add subprojects

15 files changed, 807 insertions, 0 deletions

diff --git a/centipede/js/game/game.js b/centipede/js/game/game.js
new file mode 100644
index 0000000..30454f9
--- /dev/null
+++ b/centipede/js/game/game.js
@@ -0,0 +1,39 @@
+const game = {
+  stopped: false,
+  width: document.getElementById('game-canvas').width,
+  height: document.getElementById('game-canvas').height,
+  level: 1,
+};
+
+game.resume = () => {
+  game.stopped = false;
+  game.lastTimeStamp = performance.now();
+  menu.reRegisterKeys();
+  requestAnimationFrame(gameLoop);
+}
+
+game.resetObjects = () => {
+  game.player.x = game.width/2;
+  game.player.y = game.height/2;
+  game.bullets = [];
+  game.explosions = [];
+  game.mushroomDims = {width: 40, height: 40};
+  game.mushrooms = game.Mushroom.generateMushrooms(game.mushroomDims);
+  game.centipede = game.Centipede({segments: Math.min(game.level*5 + 5, 15), startX: game.width/2, startY: 0, rot: 180, width: 40, height: 40, dx: 0.2, dy: 0});
+  game.spiders = [];
+  game.fleas = [];
+  game.scorpions = [];
+}
+
+game.gameOver = () => {
+  menu.showMenu();
+  menu.setState('game-over');
+  menu.addScore(game.score);
+
+  menu.onHide = initialize;
+}
+
+game.getObjects = () => [game.player, ...game.bullets, ...game.mushrooms, ...game.spiders, ...game.fleas, ...game.scorpions, game.centipede, ...game.explosions];
+game.getBulletCollidableObjects = () => [...game.mushrooms, ...game.spiders, ...game.fleas, ...game.scorpions, game.centipede];
+game.getMushroomCollidableObjects = () => [game.player, ...game.scorpions, game.centipede];
+game.getPlayerCollidableObjects = () => [...game.spiders, ...game.fleas, ...game.scorpions, game.centipede]
\ No newline at end of file
diff --git a/centipede/js/game/graphics.js b/centipede/js/game/graphics.js
new file mode 100644
index 0000000..3a0d7f9
--- /dev/null
+++ b/centipede/js/game/graphics.js
@@ -0,0 +1,55 @@
+game.graphics = (
+  (context) => {
+    context.imageSmoothingEnabled = false;
+    const clear = () => {
+      context.clearRect(0, 0, game.width, game.height);
+    };
+    
+    const Sprite = ({sheetSrc, spriteX, spriteY, spriteWidth, spriteHeight, timePerFrame, cols, rows, numFrames, drawFunction}) => {
+      timePerFrame = timePerFrame ?? 100;
+      numFrames = numFrames ?? 1;
+      cols = cols ?? numFrames;
+      rows = rows ?? 1;
+
+      let ready = false;
+
+      let image;
+      if (sheetSrc) {
+        image = new Image();
+        image.src = sheetSrc;
+        image.onload = () => { ready = true; };
+      }
+
+      let currentFrame = 0;
+      let lastTime = performance.now();
+
+      let draw;
+      if (!drawFunction) {
+        draw = (_elapsedTime, {x, y, rot, width, height}) => {
+
+          if (ready) {
+            if (numFrames > 1) {
+              if (performance.now()-lastTime > timePerFrame) {
+                lastTime = performance.now();
+                currentFrame = (currentFrame + 1) % numFrames;
+              }
+            }
+            context.save();
+            context.translate(x+width/2, y+height/2);
+            context.rotate(rot * Math.PI / 180);
+            context.translate(-x-width/2, -y-height/2);
+            const row = currentFrame % rows;
+            const col = Math.floor(currentFrame / rows);
+            context.drawImage(image, spriteX+col*spriteWidth, spriteY+row*spriteHeight, spriteWidth, spriteHeight, x, y, width, height);
+            context.restore();
