/************************************************************************************************ Asteroids.java Usage: Keyboard Controls: S - Start Game P - Pause Game Cursor Left - Rotate Left Cursor Up - Fire Thrusters Cursor Right - Rotate Right Cursor Down - Fire Retro Thrusters Spacebar - Fire Cannon H - Hyperspace M - Toggle Sound D - Toggle Graphics Detail ************************************************************************************************/ import java.awt.*; import java.net.*; import java.util.*; import java.applet.Applet; import java.applet.AudioClip; /************************************************************************************************ The AsteroidsSprite class defines a game object, including it's shape, position, movement and rotation. It also can detemine if two objects collide. ************************************************************************************************/ class AsteroidsSprite { // Fields: static int width; // Dimensions of the graphics area. static int height; Polygon shape; // Initial sprite shape, centered at the origin (0,0). boolean active; // Active flag. double angle; // Current angle of rotation. double deltaAngle; // Amount to change the rotation angle. double currentX, currentY; // Current position on screen. double deltaX, deltaY; // Amount to change the screen position. Polygon sprite; // Final location and shape of sprite after applying rotation and // moving to screen position. Used for drawing on the screen and // in detecting collisions. // Constructors: public AsteroidsSprite() { this.shape = new Polygon(); this.active = false; this.angle = 0.0; this.deltaAngle = 0.0; this.currentX = 0.0; this.currentY = 0.0; this.deltaX = 0.0; this.deltaY = 0.0; this.sprite = new Polygon(); } // Methods: public void advance() { // Update the rotation and position of the sprite based on the delta values. If the sprite // moves off the edge of the screen, it is wrapped around to the other side. this.angle += this.deltaAngle; if (this.angle < 0) this.angle += 2 * Math.PI; if (this.angle > 2 * Math.PI) this.angle -= 2 * Math.PI; this.currentX += this.deltaX; if (this.currentX < -width / 2) this.currentX += width; if (this.currentX > width / 2) this.currentX -= width; this.currentY -= this.deltaY; if (this.currentY < -height / 2) this.currentY += height; if (this.currentY > height / 2) this.currentY -= height; } public void render() { int i; // Render the sprite's shape and location by rotating it's base shape and moving it to // it's proper screen position. this.sprite = new Polygon(); for (i = 0; i < this.shape.npoints; i++) this.sprite.addPoint((int) Math.round(this.shape.xpoints[i] * Math.cos(this.angle) + this.shape.ypoints[i] * Math.sin(this.angle)) + (int) Math.round(this.currentX) + width / 2, (int) Math.round(this.shape.ypoints[i] * Math.cos(this.angle) - this.shape.xpoints[i] * Math.sin(this.angle)) + (int) Math.round(this.currentY) + height / 2); } public boolean isColliding(AsteroidsSprite s) { int i; // Determine if one sprite overlaps with another, i.e., if any vertice // of one sprite lands inside the other. for (i = 0; i < s.sprite.npoints; i++) if (this.sprite.inside(s.sprite.xpoints[i], s.sprite.ypoints[i])) return true; for (i = 0; i < this.sprite.npoints; i++) if (s.sprite.inside(this.sprite.xpoints[i], this.sprite.ypoints[i])) return true; return false; } } /************************************************************************************************ Main applet code. ************************************************************************************************/ public class Asteroids extends Applet implements Runnable { // Thread control variables. Thread loadThread; Thread