Initial commit

Author: Lua-Matlab-Python-R-J2EE

.github/changes/engine.js

@@ -0,0 +1,355 @@
+var sprites = {
+ ship: { sx: 0, sy: 0, w: 37, h: 42, frames: 1 },
+ missile: { sx: 0, sy: 30, w: 2, h: 10, frames: 1 },
+ enemy_purple: { sx: 37, sy: 0, w: 42, h: 43, frames: 1 },
+ enemy_bee: { sx: 79, sy: 0, w: 37, h: 43, frames: 1 },
+ enemy_ship: { sx: 116, sy: 0, w: 42, h: 43, frames: 1 },
+ enemy_circle: { sx: 158, sy: 0, w: 32, h: 33, frames: 1 },
+ explosion: { sx: 0, sy: 64, w: 64, h: 64, frames: 12 },
+ enemy_missile: { sx: 9, sy: 42, w: 3, h: 20, frame: 1 },
+};
+
+var enemies = {
+ straight: { x: 0, y: -50, sprite: "enemy_ship", health: 10, E: 100 },
+ ltr: {
+ x: 0,
+ y: -100,
+ sprite: "enemy_purple",
+ health: 10,
+ B: 75,
+ C: 1,
+ E: 100,
+ missiles: 2,
+ },
+ circle: {
+ x: 250,
+ y: -50,
+ sprite: "enemy_circle",
+ health: 10,
+ A: 0,
+ B: -100,
+ C: 1,
+ E: 20,
+ F: 100,
+ G: 1,
+ H: Math.PI / 2,
+ },
+ wiggle: {
+ x: 100,
+ y: -50,
+ sprite: "enemy_bee",
+ health: 20,
+ B: 50,
+ C: 4,
+ E: 100,
+ firePercentage: 0.001,
+ missiles: 2,
+ },
+ step: {
+ x: 0,
+ y: -50,
+ sprite: "enemy_circle",
+ health: 10,
+ B: 150,
+ C: 1.2,
+ E: 75,
+ },
+};
+
+var OBJECT_PLAYER = 1,
+ OBJECT_PLAYER_PROJECTILE = 2,
+ OBJECT_ENEMY = 4,
+ OBJECT_ENEMY_PROJECTILE = 8,
+ OBJECT_POWERUP = 16;
+
+var startGame = function () {
+ var ua = navigator.userAgent.toLowerCase();
+
+ // Only 1 row of stars
+ if (ua.match(/android/)) {
+ Game.setBoard(0, new Starfield(50, 0.6, 100, true));
+ } else {
+ Game.setBoard(0, new Starfield(20, 0.4, 100, true));
+ Game.setBoard(1, new Starfield(50, 0.6, 100));
+ Game.setBoard(2, new Starfield(100, 1.0, 50));
+ }
+ Game.setBoard(
+ 3,
+ new TitleScreen("Alien Invasion", "Press fire to start playing", playGame)
+ );
+};
+
+var level1 = [
+ // Start, End, Gap, Type, Override
+ [0, 4000, 500, "step"],
+ [6000, 13000, 800, "ltr"],
+ [10000, 16000, 400, "circle"],
+ [17800, 20000, 500, "straight", { x: 50 }],
+ [18200, 20000, 500, "straight", { x: 90 }],
+ [18200, 20000, 500, "straight", { x: 10 }],
+ [22000, 25000, 400, "wiggle", { x: 150 }],
+ [22000, 25000, 400, "wiggle", { x: 100 }],
+];
+
+var playGame = function () {
+ var board = new GameBoard();
+ board.add(new PlayerShip());
+ board.add(new Level(level1, winGame));
+ Game.setBoard(3, board);
+ Game.setBoard(5, new GamePoints(0));
+};
+
+var winGame = function () {
+ Game.setBoard(
+ 3,
+ new TitleScreen("You win!", "Press fire to play again", playGame)
+ );
+};
+
+var loseGame = function () {
+ Game.setBoard(
+ 3,
+ new TitleScreen("You lose!", "Press fire to play again", playGame)
+ );
+};
+
+var Starfield = function (speed, opacity, numStars, clear) {
+ // Set up the offscreen canvas
+ var stars = document.createElement("canvas");
+ stars.width = Game.width;
+ stars.height = Game.height;
+ var starCtx = stars.getContext("2d");
+
+ var offset = 0;
+
+ // If the clear option is set,
+ // make the background black instead of transparent
+ if (clear) {
+ starCtx.fillStyle = "#000";
+ starCtx.fillRect(0, 0, stars.width, stars.height);
+ }
+
+ // Now draw a bunch of random 2 pixel
+ // rectangles onto the offscreen canvas
+ starCtx.fillStyle = "#FFF";
+ starCtx.globalAlpha = opacity;
+ for (var i = 0; i < numStars; i++) {
+ starCtx.fillRect(
+ Math.floor(Math.random() * stars.width),
+ Math.floor(Math.random() * stars.height),
+ 2,
+ 2
+ );
+ }
+
+ // This method is called every frame
+ // to draw the starfield onto the canvas
+ this.draw = function (ctx) {
+ var intOffset = Math.floor(offset);
+ var remaining = stars.height - intOffset;
+
+ // Draw the top half of the starfield
+ if (intOffset > 0) {
+ ctx.drawImage(
+ stars,
+ 0,
+ remaining,
+ stars.width,
+ intOffset,
+ 0,
+ 0,
+ stars.width,
+ intOffset
+ );
+ }
+
+ // Draw the bottom half of the starfield
+ if (remaining > 0) {
+ ctx.drawImage(
+ stars,
+ 0,
+ 0,
+ stars.width,
+ remaining,
+ 0,
+ intOffset,
+ stars.width,
+ remaining
+ );
+ }
+ };
+
+ // This method is called to update
+ // the starfield
+ this.step = function (dt) {