+          }
+        };
+      } else {
+        draw = (elapsedTime, drawSpec) => drawFunction(elapsedTime, drawSpec, context);
+      }
+      return { draw, timePerFrame, numFrames };
+    }
+
+    return { clear, Sprite };
+  }
+)(document.getElementById("game-canvas").getContext("2d"));
\ No newline at end of file
diff --git a/centipede/js/game/input.js b/centipede/js/game/input.js
new file mode 100644
index 0000000..6ceff13
--- /dev/null
+++ b/centipede/js/game/input.js
@@ -0,0 +1,32 @@
+game.input = (() => {
+  "use strict";
+  const Keyboard = () => {
+    const keys = {};
+    const handlers = {};
+    const keyPress = (event) => {
+      keys[event.key] = event.timeStamp;
+    };
+    const keyRelease = (event) => {
+      delete keys[event.key];
+    };
+    const registerCommand = (key, handler) => {
+      handlers[key] = handler;
+    };
+    const unregisterCommand = (key) => {
+      delete handlers[key];
+    }
+    const update = (elapsedTime) => {
+      for (let key in keys) {
+        if (keys.hasOwnProperty(key)) {
+          if (handlers[key]) {
+            handlers[key](elapsedTime);
+          }
+        }
+      }
+    };
+    window.addEventListener("keydown", keyPress);
+    window.addEventListener("keyup", keyRelease);
+    return {keys, handlers, registerCommand, unregisterCommand, update};
+  }
+  return { Keyboard };
+})();
\ No newline at end of file
diff --git a/centipede/js/game/menu.js b/centipede/js/game/menu.js
new file mode 100644
index 0000000..d4a7fe9
--- /dev/null
+++ b/centipede/js/game/menu.js
@@ -0,0 +1,143 @@
+const menu = {};
+menu.initialize = () => {
+  menu.scores = localStorage.getItem("scores") ? JSON.parse(localStorage.getItem("scores")) : [];
+  menu.state = "main";
+
+  menu.controls = localStorage.getItem("controls") ? JSON.parse(localStorage.getItem("controls")) : {
+    "moveUp": "ArrowUp",
+    "moveDown": "ArrowDown",
+    "moveLeft": "ArrowLeft",
+    "moveRight": "ArrowRight",
+    "shoot": " ",
+  };
+}
+
+menu.setState = (state) => {
+  menu.state = state;
+  menu.draw();
+}
+
+menu.escapeEventListener = (e) => {
+  if (e.key == "Escape") {
+    menu.setState('main');
+    menu.draw();
+  }
+}
+
+menu.showMenu = () => {
+  menu.draw();
+  game.stopped = true;
+  window.addEventListener("keydown", menu.escapeEventListener);
+}
+
+menu.reRegisterKeys = () => {
+  Object.keys(game.keyboard.handlers).map(key => game.keyboard.unregisterCommand(key));
+  game.keyboard.registerCommand(menu.controls.moveUp, game.player.moveUp);
+  game.keyboard.registerCommand(menu.controls.moveDown, game.player.moveDown);
+  game.keyboard.registerCommand(menu.controls.moveLeft, game.player.moveLeft);
+  game.keyboard.registerCommand(menu.controls.moveRight, game.player.moveRight);
+  game.keyboard.registerCommand(menu.controls.shoot, game.player.shoot);
+  game.keyboard.registerCommand("Escape", menu.showMenu);
+  localStorage.setItem("controls", JSON.stringify(menu.controls));
+}
+
+menu.addScore = (score) => {
+  menu.scores.push(score);
+  menu.scores.sort((a, b) => b - a);
+  localStorage.setItem("scores", JSON.stringify(menu.scores));
+}
+
+menu.hide = () => {
+  const menuElement = document.getElementById("menu"); 
+  menuElement.style.display = "none";
+  menu.reRegisterKeys();
+  window.removeEventListener("keydown", menu.escapeEventListener);
+  if (menu.onHide) {
+    menu.onHide();
+    menu.onHide = null;
+  }
+  game.resume();
+}
+
