org.jbox2d.common.Mat33 Maven / Gradle / Ivy
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* Copyright (c) 2013, Daniel Murphy
* All rights reserved.
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package org.jbox2d.common;
import java.io.Serializable;
/**
* A 3-by-3 matrix. Stored in column-major order.
*
* @author Daniel Murphy
*/
public class Mat33 implements Serializable {
private static final long serialVersionUID = 2L;
public static final Mat33 IDENTITY = new Mat33(new Vec3(1, 0, 0), new Vec3(0, 1, 0), new Vec3(0,
0, 1));
public final Vec3 ex, ey, ez;
public Mat33() {
ex = new Vec3();
ey = new Vec3();
ez = new Vec3();
}
public Mat33(float exx, float exy, float exz, float eyx, float eyy, float eyz, float ezx,
float ezy, float ezz) {
ex = new Vec3(exx, exy, exz);
ey = new Vec3(eyx, eyy, eyz);
ez = new Vec3(ezx, ezy, ezz);
}
public Mat33(Vec3 argCol1, Vec3 argCol2, Vec3 argCol3) {
ex = argCol1.clone();
ey = argCol2.clone();
ez = argCol3.clone();
}
public void setZero() {
ex.setZero();
ey.setZero();
ez.setZero();
}
public void set(float exx, float exy, float exz, float eyx, float eyy, float eyz, float ezx,
float ezy, float ezz) {
ex.x = exx;
ex.y = exy;
ex.z = exz;
ey.x = eyx;
ey.y = eyy;
ey.z = eyz;
ez.x = eyx;
ez.y = eyy;
ez.z = eyz;
}
public void set(Mat33 mat) {
Vec3 vec = mat.ex;
ex.x = vec.x;
ex.y = vec.y;
ex.z = vec.z;
Vec3 vec1 = mat.ey;
ey.x = vec1.x;
ey.y = vec1.y;
ey.z = vec1.z;
Vec3 vec2 = mat.ez;
ez.x = vec2.x;
ez.y = vec2.y;
ez.z = vec2.z;
}
public void setIdentity() {
ex.x = (float) 1;
ex.y = (float) 0;
ex.z = (float) 0;
ey.x = (float) 0;
ey.y = (float) 1;
ey.z = (float) 0;
ez.x = (float) 0;
ez.y = (float) 0;
ez.z = (float) 1;
}
// / Multiply a matrix times a vector.
public static final Vec3 mul(Mat33 A, Vec3 v) {
return new Vec3(v.x * A.ex.x + v.y * A.ey.x + v.z + A.ez.x, v.x * A.ex.y + v.y * A.ey.y + v.z
* A.ez.y, v.x * A.ex.z + v.y * A.ey.z + v.z * A.ez.z);
}
public static final Vec2 mul22(Mat33 A, Vec2 v) {
return new Vec2(A.ex.x * v.x + A.ey.x * v.y, A.ex.y * v.x + A.ey.y * v.y);
}
public static final void mul22ToOut(Mat33 A, Vec2 v, Vec2 out) {
final float tempx = A.ex.x * v.x + A.ey.x * v.y;
out.y = A.ex.y * v.x + A.ey.y * v.y;
out.x = tempx;
}
public static final void mul22ToOutUnsafe(Mat33 A, Vec2 v, Vec2 out) {
assert (v != out);
out.y = A.ex.y * v.x + A.ey.y * v.y;
out.x = A.ex.x * v.x + A.ey.x * v.y;
}
public static final void mulToOut(Mat33 A, Vec3 v, Vec3 out) {
final float tempy = v.x * A.ex.y + v.y * A.ey.y + v.z * A.ez.y;
final float tempz = v.x * A.ex.z + v.y * A.ey.z + v.z * A.ez.z;
out.x = v.x * A.ex.x + v.y * A.ey.x + v.z * A.ez.x;
out.y = tempy;
out.z = tempz;
}
public static final void mulToOutUnsafe(Mat33 A, Vec3 v, Vec3 out) {
assert (out != v);
out.x = v.x * A.ex.x + v.y * A.ey.x + v.z * A.ez.x;
out.y = v.x * A.ex.y + v.y * A.ey.y + v.z * A.ez.y;
out.z = v.x * A.ex.z + v.y * A.ey.z + v.z * A.ez.z;
}
/**
* Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
* in one-shot cases.
