/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/
package com.glview.libgdx.graphics.math;
import java.io.Serializable;
/** Encapsulates a 2D vector. Allows chaining methods by returning a reference to itself
* @author badlogicgames@gmail.com */
public class Vector2 implements Serializable, Vector<Vector2> {
private static final long serialVersionUID = 913902788239530931L;
public final static Vector2 X = new Vector2(1, 0);
public final static Vector2 Y = new Vector2(0, 1);
public final static Vector2 Zero = new Vector2(0, 0);
/** the x-component of this vector **/
public float x;
/** the y-component of this vector **/
public float y;
/** Constructs a new vector at (0,0) */
public Vector2 () {
}
/** Constructs a vector with the given components
* @param x The x-component
* @param y The y-component */
public Vector2 (float x, float y) {
this.x = x;
this.y = y;
}
/** Constructs a vector from the given vector
* @param v The vector */
public Vector2 (Vector2 v) {
set(v);
}
/** @return a copy of this vector */
public Vector2 cpy () {
return new Vector2(this);
}
/** @return The euclidian length */
public float len () {
return (float)Math.sqrt(x * x + y * y);
}
/** @return The squared euclidian length */
public float len2 () {
return x * x + y * y;
}
/** Sets this vector from the given vector
* @param v The vector
* @return This vector for chaining */
public Vector2 set (Vector2 v) {
x = v.x;
y = v.y;
return this;
}
/** Sets the components of this vector
* @param x The x-component
* @param y The y-component
* @return This vector for chaining */
public Vector2 set (float x, float y) {
this.x = x;
this.y = y;
return this;
}
/** Subtracts the given vector from this vector.
* @param v The vector
* @return This vector for chaining */
public Vector2 sub (Vector2 v) {
x -= v.x;
y -= v.y;
return this;
}
/** Normalizes this vector. Does nothing if it is zero.
* @return This vector for chaining */
public Vector2 nor () {
float len = len();
if (len != 0) {
x /= len;
y /= len;
}
return this;
}
/** Adds the given vector to this vector
* @param v The vector
* @return This vector for chaining */
public Vector2 add (Vector2 v) {
x += v.x;
y += v.y;
return this;
}
/** Adds the given components to this vector
* @param x The x-component
* @param y The y-component
* @return This vector for chaining */
public Vector2 add (float x, float y) {
this.x += x;
this.y += y;
return this;
}
/** @param v The other vector
* @return The dot product between this and the other vector */
public float dot (Vector2 v) {
return x * v.x + y * v.y;
}
/** Multiplies this vector by a scalar
* @param scalar The scalar
* @return This vector for chaining */
public Vector2 scl (float scalar) {
x *= scalar;
y *= scalar;
return this;
}
/** @deprecated Use {@link #scl(float)} instead. */
public Vector2 mul (float scalar) {
return scl(scalar);
}
/** Multiplies this vector by a scalar
* @return This vector for chaining */
public Vector2 scl (float x, float y) {
this.x *= x;
this.y *= y;
return this;
}
/** @deprecated Use {@link #scl(float, float)} instead. */
public Vector2 mul (float x, float y) {
return scl(x, y);
}
/** Multiplies this vector by a vector
* @return This vector for chaining */
public Vector2 scl (Vector2 v) {
this.x *= v.x;
this.y *= v.y;
return this;
}
/** @deprecated Use {@link #scl(Vector2)} instead. */
public Vector2 mul (Vector2 v) {
return scl(v);
}
public Vector2 div (float value) {
return this.scl(1 / value);
}
public Vector2 div (float vx, float vy) {
return this.scl(1 / vx, 1 / vy);
}
public Vector2 div (Vector2 other) {
return this.scl(1 / other.x, 1 / other.y);
}
/** @param v The other vector
* @return the distance between this and the other vector */
public float dst (Vector2 v) {
final float x_d = v.x - x;
final float y_d = v.y - y;
return (float)Math.sqrt(x_d * x_d + y_d * y_d);
}
/** @param x The x-component of the other vector
* @param y The y-component of the other vector
* @return the distance between this and the other vector */
public float dst (float x, float y) {
final float x_d = x - this.x;
final float y_d = y - this.y;
return (float)Math.sqrt(x_d * x_d + y_d * y_d);
}
/** @param v The other vector
* @return the squared distance between this and the other vector */
public float dst2 (Vector2 v) {
final float x_d = v.x - x;
final float y_d = v.y - y;
return x_d * x_d + y_d * y_d;
}
/** @param x The x-component of the other vector
* @param y The y-component of the other vector
* @return the squared distance between this and the other vector */
public float dst2 (float x, float y) {
final float x_d = x - this.x;
final float y_d = y - this.y;
return x_d * x_d + y_d * y_d;
}
/** Limits this vector's length to given value
* @param limit Max length
* @return This vector for chaining */
public Vector2 limit (float limit) {
if (len2() > limit * limit) {
nor();
scl(limit);
}
return this;
}
/** Clamps this vector's length to given value
* @param min Min length
* @param max Max length
* @return This vector for chaining */
public Vector2 clamp (float min, float max) {
final float l2 = len2();
if (l2 == 0f) return this;
if (l2 > max * max) return nor().scl(max);
if (l2 < min * min) return nor().scl(min);
return this;
}
public String toString () {
return "[" + x + ":" + y + "]";
}
/** Substracts the other vector from this vector.