+menu.listenFor = (action, elementId) => {
+  const element = document.getElementById(elementId);
+  element.innerHTML = "Listening...";
+  const handleKey = (event) => {
+    window.removeEventListener("keydown", handleKey);
+    if (event.key == "Escape") {
+      element.innerHTML = menu.controls[action];
+      return;
+    }
+    menu.controls[action] = event.key;
+    element.innerHTML = event.key;
+  }
+  window.addEventListener("keydown", handleKey);
+}
+
+menu.draw = () => {
+  const menuElement = document.getElementById("menu"); 
+  menuElement.style.display = "block";
+  menuElement.innerHTML = `<h1>Centipede</h1>`;
+  if (menu.state == "main") {
+    menuElement.innerHTML += `
+      <div class='menu-button' onclick='menu.setState("controls")'>Change Controls</div>
+      <div class='menu-button' onclick='menu.setState("credits")'>Credits</div>
+      <div class='menu-button' onclick='menu.setState("scores")'>High Scores</div>
+    `;
+  }
+  else if (menu.state == "controls") {
+    menuElement.innerHTML += `
+      <div>
+        <p>
+          Move left: <button id="moveLeft" onfocus='menu.listenFor("moveLeft", "moveLeft")'>${menu.controls.moveLeft}</button>
+          <br>
+          Move right: <button id="moveRight" onfocus='menu.listenFor("moveRight", "moveRight")'>${menu.controls.moveRight}</button>
+          <br>
+          Move up: <button id="moveUp" onfocus='menu.listenFor("moveUp", "moveUp")'>${menu.controls.moveUp}</button>
+          <br>
+          Move down: <button id="moveDown" onfocus='menu.listenFor("moveDown", "moveDown")'>${menu.controls.moveDown}</button>
+          <br>
+          Shoot: <button id="shoot" onfocus='menu.listenFor("shoot", "shoot")'>${menu.controls.shoot}</button>
+        </p>
+      </div>
+    `
+  } else if (menu.state == "credits") {
+    menuElement.innerHTML += `
+      <div>
+        <p>
+          Sounds from <a href="https://opengameart.org/content/laser-fire">dklon</a>
+          <br>
+          Sprites from <a href="https://www.pngkit.com/view/u2w7r5u2e6u2a9r5_general-sprites-centipede-arcade-game-sprites/">PNGKit</a>
+          <br>
+          Some code from <a href="https://www.usu.edu/directory/?person=56DB0BFCCAEECEC8D5">Dr. Mathias</a>
+          <br>
+          Developed by Logan Hunt
+        </p>
+      </div>
+    `
+  } else if (menu.state == "scores") {
+    menuElement.innerHTML += `
+      <div>
+        <p>
+        ${menu.scores.map((score, index) => `${index + 1}: ${score}<br>`).join("")}
+        </p>
+      </div>
+    `
+  } else if (menu.state == "game-over") {
+    menuElement.innerHTML += `
+      <div>
+        <p>
+          Game Over
+          <br>
+          Your final score was: ${game.score}
+      </div>
+    `
+  }
+
+  menuElement.innerHTML += "<div class='menu-button' onclick='menu.hide()'>Resume Game</div>"
+  if (menu.state !== "main") {
+    menuElement.innerHTML += "<div class='menu-button' onclick='menu.setState(\"main\")'>Back</div>"
+  }
+}
+
+menu.initialize();
\ No newline at end of file
diff --git a/centipede/js/game/object.js b/centipede/js/game/object.js
new file mode 100644
index 0000000..1e22ec6
--- /dev/null
+++ b/centipede/js/game/object.js
@@ -0,0 +1,51 @@
+game.Object = (object) => {
+  object.dx = object.dx ?? 0;
+  object.dy = object.dy ?? 0;
+  object.rot = object.rot ?? 0;
+  object.drot = object.drot ?? 0;
+  object.alive = object.alive ?? true;
+
+  object.poisonedTimer = object.poisonedTimer ?? 4000;