*
* @param b
* @return
*/
public final Vec2 solve22(Vec2 b) {
Vec2 x = new Vec2();
solve22ToOut(b, x);
return x;
}
/**
* Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
* in one-shot cases.
*
* @param b
* @return
*/
public final void solve22ToOut(Vec2 b, Vec2 out) {
final float a11 = ex.x, a12 = ey.x, a21 = ex.y, a22 = ey.y;
float det = a11 * a22 - a12 * a21;
if (det != 0.0f) {
det = 1.0f / det;
}
out.x = det * (a22 * b.x - a12 * b.y);
out.y = det * (a11 * b.y - a21 * b.x);
}
// djm pooling from below
/**
* Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
* in one-shot cases.
*
* @param b
* @return
*/
public final Vec3 solve33(Vec3 b) {
Vec3 x = new Vec3();
solve33ToOut(b, x);
return x;
}
/**
* Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
* in one-shot cases.
*
* @param b
* @param out the result
*/
public final void solve33ToOut(Vec3 b, Vec3 out) {
assert (b != out);
Vec3.crossToOutUnsafe(ey, ez, out);
float det = Vec3.dot(ex, out);
if (det != 0.0f) {
det = 1.0f / det;
}
Vec3.crossToOutUnsafe(ey, ez, out);
final float x = det * Vec3.dot(b, out);
Vec3.crossToOutUnsafe(b, ez, out);
final float y = det * Vec3.dot(ex, out);
Vec3.crossToOutUnsafe(ey, b, out);
float z = det * Vec3.dot(ex, out);
out.x = x;
out.y = y;
out.z = z;
}
public void getInverse22(Mat33 M) {
float a = ex.x, b = ey.x, c = ex.y, d = ey.y;
float det = a * d - b * c;
if (det != 0.0f) {
det = 1.0f / det;
}
M.ex.x = det * d;
M.ey.x = -det * b;
M.ex.z = 0.0f;
M.ex.y = -det * c;
M.ey.y = det * a;
M.ey.z = 0.0f;
M.ez.x = 0.0f;
M.ez.y = 0.0f;
M.ez.z = 0.0f;
}
// / Returns the zero matrix if singular.
public void getSymInverse33(Mat33 M) {
float bx = ey.y * ez.z - ey.z * ez.y;
float by = ey.z * ez.x - ey.x * ez.z;
float bz = ey.x * ez.y - ey.y * ez.x;
float det = ex.x * bx + ex.y * by + ex.z * bz;
if (det != 0.0f) {
det = 1.0f / det;
}
float a11 = ex.x, a12 = ey.x, a13 = ez.x;
float a22 = ey.y, a23 = ez.y;
float a33 = ez.z;
M.ex.x = det * (a22 * a33 - a23 * a23);
M.ex.y = det * (a13 * a23 - a12 * a33);
M.ex.z = det * (a12 * a23 - a13 * a22);
M.ey.x = M.ex.y;
M.ey.y = det * (a11 * a33 - a13 * a13);
M.ey.z = det * (a13 * a12 - a11 * a23);
M.ez.x = M.ex.z;
M.ez.y = M.ey.z;
M.ez.z = det * (a11 * a22 - a12 * a12);
}
public final static void setScaleTransform(float scale, Mat33 out) {
out.ex.x = scale;
out.ey.y = scale;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((ex == null) ? 0 : ex.hashCode());
result = prime * result + ((ey == null) ? 0 : ey.hashCode());
result = prime * result + ((ez == null) ? 0 : ez.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
Mat33 other = (Mat33) obj;
if (ex == null) {
if (other.ex != null) return false;
} else if (!ex.equals(other.ex)) return false;
if (ey == null) {
if (other.ey != null) return false;
} else if (!ey.equals(other.ey)) return false;
if (ez == null) {
if (other.ez != null) return false;
} else if (!ez.equals(other.ez)) return false;
return true;
}
}
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