Examples:SpaceInvaders Entity

 /* * Copyright (c) 2002-2010 LWJGL Project * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright *  notice, this list of conditions and the following disclaimer. * * * Redistributions in binary form must reproduce the above copyright *  notice, this list of conditions and the following disclaimer in the *  documentation and/or other materials provided with the distribution. * * * Neither the name of 'LWJGL' nor the names of *  its contributors may be used to endorse or promote products derived *  from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package org.lwjgl.examples.spaceinvaders;

import java.awt.Rectangle;

/** * An entity represents any element that appears in the game. The * entity is responsible for resolving collisions and movement * based on a set of properties defined either by subclass or externally. * * Note that doubles are used for positions. This may seem strange * given that pixels locations are integers. However, using double means * that an entity can move a partial pixel. It doesn't of course mean that * they will be display half way through a pixel but allows us not lose * accuracy as we move. * * @author Kevin Glass */ public abstract class Entity {

/** The current x location of this entity */ protected float	x;

/** The current y location of this entity */ protected float	y;

/** The sprite that represents this entity */ protected Sprite	sprite;

/** The current speed of this entity horizontally (pixels/sec) */ protected float	dx;

/** The current speed of this entity vertically (pixels/sec) */ protected float	dy;

/** The rectangle used for this entity during collisions resolution */ private Rectangle	me	= new Rectangle;

/** The rectangle used for other entities during collision resolution */ private Rectangle	him	= new Rectangle;

/**	 * Construct a entity based on a sprite image and a location. *	 * @param sprite The reference to the image to be displayed for this entity * @param x The initial x location of this entity * @param y The initial y location of this entity */	protected Entity(Sprite sprite, int x, int y) { this.sprite = sprite; this.x = x;		this.y = y;	}

/**	 * Request that this entity move itself based on a certain ammount * of time passing. *	 * @param delta The ammount of time that has passed in milliseconds */	public void move(long delta) { // update the location of the entity based on move speeds x += (delta * dx) / 1000; y += (delta * dy) / 1000; }

/**	 * Set the horizontal speed of this entity *	 * @param dx The horizontal speed of this entity (pixels/sec) */	public void setHorizontalMovement(float dx) { this.dx = dx; }

/**	 * Set the vertical speed of this entity *	 * @param dy The vertical speed of this entity (pixels/sec) */	public void setVerticalMovement(float dy) { this.dy = dy; }

/**	 * Get the horizontal speed of this entity *	 * @return The horizontal speed of this entity (pixels/sec) */	public float getHorizontalMovement { return dx; }

/**	 * Get the vertical speed of this entity *	 * @return The vertical speed of this entity (pixels/sec) */	public float getVerticalMovement { return dy; }

/**	 * Draw this entity to the graphics context provided */	public void draw { sprite.draw((int) x, (int) y); }

/**	 * Do the logic associated with this entity. This method * will be called periodically based on game events */	public void doLogic { }

/**	 * Get the x location of this entity *	 * @return The x location of this entity */	public int getX { return (int) x;	}

/**	 * Get the y location of this entity *	 * @return The y location of this entity */	public int getY { return (int) y;	}

/**	 * Check if this entity collised with another. *	 * @param other The other entity to check collision against * @return True if the entities collide with each other */	public boolean collidesWith(Entity other) { me.setBounds((int) x, (int) y, sprite.getWidth, sprite.getHeight); him.setBounds((int) other.x, (int) other.y, other.sprite.getWidth, other.sprite.getHeight);

return me.intersects(him); }

/**	 * Notification that this entity collided with another. *	 * @param other The entity with which this entity collided. */	public abstract void collidedWith(Entity other); }