+  object.poisoned = false;
+  object.elapsedPoisonedTimer = 0;
+  object.poison = () => {
+    object.poisoned = true;
+    object.elapsedPoisonedTimer = 0;
+  }
+
+  object.intersects = (other) => {
+    if (object.x + object.width <= other.x) {
+      return false;
+    }
+    if (object.x >= other.x + other.width) {
+      return false;
+    }
+    if (object.y + object.height <= other.y) {
+      return false;
+    }
+    if (object.y >= other.y + other.height) {
+      return false;
+    }
+    return true;
+  }
+
+  object.update = (elapsedTime) => {
+    if (object.poisoned && object.y >= game.height - object.height) {
+      object.elapsedPoisonedTimer += elapsedTime;
+      if (object.elapsedPoisonedTimer > object.poisonedTimer) {
+        object.poisoned = false;
+        object.elapsedPoisonedTimer = 0;
+      }
+    }
+
+    object.x += (object.poisoned ? 0 : object.dx)*elapsedTime;
+    object.y += (object.poisoned ? 0.2 : object.dy)*elapsedTime;
+    object.rot += object.drot*elapsedTime;
+  };
+
+  object.draw = (elapsedTime) => {
+    object.sprite.draw(elapsedTime, object);
+  };
+
+  return object;
+};
diff --git a/centipede/js/game/objects/bullet.js b/centipede/js/game/objects/bullet.js
new file mode 100644
index 0000000..5791aca
--- /dev/null
+++ b/centipede/js/game/objects/bullet.js
@@ -0,0 +1,11 @@
+game.Bullet = (spec) => {
+  const object = game.Object(spec);
+  const parentUpdate = object.update; 
+  object.update = (elapsedTime) => {
+    parentUpdate(elapsedTime);
+    if (object.y < 0) {
+      object.alive = false;
+    }
+  };
+  return object;
+}
\ No newline at end of file
diff --git a/centipede/js/game/objects/centipede.js b/centipede/js/game/objects/centipede.js
new file mode 100644
index 0000000..7e4c8f6
--- /dev/null
+++ b/centipede/js/game/objects/centipede.js
@@ -0,0 +1,105 @@
+game.CentipedePiece = (spec) => {
+  const object = game.Object(spec);
+  object.poisonedTimer = 1000;
+  const parentUpdate = object.update;
+  object.turningState = {
+    turning: false,
+    turnDirectionY: 1,
+    objectStateBeforeTurn: null,
+  };
+  object.turn = () => {
+    object.turningState.objectStateBeforeTurn = {dx: object.dx, dy: object.dy, x: object.x, y: object.y};
+    object.turningState.turning = true;
+    if (object.y >= game.height - object.height) {
+      object.turningState.turnDirectionY = -1;
+    }
+    if (object.y <= 0) {
+      object.turningState.turnDirectionY = 1;
+    }
+  };
+  object.update = (elapsedTime) => {
+    if (object.poisoned) {
+      object.turningState.turning = false;
+    }
+    else if ((object.x+object.width > game.width || object.x < 0) && !object.turningState.turning) {
+      object.x = Math.min(Math.max(object.x, 0), game.width - object.width);
+      object.turn();
+    }
+    if (object.turningState.turning) {
+      object.dx = 0;
+      object.dy = Math.abs(object.turningState.objectStateBeforeTurn.dx) * object.turningState.turnDirectionY;
+      object.rot = object.dy > 0 ? -90 : 90;
+      if (Math.abs(object.turningState.objectStateBeforeTurn.y - object.y) >= object.height) {
+        object.y = object.turningState.objectStateBeforeTurn.y + object.height * object.turningState.turnDirectionY;
+        object.dx = -object.turningState.objectStateBeforeTurn.dx;
+        object.rot = object.dx > 0 ? 180 : 0;
+        object.dy = 0;
+        object.turningState.turning = false;
+      }
+    }
