prestonbane/src/engine/math/Matrix4f.java

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//      Magicbane Emulator Project © 2013 - 2022
//                www.magicbane.com

package engine.math;

import org.pmw.tinylog.Logger;

import java.nio.FloatBuffer;


/**
 * <code>Matrix4f</code> defines and maintains a 4x4 matrix in row major order.
 * This matrix is intended for use in a translation and rotational capacity. It
 * provides convenience methods for creating the matrix from a multitude of
 * sources.
 * <p>
 * Matrices are stored assuming column vectors on the right, with the
 * translation in the rightmost column. Element numbering is row,column, so m03
 * is the zeroth row, third column, which is the "x" translation part. This
 * means that the implicit storage order is column major. However, the get() and
 * set() functions on float arrays default to row major order!
 */
public class Matrix4f {

    public float m00, m01, m02, m03;

    public float m10, m11, m12, m13;

    public float m20, m21, m22, m23;

    public float m30, m31, m32, m33;

    /**
     * Constructor instantiates a new <code>Matrix</code> that is set to the
     * identity matrix.
     */
    public Matrix4f() {
        loadIdentity();
    }

    /**
     * constructs a matrix with the given values.
     */
    public Matrix4f(float m00, float m01, float m02, float m03, float m10, float m11, float m12, float m13, float m20, float m21,
                    float m22, float m23, float m30, float m31, float m32, float m33) {

        this.m00 = m00;
        this.m01 = m01;
        this.m02 = m02;
        this.m03 = m03;
        this.m10 = m10;
        this.m11 = m11;
        this.m12 = m12;
        this.m13 = m13;
        this.m20 = m20;
        this.m21 = m21;
        this.m22 = m22;
        this.m23 = m23;
        this.m30 = m30;
        this.m31 = m31;
        this.m32 = m32;
        this.m33 = m33;
    }

    /**
     * Create a new Matrix4f, given data in column-major format.
     *
     * @param array An array of 16 floats in column-major format (translation in
     *              elements 12, 13 and 14).
     * @throws Exception
     */
    public Matrix4f(float[] array) throws Exception {
        set(array, false);
    }

    /**
     * Constructor instantiates a new <code>Matrix</code> that is set to the
     * provided matrix. This constructor copies a given Matrix. If the provided
     * matrix is null, the constructor sets the matrix to the identity.
     *
     * @param mat the matrix to copy.
     */
    public Matrix4f(Matrix4f mat) {
        copy(mat);
    }

    static boolean equalIdentity(Matrix4f mat) {
        if (Math.abs(mat.m00 - 1) > 1e-4)
            return false;
        if (Math.abs(mat.m11 - 1) > 1e-4)
            return false;
        if (Math.abs(mat.m22 - 1) > 1e-4)
            return false;
        if (Math.abs(mat.m33 - 1) > 1e-4)
            return false;

        if (Math.abs(mat.m01) > 1e-4)
            return false;
        if (Math.abs(mat.m02) > 1e-4)
            return false;
        if (Math.abs(mat.m03) > 1e-4)
            return false;

        if (Math.abs(mat.m10) > 1e-4)
            return false;
        if (Math.abs(mat.m12) > 1e-4)
            return false;
        if (Math.abs(mat.m13) > 1e-4)
            return false;

        if (Math.abs(mat.m20) > 1e-4)
            return false;
        if (Math.abs(mat.m21) > 1e-4)
            return false;
        if (Math.abs(mat.m23) > 1e-4)
            return false;

        if (Math.abs(mat.m30) > 1e-4)
            return false;
        if (Math.abs(mat.m31) > 1e-4)
            return false;
        return !(Math.abs(mat.m32) > 1e-4);
    }

    /**
     * <code>copy</code> transfers the contents of a given matrix to this
     * matrix. If a null matrix is supplied, this matrix is set to the identity
     * matrix.
     *
     * @param matrix the matrix to copy.
     */
    public void copy(Matrix4f matrix) {
        if (null == matrix) {
            loadIdentity();
        } else {
            m00 = matrix.m00;
            m01 = matrix.m01;
            m02 = matrix.m02;
            m03 = matrix.m03;
            m10 = matrix.m10;
            m11 = matrix.m11;
            m12 = matrix.m12;
            m13 = matrix.m13;
            m20 = matrix.m20;
            m21 = matrix.m21;
            m22 = matrix.m22;
            m23 = matrix.m23;
            m30 = matrix.m30;
            m31 = matrix.m31;
            m32 = matrix.m32;
            m33 = matrix.m33;
        }
    }

    /**
     * <code>get</code> retrieves the values of this object into a float array
     * in row-major order.
     *
     * @param matrix the matrix to set the values into.
     * @throws Exception
     */
    public void get(float[] matrix) throws Exception {
        get(matrix, true);
    }

    /**
     * <code>set</code> retrieves the values of this object into a float array.
     *
     * @param matrix   the matrix to set the values into.
     * @param rowMajor whether the outgoing data is in row or column major order.
     * @throws Exception
     */
    public void get(float[] matrix, boolean rowMajor) throws Exception {
        if (matrix.length != 16)
            throw new Exception("Array must be of size 16.");

        if (rowMajor) {
            matrix[0] = m00;
            matrix[1] = m01;
            matrix[2] = m02;
            matrix[3] = m03;
            matrix[4] = m10;
            matrix[5] = m11;
            matrix[6] = m12;
            matrix[7] = m13;
            matrix[8] = m20;
            matrix[9] = m21;
            matrix[10] = m22;
            matrix[11] = m23;
            matrix[12] = m30;
            matrix[13] = m31;
            matrix[14] = m32;
            matrix[15] = m33;
        } else {
            matrix[0] = m00;
            matrix[4] = m01;
            matrix[8] = m02;
            matrix[12] = m03;
            matrix[1] = m10;
            matrix[5] = m11;
            matrix[9] = m12;
            matrix[13] = m13;
            matrix[2] = m20;
            matrix[6] = m21;
            matrix[10] = m22;
            matrix[14] = m23;
            matrix[3] = m30;
            matrix[7] = m31;
            matrix[11] = m32;
            matrix[15] = m33;
        }
    }