* @param x The x-component of the other vector
* @param y The y-component of the other vector
* @return This vector for chaining */
public Vector2 sub (float x, float y) {
this.x -= x;
this.y -= y;
return this;
}
/** Left-multiplies this vector by the given matrix
* @param mat the matrix
* @return this vector */
public Vector2 mul (Matrix3 mat) {
float x = this.x * mat.val[0] + this.y * mat.val[3] + mat.val[6];
float y = this.x * mat.val[1] + this.y * mat.val[4] + mat.val[7];
this.x = x;
this.y = y;
return this;
}
/** Calculates the 2D cross product between this and the given vector.
* @param v the other vector
* @return the cross product */
public float crs (Vector2 v) {
return this.x * v.y - this.y * v.x;
}
/** Calculates the 2D cross product between this and the given vector.
* @param x the x-coordinate of the other vector
* @param y the y-coordinate of the other vector
* @return the cross product */
public float crs (float x, float y) {
return this.x * y - this.y * x;
}
/** @return the angle in degrees of this vector (point) relative to the x-axis. Angles are towards the positive y-axis (typically
* counter-clockwise) and between 0 and 360. */
public float angle () {
float angle = (float)Math.atan2(y, x) * MathUtils.radiansToDegrees;
if (angle < 0) angle += 360;
return angle;
}
/** Sets the angle of the vector in degrees relative to the x-axis, towards the positive y-axis (typically counter-clockwise).
* @param degrees The angle to set. */
public Vector2 setAngle (float degrees) {
this.set(len(), 0f);
this.rotate(degrees);
return this;
}
/** Rotates the Vector2 by the given angle, counter-clockwise assuming the y-axis points up.
* @param degrees the angle in degrees */
public Vector2 rotate (float degrees) {
float rad = degrees * MathUtils.degreesToRadians;
float cos = (float)Math.cos(rad);
float sin = (float)Math.sin(rad);
float newX = this.x * cos - this.y * sin;
float newY = this.x * sin + this.y * cos;
this.x = newX;
this.y = newY;
return this;
}
/** Rotates the Vector2 by 90 degrees in the specified direction, where >= 0 is counter-clockwise and < 0 is clockwise. */
public Vector2 rotate90 (int dir) {
float x = this.x;
if (dir >= 0) {
this.x = -y;
y = x;
} else {
this.x = y;
y = -x;
}
return this;
}
/** Linearly interpolates between this vector and the target vector by alpha which is in the range [0,1]. The result is stored
* in this vector.
*
* @param target The target vector
* @param alpha The interpolation coefficient
* @return This vector for chaining. */
public Vector2 lerp (Vector2 target, float alpha) {
final float invAlpha = 1.0f - alpha;
this.x = (x * invAlpha) + (target.x * alpha);
this.y = (y * invAlpha) + (target.y * alpha);
return this;
}
@Override
public int hashCode () {
final int prime = 31;
int result = 1;
result = prime * result + NumberUtils.floatToIntBits(x);
result = prime * result + NumberUtils.floatToIntBits(y);
return result;
}
@Override
public boolean equals (Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
Vector2 other = (Vector2)obj;
if (NumberUtils.floatToIntBits(x) != NumberUtils.floatToIntBits(other.x)) return false;
if (NumberUtils.floatToIntBits(y) != NumberUtils.floatToIntBits(other.y)) return false;
return true;
}
/** Compares this vector with the other vector, using the supplied epsilon for fuzzy equality testing.
* @param obj
* @param epsilon
* @return whether the vectors are the same. */
public boolean epsilonEquals (Vector2 obj, float epsilon) {
if (obj == null) return false;
if (Math.abs(obj.x - x) > epsilon) return false;
if (Math.abs(obj.y - y) > epsilon) return false;
return true;
}
/** Compares this vector with the other vector, using the supplied epsilon for fuzzy equality testing.
* @param x
* @param y
* @param epsilon
* @return whether the vectors are the same. */
public boolean epsilonEquals (float x, float y, float epsilon) {
if (Math.abs(x - this.x) > epsilon) return false;
if (Math.abs(y - this.y) > epsilon) return false;
return true;
}
public Vector2 zero(){
return this.Zero;
}
}