+    parentUpdate(elapsedTime);
+    object.y = Math.min(Math.max(object.y, 0), game.height - object.height);
+  };
+  object.onMushroomCollision = (mushroom) => {
+    if (mushroom.poisoned && object.dy === 0) {
+      object.poison();
+      return;
+    }
+    if (!object.turningState.turning) {
+      if (mushroom.x < object.x && object.dx > 0) {
+        return;
+      }
+      object.turn();
+    }
+  }
+  return object;
+}
+
+game.Centipede = (spec) => {
+  const segments = [
+    ...Array(spec.segments).fill(0).map((_, i) => game.CentipedePiece({...spec, x: spec.startX - spec.width*(i+1), y: spec.startY, sprite: game.sprites.centipedeBody})),
+    game.CentipedePiece({...spec, x: spec.startX, y: spec.startY, sprite: game.sprites.centipedeHead}),
+  ];
+
+  const update = (elapsedTime) => {
+    segments.map((segment) => segment.update(elapsedTime));
+  }
+
+  const draw = (elapsedTime) => {
+    segments.map((segment) => segment.draw(elapsedTime));
+  }
+  
+  const intersects = (object) => {
+    return segments.filter((segment) => segment.intersects(object)).length;
+  }
+
+  const onBulletCollision = (bullet) => {
+    if (bullet.alive) {
+      const segment = segments.find((segment) => segment.intersects(bullet));
+      const segmentIndex = segments.indexOf(segment);
+
+      const {mushX, mushY} = game.Mushroom.toMushCoords(segment);
+      game.explosions.push(game.Explosion({...game.Mushroom.toGameCoords({mushX, mushY}), width: segment.width, height: segment.height, sprite: game.sprites.explosionSmall}));
+      if (!game.mushrooms.find((mushroom) => mushroom.mushX === mushX && mushroom.mushY === mushY)) {
+        game.mushrooms.push(game.Mushroom({mushX, mushY, ...game.mushroomDims}));
+      }
+      game.score += segment.sprite === game.sprites.centipedeHead ? 20 : 5;
+      game.sounds.enemy_hit.load();
+      game.sounds.enemy_hit.play();
+      segments.splice(segmentIndex, 1);
+    }
+    bullet.alive = false;
+  }
+
+  const onMushroomCollision = (mushroom) => {
+    segments.find((segment) => segment.intersects(mushroom)).onMushroomCollision(mushroom);
+  }
+
+  const onPlayerCollision = (player) => {
+    player.kill();
+  }
+
+  const alive = () => segments.length ? true : false; 
+
+  return {update, draw, segments, intersects, onBulletCollision, onMushroomCollision, onPlayerCollision, alive};
+}
\ No newline at end of file
diff --git a/centipede/js/game/objects/explosion.js b/centipede/js/game/objects/explosion.js
new file mode 100644
index 0000000..f38d820
--- /dev/null
+++ b/centipede/js/game/objects/explosion.js
@@ -0,0 +1,14 @@
+game.Explosion = (spec) => {
+  const object = game.Object(spec);
+  let explosionTime = 0;
+  const parentUpdate = object.update;
+  object.update = (elapsedTime) => {
+    parentUpdate(elapsedTime);
+    explosionTime += elapsedTime;
+
+    if (explosionTime > (object.sprite.numFrames * object.sprite.timePerFrame)) {
+      object.alive = false;
+    }
+  }
+  return object;
+}
\ No newline at end of file
diff --git a/centipede/js/game/objects/flea.js b/centipede/js/game/objects/flea.js
new file mode 100644
index 0000000..23479cc
--- /dev/null
+++ b/centipede/js/game/objects/flea.js
@@ -0,0 +1,49 @@
+game.Flea = (spec) => {
+  const object = game.Object(spec);
+  const parentUpdate = object.update; 
+  object.mushroomCoords = game.Mushroom.toMushCoords(object);
+  object.update = (elapsedTime) => {
+    const newMushroomCoords = game.Mushroom.toMushCoords(object);
