projectile.java

用java开发的一个实施策略游戏源码 值得学习一下

/*
	Netwar
	Copyright (C) 2002  Daniel Grund, Kyle Kakligian, Jason Komutrattananon, & Brian Hibler.

	This file is part of Netwar.

	Netwar is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	Netwar is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with Netwar; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package netwar.game;
import netwar.utils.*;
import netwar.utils.vectorgraphics.*;

/** Abstract class representing one shot fired from some weapon.
 * @author Group N2 - Project Netwar
 * @author Daniel Grund
 */
public abstract class Projectile {
	/** The game-space location of the center of the projectile. */
	protected Point3D center;
	/** The velocity of the projectile, in game-space units per time-step */
	protected Point3D velocity;
	/** The object that fired this shot (in case it is relevant) */
	protected GameObject maker;
	/** The object that the shot was intended to hit (in case it is relevant) */
	protected GameObject enemy;
	/** Graphical representation */
	protected netwar.utils.vectorgraphics.GraphicThing appearance;
	/** The number of frames remaining before this projectile must cease existing (it may cease before then) */
	protected int life;
	/** The amount of damage the shot will deal if it hits something. */
	protected int damage;
	/** The square of the radius of explosion for this shot. */
	protected int radiusSquared;
	/** The vector containing all currently existing Projectiles. */
	static protected Vector Projectiles = new LVector();
	/** This method initializes a Projectile.
	 * This performs the following processes:
	 * <BR> Initializes the center, velocity, damage, radiusSquared, life, maker, and enemy fields.
	 * <BR> Adds the Projectile into the Vector.
	 * @param add The Projectile to incorporate into the game.
	 * @param where The initial value of center.
	 * @param going The initial value of velocity.
	 * @param power The initial value of damage.
	 * @param rad2 The initial value of radiusSquared.
	 * @param duration The initial value of life.
	 * @param origin The initial value of maker.
	 * @param target The initial value of enemy.
	 */
	public static void newProjectile(Projectile add, Point3D where, Point3D going, int power, int rad2, int duration, GameObject origin, GameObject target) {
		add.center = new Point3D(where);
		add.velocity = new Point3D(going);
		add.damage = power;
		add.radiusSquared = rad2;
		add.life = duration;
		add.maker = origin;
		add.enemy = target;

		add.makeGraphics();
		netwar.gui.HexViewer.getHexViewer().add(add.appearance);
		
		Projectiles.append(add);
	}
	/** Make the GraphicThing appearance. */
	protected abstract void makeGraphics();
	
	/** Calls update() on all Projectiles in the Vector. */
	public static void UpdateAll() {
		Projectiles.goFirst();
		while(Projectiles.isInList()) {
			if(((Projectile)Projectiles.get()).basicUpdate())
				((Projectile)Projectiles.get()).Update();
			Projectiles.goNext();
		}		
	}
 
	/** Performs functions which will be needed by most Projectiles during Update().
	 * Specifically, it decrements life. If life reaches zero, it calls
	 * Explode() if mustExplode() returns true, Fizzle() if mustExplode() returns false.
	 * Then it returns false. If life did not reach zero, it returns true.
	 */
	protected boolean basicUpdate() {
		life--;
		if(life == 0){
			if(mustExplode())
				Explode();
			else
				Fizzle();
		}
		return (life > 0);
	}
	/** Function to perform the processing needed during a single time-step. */
	protected abstract void Update();
	/** Draws all projectiles in the game onto GameViewer v 
	 * @param v The GameViewer seeking to display all the Projectiles.
	 */
	public static void DrawAll(GameViewer v) {
		Projectiles.goFirst();
		while(Projectiles.isInList()) {
			//if(((Projectile)Projectiles.get()).center is on/near the screen))
			((Projectile)Projectiles.get()).draw(v);
			Projectiles.goNext();
		}		
	}
	/** Displays this projectile on GameViewer v.
	 * @param v The GameViewer seeking to display this Projectile.
	 */
	public void draw(GameViewer v) {
		appearance.draw(v);
	}
    
	/** Return true iff it should detonate when it's life runs out.
	 * @return true if this should not just Fizzle() when life runs out.
	 */
	protected abstract boolean mustExplode();
    
	/** Deals damage to nearby GameObjects, makes flashy graphics, and calls Fizzle(). */
	protected abstract void Explode();
	/** Removes this from the game */
	protected void Fizzle() {
		appearance.kill();
		Projectiles.goFirst();
		while(Projectiles.get() != this)
			Projectiles.goNext();
		Projectiles.remove();
	}
}