    /**
     * <code>get</code> retrieves a value from the matrix at the given position.
     * If the position is invalid a <code>Exception</code> is thrown.
     *
     * @param i the row index.
     * @param j the column index.
     * @return the value at (i, j).
     * @throws Exception
     */
    public float get(int i, int j) throws Exception {
        switch (i) {
            case 0:
                switch (j) {
                    case 0:
                        return m00;
                    case 1:
                        return m01;
                    case 2:
                        return m02;
                    case 3:
                        return m03;
                }
            case 1:
                switch (j) {
                    case 0:
                        return m10;
                    case 1:
                        return m11;
                    case 2:
                        return m12;
                    case 3:
                        return m13;
                }
            case 2:
                switch (j) {
                    case 0:
                        return m20;
                    case 1:
                        return m21;
                    case 2:
                        return m22;
                    case 3:
                        return m23;
                }
            case 3:
                switch (j) {
                    case 0:
                        return m30;
                    case 1:
                        return m31;
                    case 2:
                        return m32;
                    case 3:
                        return m33;
                }
        }

        throw new Exception("Invalid indices into matrix.");
    }

    /**
     * <code>getColumn</code> returns one of three columns specified by the
     * parameter. This column is returned as a float array of length 4.
     *
     * @param i the column to retrieve. Must be between 0 and 3.
     * @return the column specified by the index.
     * @throws Exception
     */
    public float[] getColumn(int i) throws Exception {
        return getColumn(i, null);
    }

    /**
     * <code>getColumn</code> returns one of three columns specified by the
     * parameter. This column is returned as a float[4].
     *
     * @param i     the column to retrieve. Must be between 0 and 3.
     * @param store the float array to store the result in. if null, a new one is
     *              created.
     * @return the column specified by the index.
     */
    public float[] getColumn(int i, float[] store) throws Exception {
        if (store == null)
            store = new float[4];
        switch (i) {
            case 0:
                store[0] = m00;
                store[1] = m10;
                store[2] = m20;
                store[3] = m30;
                break;
            case 1:
                store[0] = m01;
                store[1] = m11;
                store[2] = m21;
                store[3] = m31;
                break;
            case 2:
                store[0] = m02;
                store[1] = m12;
                store[2] = m22;
                store[3] = m32;
                break;
            case 3:
                store[0] = m03;
                store[1] = m13;
                store[2] = m23;
                store[3] = m33;
                break;
            default:
                throw new Exception("Invalid column index. " + i);
        }
        return store;
    }

    /**
     * <code>setColumn</code> sets a particular column of this matrix to that
     * represented by the provided vector.
     *
     * @param i      the column to set.
     * @param column the data to set.
     */
    public void setColumn(int i, float[] column) throws Exception {

        if (column == null) {
            return;
        }
        switch (i) {
            case 0:
                m00 = column[0];
                m10 = column[1];
                m20 = column[2];
                m30 = column[3];
                break;
            case 1:
                m01 = column[0];
                m11 = column[1];
                m21 = column[2];
                m31 = column[3];
                break;
            case 2:
                m02 = column[0];
                m12 = column[1];
                m22 = column[2];
                m32 = column[3];
                break;
            case 3:
                m03 = column[0];
                m13 = column[1];
                m23 = column[2];
                m33 = column[3];
                break;
            default:
                throw new Exception("Invalid column index. " + i);
        }
    }

    /**
     * <code>set</code> places a given value into the matrix at the given
     * position. If the position is invalid a <code>Exception</code> is thrown.
     *
     * @param i     the row index.
     * @param j     the column index.
     * @param value the value for (i, j).
     */
    public void set(int i, int j, float value) throws Exception {
        switch (i) {
            case 0:
                switch (j) {
                    case 0:
                        m00 = value;
                        return;
                    case 1:
                        m01 = value;
                        return;
                    case 2:
                        m02 = value;
                        return;
                    case 3:
                        m03 = value;
                        return;
                }
            case 1:
                switch (j) {
                    case 0:
                        m10 = value;
                        return;
                    case 1:
                        m11 = value;
                        return;
                    case 2:
                        m12 = value;
                        return;
                    case 3:
                        m13 = value;
                        return;
                }
            case 2:
                switch (j) {
                    case 0:
                        m20 = value;
                        return;
                    case 1:
                        m21 = value;
                        return;
                    case 2:
                        m22 = value;
                        return;
                    case 3:
                        m23 = value;
                        return;
                }
            case 3:
                switch (j) {
                    case 0:
                        m30 = value;
                        return;
                    case 1:
                        m31 = value;
                        return;
                    case 2:
                        m32 = value;
                        return;
                    case 3:
                        m33 = value;
                        return;
                }
        }
        throw new Exception("Invalid indices into matrix.");
    }

    /**
     * <code>set</code> sets the values of this matrix from an array of values.
     *
     * @param matrix the matrix to set the value to.
     * @throws Exception if the array is not of size 16.
     */
    public void set(float[][] matrix) throws Exception {
        if (matrix.length != 4 || matrix[0].length != 4) {
            throw new Exception("Array must be of size 16.");
        }

        m00 = matrix[0][0];
        m01 = matrix[0][1];
        m02 = matrix[0][2];
        m03 = matrix[0][3];
        m10 = matrix[1][0];
        m11 = matrix[1][1];
        m12 = matrix[1][2];
        m13 = matrix[1][3];
        m20 = matrix[2][0];
        m21 = matrix[2][1];
        m22 = matrix[2][2];
        m23 = matrix[2][3];
        m30 = matrix[3][0];
        m31 = matrix[3][1];
        m32 = matrix[3][2];
        m33 = matrix[3][3];
    }

    /**
     * <code>set</code> sets the values of this matrix from another matrix.
     *
     * @param matrix the matrix to read the value from.
     */
    public Matrix4f set(Matrix4f matrix) {
        m00 = matrix.m00;
        m01 = matrix.m01;
        m02 = matrix.m02;
        m03 = matrix.m03;
        m10 = matrix.m10;
        m11 = matrix.m11;
        m12 = matrix.m12;
        m13 = matrix.m13;
        m20 = matrix.m20;
        m21 = matrix.m21;
        m22 = matrix.m22;
        m23 = matrix.m23;
        m30 = matrix.m30;
        m31 = matrix.m31;
        m32 = matrix.m32;
        m33 = matrix.m33;
        return this;
    }

    /**
     * <code>set</code> sets the values of this matrix from an array of values
     * assuming that the data is rowMajor order;
     *
     * @param matrix the matrix to set the value to.
     * @throws Exception
     */
    public void set(float[] matrix) throws Exception {
        set(matrix, true);
    }

    /**
     * <code>set</code> sets the values of this matrix from an array of values;
     *
     * @param matrix   the matrix to set the value to.
     * @param rowMajor whether the incoming data is in row or column major order.
     * @throws Exception
     */
    public void set(float[] matrix, boolean rowMajor) throws Exception {
        if (matrix.length != 16)
            throw new Exception("Array must be of size 16.");

        if (rowMajor) {
            m00 = matrix[0];
            m01 = matrix[1];
            m02 = matrix[2];
            m03 = matrix[3];
            m10 = matrix[4];
            m11 = matrix[5];
            m12 = matrix[6];
            m13 = matrix[7];
            m20 = matrix[8];
            m21 = matrix[9];
            m22 = matrix[10];
            m23 = matrix[11];
            m30 = matrix[12];
            m31 = matrix[13];
            m32 = matrix[14];
            m33 = matrix[15];
        } else {
            m00 = matrix[0];
            m01 = matrix[4];
            m02 = matrix[8];
            m03 = matrix[12];
            m10 = matrix[1];
            m11 = matrix[5];
            m12 = matrix[9];
            m13 = matrix[13];
            m20 = matrix[2];
            m21 = matrix[6];
            m22 = matrix[10];
            m23 = matrix[14];
            m30 = matrix[3];
            m31 = matrix[7];
            m32 = matrix[11];
            m33 = matrix[15];
        }
    }

    public Matrix4f transpose() throws Exception {
        float[] tmp = new float[16];
        get(tmp, true);
        return new Matrix4f(tmp);
    }

