vector2f.java

java 3d game jme 工程开发源代码

        return this;
    }

    /**
     * Multiplies this Vector2f's x and y by the scalar and stores the result in
     * product. The result is returned for chaining. Similar to
     * product=this*scalar;
     * 
     * @param scalar
     *            The scalar to multiply by.
     * @param product
     *            The vector2f to store the result in.
     * @return product, after multiplication.
     */
    public Vector2f mult(float scalar, Vector2f product) {
        if (null == product) {
            product = new Vector2f();
        }

        product.x = x * scalar;
        product.y = y * scalar;
        return product;
    }

    /**
     * <code>divide</code> divides the values of this vector by a scalar and
     * returns the result. The values of this vector remain untouched.
     * 
     * @param scalar
     *            the value to divide this vectors attributes by.
     * @return the result <code>Vector</code>.
     */
    public Vector2f divide(float scalar) {
        return new Vector2f(x / scalar, y / scalar);
    }

    /**
     * <code>divideLocal</code> divides this vector by a scalar internally,
     * and returns a handle to this vector for easy chaining of calls. Dividing
     * by zero will result in an exception.
     * 
     * @param scalar
     *            the value to divides this vector by.
     * @return this
     */
    public Vector2f divideLocal(float scalar) {
        x /= scalar;
        y /= scalar;
        return this;
    }

    /**
     * <code>negate</code> returns the negative of this vector. All values are
     * negated and set to a new vector.
     * 
     * @return the negated vector.
     */
    public Vector2f negate() {
        return new Vector2f(-x, -y);
    }

    /**
     * <code>negateLocal</code> negates the internal values of this vector.
     * 
     * @return this.
     */
    public Vector2f negateLocal() {
        x = -x;
        y = -y;
        return this;
    }

    /**
     * <code>subtract</code> subtracts the values of a given vector from those
     * of this vector creating a new vector object. If the provided vector is
     * null, an exception is thrown.
     * 
     * @param vec
     *            the vector to subtract from this vector.
     * @return the result vector.
     */
    public Vector2f subtract(Vector2f vec) {
        return subtract(vec, null);
    }

    /**
     * <code>subtract</code> subtracts the values of a given vector from those
     * of this vector storing the result in the given vector object. If the
     * provided vector is null, an exception is thrown.
     * 
     * @param vec
     *            the vector to subtract from this vector.
     * @param store
     *            the vector to store the result in. It is safe for this to be
     *            the same as vec. If null, a new vector is created.
     * @return the result vector.
     */
    public Vector2f subtract(Vector2f vec, Vector2f store) {
        if (store == null)
            store = new Vector2f();
        store.x = x - vec.x;
        store.y = y - vec.y;
        return store;
    }

    /**
     * <code>subtract</code> subtracts the given x,y values from those of this
     * vector creating a new vector object.
     * 
     * @param valX
     *            value to subtract from x
     * @param valY
     *            value to subtract from y
     * @return this
     */
    public Vector2f subtract(float valX, float valY) {
        return new Vector2f(x - valX, y - valY);
    }

    /**
     * <code>subtractLocal</code> subtracts a provided vector to this vector
     * internally, and returns a handle to this vector for easy chaining of
     * calls. If the provided vector is null, null is returned.
     * 
     * @param vec
     *            the vector to subtract
     * @return this
     */
    public Vector2f subtractLocal(Vector2f vec) {
        if (null == vec) {
            logger.warning("Provided vector is null, null returned.");
            return null;
        }
        x -= vec.x;
        y -= vec.y;
        return this;
    }

    /**
     * <code>subtractLocal</code> subtracts the provided values from this
     * vector internally, and returns a handle to this vector for easy chaining
     * of calls.
     * 
     * @param valX
     *            value to subtract from x
     * @param valY
     *            value to subtract from y
     * @return this
     */
    public Vector2f subtractLocal(float valX, float valY) {
        x -= valX;
        y -= valY;
        return this;
    }

    /**
     * <code>normalize</code> returns the unit vector of this vector.
     * 
     * @return unit vector of this vector.
     */
    public Vector2f normalize() {
        float length = length();
        if (length != 0) {
            return divide(length);
        }

        return divide(1);
    }

    /**
     * <code>normalizeLocal</code> makes this vector into a unit vector of
     * itself.
     * 
     * @return this.
     */
    public Vector2f normalizeLocal() {
        float length = length();
        if (length != 0) {
            return divideLocal(length);
        }

        return divideLocal(1);
    }

    /**
     * <code>smallestAngleBetween</code> returns (in radians) the minimum
     * angle between two vectors. It is assumed that both this vector and the
     * given vector are unit vectors (iow, normalized).
     * 
     * @param otherVector
     *            a unit vector to find the angle against
     * @return the angle in radians.
     */
    public float smallestAngleBetween(Vector2f otherVector) {
        float dotProduct = dot(otherVector);
        float angle = FastMath.acos(dotProduct);
        return angle;
    }

