asteroids-day 3 Class Space

Transcription

1 Class Space // (World, Actor, GreenfootImage, Greenfoot and MouseInfo) import greenfoot.*; * Space -- something for rockets to fly in. * Prof. Carl B. Struck November 2010 public class Space extends World private static final int START_ASTEROIDS = 3; * Create a new world with 600x400 and cell size of 1 pixel. public Space() // Create a new world super(600, 400, 1); Rocket rocket = new Rocket(); addobject( rocket, getwidth() / , getheight() / 2 ); addasteroids(start_asteroids); * Add a given number of asteroids to the world. * Asteroids are only added into the left half of the world. private void addasteroids(int count) for(int i = 0; i < count; i++) int x = Greenfoot.getRandomNumber( getwidth() / 2 ); int y = Greenfoot.getRandomNumber( getheight() ); addobject(new Asteroid(), x, y); 1

2 Class Rocket // (World, Actor, GreenfootImage, Greenfoot and MouseInfo) import greenfoot.*; * A rocket that can be controlled by arrow keys: up, left, and right. * The gun is fired by hitting the 'space' key. * Prof. Carl B. Struck November 2010 public class Rocket extends SmoothMover // The minimum delay between firing the gun. private static final int GUN_RELOAD_TIME = 5; // How long ago we fired the gun the last time. private int reloaddelaycount; private GreenfootImage rocket = new GreenfootImage("rocket.png"); private GreenfootImage rocketwiththrust = new GreenfootImage("rocketWithThrust.png"); * Initialize this rocket public Rocket() reloaddelaycount = 5; addforce( new Vector(13, 0.3) ); * Do whatever the Rocket wants to do which is mostly flying about, * turning, accelerating and shooting when the right keys are pressed. public void act() move(); checkkeys(); checkcollision(); reloaddelaycount++; 2

3 * Check whether there are any keys pressed and react to them. public void checkkeys() ignite( Greenfoot.isKeyDown("up") ); if ( Greenfoot.isKeyDown("left") ) setrotation( getrotation() - 5 ); if ( Greenfoot.isKeyDown("right") ) setrotation( getrotation() + 5 ); if ( Greenfoot.isKeyDown("space") ) fire(); * Should the rocket be ignited? private void ignite(boolean boosteron) if (boosteron) setimage( rocketwiththrust ); addforce( new Vector( getrotation(), 0.3) ); else setimage(rocket); * Fire a bullet if the gun is ready. public void fire() Bullet bullet = new Bullet( getmovement().copy(), getrotation() ); getworld().addobject( bullet, getx(), gety() ); bullet.move(); reloaddelaycount = 0; 3

4 * Check whether we have collided with an asteroid. private void checkcollision() Actor actor = getoneintersectingobject(asteroid.class); if (actor!= null) Space space = (Space) getworld(); space.addobject( new Explosion(), getx(), gety() ); space.removeobject(this); 4

5 Class Bullet // (World, Actor, GreenfootImage, Greenfoot and MouseInfo) import greenfoot.*; * A bullet that can hit asteroids. * Prof. Carl B. Struck November 2010 public class Bullet extends SmoothMover // A bullet looses one life with each act, and disappears when life = 0 private int life = 30; // The damage this buller will deal. private static final int DAMAGE = 16; Instantiate a bullet with a speed instantiated from class Vector * and shooting at a particular angle (rotation). public Bullet(Vector speed, int rotation) super(speed); setrotation(rotation); addforce( new Vector(rotation, 15) ); Greenfoot.playSound("EnergyGun.wav"); * The bullet will damage asteroids if it hits them. public void act() if (life <= 0) getworld().removeobject(this); else life--; move(); checkasteroidhit(); 5

6 * Check whether we have hit asteroid. public void checkasteroidhit() Asteroid asteroid = (Asteroid) getoneintersectingobject(asteroid.class); if (asteroid!= null) getworld().removeobject(this); asteroid.hit(damage); 6

7 Class Asteroid // (World, Actor, GreenfootImage, Greenfoot and MouseInfo) import greenfoot.*; * A rock in space. * Prof. Carl B. Struck Fall 2010 public class Asteroid extends SmoothMover // Size of this asteroid private int size; // When the stability reaches zero, the asteroid will explode private int stability; * Default constructor sets initial size to 50 * by calling constructor Asteroid(int size). public Asteroid() this(50); * Constructor takes an initial custom size * and sets vector with a random direction. public Asteroid(int size) super( new Vector( Greenfoot.getRandomNumber(360), 2 ) ); setsize(size); * Constructor takes initial custom size and vector values. public Asteroid(int size, Vector speed) super(speed); setsize(size); public void act() move(); 7

8 * Set the size of this asteroid. Note that stability is directly * related to size. Smaller asteroids are less stable. public void setsize(int size) stability = size; this.size = size; GreenfootImage image = getimage(); image.scale(size, size); * Hit this asteroid dealing the given amount of damage. public void hit(int damage) stability -= damage; if(stability <= 0) breakup(); 8

9 * Break up this asteroid. * If it is still big enough, creates two smaller asteroids. * If it is small already, it disappears. private void breakup() Greenfoot.playSound("Explosion.wav"); if(size <= 16) getworld().removeobject(this); else int r = getmovement().getdirection() + Greenfoot.getRandomNumber(45); double l = getmovement().getlength(); Vector speed1 = new Vector(r + 60, l * 1.2); Vector speed2 = new Vector(r - 60, l * 1.2); Asteroid a1 = new Asteroid( size / 2, speed1 ); Asteroid a2 = new Asteroid( size / 2, speed2 ); getworld().addobject( a1, getx(), gety() ); getworld().addobject( a2, getx(), gety() ); a1.move(); a2.move(); getworld().removeobject(this); 9