    /**
     * <code>transpose</code> locally transposes this Matrix.
     *
     * @return this object for chaining.
     */
    public Matrix4f transposeLocal() {
        float tmp = m01;
        m01 = m10;
        m10 = tmp;

        tmp = m02;
        m02 = m20;
        m20 = tmp;

        tmp = m03;
        m03 = m30;
        m30 = tmp;

        tmp = m12;
        m12 = m21;
        m21 = tmp;

        tmp = m13;
        m13 = m31;
        m31 = tmp;

        tmp = m23;
        m23 = m32;
        m32 = tmp;

        return this;
    }

    /**
     * <code>fillFloatBuffer</code> fills a FloatBuffer object with the matrix
     * data.
     *
     * @param fb the buffer to fill, must be correct size
     * @return matrix data as a FloatBuffer.
     */
    public FloatBuffer fillFloatBuffer(FloatBuffer fb) {
        return fillFloatBuffer(fb, false);
    }

    /**
     * <code>fillFloatBuffer</code> fills a FloatBuffer object with the matrix
     * data.
     *
     * @param fb          the buffer to fill, starting at current position. Must have
     *                    room for 16 more floats.
     * @param columnMajor if true, this buffer should be filled with column major data,
     *                    otherwise it will be filled row major.
     * @return matrix data as a FloatBuffer. (position is advanced by 16 and any
     * limit set is not changed).
     */
    public FloatBuffer fillFloatBuffer(FloatBuffer fb, boolean columnMajor) {
        if (columnMajor) {
            fb.put(m00).put(m10).put(m20).put(m30);
            fb.put(m01).put(m11).put(m21).put(m31);
            fb.put(m02).put(m12).put(m22).put(m32);
            fb.put(m03).put(m13).put(m23).put(m33);
        } else {
            fb.put(m00).put(m01).put(m02).put(m03);
            fb.put(m10).put(m11).put(m12).put(m13);
            fb.put(m20).put(m21).put(m22).put(m23);
            fb.put(m30).put(m31).put(m32).put(m33);
        }
        return fb;
    }

    /**
     * <code>readFloatBuffer</code> reads value for this matrix from a
     * FloatBuffer.
     *
     * @param fb the buffer to read from, must be correct size
     * @return this data as a FloatBuffer.
     */
    public Matrix4f readFloatBuffer(FloatBuffer fb) {
        return readFloatBuffer(fb, false);
    }

    /**
     * <code>readFloatBuffer</code> reads value for this matrix from a
     * FloatBuffer.
     *
     * @param fb          the buffer to read from, must be correct size
     * @param columnMajor if true, this buffer should be filled with column major data,
     *                    otherwise it will be filled row major.
     * @return this data as a FloatBuffer.
     */
    public Matrix4f readFloatBuffer(FloatBuffer fb, boolean columnMajor) {

        if (columnMajor) {
            m00 = fb.get();
            m10 = fb.get();
            m20 = fb.get();
            m30 = fb.get();
            m01 = fb.get();
            m11 = fb.get();
            m21 = fb.get();
            m31 = fb.get();
            m02 = fb.get();
            m12 = fb.get();
            m22 = fb.get();
            m32 = fb.get();
            m03 = fb.get();
            m13 = fb.get();
            m23 = fb.get();
            m33 = fb.get();
        } else {
            m00 = fb.get();
            m01 = fb.get();
            m02 = fb.get();
            m03 = fb.get();
            m10 = fb.get();
            m11 = fb.get();
            m12 = fb.get();
            m13 = fb.get();
            m20 = fb.get();
            m21 = fb.get();
            m22 = fb.get();
            m23 = fb.get();
            m30 = fb.get();
            m31 = fb.get();
            m32 = fb.get();
            m33 = fb.get();
        }
        return this;
    }

    /**
     * Legacy wrapper. This name implies that an identity matrix is "loaded",
     * but one is not. Instead, the elements of 'this' identity are set.
     */
    public void loadIdentity() {
        setIdentity();
    }

    /**
     * Sets this matrix to the identity matrix, namely all zeros with ones along
     * the diagonal.
     */
    public void setIdentity() {
        m01 = m02 = m03 = m10 = m12 = m13 = m20 = m21 = m23 = m30 = m31 = m32 = 0.0f;
        m00 = m11 = m22 = m33 = 1.0f;
    }

    /**
     * <code>fromAngleAxis</code> sets this matrix4f to the values specified by
     * an angle and an axis of rotation. This method creates an object, so use
     * fromAngleNormalAxis if your axis is already normalized.
     *
     * @param angle the angle to rotate (in radians).
     * @param axis  the axis of rotation.
     */
    public void fromAngleAxis(float angle, Vector3f axis) {
        Vector3f normAxis = axis.normalize();
        fromAngleNormalAxis(angle, normAxis);
    }

    /**
     * <code>fromAngleNormalAxis</code> sets this matrix4f to the values
     * specified by an angle and a normalized axis of rotation.
     *
     * @param angle the angle to rotate (in radians).
     * @param axis  the axis of rotation (already normalized).
     */
    public void fromAngleNormalAxis(float angle, Vector3f axis) {
        zero();
        m33 = 1;

        float fCos = FastMath.cos(angle);
        float fSin = FastMath.sin(angle);
        float fOneMinusCos = ((float) 1.0) - fCos;
        float fX2 = axis.x * axis.x;
        float fY2 = axis.y * axis.y;
        float fZ2 = axis.z * axis.z;
        float fXYM = axis.x * axis.y * fOneMinusCos;
        float fXZM = axis.x * axis.z * fOneMinusCos;
        float fYZM = axis.y * axis.z * fOneMinusCos;
        float fXSin = axis.x * fSin;
        float fYSin = axis.y * fSin;
        float fZSin = axis.z * fSin;

        m00 = fX2 * fOneMinusCos + fCos;
        m01 = fXYM - fZSin;
        m02 = fXZM + fYSin;
        m10 = fXYM + fZSin;
        m11 = fY2 * fOneMinusCos + fCos;
        m12 = fYZM - fXSin;
        m20 = fXZM - fYSin;
        m21 = fYZM + fXSin;
        m22 = fZ2 * fOneMinusCos + fCos;
    }

