\t" + d + "\t" + "]" +
+ "\n [ " + e + "\t" + f + "\t" + g + "\t" + h + "\t" + "]" +
+ "\n [ " + i + "\t" + j + "\t" + k + "\t" + l + "\t" + "]" +
+ "\n [ " + m + "\t" + n + "\t" + o + "\t" + p + "\t" + "]\n";
+ }
+
+ public boolean equals(Object oo) {
+ if (oo==null) return false;
+ if (!(oo instanceof Matrix)) return false;
+ Matrix z = (Matrix)oo;
+ return
+ near(a,z.a) &&
+ near(b,z.b) &&
+ near(c,z.c) &&
+ near(d,z.d) &&
+ near(e,z.e) &&
+ near(f,z.f) &&
+ near(g,z.g) &&
+ near(h,z.h) &&
+ near(i,z.i) &&
+ near(j,z.j) &&
+ near(k,z.k) &&
+ near(l,z.l) &&
+ near(m,z.m) &&
+ near(n,z.n) &&
+ near(o,z.o) &&
+ near(p,z.p);
+ }
+ private static final float EPSILON = 0.001f;
+ private static boolean near(float a, float b) { return Math.abs(a-b)<EPSILON; }
+
+ public int hashCode() {
+ return
+ Float.floatToIntBits(a) ^
+ Float.floatToIntBits(b) ^
+ Float.floatToIntBits(c) ^
+ Float.floatToIntBits(d) ^
+ Float.floatToIntBits(e) ^
+ Float.floatToIntBits(f) ^
+ Float.floatToIntBits(g) ^
+ Float.floatToIntBits(h) ^
+ Float.floatToIntBits(i) ^
+ Float.floatToIntBits(j) ^
+ Float.floatToIntBits(k) ^
+ Float.floatToIntBits(l) ^
+ Float.floatToIntBits(m) ^
+ Float.floatToIntBits(n) ^
+ Float.floatToIntBits(o) ^
+ Float.floatToIntBits(p);
+ }
+
+ public static Matrix getProjectionMatrix(GL gl) {
+ int view[] = new int[4];
+ double mvmatrix[] = new double[16];
+ double projmatrix[] = new double[16];
+ gl.glGetIntegerv(GL.GL_VIEWPORT, view, 0);
+ gl.glGetDoublev(GL.GL_MODELVIEW_MATRIX, mvmatrix, 0);
+ gl.glGetDoublev(GL.GL_PROJECTION_MATRIX, projmatrix, 0);
+ Matrix m = new Matrix(mvmatrix[0],
+ mvmatrix[4],
+ mvmatrix[8],
+ mvmatrix[12],
+ mvmatrix[1],
+ mvmatrix[5],
+ mvmatrix[9],
+ mvmatrix[13],
+ mvmatrix[2],
+ mvmatrix[6],
+ mvmatrix[10],
+ mvmatrix[14],
+ mvmatrix[3],
+ mvmatrix[7],
+ mvmatrix[11],
+ mvmatrix[15]);
+ Matrix p = new Matrix(projmatrix[0],
+ projmatrix[4],
+ projmatrix[8],
+ projmatrix[12],
+ projmatrix[1],
+ projmatrix[5],
+ projmatrix[9],
+ projmatrix[13],
+ projmatrix[2],
+ projmatrix[6],
+ projmatrix[10],
+ projmatrix[14],
+ projmatrix[3],
+ projmatrix[7],
+ projmatrix[11],
+ projmatrix[15]);
+ Matrix z =
+ new Matrix(0.5*view[2], 0, 0, view[0]+view[2]*0.5,
+ 0, 0.5*view[3], 0, view[1]+view[3]*0.5,
+ 0, 0, 0.5, 0.5,
+ 0, 0, 0, 1);
+ return z.times(p).times(m);
+ }
+