loopThread; // Constants static final int DELAY = 50; // Milliseconds between screen updates. static final int MAX_SHIPS = 3; // Starting number of ships per game. static final int MAX_SHOTS = 6; // Maximum number of sprites for photons, static final int MAX_ROCKS = 8; // asteroids and explosions. static final int MAX_SCRAP = 20; static final int SCRAP_COUNT = 30; // Counter starting values. static final int HYPER_COUNT = 60; static final int STORM_PAUSE = 30; static final int UFO_PASSES = 3; static final int MIN_ROCK_SIDES = 8; // Asteroid shape and size ranges. static final int MAX_ROCK_SIDES = 12; static final int MIN_ROCK_SIZE = 20; static final int MAX_ROCK_SIZE = 40; static final int MIN_ROCK_SPEED = 2; static final int MAX_ROCK_SPEED = 12; static final int BIG_POINTS = 25; // Points for shooting different objects. static final int SMALL_POINTS = 50; static final int UFO_POINTS = 250; static final int MISSLE_POINTS = 500; static final int NEW_SHIP_POINTS = 5000; // Number of points needed to earn a new ship. static final int NEW_UFO_POINTS = 2750; // Number of points between flying saucers. // Background stars. int numStars; Point[] stars; // Game data. int score; int highScore; int newShipScore; int newUfoScore; boolean loaded = false; boolean paused; boolean playing; boolean sound; boolean detail; // Key flags. boolean left = false; boolean right = false; boolean up = false; boolean down = false; // Sprite objects. AsteroidsSprite ship; AsteroidsSprite ufo; AsteroidsSprite missle; AsteroidsSprite[] photons = new AsteroidsSprite[MAX_SHOTS]; AsteroidsSprite[] asteroids = new AsteroidsSprite[MAX_ROCKS]; AsteroidsSprite[] explosions = new AsteroidsSprite[MAX_SCRAP]; // Ship data. int shipsLeft; // Number of ships left to play, including current one. int shipCounter; // Time counter for ship explosion. int hyperCounter; // Time counter for hyperspace. // Photon data. int[] photonCounter = new int[MAX_SHOTS]; // Time counter for life of a photon. int photonIndex; // Next available photon sprite. // Flying saucer data. int ufoPassesLeft; // Number of flying saucer passes. int ufoCounter; // Time counter for each pass. // Missle data. int missleCounter; // Counter for life of missle. // Asteroid data. boolean[] asteroidIsSmall = new boolean[MAX_ROCKS]; // Asteroid size flag. int asteroidsCounter; // Break-time counter. int asteroidsSpeed; // Asteroid speed. int asteroidsLeft; // Number of active asteroids. // Explosion data. int[] explosionCounter = new int[MAX_SCRAP]; // Time counters for explosions. int explosionIndex; // Next available explosion sprite. // Sound clips. AudioClip crashSound; AudioClip explosionSound; AudioClip fireSound; AudioClip missleSound; AudioClip saucerSound; AudioClip thrustersSound; AudioClip warpSound; // Flags for looping sound clips. boolean thrustersPlaying; boolean saucerPlaying; boolean misslePlaying; // Values for the offscreen image. Dimension offDimension; Image offImage; Graphics offGraphics; // Font data. Font font = new Font("Helvetica", Font.BOLD, 12); FontMetrics fm; int fontWidth; int fontHeight; // Applet information. public String getAppletInfo() { return("Asteroids, Copyright 1998 by Mike Hall."); } public void init() { Graphics g; Dimension d; int i; // Take credit. System.out.println("Asteroids, Copyright 1998 by Mike Hall."); // Find the size of the screen and set the values for sprites. g = getGraphics(); d = size(); AsteroidsSprite.width = d.width; AsteroidsSprite.height = d.height; // Generate starry background. numStars = AsteroidsSprite.width * AsteroidsSprite.height / 5000; stars = new Point[numStars]; for (i = 0; i < numStars; i++) stars[i] = new Point((int) (Math.random() * AsteroidsSprite.width), (int) (Math.random() * AsteroidsSprite.height)); // Create