+ offset += dt * speed;
+ offset = offset % stars.height;
+ };
+};
+
+var PlayerShip = function () {
+ this.setup("ship", { vx: 0, reloadTime: 0.25, maxVel: 200 });
+
+ this.reload = this.reloadTime;
+ this.x = Game.width / 2 - this.w / 2;
+ this.y = Game.height - Game.playerOffset - this.h;
+
+ this.step = function (dt) {
+ if (Game.keys["left"]) {
+ this.vx = -this.maxVel;
+ } else if (Game.keys["right"]) {
+ this.vx = this.maxVel;
+ } else {
+ this.vx = 0;
+ }
+
+ this.x += this.vx * dt;
+
+ if (this.x < 0) {
+ this.x = 0;
+ } else if (this.x > Game.width - this.w) {
+ this.x = Game.width - this.w;
+ }
+
+ this.reload -= dt;
+ if (Game.keys["fire"] && this.reload < 0) {
+ Game.keys["fire"] = false;
+ this.reload = this.reloadTime;
+
+ this.board.add(new PlayerMissile(this.x, this.y + this.h / 2));
+ this.board.add(new PlayerMissile(this.x + this.w, this.y + this.h / 2));
+ }
+ };
+};
+
+PlayerShip.prototype = new Sprite();
+PlayerShip.prototype.type = OBJECT_PLAYER;
+
+PlayerShip.prototype.hit = function (damage) {
+ if (this.board.remove(this)) {
+ loseGame();
+ }
+};
+
+var PlayerMissile = function (x, y) {
+ this.setup("missile", { vy: -700, damage: 10 });
+ this.x = x - this.w / 2;
+ this.y = y - this.h;
+};
+
+PlayerMissile.prototype = new Sprite();
+PlayerMissile.prototype.type = OBJECT_PLAYER_PROJECTILE;
+
+PlayerMissile.prototype.step = function (dt) {
+ this.y += this.vy * dt;
+ var collision = this.board.collide(this, OBJECT_ENEMY);
+ if (collision) {
+ collision.hit(this.damage);
+ this.board.remove(this);
+ } else if (this.y < -this.h) {
+ this.board.remove(this);
+ }
+};
+
+var Enemy = function (blueprint, override) {
+ this.merge(this.baseParameters);
+ this.setup(blueprint.sprite, blueprint);
+ this.merge(override);
+};
+
+Enemy.prototype = new Sprite();
+Enemy.prototype.type = OBJECT_ENEMY;
+
+Enemy.prototype.baseParameters = {
+ A: 0,
+ B: 0,
+ C: 0,
+ D: 0,
+ E: 0,
+ F: 0,
+ G: 0,
+ H: 0,
+ t: 0,
+ reloadTime: 0.75,
+ reload: 0,
+};
+
+Enemy.prototype.step = function (dt) {
+ this.t += dt;
+
+ this.vx = this.A + this.B * Math.sin(this.C * this.t + this.D);
+ this.vy = this.E + this.F * Math.sin(this.G * this.t + this.H);
+
+ this.x += this.vx * dt;
+ this.y += this.vy * dt;
+
+ var collision = this.board.collide(this, OBJECT_PLAYER);
+ if (collision) {
+ collision.hit(this.damage);
+ this.board.remove(this);
+ }
+
+ if (Math.random() < 0.01 && this.reload <= 0) {
+ this.reload = this.reloadTime;
+ if (this.missiles == 2) {
+ this.board.add(new EnemyMissile(this.x + this.w - 2, this.y + this.h));
+ this.board.add(new EnemyMissile(this.x + 2, this.y + this.h));
+ } else {
+ this.board.add(new EnemyMissile(this.x + this.w / 2, this.y + this.h));
+ }
+ }
+ this.reload -= dt;
+
+ if (this.y > Game.height || this.x < -this.w || this.x > Game.width) {
+ this.board.remove(this);
+ }
+};
+
+Enemy.prototype.hit = function (damage) {
+ this.health -= damage;
+ if (this.health <= 0) {
+ if (this.board.remove(this)) {
+ Game.points += this.points || 100;
+ this.board.add(new Explosion(this.x + this.w / 2, this.y + this.h / 2));
+ }
+ }
+};
+
+var EnemyMissile = function (x, y) {
+ this.setup("enemy_missile", { vy: 200, damage: 10 });
+ this.x = x - this.w / 2;
+ this.y = y;
+};
+
+EnemyMissile.prototype = new Sprite();
+EnemyMissile.prototype.type = OBJECT_ENEMY_PROJECTILE;
+
+EnemyMissile.prototype.step = function (dt) {
+ this.y += this.vy * dt;
+ var collision = this.board.collide(this, OBJECT_PLAYER);
+ if (collision) {
+ collision.hit(this.damage);
+ this.board.remove(this);
+ } else if (this.y > Game.height) {
+ this.board.remove(this);
+ }
+};
+
+var Explosion = function (centerX, centerY) {
+ this.setup("explosion", { frame: 0 });
+ this.x = centerX - this.w / 2;
+ this.y = centerY - this.h / 2;
+};
+
+Explosion.prototype = new Sprite();
+
+Explosion.prototype.step = function (dt) {
+ this.frame++;
+ if (this.frame >= 12) {
+ this.board.remove(this);
+ }
+};
+
+window.addEventListener("load", function () {
+ Game.initialize("game", sprites, startGame);
+});