+    if (newMushroomCoords.mushY !== object.mushroomCoords.mushY || newMushroomCoords.mushX !== object.mushroomCoords.mushX) {
+      if (Math.random() < Math.min(0.15 + 0.05*game.level, 0.7)) {
+        if (!game.mushrooms.find((mushroom) => mushroom.mushX === newMushroomCoords.mushX && mushroom.mushY === newMushroomCoords.mushY)) {
+          game.mushrooms.push(game.Mushroom({...newMushroomCoords, ...game.mushroomDims}));
+        }
+      }
+      object.mushroomCoords = newMushroomCoords;
+    }
+    parentUpdate(elapsedTime);
+  };
+
+  object.onMushroomCollision = (mushroom) => {
+    if (mushroom.poisoned) {
+      mushroom.state = 0;
+      object.poison();
+    }
+  }
+
+  object.explode = () => {
+    game.explosions.push(game.Explosion({x: object.x, y: object.y, width: object.width, height: object.height, sprite: game.sprites.explosionSmall}));
+    game.sounds.enemy_hit.load();
+    game.sounds.enemy_hit.play();
+  }  
+
+  object.onBulletCollision = (bullet) => {
+    game.score += 20;
+    object.alive = false;
+    object.explode();
+  }
+
+  object.onPlayerCollision = (player) => {
+    object.alive = false;
+    player.kill();
+    object.explode();
+  }
+
+  object.onBulletCollision = (bullet) => {
+    object.explode();
+    object.alive = false;
+  }
+
+  return object;
+}
\ No newline at end of file
diff --git a/centipede/js/game/objects/mushroom.js b/centipede/js/game/objects/mushroom.js
new file mode 100644
index 0000000..b1f4787
--- /dev/null
+++ b/centipede/js/game/objects/mushroom.js
@@ -0,0 +1,43 @@
+game.Mushroom = (spec) => {
+  spec.state = spec.state ?? 4;
+  const {mushX, mushY} = spec;
+  const objectSpec = {...spec};
+  objectSpec.x = mushX * objectSpec.width;
+  objectSpec.y = mushY * objectSpec.height;
+  const object = {...spec, ...game.Object(objectSpec)};
+  object.onBulletCollision = (bullet) => {
+    if (bullet.alive) {
+      object.state--;
+      game.score += 5;
+      game.sounds.mushroom_hit.load();
+      game.sounds.mushroom_hit.play();
+    }
+    bullet.alive = false;
+  }; 
+  object.draw = (elapsedTime) => {
+    if (object.state) {
+      object.sprite = object.poisoned ? game.sprites.poisonMushrooms[object.state-1] : game.sprites.regularMushrooms[object.state-1];
+      object.sprite.draw(elapsedTime, object);
+    }
+  }
+  return object;
+};
+
+game.Mushroom.toMushCoords = (coords) => {
+  return {mushX: Math.ceil(coords.x / game.mushroomDims.width), mushY: Math.ceil(coords.y / game.mushroomDims.height)};
+}
+
+game.Mushroom.toGameCoords = (mushCoords) => {
+  return {x: mushCoords.mushX * game.mushroomDims.width, y: mushCoords.mushY * game.mushroomDims.height};
+}
+
+game.Mushroom.generateMushrooms = (mushroomSpec) => {
+  const mushPositions = new Set();
+  for (let i = 0; i < Math.max(Math.random(), 0.05) * game.height / mushroomSpec.height * game.width / mushroomSpec.width * game.level * 0.5; i++) {
+    mushPositions.add(JSON.stringify([Math.floor(Math.random() * game.width / mushroomSpec.width), Math.max(1, Math.floor(Math.random() * (game.height / mushroomSpec.height - 3)))]));
+  }
+  return Array.from(mushPositions).map((pos) => {
+    const [mushX, mushY] = JSON.parse(pos);
+    return game.Mushroom({...mushroomSpec, mushX, mushY});
+  });
+}
diff --git a/centipede/js/game/objects/player.js b/centipede/js/game/objects/player.js
new file mode 100644
index 0000000..a1f6ea0
--- /dev/null
+++ b/centipede/js/game/objects/player.js