shape for the ship sprite. ship = new AsteroidsSprite(); ship.shape.addPoint(0, -10); ship.shape.addPoint(7, 10); ship.shape.addPoint(-7, 10); // Create shape for the photon sprites. for (i = 0; i < MAX_SHOTS; i++) { photons[i] = new AsteroidsSprite(); photons[i].shape.addPoint(1, 1); photons[i].shape.addPoint(1, -1); photons[i].shape.addPoint(-1, 1); photons[i].shape.addPoint(-1, -1); } // Create shape for the flying saucer. ufo = new AsteroidsSprite(); ufo.shape.addPoint(-15, 0); ufo.shape.addPoint(-10, -5); ufo.shape.addPoint(-5, -5); ufo.shape.addPoint(-5, -9); ufo.shape.addPoint(5, -9); ufo.shape.addPoint(5, -5); ufo.shape.addPoint(10, -5); ufo.shape.addPoint(15, 0); ufo.shape.addPoint(10, 5); ufo.shape.addPoint(-10, 5); // Create shape for the guided missle. missle = new AsteroidsSprite(); missle.shape.addPoint(0, -4); missle.shape.addPoint(1, -3); missle.shape.addPoint(1, 3); missle.shape.addPoint(2, 4); missle.shape.addPoint(-2, 4); missle.shape.addPoint(-1, 3); missle.shape.addPoint(-1, -3); // Create asteroid sprites. for (i = 0; i < MAX_ROCKS; i++) asteroids[i] = new AsteroidsSprite(); // Create explosion sprites. for (i = 0; i < MAX_SCRAP; i++) explosions[i] = new AsteroidsSprite(); // Set font data. g.setFont(font); fm = g.getFontMetrics(); fontWidth = fm.getMaxAdvance(); fontHeight = fm.getHeight(); // Initialize game data and put us in 'game over' mode. highScore = 0; sound = true; detail = true; initGame(); endGame(); } public void initGame() { // Initialize game data and sprites. score = 0; shipsLeft = MAX_SHIPS; asteroidsSpeed = MIN_ROCK_SPEED; newShipScore = NEW_SHIP_POINTS; newUfoScore = NEW_UFO_POINTS; initShip(); initPhotons(); stopUfo(); stopMissle(); initAsteroids(); initExplosions(); playing = true; paused = false; } public void endGame() { // Stop ship, flying saucer, guided missle and associated sounds. playing = false; stopShip(); stopUfo(); stopMissle(); } public void start() { if (loopThread == null) { loopThread = new Thread(this); loopThread.start(); } if (!loaded && loadThread == null) { loadThread = new Thread(this); loadThread.start(); } } public void stop() { if (loopThread != null) { loopThread.stop(); loopThread = null; } if (loadThread != null) { loadThread.stop(); loadThread = null; } } public void run() { int i, j; long startTime; // Lower this thread's priority and get the current time. Thread.currentThread().setPriority(Thread.MIN_PRIORITY); startTime = System.currentTimeMillis(); // Run thread for loading sounds. if (!loaded && Thread.currentThread() == loadThread) { loadSounds(); loaded = true; loadThread.stop(); } // This is the main loop. while (Thread.currentThread() == loopThread) { if (!paused) { // Move and process all sprites. updateShip(); updatePhotons(); updateUfo(); updateMissle(); updateAsteroids(); updateExplosions(); // Check the score and advance high score, add a new ship or start the flying // saucer as necessary. if (score > highScore) highScore = score; if (score > newShipScore) { newShipScore += NEW_SHIP_POINTS; shipsLeft++; } if (playing && score > newUfoScore && !ufo.active) { newUfoScore += NEW_UFO_POINTS; ufoPassesLeft = UFO_PASSES; initUfo(); } // If all asteroids have been destroyed create a new batch. if (asteroidsLeft <= 0) if (--asteroidsCounter <= 0) initAsteroids(); } // Update the screen and set the timer for the next loop. repaint(); try { startTime += DELAY; Thread.sleep(Math.max(0, startTime - System.currentTimeMillis())); } catch (InterruptedException e) { break; } } } public void loadSounds() { // Load all sound clips by playing and immediately stopping them. try { crashSound = getAudioClip(new URL(getDocumentBase(), "crash.au")); explosionSound = getAudioClip(new URL(getDocumentBase(), "explosion.au")); fireSound = getAudioClip(new URL(getDocumentBase(), "fire.au")); missleSound = getAudioClip(new URL(getDocumentBase(), "missle.au")); saucerSound = getAudioClip(new URL(getDocumentBase(), "saucer.au")); thrustersSound = getAudioClip(new URL(getDocumentBase(), "thrusters.au")); warpSound = getAudioClip(new URL(getDocumentBase(), "warp.au")); } catch (MalformedURLException e) {} crashSound.play(); crashSound.stop(); explosionSound.play(); explosionSound.stop(); fireSound.play(); fireSound.stop(); missleSound.play(); missleSound.stop(); saucerSound.play(); saucerSound.stop(); thrustersSound.play(); thrustersSound.stop(); warpSound.play(); warpSound.stop(); } public void initShip() { ship.active = true; ship.angle = 0.0; ship.deltaAngle = 0.0; ship.currentX = 0.0; ship.currentY = 0.0; ship.deltaX = 0.0; ship.deltaY = 0.0; ship.render(); if (loaded) thrustersSound.stop(); thrustersPlaying = false; hyperCounter = 0; } public void updateShip() { double dx, dy, limit; if (!playing) return; // Rotate the ship if left or right cursor key is down. if (left) { ship.angle += Math.PI / 16.0; if (ship.angle > 2 * Math.PI) ship.angle -= 2 * Math.PI; } if (right) { ship.angle -= Math.PI / 16.0; if (ship.angle < 0) ship.angle += 2 * Math.PI; } // Fire thrusters if up or down cursor key is down. Don't let ship go past // the speed limit. dx = -Math.sin(ship.angle); dy = Math.cos(ship.angle); limit = 0.8 * MIN_ROCK_SIZE; if (up) { if (ship.deltaX + dx > -limit && ship.deltaX + dx < limit) ship.deltaX += dx; if (ship.deltaY + dy > -limit && ship.deltaY + dy < limit) ship.deltaY += dy; } if (down) { if (ship.deltaX - dx > -limit && ship.deltaX - dx < limit) ship.deltaX -= dx; if (ship.deltaY - dy > -limit && ship.deltaY - dy < limit) ship.deltaY -= dy; } // Move the ship. If it is currently in hyperspace, advance the countdown. if (ship.active) { ship.advance(); ship.render(); if (hyperCounter > 0) hyperCounter--; } // Ship is exploding, advance the countdown or create a new ship if it is // done exploding. The new ship is added as though it were in hyperspace. // (This gives the player time to move the ship if it is in imminent danger.) // If that was the last ship, end the game. else if (--shipCounter <= 0) if (shipsLeft > 0) { initShip(); hyperCounter = HYPER_COUNT; } else endGame(); } public void stopShip() { ship.active = false; shipCounter = SCRAP_COUNT; if (shipsLeft > 0) shipsLeft--; if (loaded) thrustersSound.stop(); thrustersPlaying = false; } public void initPhotons() { int i; for (i = 0; i < MAX_SHOTS; i++) { photons[i].active = false; photonCounter[i] = 0; } photonIndex = 0; } public void updatePhotons() { int i; // Move any active photons. Stop it when its counter has expired. for (i = 0; i < MAX_SHOTS; i++) if (photons[i].active) { photons[i].advance(); photons[i].render(); if (--photonCounter[i] < 0) photons[i].active = false; } } public void initUfo() { double temp; // Randomly set flying saucer at left or right edge of the screen. ufo.active = true; ufo.currentX = -AsteroidsSprite.width / 2; ufo.currentY = Math.random() * AsteroidsSprite.height; ufo.deltaX = MIN_ROCK_SPEED + Math.random() * (MAX_ROCK_SPEED - MIN_ROCK_SPEED); if (Math.random() < 0.5) { ufo.deltaX = -ufo.deltaX; ufo.currentX = AsteroidsSprite.width / 2; } ufo.deltaY = MIN_ROCK_SPEED + Math.random() * (MAX_ROCK_SPEED - MIN_ROCK_SPEED); if (Math.random() < 0.5) ufo.deltaY = -ufo.deltaY; ufo.render(); saucerPlaying = true; if (sound) saucerSound.loop(); // Set counter for this pass. ufoCounter = (int) Math.floor(AsteroidsSprite.width / Math.abs(ufo.deltaX)); } public void updateUfo() { int i, d; // Move the flying