    /**
     * <code>mult</code> multiplies this matrix by a scalar.
     *
     * @param scalar the scalar to multiply this matrix by.
     */
    public void multLocal(float scalar) {
        m00 *= scalar;
        m01 *= scalar;
        m02 *= scalar;
        m03 *= scalar;
        m10 *= scalar;
        m11 *= scalar;
        m12 *= scalar;
        m13 *= scalar;
        m20 *= scalar;
        m21 *= scalar;
        m22 *= scalar;
        m23 *= scalar;
        m30 *= scalar;
        m31 *= scalar;
        m32 *= scalar;
        m33 *= scalar;
    }

    public Matrix4f mult(float scalar) {
        Matrix4f out = new Matrix4f();
        out.set(this);
        out.multLocal(scalar);
        return out;
    }

    public Matrix4f mult(float scalar, Matrix4f store) {
        store.set(this);
        store.multLocal(scalar);
        return store;
    }

    /**
     * <code>mult</code> multiplies this matrix with another matrix. The result
     * matrix will then be returned. This matrix will be on the left hand side,
     * while the parameter matrix will be on the right.
     *
     * @param in2 the matrix to multiply this matrix by.
     * @return the resultant matrix
     */
    public Matrix4f mult(Matrix4f in2) {
        return mult(in2, null);
    }

    /**
     * <code>mult</code> multiplies this matrix with another matrix. The result
     * matrix will then be returned. This matrix will be on the left hand side,
     * while the parameter matrix will be on the right.
     *
     * @param in2   the matrix to multiply this matrix by.
     * @param store where to store the result. It is safe for in2 and store to be
     *              the same object.
     * @return the resultant matrix
     */
    public Matrix4f mult(Matrix4f in2, Matrix4f store) {
        if (store == null)
            store = new Matrix4f();

        float temp00, temp01, temp02, temp03;
        float temp10, temp11, temp12, temp13;
        float temp20, temp21, temp22, temp23;
        float temp30, temp31, temp32, temp33;

        temp00 = m00 * in2.m00 + m01 * in2.m10 + m02 * in2.m20 + m03 * in2.m30;
        temp01 = m00 * in2.m01 + m01 * in2.m11 + m02 * in2.m21 + m03 * in2.m31;
        temp02 = m00 * in2.m02 + m01 * in2.m12 + m02 * in2.m22 + m03 * in2.m32;
        temp03 = m00 * in2.m03 + m01 * in2.m13 + m02 * in2.m23 + m03 * in2.m33;

        temp10 = m10 * in2.m00 + m11 * in2.m10 + m12 * in2.m20 + m13 * in2.m30;
        temp11 = m10 * in2.m01 + m11 * in2.m11 + m12 * in2.m21 + m13 * in2.m31;
        temp12 = m10 * in2.m02 + m11 * in2.m12 + m12 * in2.m22 + m13 * in2.m32;
        temp13 = m10 * in2.m03 + m11 * in2.m13 + m12 * in2.m23 + m13 * in2.m33;

        temp20 = m20 * in2.m00 + m21 * in2.m10 + m22 * in2.m20 + m23 * in2.m30;
        temp21 = m20 * in2.m01 + m21 * in2.m11 + m22 * in2.m21 + m23 * in2.m31;
        temp22 = m20 * in2.m02 + m21 * in2.m12 + m22 * in2.m22 + m23 * in2.m32;
        temp23 = m20 * in2.m03 + m21 * in2.m13 + m22 * in2.m23 + m23 * in2.m33;

        temp30 = m30 * in2.m00 + m31 * in2.m10 + m32 * in2.m20 + m33 * in2.m30;
        temp31 = m30 * in2.m01 + m31 * in2.m11 + m32 * in2.m21 + m33 * in2.m31;
        temp32 = m30 * in2.m02 + m31 * in2.m12 + m32 * in2.m22 + m33 * in2.m32;
        temp33 = m30 * in2.m03 + m31 * in2.m13 + m32 * in2.m23 + m33 * in2.m33;

        store.m00 = temp00;
        store.m01 = temp01;
        store.m02 = temp02;
        store.m03 = temp03;
        store.m10 = temp10;
        store.m11 = temp11;
        store.m12 = temp12;
        store.m13 = temp13;
        store.m20 = temp20;
        store.m21 = temp21;
        store.m22 = temp22;
        store.m23 = temp23;
        store.m30 = temp30;
        store.m31 = temp31;
        store.m32 = temp32;
        store.m33 = temp33;

        return store;
    }

    /**
     * <code>mult</code> multiplies this matrix with another matrix. The results
     * are stored internally and a handle to this matrix will then be returned.
     * This matrix will be on the left hand side, while the parameter matrix
     * will be on the right.
     *
     * @param in2 the matrix to multiply this matrix by.
     * @return the resultant matrix
     */
    public Matrix4f multLocal(Matrix4f in2) {

        return mult(in2, this);
    }

    /**
     * <code>mult</code> multiplies a vector about a rotation matrix. The
     * resulting vector is returned as a new Vector3f.
     *
     * @param vec vec to multiply against.
     * @return the rotated vector.
     */
    public Vector3f mult(Vector3f vec) {
        return mult(vec, null);
    }

    /**
     * <code>mult</code> multiplies a vector about a rotation matrix and adds
     * translation. The resulting vector is returned.
     *
     * @param vec   vec to multiply against.
     * @param store a vector to store the result in. Created if null is passed.
     * @return the rotated vector.
     */
    public Vector3f mult(Vector3f vec, Vector3f store) {
        if (store == null)
            store = new Vector3f();

        float vx = vec.x, vy = vec.y, vz = vec.z;
        store.x = m00 * vx + m01 * vy + m02 * vz + m03;
        store.y = m10 * vx + m11 * vy + m12 * vz + m13;
        store.z = m20 * vx + m21 * vy + m22 * vz + m23;

        return store;
    }

    /**
     * <code>mult</code> multiplies a vector about a rotation matrix. The
     * resulting vector is returned.
     *
     * @param vec   vec to multiply against.
     * @param store a vector to store the result in. created if null is passed.
     * @return the rotated vector.
     */
    public Vector3f multAcross(Vector3f vec, Vector3f store) {
        if (null == vec) {
            return null;
        }
        if (store == null)
            store = new Vector3f();

        float vx = vec.x, vy = vec.y, vz = vec.z;
        store.x = m00 * vx + m10 * vy + m20 * vz + m30 * 1;
        store.y = m01 * vx + m11 * vy + m21 * vz + m31 * 1;
        store.z = m02 * vx + m12 * vy + m22 * vz + m32 * 1;

        return store;
    }

    /**
     * <code>mult</code> multiplies a quaternion about a matrix. The resulting
     * vector is returned.
     *
     * @param vec   vec to multiply against.
     * @param store a quaternion to store the result in. created if null is
     *              passed.
     * @return store = this * vec
     */
    public Quaternion mult(Quaternion vec, Quaternion store) {

        if (null == vec) {
            return null;
        }
        if (store == null)
            store = new Quaternion();

        float x = m00 * vec.x + m10 * vec.y + m20 * vec.z + m30 * vec.w;
        float y = m01 * vec.x + m11 * vec.y + m21 * vec.z + m31 * vec.w;
        float z = m02 * vec.x + m12 * vec.y + m22 * vec.z + m32 * vec.w;
        float w = m03 * vec.x + m13 * vec.y + m23 * vec.z + m33 * vec.w;
        store.x = x;
        store.y = y;
        store.z = z;
        store.w = w;

        return store;
    }

    /**
     * <code>mult</code> multiplies an array of 4 floats against this rotation
     * matrix. The results are stored directly in the array. (vec4f x mat4f)
     *
     * @param vec4f float array (size 4) to multiply against the matrix.
     * @return the vec4f for chaining.
     */
    public float[] mult(float[] vec4f) {
        if (null == vec4f || vec4f.length != 4) {
            return null;
        }

        float x = vec4f[0], y = vec4f[1], z = vec4f[2], w = vec4f[3];

        vec4f[0] = m00 * x + m01 * y + m02 * z + m03 * w;
        vec4f[1] = m10 * x + m11 * y + m12 * z + m13 * w;
        vec4f[2] = m20 * x + m21 * y + m22 * z + m23 * w;
        vec4f[3] = m30 * x + m31 * y + m32 * z + m33 * w;

        return vec4f;
    }

    /**
     * <code>mult</code> multiplies an array of 4 floats against this rotation
     * matrix. The results are stored directly in the array. (vec4f x mat4f)
     *
     * @param vec4f float array (size 4) to multiply against the matrix.
     * @return the vec4f for chaining.
     */
    public float[] multAcross(float[] vec4f) {
        if (null == vec4f || vec4f.length != 4) {
            return null;
        }

        float x = vec4f[0], y = vec4f[1], z = vec4f[2], w = vec4f[3];

        vec4f[0] = m00 * x + m10 * y + m20 * z + m30 * w;
        vec4f[1] = m01 * x + m11 * y + m21 * z + m31 * w;
        vec4f[2] = m02 * x + m12 * y + m22 * z + m32 * w;
        vec4f[3] = m03 * x + m13 * y + m23 * z + m33 * w;

        return vec4f;
    }

    /**
     * Inverts this matrix as a new Matrix4f.
     *
     * @return The new inverse matrix
     */
    public Matrix4f invert() {
        return invert(null);
    }

    /**
     * Inverts this matrix and stores it in the given store.
     *
     * @return The store
     */
    public Matrix4f invert(Matrix4f store) {
        if (store == null)
            store = new Matrix4f();

        float fA0 = m00 * m11 - m01 * m10;
        float fA1 = m00 * m12 - m02 * m10;
        float fA2 = m00 * m13 - m03 * m10;
        float fA3 = m01 * m12 - m02 * m11;
        float fA4 = m01 * m13 - m03 * m11;
        float fA5 = m02 * m13 - m03 * m12;
        float fB0 = m20 * m31 - m21 * m30;
        float fB1 = m20 * m32 - m22 * m30;
        float fB2 = m20 * m33 - m23 * m30;
        float fB3 = m21 * m32 - m22 * m31;
        float fB4 = m21 * m33 - m23 * m31;
        float fB5 = m22 * m33 - m23 * m32;
        float fDet = fA0 * fB5 - fA1 * fB4 + fA2 * fB3 + fA3 * fB2 - fA4 * fB1 + fA5 * fB0;

        if (FastMath.abs(fDet) <= 0)
            return store.zero();

        store.m00 = +m11 * fB5 - m12 * fB4 + m13 * fB3;
        store.m10 = -m10 * fB5 + m12 * fB2 - m13 * fB1;
        store.m20 = +m10 * fB4 - m11 * fB2 + m13 * fB0;
        store.m30 = -m10 * fB3 + m11 * fB1 - m12 * fB0;
        store.m01 = -m01 * fB5 + m02 * fB4 - m03 * fB3;
        store.m11 = +m00 * fB5 - m02 * fB2 + m03 * fB1;
        store.m21 = -m00 * fB4 + m01 * fB2 - m03 * fB0;
        store.m31 = +m00 * fB3 - m01 * fB1 + m02 * fB0;
        store.m02 = +m31 * fA5 - m32 * fA4 + m33 * fA3;
        store.m12 = -m30 * fA5 + m32 * fA2 - m33 * fA1;
        store.m22 = +m30 * fA4 - m31 * fA2 + m33 * fA0;
        store.m32 = -m30 * fA3 + m31 * fA1 - m32 * fA0;
        store.m03 = -m21 * fA5 + m22 * fA4 - m23 * fA3;
        store.m13 = +m20 * fA5 - m22 * fA2 + m23 * fA1;
        store.m23 = -m20 * fA4 + m21 * fA2 - m23 * fA0;
        store.m33 = +m20 * fA3 - m21 * fA1 + m22 * fA0;

        float fInvDet = 1.0f / fDet;
        store.multLocal(fInvDet);

        return store;
    }

    /**
     * Inverts this matrix locally.
     *
     * @return this
     */
    public Matrix4f invertLocal() {

        float fA0 = m00 * m11 - m01 * m10;
        float fA1 = m00 * m12 - m02 * m10;
        float fA2 = m00 * m13 - m03 * m10;
        float fA3 = m01 * m12 - m02 * m11;
        float fA4 = m01 * m13 - m03 * m11;
        float fA5 = m02 * m13 - m03 * m12;
        float fB0 = m20 * m31 - m21 * m30;
        float fB1 = m20 * m32 - m22 * m30;
        float fB2 = m20 * m33 - m23 * m30;
        float fB3 = m21 * m32 - m22 * m31;
        float fB4 = m21 * m33 - m23 * m31;
        float fB5 = m22 * m33 - m23 * m32;
        float fDet = fA0 * fB5 - fA1 * fB4 + fA2 * fB3 + fA3 * fB2 - fA4 * fB1 + fA5 * fB0;

        if (FastMath.abs(fDet) <= FastMath.FLT_EPSILON)
            return zero();