    /**
     * <code>angleBetween</code> returns (in radians) the angle required to
     * rotate a ray represented by this vector to lie colinear to a ray
     * described by the given vector. It is assumed that both this vector and
     * the given vector are unit vectors (iow, normalized).
     * 
     * @param otherVector
     *            the "destination" unit vector
     * @return the angle in radians.
     */
    public float angleBetween(Vector2f otherVector) {
        float angle = FastMath.atan2(otherVector.y, otherVector.x)
                - FastMath.atan2(y, x);
        return angle;
    }
    
    public float getX() {
        return x;
    }

    public void setX(float x) {
        this.x = x;
    }

    public float getY() {
        return y;
    }

    public void setY(float y) {
        this.y = y;
    }
    /**
     * <code>getAngle</code> returns (in radians) the angle represented by
     * this Vector2f as expressed by a conversion from rectangular coordinates (<code>x</code>,&nbsp;<code>y</code>)
     * to polar coordinates (r,&nbsp;<i>theta</i>).
     * 
     * @return the angle in radians. [-pi, pi)
     */
    public float getAngle() {
        return -FastMath.atan2(y, x);
    }

    /**
     * <code>zero</code> resets this vector's data to zero internally.
     */
    public void zero() {
        x = y = 0;
    }

    /**
     * <code>hashCode</code> returns a unique code for this vector object
     * based on it's values. If two vectors are logically equivalent, they will
     * return the same hash code value.
     * 
     * @return the hash code value of this vector.
     */
    public int hashCode() {
        int hash = 37;
        hash += 37 * hash + Float.floatToIntBits(x);
        hash += 37 * hash + Float.floatToIntBits(y);
        return hash;
    }

    @Override
    public Vector2f clone() {
        try {
            return (Vector2f) super.clone();
        } catch (CloneNotSupportedException e) {
            throw new AssertionError(); // can not happen
        }
    }

    /**
     * Saves this Vector2f into the given float[] object.
     * 
     * @param floats
     *            The float[] to take this Vector2f. If null, a new float[2] is
     *            created.
     * @return The array, with X, Y float values in that order
     */
    public float[] toArray(float[] floats) {
        if (floats == null) {
            floats = new float[2];
        }
        floats[0] = x;
        floats[1] = y;
        return floats;
    }

    /**
     * are these two vectors the same? they are is they both have the same x and
     * y values.
     * 
     * @param o
     *            the object to compare for equality
     * @return true if they are equal
     */
    public boolean equals(Object o) {
        if (!(o instanceof Vector2f)) {
            return false;
        }

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

        Vector2f comp = (Vector2f) o;
        if (Float.compare(x, comp.x) != 0)
            return false;
        if (Float.compare(y, comp.y) != 0)
            return false;
        return true;
    }

    /**
     * <code>toString</code> returns the string representation of this vector
     * object. The format of the string is such: com.jme.math.Vector2f
     * [X=XX.XXXX, Y=YY.YYYY]
     * 
     * @return the string representation of this vector.
     */
    public String toString() {
        return "com.jme.math.Vector2f [X=" + x + ", Y=" + y + "]";
    }

    /**
     * Used with serialization. Not to be called manually.
     * 
     * @param in
     *            ObjectInput
     * @throws IOException
     * @throws ClassNotFoundException
     * @see java.io.Externalizable
     */
    public void readExternal(ObjectInput in) throws IOException,
            ClassNotFoundException {
        x = in.readFloat();
        y = in.readFloat();
    }

    /**
     * Used with serialization. Not to be called manually.
     * 
     * @param out
     *            ObjectOutput
     * @throws IOException
     * @see java.io.Externalizable
     */
    public void writeExternal(ObjectOutput out) throws IOException {
        out.writeFloat(x);
        out.writeFloat(y);
    }

    public void write(JMEExporter e) throws IOException {
        OutputCapsule capsule = e.getCapsule(this);
        capsule.write(x, "x", 0);
        capsule.write(y, "y", 0);
    }

    public void read(JMEImporter e) throws IOException {
        InputCapsule capsule = e.getCapsule(this);
        x = capsule.readFloat("x", 0);
        y = capsule.readFloat("y", 0);
    }

    public Class<? extends Vector2f> getClassTag() {
        return this.getClass();
    }

    public void rotateAroundOrigin(float angle, boolean cw) {
        if (cw)
            angle = -angle;
        float newX = FastMath.cos(angle) * x - FastMath.sin(angle) * y;
        float newY = FastMath.sin(angle) * x + FastMath.cos(angle) * y;
        x = newX;
        y = newY;
    }
}