Ball.java

/**
* Copyright (c) 2012-2013 Nokia Corporation. All rights reserved.
* Nokia and Nokia Connecting People are registered trademarks of Nokia Corporation. 
* Oracle and Java are trademarks or registered trademarks of Oracle and/or its
* affiliates. Other product and company names mentioned herein may be trademarks
* or trade names of their respective owners. 
* See LICENSE.TXT for license information.
*/

package com.nokia.example.explonoid.game;

import javax.microedition.lcdui.game.Sprite;

/**
 * Responsible for moving the ball into different directions and changing its speed.
 * 
 * For usage, see the class Game.
 * 
 * @see com.nokia.example.explonoid.game.Game
 */
public class Ball
        extends Sprite {

    private static final int PADDING = 6;
    private int velocityX;
    private int velocityY;

    public Ball(Resources r) {
        super(r.ball);
        setCollisionRectangle(r);
        defineReferencePixel((int) (getWidth() * 0.5 + 0.5), (int) (getHeight() * 0.5 + 0.5));
    }

    private void setCollisionRectangle(Resources r) {
        int width = this.getWidth();
        int padding = r.scale(PADDING);
        defineCollisionRectangle(padding, padding, width - padding, width - padding);
    }

    public void move() {
        move(getVelocityX(), getVelocityY());
    }

    public void bounceVertically() {
        velocityY *= -1;
    }

    public void bounceHorizontally() {
        velocityX *= -1;
    }

    public void bounceLeft() {
        if (velocityX > 0) {
            bounceHorizontally();
        }
    }

    public void bounceRight() {
        if (velocityX < 0) {
            bounceHorizontally();
        }
    }

    public void bounceUp() {
        if (velocityY > 0) {
            bounceVertically();
        }
    }

    public void bounceDown() {
        if (velocityY < 0) {
            bounceVertically();
        }
    }

    public int getVelocityX() {
        return velocityX;
    }

    public int getVelocityY() {
        return velocityY;
    }

    public void setVelocityX(int velocity) {
        this.velocityX = velocity;
    }

    public void setVelocityY(int velocity) {
        this.velocityY = velocity;
    }

    public void changeVelocityX(int amount) {
        velocityX += amount;
    }
}