        float f00 = +m11 * fB5 - m12 * fB4 + m13 * fB3;
        float f10 = -m10 * fB5 + m12 * fB2 - m13 * fB1;
        float f20 = +m10 * fB4 - m11 * fB2 + m13 * fB0;
        float f30 = -m10 * fB3 + m11 * fB1 - m12 * fB0;
        float f01 = -m01 * fB5 + m02 * fB4 - m03 * fB3;
        float f11 = +m00 * fB5 - m02 * fB2 + m03 * fB1;
        float f21 = -m00 * fB4 + m01 * fB2 - m03 * fB0;
        float f31 = +m00 * fB3 - m01 * fB1 + m02 * fB0;
        float f02 = +m31 * fA5 - m32 * fA4 + m33 * fA3;
        float f12 = -m30 * fA5 + m32 * fA2 - m33 * fA1;
        float f22 = +m30 * fA4 - m31 * fA2 + m33 * fA0;
        float f32 = -m30 * fA3 + m31 * fA1 - m32 * fA0;
        float f03 = -m21 * fA5 + m22 * fA4 - m23 * fA3;
        float f13 = +m20 * fA5 - m22 * fA2 + m23 * fA1;
        float f23 = -m20 * fA4 + m21 * fA2 - m23 * fA0;
        float f33 = +m20 * fA3 - m21 * fA1 + m22 * fA0;

        m00 = f00;
        m01 = f01;
        m02 = f02;
        m03 = f03;
        m10 = f10;
        m11 = f11;
        m12 = f12;
        m13 = f13;
        m20 = f20;
        m21 = f21;
        m22 = f22;
        m23 = f23;
        m30 = f30;
        m31 = f31;
        m32 = f32;
        m33 = f33;

        float fInvDet = 1.0f / fDet;
        multLocal(fInvDet);

        return this;
    }

    /**
     * Returns a new matrix representing the adjoint of this matrix.
     *
     * @return The adjoint matrix
     */
    public Matrix4f adjoint() {
        return adjoint(null);
    }

    /**
     * Places the adjoint of this matrix in store (creates store if null.)
     *
     * @param store The matrix to store the result in. If null, a new matrix is
     *              created.
     * @return store
     */
    public Matrix4f adjoint(Matrix4f store) {
        if (store == null)
            store = new Matrix4f();

        float fA0 = m00 * m11 - m01 * m10;
        float fA1 = m00 * m12 - m02 * m10;
        float fA2 = m00 * m13 - m03 * m10;
        float fA3 = m01 * m12 - m02 * m11;
        float fA4 = m01 * m13 - m03 * m11;
        float fA5 = m02 * m13 - m03 * m12;
        float fB0 = m20 * m31 - m21 * m30;
        float fB1 = m20 * m32 - m22 * m30;
        float fB2 = m20 * m33 - m23 * m30;
        float fB3 = m21 * m32 - m22 * m31;
        float fB4 = m21 * m33 - m23 * m31;
        float fB5 = m22 * m33 - m23 * m32;

        store.m00 = +m11 * fB5 - m12 * fB4 + m13 * fB3;
        store.m10 = -m10 * fB5 + m12 * fB2 - m13 * fB1;
        store.m20 = +m10 * fB4 - m11 * fB2 + m13 * fB0;
        store.m30 = -m10 * fB3 + m11 * fB1 - m12 * fB0;
        store.m01 = -m01 * fB5 + m02 * fB4 - m03 * fB3;
        store.m11 = +m00 * fB5 - m02 * fB2 + m03 * fB1;
        store.m21 = -m00 * fB4 + m01 * fB2 - m03 * fB0;
        store.m31 = +m00 * fB3 - m01 * fB1 + m02 * fB0;
        store.m02 = +m31 * fA5 - m32 * fA4 + m33 * fA3;
        store.m12 = -m30 * fA5 + m32 * fA2 - m33 * fA1;
        store.m22 = +m30 * fA4 - m31 * fA2 + m33 * fA0;
        store.m32 = -m30 * fA3 + m31 * fA1 - m32 * fA0;
        store.m03 = -m21 * fA5 + m22 * fA4 - m23 * fA3;
        store.m13 = +m20 * fA5 - m22 * fA2 + m23 * fA1;
        store.m23 = -m20 * fA4 + m21 * fA2 - m23 * fA0;
        store.m33 = +m20 * fA3 - m21 * fA1 + m22 * fA0;

        return store;
    }

    /**
     * <code>determinant</code> generates the determinate of this matrix.
     *
     * @return the determinate
     */
    public float determinant() {
        float fA0 = m00 * m11 - m01 * m10;
        float fA1 = m00 * m12 - m02 * m10;
        float fA2 = m00 * m13 - m03 * m10;
        float fA3 = m01 * m12 - m02 * m11;
        float fA4 = m01 * m13 - m03 * m11;
        float fA5 = m02 * m13 - m03 * m12;
        float fB0 = m20 * m31 - m21 * m30;
        float fB1 = m20 * m32 - m22 * m30;
        float fB2 = m20 * m33 - m23 * m30;
        float fB3 = m21 * m32 - m22 * m31;
        float fB4 = m21 * m33 - m23 * m31;
        float fB5 = m22 * m33 - m23 * m32;
        return fA0 * fB5 - fA1 * fB4 + fA2 * fB3 + fA3 * fB2 - fA4 * fB1 + fA5 * fB0;
    }

    /**
     * Sets all of the values in this matrix to zero.
     *
     * @return this matrix
     */
    public Matrix4f zero() {
        m00 = m01 = m02 = m03 = m10 = m11 = m12 = m13 = m20 = m21 = m22 = m23 = m30 = m31 = m32 = m33 = 0.0f;
        return this;
    }

    public Matrix4f add(Matrix4f mat) {
        Matrix4f result = new Matrix4f();
        result.m00 = this.m00 + mat.m00;
        result.m01 = this.m01 + mat.m01;
        result.m02 = this.m02 + mat.m02;
        result.m03 = this.m03 + mat.m03;
        result.m10 = this.m10 + mat.m10;
        result.m11 = this.m11 + mat.m11;
        result.m12 = this.m12 + mat.m12;
        result.m13 = this.m13 + mat.m13;
        result.m20 = this.m20 + mat.m20;
        result.m21 = this.m21 + mat.m21;
        result.m22 = this.m22 + mat.m22;
        result.m23 = this.m23 + mat.m23;
        result.m30 = this.m30 + mat.m30;
        result.m31 = this.m31 + mat.m31;
        result.m32 = this.m32 + mat.m32;
        result.m33 = this.m33 + mat.m33;
        return result;
    }

    /**
     * <code>add</code> adds the values of a parameter matrix to this matrix.
     *
     * @param mat the matrix to add to this.
     */
    public void addLocal(Matrix4f mat) {
        m00 += mat.m00;
        m01 += mat.m01;
        m02 += mat.m02;
        m03 += mat.m03;
        m10 += mat.m10;
        m11 += mat.m11;
        m12 += mat.m12;
        m13 += mat.m13;
        m20 += mat.m20;
        m21 += mat.m21;
        m22 += mat.m22;
        m23 += mat.m23;
        m30 += mat.m30;
        m31 += mat.m31;
        m32 += mat.m32;
        m33 += mat.m33;
    }

    public Vector3f toTranslationVector() {
        return new Vector3f(m03, m13, m23);
    }

    public void toTranslationVector(Vector3f vector) {
        vector.set(m03, m13, m23);
    }

    public Quaternion toRotationQuat() {
        Quaternion quat = new Quaternion();
        quat.fromRotationMatrix(toRotationMatrix());
        return quat;
    }

    public void toRotationQuat(Quaternion q) {
        q.fromRotationMatrix(toRotationMatrix());
    }

    public Matrix3f toRotationMatrix() {
        return new Matrix3f(m00, m01, m02, m10, m11, m12, m20, m21, m22);

    }

    public void toRotationMatrix(Matrix3f mat) {
        mat.m00 = m00;
        mat.m01 = m01;
        mat.m02 = m02;
        mat.m10 = m10;
        mat.m11 = m11;
        mat.m12 = m12;
        mat.m20 = m20;
        mat.m21 = m21;
        mat.m22 = m22;

    }

    /**
     * <code>setTranslation</code> will set the matrix's translation values.
     *
     * @param translation the new values for the translation.
     * @throws Exception if translation is not size 3.
     */
    public void setTranslation(float[] translation) throws Exception {
        if (translation.length != 3) {
            throw new Exception("Translation size must be 3.");
        }
        m03 = translation[0];
        m13 = translation[1];
        m23 = translation[2];
    }

    /**
     * <code>setTranslation</code> will set the matrix's translation values.
     *
     * @param x value of the translation on the x axis
     * @param y value of the translation on the y axis
     * @param z value of the translation on the z axis
     */
    public void setTranslation(float x, float y, float z) {
        m03 = x;
        m13 = y;
        m23 = z;
    }

    /**
     * <code>setTranslation</code> will set the matrix's translation values.
     *
     * @param translation the new values for the translation.
     */
    public void setTranslation(Vector3f translation) {
        m03 = translation.x;
        m13 = translation.y;
        m23 = translation.z;
    }

    /**
     * <code>setInverseTranslation</code> will set the matrix's inverse
     * translation values.
     *
     * @param translation the new values for the inverse translation.
     * @throws Exception if translation is not size 3.
     */
    public void setInverseTranslation(float[] translation) throws Exception {
        if (translation.length != 3) {
            throw new Exception("Translation size must be 3.");
        }
        m03 = -translation[0];
        m13 = -translation[1];
        m23 = -translation[2];
    }

    /**
     * <code>angleRotation</code> sets this matrix to that of a rotation about
     * three axes (x, y, z). Where each axis has a specified rotation in
     * degrees. These rotations are expressed in a single <code>Vector3f</code>
     * object.
     *
     * @param angles the angles to rotate.
     */
    public void angleRotation(Vector3f angles) {
        float angle;
        float sr, sp, sy, cr, cp, cy;

        angle = (angles.z * FastMath.DEG_TO_RAD);
        sy = FastMath.sin(angle);
        cy = FastMath.cos(angle);
        angle = (angles.y * FastMath.DEG_TO_RAD);
        sp = FastMath.sin(angle);
        cp = FastMath.cos(angle);
        angle = (angles.x * FastMath.DEG_TO_RAD);
        sr = FastMath.sin(angle);
        cr = FastMath.cos(angle);

        // matrix = (Z * Y) * X
        m00 = cp * cy;
        m10 = cp * sy;
        m20 = -sp;
        m01 = sr * sp * cy + cr * -sy;
        m11 = sr * sp * sy + cr * cy;
        m21 = sr * cp;
        m02 = (cr * sp * cy + -sr * -sy);
        m12 = (cr * sp * sy + -sr * cy);
        m22 = cr * cp;
        m03 = 0.0f;
        m13 = 0.0f;
        m23 = 0.0f;
    }

    /**
     * <code>setRotationQuaternion</code> builds a rotation from a
     * <code>Quaternion</code>.
     *
     * @param quat the quaternion to build the rotation from.
     * @throws NullPointerException if quat is null.
     */
    public void setRotationQuaternion(Quaternion quat) {
        quat.toRotationMatrix(this);
    }

    /**
     * <code>setInverseRotationRadians</code> builds an inverted rotation from
     * Euler angles that are in radians.
     *
     * @param angles the Euler angles in radians.
     * @throws Exception if angles is not size 3.
     */
    public void setInverseRotationRadians(float[] angles) throws Exception {
        if (angles.length != 3) {
            throw new Exception("Angles must be of size 3.");
        }
        double cr = FastMath.cos(angles[0]);
        double sr = FastMath.sin(angles[0]);
        double cp = FastMath.cos(angles[1]);
        double sp = FastMath.sin(angles[1]);
        double cy = FastMath.cos(angles[2]);
        double sy = FastMath.sin(angles[2]);

        m00 = (float) (cp * cy);
        m10 = (float) (cp * sy);
        m20 = (float) (-sp);

        double srsp = sr * sp;
        double crsp = cr * sp;

        m01 = (float) (srsp * cy - cr * sy);
        m11 = (float) (srsp * sy + cr * cy);
        m21 = (float) (sr * cp);

        m02 = (float) (crsp * cy + sr * sy);
        m12 = (float) (crsp * sy - sr * cy);
        m22 = (float) (cr * cp);
    }

    /**
     * <code>setInverseRotationDegrees</code> builds an inverted rotation from
     * Euler angles that are in degrees.
     *
     * @param angles the Euler angles in degrees.
     * @throws Exception if angles is not size 3.
     */
    public void setInverseRotationDegrees(float[] angles) throws Exception {
        if (angles.length != 3) {
            throw new Exception("Angles must be of size 3.");
        }
        float vec[] = new float[3];
        vec[0] = (angles[0] * FastMath.RAD_TO_DEG);
        vec[1] = (angles[1] * FastMath.RAD_TO_DEG);
        vec[2] = (angles[2] * FastMath.RAD_TO_DEG);
        setInverseRotationRadians(vec);
    }

    /**
     * <code>inverseTranslateVect</code> translates a given Vector3f by the
     * translation part of this matrix.
     *
     * @param vec the Vector3f data to be translated.
     * @throws Exception if the size of the Vector3f is not 3.
     */
    public void inverseTranslateVect(float[] vec) throws Exception {
        if (vec.length != 3) {
            throw new Exception("vec must be of size 3.");
        }

        vec[0] -= m03;
        vec[1] -= m13;
        vec[2] -= m23;
    }

    /**
     * <code>inverseTranslateVect</code> translates a given Vector3f by the
     * translation part of this matrix.
     *
     * @param data the Vector3f to be translated.
     * @throws Exception if the size of the Vector3f is not 3.
     */
    public void inverseTranslateVect(Vector3f data) {
        data.x -= m03;
        data.y -= m13;
        data.z -= m23;
    }

    /**
     * <code>inverseTranslateVect</code> translates a given Vector3f by the
     * translation part of this matrix.
     *
     * @param data the Vector3f to be translated.
     * @throws Exception if the size of the Vector3f is not 3.
     */
    public void translateVect(Vector3f data) {
        data.x += m03;
        data.y += m13;
        data.z += m23;
    }

    /**
     * <code>inverseRotateVect</code> rotates a given Vector3f by the rotation
     * part of this matrix.
     *
     * @param vec the Vector3f to be rotated.
     */
    public void inverseRotateVect(Vector3f vec) {
        float vx = vec.x, vy = vec.y, vz = vec.z;

        vec.x = vx * m00 + vy * m10 + vz * m20;
        vec.y = vx * m01 + vy * m11 + vz * m21;
        vec.z = vx * m02 + vy * m12 + vz * m22;
    }

    public void rotateVect(Vector3f vec) {
        float vx = vec.x, vy = vec.y, vz = vec.z;

        vec.x = vx * m00 + vy * m01 + vz * m02;
        vec.y = vx * m10 + vy * m11 + vz * m12;
        vec.z = vx * m20 + vy * m21 + vz * m22;
    }

    /**
     * <code>toString</code> returns the string representation of this object.
     * It is in a format of a 4x4 matrix. For example, an identity matrix would
     * be represented by the following string. com.jme.math.Matrix3f <br>
     * [<br>
     * 1.0 0.0 0.0 0.0 <br>
     * 0.0 1.0 0.0 0.0 <br>
     * 0.0 0.0 1.0 0.0 <br>
     * 0.0 0.0 0.0 1.0 <br>
     * ]<br>
     *
     * @return the string representation of this object.
     */
    @Override
    public String toString() {
        StringBuffer result = new StringBuffer("com.jme.math.Matrix4f\n[\n");
        result.append(' ');
        result.append(m00);
        result.append("  ");
        result.append(m01);
        result.append("  ");
        result.append(m02);
        result.append("  ");
        result.append(m03);
        result.append(" \n");
        result.append(' ');
        result.append(m10);
        result.append("  ");
        result.append(m11);
        result.append("  ");
        result.append(m12);
        result.append("  ");
        result.append(m13);
        result.append(" \n");
        result.append(' ');
        result.append(m20);
        result.append("  ");
        result.append(m21);
        result.append("  ");
        result.append(m22);
        result.append("  ");
        result.append(m23);
        result.append(" \n");
        result.append(' ');
        result.append(m30);
        result.append("  ");
        result.append(m31);
        result.append("  ");
        result.append(m32);
        result.append("  ");
        result.append(m33);
        result.append(" \n]");
        return result.toString();
    }

    /**
     * <code>hashCode</code> returns the hash code value as an integer and is
     * supported for the benefit of hashing based collection classes such as
     * Hashtable, HashMap, HashSet etc.
     *
     * @return the hashcode for this instance of Matrix4f.
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        int hash = 37;
        hash = 37 * hash + Float.floatToIntBits(m00);
        hash = 37 * hash + Float.floatToIntBits(m01);
        hash = 37 * hash + Float.floatToIntBits(m02);
        hash = 37 * hash + Float.floatToIntBits(m03);

        hash = 37 * hash + Float.floatToIntBits(m10);
        hash = 37 * hash + Float.floatToIntBits(m11);
        hash = 37 * hash + Float.floatToIntBits(m12);
        hash = 37 * hash + Float.floatToIntBits(m13);

        hash = 37 * hash + Float.floatToIntBits(m20);
        hash = 37 * hash + Float.floatToIntBits(m21);
        hash = 37 * hash + Float.floatToIntBits(m22);
        hash = 37 * hash + Float.floatToIntBits(m23);

        hash = 37 * hash + Float.floatToIntBits(m30);
        hash = 37 * hash + Float.floatToIntBits(m31);
        hash = 37 * hash + Float.floatToIntBits(m32);
        hash = 37 * hash + Float.floatToIntBits(m33);

        return hash;
    }

    /**
     * are these two matrices the same? they are is they both have the same mXX
     * values.
     *
     * @param o the object to compare for equality
     * @return true if they are equal
     */
    @Override
    public boolean equals(Object o) {
        if (!(o instanceof Matrix4f) || o == null) {
            return false;
        }

        if (this == o) {
            return true;
        }

        Matrix4f comp = (Matrix4f) o;
        if (Float.compare(m00, comp.m00) != 0)
            return false;
        if (Float.compare(m01, comp.m01) != 0)
            return false;
        if (Float.compare(m02, comp.m02) != 0)
            return false;
        if (Float.compare(m03, comp.m03) != 0)
            return false;

        if (Float.compare(m10, comp.m10) != 0)
            return false;
        if (Float.compare(m11, comp.m11) != 0)
            return false;
        if (Float.compare(m12, comp.m12) != 0)
            return false;
        if (Float.compare(m13, comp.m13) != 0)
            return false;

        if (Float.compare(m20, comp.m20) != 0)
            return false;
        if (Float.compare(m21, comp.m21) != 0)
            return false;
        if (Float.compare(m22, comp.m22) != 0)
            return false;
        if (Float.compare(m23, comp.m23) != 0)
            return false;

        if (Float.compare(m30, comp.m30) != 0)
            return false;
        if (Float.compare(m31, comp.m31) != 0)
            return false;
        if (Float.compare(m32, comp.m32) != 0)
            return false;
        return Float.compare(m33, comp.m33) == 0;
    }

    /**
     * @return true if this matrix is identity
     */
    public boolean isIdentity() {
        return (m00 == 1 && m01 == 0 && m02 == 0 && m03 == 0) && (m10 == 0 && m11 == 1 && m12 == 0 && m13 == 0)
                && (m20 == 0 && m21 == 0 && m22 == 1 && m23 == 0) && (m30 == 0 && m31 == 0 && m32 == 0 && m33 == 1);
    }

    /**
     * Apply a scale to this matrix.
     *
     * @param scale the scale to apply
     */
    public void scale(Vector3f scale) {
        m00 *= scale.getX();
        m10 *= scale.getX();
        m20 *= scale.getX();
        m30 *= scale.getX();
        m01 *= scale.getY();
        m11 *= scale.getY();
        m21 *= scale.getY();
        m31 *= scale.getY();
        m02 *= scale.getZ();
        m12 *= scale.getZ();
        m22 *= scale.getZ();
        m32 *= scale.getZ();
    }

    // XXX: This tests more solid than converting the q to a matrix and
    // multiplying... why?
    public void multLocal(Quaternion rotation) {
        Vector3f axis = new Vector3f();
        float angle = rotation.toAngleAxis(axis);
        Matrix4f matrix4f = new Matrix4f();
        matrix4f.fromAngleAxis(angle, axis);
        multLocal(matrix4f);
    }

    @Override
    public Matrix4f clone() {
        try {
            return (Matrix4f) super.clone();
        } catch (CloneNotSupportedException e) {
            Logger.error(e);
            throw new AssertionError(); // can not happen
        }
    }
}