saucer and check for collision with a photon. Stop it when its // counter has expired. if (ufo.active) { ufo.advance(); ufo.render(); if (--ufoCounter <= 0) if (--ufoPassesLeft > 0) initUfo(); else stopUfo(); else { for (i = 0; i < MAX_SHOTS; i++) if (photons[i].active && ufo.isColliding(photons[i])) { if (sound) crashSound.play(); explode(ufo); stopUfo(); score += UFO_POINTS; } // On occassion, fire a missle at the ship if the saucer is not // too close to it. d = (int) Math.max(Math.abs(ufo.currentX - ship.currentX), Math.abs(ufo.currentY - ship.currentY)); if (ship.active && hyperCounter <= 0 && ufo.active && !missle.active && d > 4 * MAX_ROCK_SIZE && Math.random() < .03) initMissle(); } } } public void stopUfo() { ufo.active = false; ufoCounter = 0; ufoPassesLeft = 0; if (loaded) saucerSound.stop(); saucerPlaying = false; } public void initMissle() { missle.active = true; missle.angle = 0.0; missle.deltaAngle = 0.0; missle.currentX = ufo.currentX; missle.currentY = ufo.currentY; missle.deltaX = 0.0; missle.deltaY = 0.0; missle.render(); missleCounter = 3 * Math.max(AsteroidsSprite.width, AsteroidsSprite.height) / MIN_ROCK_SIZE; if (sound) missleSound.loop(); misslePlaying = true; } public void updateMissle() { int i; // Move the guided missle and check for collision with ship or photon. Stop it when its // counter has expired. if (missle.active) { if (--missleCounter <= 0) stopMissle(); else { guideMissle(); missle.advance(); missle.render(); for (i = 0; i < MAX_SHOTS; i++) if (photons[i].active && missle.isColliding(photons[i])) { if (sound) crashSound.play(); explode(missle); stopMissle(); score += MISSLE_POINTS; } if (missle.active && ship.active && hyperCounter <= 0 && ship.isColliding(missle)) { if (sound) crashSound.play(); explode(ship); stopShip(); stopUfo(); stopMissle(); } } } } public void guideMissle() { double dx, dy, angle; if (!ship.active || hyperCounter > 0) return; // Find the angle needed to hit the ship. dx = ship.currentX - missle.currentX; dy = ship.currentY - missle.currentY; if (dx == 0 && dy == 0) angle = 0; if (dx == 0) { if (dy < 0) angle = -Math.PI / 2; else angle = Math.PI / 2; } else { angle = Math.atan(Math.abs(dy / dx)); if (dy > 0) angle = -angle; if (dx < 0) angle = Math.PI - angle; } // Adjust angle for screen coordinates. missle.angle = angle - Math.PI / 2; // Change the missle's angle so that it points toward the ship. missle.deltaX = MIN_ROCK_SIZE / 3 * -Math.sin(missle.angle); missle.deltaY = MIN_ROCK_SIZE / 3 * Math.cos(missle.angle); } public void stopMissle() { missle.active = false; missleCounter = 0; if (loaded) missleSound.stop(); misslePlaying = false; } public void initAsteroids() { int i, j; int s; double theta, r; int x, y; // Create random shapes, positions and movements for each asteroid. for (i = 0; i < MAX_ROCKS; i++) { // Create a jagged shape for the asteroid and give it a random rotation. asteroids[i].shape = new Polygon(); s = MIN_ROCK_SIDES + (int) (Math.random() * (MAX_ROCK_SIDES - MIN_ROCK_SIDES)); for (j = 0; j < s; j ++) { theta = 2 * Math.PI / s * j; r = MIN_ROCK_SIZE + (int) (Math.random() * (MAX_ROCK_SIZE - MIN_ROCK_SIZE)); x = (int) -Math.round(r * Math.sin(theta)); y = (int) Math.round(r * Math.cos(theta)); asteroids[i].shape.addPoint(x, y); } asteroids[i].active = true; asteroids[i].angle = 0.0; asteroids[i].deltaAngle = (Math.random() - 0.5) / 10; // Place the asteroid at one edge of the screen. if (Math.random() < 0.5) { asteroids[i].currentX = -AsteroidsSprite.width / 2; if (Math.random() < 0.5) asteroids[i].currentX = AsteroidsSprite.width / 2; asteroids[i].currentY = Math.random() * AsteroidsSprite.height; } else { asteroids[i].currentX = Math.random() * AsteroidsSprite.width; asteroids[i].currentY = -AsteroidsSprite.height / 2; if (Math.random() < 0.5) asteroids[i].currentY = AsteroidsSprite.height / 2; } // Set a random motion for the asteroid. asteroids[i].deltaX = Math.random() * asteroidsSpeed; if (Math.random() < 0.5) asteroids[i].deltaX = -asteroids[i].deltaX; asteroids[i].deltaY = Math.random() * asteroidsSpeed; if (Math.random() < 0.5) asteroids[i].deltaY = -asteroids[i].deltaY; asteroids[i].render(); asteroidIsSmall[i] = false; } asteroidsCounter = STORM_PAUSE; asteroidsLeft = MAX_ROCKS; if (asteroidsSpeed < MAX_ROCK_SPEED) asteroidsSpeed++; } public void initSmallAsteroids(int n) { int count; int i, j; int s; double tempX, tempY; double theta, r; int x, y; // Create one or two smaller asteroids from a larger one using inactive asteroids. The new // asteroids will be placed in the same position as the old one but will have a new, smaller // shape and new, randomly generated movements. count = 0; i = 0; tempX = asteroids[n].currentX; tempY = asteroids[n].currentY; do { if (!asteroids[i].active) { asteroids[i].shape = new Polygon(); s = MIN_ROCK_SIDES + (int) (Math.random() * (MAX_ROCK_SIDES - MIN_ROCK_SIDES)); for (j = 0; j < s; j ++) { theta = 2 * Math.PI / s * j; r = (MIN_ROCK_SIZE + (int) (Math.random() * (MAX_ROCK_SIZE - MIN_ROCK_SIZE))) / 2; x = (int) -Math.round(r * Math.sin(theta)); y = (int) Math.round(r * Math.cos(theta)); asteroids[i].shape.addPoint(x, y); } asteroids[i].active = true; asteroids[i].angle = 0.0; asteroids[i].deltaAngle = (Math.random() - 0.5) / 10; asteroids[i].currentX = tempX; asteroids[i].currentY = tempY; asteroids[i].deltaX = Math.random() * 2 * asteroidsSpeed - asteroidsSpeed; asteroids[i].deltaY = Math.random() * 2 * asteroidsSpeed - asteroidsSpeed; asteroids[i].render(); asteroidIsSmall[i] = true; count++; asteroidsLeft++; } i++; } while (i < MAX_ROCKS && count < 2); } public void updateAsteroids() { int i, j; // Move any active asteroids and check for collisions. for (i = 0; i < MAX_ROCKS; i++) if (asteroids[i].active) { asteroids[i].advance(); asteroids[i].render(); // If hit by photon, kill asteroid and advance score. If asteroid is large, // make some smaller ones to replace it. for (j = 0; j < MAX_SHOTS; j++) if (photons[j].active && asteroids[i].active && asteroids[i].isColliding(photons[j])) { asteroidsLeft--; asteroids[i].active = false; photons[j].active = false; if (sound) explosionSound.play(); explode(asteroids[i]); if (!asteroidIsSmall[i]) { score += BIG_POINTS; initSmallAsteroids(i); } else score += SMALL_POINTS; } // If the ship is not in hyperspace, see if it is hit. if (ship.active && hyperCounter <= 0 && asteroids[i].active && asteroids[i].isColliding(ship)) { if (sound) crashSound.play(); explode(ship); stopShip(); stopUfo(); stopMissle(); } } } public void initExplosions() { int i; for (i = 0; i < MAX_SCRAP; i++) { explosions[i].shape = new Polygon(); explosions[i].active = false; explosionCounter[i] = 0; } explosionIndex = 0; } public void explode(AsteroidsSprite s) { int c, i, j; // Create sprites for explosion animation. The each individual line segment of the given sprite // is used to create a new sprite that will move outward from the sprite's original position // with a random rotation. s.render(); c = 2; if (detail || s.sprite.npoints < 6) c = 1; for (i = 0; i < s.sprite.npoints; i += c) { explosionIndex++; if (explosionIndex >= MAX_SCRAP) explosionIndex = 0; explosions[explosionIndex].active = true; explosions[explosionIndex].shape = new Polygon(); explosions[explosionIndex].shape.addPoint(s.shape.xpoints[i], s.shape.ypoints[i]); j = i + 1; if (j >= s.sprite.npoints) j -= s.sprite.npoints; explosions[explosionIndex].shape.addPoint(s.shape.xpoints[j], s.shape.ypoints[j]); explosions[explosionIndex].angle = s.angle; explosions[explosionIndex].deltaAngle = (Math.random() * 2 * Math.PI - Math.PI) / 15; explosions[explosionIndex].currentX = s.currentX; explosions[explosionIndex].currentY = s.currentY; explosions[explosionIndex].deltaX = -s.shape.xpoints[i] / 5; explosions[explosionIndex].deltaY = -s.shape.ypoints[i] / 5; explosionCounter[explosionIndex] = SCRAP_COUNT; } } public void updateExplosions() { int i; // Move any active explosion debris. Stop explosion when its counter has expired. for (i = 0; i < MAX_SCRAP; i++) if (explosions[i].active) { explosions[i].advance(); explosions[i].render(); if (--explosionCounter[i] < 0) explosions[i].active = false; } } public boolean keyDown(Event e, int key) { // Check if any cursor keys have been pressed and set flags. if (key == Event.LEFT) left = true; if (key == Event.RIGHT) right = true; if (key == Event.UP) up = true; if (key == Event.DOWN) down = true; if ((up || down) && ship.active && !thrustersPlaying) { if (sound && !paused) thrustersSound.loop(); thrustersPlaying = true; } // Spacebar: fire a photon and start its counter. if (key == 32 && ship.active) { if (sound & !paused) fireSound.play(); photonIndex++; if (photonIndex >= MAX_SHOTS) photonIndex = 0; photons[photonIndex].active = true; photons[photonIndex].currentX = ship.currentX; photons[photonIndex].currentY = ship.currentY; photons[photonIndex].deltaX = MIN_ROCK_SIZE * -Math.sin(ship.angle); photons[photonIndex].deltaY = MIN_ROCK_SIZE * Math.cos(ship.angle); photonCounter[photonIndex] = Math.min(AsteroidsSprite.width, AsteroidsSprite.height) / MIN_ROCK_SIZE; } // 'H' key: warp ship into hyperspace by moving to a random location and starting counter. if (key == 104 && ship.active && hyperCounter <= 0) { ship.currentX = Math.random() * AsteroidsSprite.width; ship.currentX = Math.random() * AsteroidsSprite.height; hyperCounter = HYPER_COUNT; if (sound & !paused) warpSound.play(); } // 'P' key: toggle pause mode and start or stop any active looping sound clips. if (key == 112) { if (paused) { if (sound && misslePlaying) missleSound.loop(); if (sound && saucerPlaying) saucerSound.loop(); if (sound && thrustersPlaying) thrustersSound.loop(); } else { if (misslePlaying) missleSound.stop(); if (saucerPlaying) saucerSound.stop(); if (thrustersPlaying) thrustersSound.stop(); } paused = !paused; } // 'M' key: toggle sound on or off and stop any looping sound clips. if (key == 109 && loaded) { if (sound) { crashSound.stop(); explosionSound.stop(); fireSound.stop(); missleSound.stop(); saucerSound.stop(); thrustersSound.stop(); warpSound.stop(); } else { if (misslePlaying && !paused) missleSound.loop(); if (saucerPlaying && !paused) saucerSound.loop(); if (thrustersPlaying && !paused) thrustersSound.loop(); } sound = !sound; } // 'D' key: toggle graphics detail on or off. if (key == 100) detail = !detail; // 'S' key: start the game, if not already in progress. if (key == 115 && loaded && !playing) initGame(); return true; } public boolean keyUp(Event e, int key) { // Check if any cursor keys where released and set flags. if (key == Event.LEFT) left = false; if (key == Event.RIGHT) right = false; if (key == Event.UP) up = false; if (key == Event.DOWN) down = false; if (!up && !down && thrustersPlaying) { thrustersSound.stop(); thrustersPlaying = false; } return true; } public void paint(Graphics g) { update(g); } public void update(Graphics g) { Dimension d = size(); int i; int c; String s; // Create the offscreen graphics context, if no good one exists. if (offGraphics == null || d.width != offDimension.width || d.height != offDimension.height) { offDimension = d; offImage = createImage(d.width, d.height); offGraphics = offImage.getGraphics(); } // Fill in background and stars. offGraphics.setColor(Color.black); offGraphics.fillRect(0, 0, d.width, d.height); if (detail) { offGraphics.setColor(Color.white); for (i = 0; i < numStars; i++) offGraphics.drawLine(stars[i].x, stars[i].y, stars[i].x, stars[i].y); } // Draw photon bullets. offGraphics.setColor(Color.white); for (i = 0; i < MAX_SHOTS; i++) if (photons[i].active) offGraphics.drawPolygon(photons[i].sprite); // Draw the guided missle, counter is used to quickly fade color to black when near expiration. c = Math.min(missleCounter * 24, 255); offGraphics.setColor(new Color(c, c, c)); if (missle.active) { offGraphics.drawPolygon(missle.sprite); offGraphics.drawLine(missle.sprite.xpoints[missle.sprite.npoints - 1], missle.sprite.ypoints[missle.sprite.npoints - 1], missle.sprite.xpoints[0], missle.sprite.ypoints[0]); } // Draw the asteroids. for (i = 0; i < MAX_ROCKS; i++) if (asteroids[i].active) { if (detail) { offGraphics.setColor(Color.black); offGraphics.fillPolygon(asteroids[i].sprite); } offGraphics.setColor(Color.white); offGraphics.drawPolygon(asteroids[i].sprite); offGraphics.drawLine(asteroids[i].sprite.xpoints[asteroids[i].sprite.npoints - 1], asteroids[i].sprite.ypoints[asteroids[i].sprite.npoints - 1], asteroids[i].sprite.xpoints[0], asteroids[i].sprite.ypoints[0]); } // Draw the flying saucer. if (ufo.active) { if (detail) { offGraphics.setColor(Color.black); offGraphics.fillPolygon(ufo.sprite); } offGraphics.setColor(Color.white); offGraphics.drawPolygon(ufo.sprite); offGraphics.drawLine(ufo.sprite.xpoints[ufo.sprite.npoints - 1], ufo.sprite.ypoints[ufo.sprite.npoints - 1], ufo.sprite.xpoints[0], ufo.sprite.ypoints[0]); } // Draw the ship, counter is used to fade color to white on hyperspace. c = 255 - (255 / HYPER_COUNT) * hyperCounter; if (ship.active) { if (detail && hyperCounter == 0) { offGraphics.setColor(Color.black); offGraphics.fillPolygon(ship.sprite); } offGraphics.setColor(new Color(c, c, c)); offGraphics.drawPolygon(ship.sprite); offGraphics.drawLine(ship.sprite.xpoints[ship.sprite.npoints - 1], ship.sprite.ypoints[ship.sprite.npoints - 1], ship.sprite.xpoints[0], ship.sprite.ypoints[0]); } // Draw any explosion debris, counters are used to fade color to black. for (i = 0; i < MAX_SCRAP; i++) if (explosions[i].active) { c = (255 / SCRAP_COUNT) * explosionCounter [i]; offGraphics.setColor(new Color(c, c, c)); offGraphics.drawPolygon(explosions[i].sprite); } // Display status and messages. offGraphics.setFont(font); offGraphics.setColor(Color.white); offGraphics.drawString("Score: " + score, fontWidth, fontHeight); offGraphics.drawString("Ships: " + shipsLeft, fontWidth, d.height - fontHeight); s = "High: " + highScore; offGraphics.drawString(s, d.width - (fontWidth + fm.stringWidth(s)), fontHeight); if (!sound) { s = "Mute"; offGraphics.drawString(s, d.width - (fontWidth + fm.stringWidth(s)), d.height - fontHeight); } if (!playing) { s = "A S T E R O I D S"; offGraphics.drawString(s, (d.width - fm.stringWidth(s)) / 2, d.height / 2); s = "Copyright 1998 by Mike Hall"; offGraphics.drawString(s, (d.width - fm.stringWidth(s)) / 2, d.height / 2 + fontHeight); if (!loaded) { s = "Loading sounds..."; offGraphics.drawString(s, (d.width - fm.stringWidth(s)) / 2, d.height / 4); } else { s = "Game Over"; offGraphics.drawString(s, (d.width - fm.stringWidth(s)) / 2, d.height / 4); s = "'S' to Start"; offGraphics.drawString(s, (d.width - fm.stringWidth(s)) / 2, d.height / 4 + fontHeight); } } else if (paused) { s = "Game Paused"; offGraphics.drawString(s, (d.width - fm.stringWidth(s)) / 2, d.height / 4); } // Copy the off screen buffer to the screen. g.drawImage(offImage, 0, 0, this); } }


gamelinks

asteroids: