//===========================================================================//=-------------------------------------------------------------------------=//= Module history:                                                         =//= - November 3 2006 - Oscar Chavarro: Original base version               =//===========================================================================package vsdk.toolkit.common;import vsdk.toolkit.common.VSDK;public class Vector4D extends FundamentalEntity {    /// Check the general attribute description in superclass Entity.    public static final long serialVersionUID = 20061103L;    /// Yes, they are public due to efficiency issues    public double x, y, z, w;    /**     The default Vector4D value is the zero vector in 3D (Unit in homogenous     space     */    public Vector4D() {        x = 0;        y = 0;        z = 0;        w = 1;    }    /**     *     * @param x double     * @param y double     * @param z double     */    public Vector4D(double x, double y, double z) {        this.x = x; this.y = y; this.z = z;        w = 1;    }    public Vector4D(double x, double y, double z, double w) {        this.x = x; this.y = y; this.z = z;        this.w = w;    }    public Vector4D(Vector3D B) {        this.x = B.x; this.y = B.y; this.z = B.z;        w = 1;    }    public Vector4D(Vector4D B) {        this.x = B.x; this.y = B.y; this.z = B.z;        this.w= B.w;    }    public final Vector4D multiply(double a) {        return new Vector4D(a * x, a * y, a * z, a * w);    }    /**     *     * @param B Vector4D     * @return Vector4D     *//*NOT DEFINED YET!    public final Vector4D crossProduct(Vector4D B) {        return new Vector4D(?);    }*/    /**     *     * @param B Vector4D     * @return double     *//*NOT DEFINED YET!    public final double dotProduct(Vector4D B) {        return ?    }*/    /**     *     */    public final void normalize() {        double t = x*x + y*y + z*z + w*w;        if ( Math.abs(t) < VSDK.EPSILON ) return;        if (t != 0 && t != 1) t = (1.0 / Math.sqrt(t));        x *= t;        y *= t;        z *= t;        w *= t;    }    public final void divideByW() {        if ( Math.abs(w) < VSDK.EPSILON ) return;        x /= w;        y /= w;        z /= w;        w /= w;    }    /**     *     * @return double     */    public final double length() {        return Math.sqrt(x*x + y*y + z*z + w*w);    }    public final Vector4D add(Vector4D b)    {        return new Vector4D(x + b.x, y + b.y, z + b.z, w + b.w);    }    public final Vector4D substract(Vector4D b)    {        return new Vector4D(x - b.x, y - b.y, z - b.z, w - b.w);    }    public float[] exportFloatToArray()    {        float[] ret={(float)x, (float)y, (float)z, (float)w};        return ret;    }    public double[] exportToDoubleArray()    {        double[] ret={x, y, z, w};        return ret;    }    /**    Provides an object to text report convertion, optimized for human    readability and debugging. Do not use for serialization or persistence    purposes.    */    public String toString()    {        String msg;        msg = "<" + VSDK.formatDouble(x) + ", " + VSDK.formatDouble(y) +              ", " + VSDK.formatDouble(z) + ", " + VSDK.formatDouble(w) + ">";        return msg;    }}//===========================================================================//= EOF                                                                     =//===========================================================================