@@ -0,0 +1,63 @@
+game.Player = (spec) => {
+  const object = game.Object(spec);
+  object.poisonedTimer = 4000;
+  object.elapsedPoisonedTimer = 0;
+  object.poisoned = false;
+  object.bulletTimer = spec.bulletTimer ?? 150;
+  object.maxPlayerHeight = spec.maxPlayerHeight ?? game.height - object.height*6;
+  object.elapsedBulletTimer = 0;
+  object.lives = spec.lives ?? 3;
+
+  const parentUpdate = object.update; 
+  object.update = (elapsedTime) => {
+    parentUpdate(elapsedTime);
+    object.x = Math.max(0, Math.min(object.x, game.width - object.width));
+    object.y = Math.max(object.maxPlayerHeight, Math.min(object.y, game.height - object.height));
+    object.dx = object.dy = 0;
+    object.elapsedBulletTimer += elapsedTime;
+  };
+  object.moveUp = () => {
+    object.dy = -0.75;
+  }
+  object.moveDown = () => {
+    object.dy = 0.75;
+  }
+  object.moveLeft = () => {
+    object.dx = -0.5;
+  }
+  object.moveRight = () => {
+    object.dx = 0.5;
+  }
+
+  object.shoot = () => {
+    if (object.elapsedBulletTimer > object.bulletTimer) {
+      object.elapsedBulletTimer = 0;
+      game.bullets.push(game.Bullet({x: object.x + object.width/2 - 5, y: object.y-object.height/2, dx: 0, dy: -1.5, width: 5, height: 50, sprite: game.sprites.bullet}));
+      game.sounds.laser.load();
+      game.sounds.laser.play();
+    }
+  }
+
+  object.onMushroomCollision = (mushroom) => {
+    if (mushroom.poisoned) {
+      mushroom.state = 0;
+      object.poison();
+    }
+    if (mushroom.x > object.x) {
+      object.x = mushroom.x - mushroom.width;
+    }
+    if (mushroom.x < object.x) {
+      object.x = mushroom.x + mushroom.width;
+    }
+  }
+
+  object.kill = () => {
+    object.lives--;
+    game.resetObjects();
+    if (object.lives == 0) {
+      game.gameOver();
+    }
+  }
+
+  return object;
+}
\ No newline at end of file
diff --git a/centipede/js/game/objects/scorpion.js b/centipede/js/game/objects/scorpion.js
new file mode 100644
index 0000000..036db14
--- /dev/null
+++ b/centipede/js/game/objects/scorpion.js
@@ -0,0 +1,32 @@
+game.Scorpion = (spec) => {
+  const object = game.Object(spec);
+
+  const parentUpdate = object.update; 
+  object.update = (elapsedTime) => {
+    parentUpdate(elapsedTime);
+  };
+
+  object.explode = () => {
+    game.explosions.push(game.Explosion({x: object.x, y: object.y, width: object.width, height: object.height, sprite: game.sprites.explosionBig}));
+    game.sounds.enemy_hit.load();
+    game.sounds.enemy_hit.play();
+  }  
+
+  object.onBulletCollision = (bullet) => {
+    game.score += 100;
+    object.alive = false;
+    object.explode();
+  }
+
+  object.onPlayerCollision = (player) => {
+    object.alive = false;
+    player.kill();
+    object.explode();
+  }
+
+  object.onMushroomCollision = (mushroom) => {
+    mushroom.poisoned = true;
+  }
+
+  return object;
+}
\ No newline at end of file
diff --git a/centipede/js/game/objects/spider.js b/centipede/js/game/objects/spider.js
new file mode 100644
index 0000000..732c0a3
--- /dev/null
+++ b/centipede/js/game/objects/spider.js
@@ -0,0 +1,45 @@
+game.Spider = (spec) => {
+  const object = game.Object(spec);
+
+  const parentUpdate = object.update; 
+  
+  object.randomizeVel = () => {
+    object.dx = Math.min(Math.random(), 0.25 + 0.05*game.level) * (Math.random() > 0.5 ? 1 : -1);
+    object.dy = Math.min(Math.random(), 0.25 + 0.05*game.level) * (Math.random() > 0.5 ? 1 : -1);
+  }
+
+  object.update = (elapsedTime) => {
+    if (Math.random() < 0.01*game.level) {
+      object.randomizeVel();
+    }
+    if (object.x < 0 || object.x > game.width - object.width) {
+      object.dx = -object.dx;
+    }
+    if (object.y < 0 || object.y > game.height - object.height) {
+      object.dy = -object.dy;
+    }
+    object.x = Math.max(0, Math.min(game.width - object.width, object.x));
+    object.y = Math.max(0, Math.min(game.height - object.height, object.y));
+    parentUpdate(elapsedTime);
+  };
+
+  object.explode = () => {
+    game.explosions.push(game.Explosion({x: object.x, y: object.y, width: object.width, height: object.height, sprite: game.sprites.explosionBig}));
+    game.sounds.enemy_hit.load();
+    game.sounds.enemy_hit.play();
+  }  
+
+  object.onBulletCollision = (bullet) => {
+    game.score += 150;
+    object.alive = false;
+    object.explode();
+  }
+
+  object.onPlayerCollision = (player) => {
+    object.alive = false;
+    player.kill();
+    object.explode();
+  }
+
+  return object;
+}
\ No newline at end of file
diff --git a/centipede/js/game/sounds.js b/centipede/js/game/sounds.js
new file mode 100644
index 0000000..584dbd3
--- /dev/null
+++ b/centipede/js/game/sounds.js
@@ -0,0 +1,5 @@
+game.sounds = {
+  mushroom_hit: new Audio("assets/sounds/mushroom_hit.wav"),
+  enemy_hit: new Audio("assets/sounds/enemy_hit.wav"),
+  laser: new Audio("assets/sounds/laser.wav"),
+}
\ No newline at end of file
diff --git a/centipede/js/game/sprites.js b/centipede/js/game/sprites.js
new file mode 100644
index 0000000..3cdd77f
--- /dev/null
+++ b/centipede/js/game/sprites.js
@@ -0,0 +1,120 @@
+game.sprites = {
+  centipedeHead: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png", 
+    spriteX: 0,
+    spriteY: 0,
+    spriteWidth: 40,
+    spriteHeight: 40,
+    numFrames: 4,
+    timePerFrame: 100,
+  }),
+  centipedeBody: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png", 
+    spriteX: 0,
+    spriteY: 80,
+    spriteWidth: 40,
+    spriteHeight: 40,
+    numFrames: 4,
+    timePerFrame: 100,
+  }),
+  spider: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png",
+    spriteX: 0,
+    spriteY: 160,
+    spriteWidth: 80,
+    spriteHeight: 40,
+    numFrames: 8,
+    timePerFrame: 100,
+    cols: 4,
+    rows: 2,
+  }),
+  flea: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png",
+    spriteX: 320,
+    spriteY: 160,
+    spriteWidth: 45,
+    spriteHeight: 40,
+    numFrames: 4,
+    timePerFrame: 500,
+    cols: 2,
+    rows: 2,
+  }),
+  scorpion: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png",
+    spriteX: 0,
+    spriteY: 280,
+    spriteWidth: 80,
+    spriteHeight: 40,
+    numFrames: 4,
+    timePerFrame: 500,
+    cols: 4,
+  }),
+  ship: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png",
+    spriteX: 0,
+    spriteY: 400,
+    spriteWidth: 40,
+    spriteHeight: 40,
+    numFrames: 1,
+    timePerFrame: 0,
+    cols: 1,
+    rows: 1
+  }),
+  bullet: game.graphics.Sprite({
+    drawFunction: (_elapsedTime, {x, y, rot, width, height}, context) => {
+      context.save();
+      context.translate(x+width/2, y+height/2);
+      context.rotate(rot * Math.PI / 180);
+      context.translate(-x-width/2, -y-height/2);
+      const fillStyle = context.fillStyle;
+      context.fillStyle = "#FF0000";
+      context.fillRect(x, y, width, height);
+      context.fillStyle = fillStyle;
+      context.restore();
+    }
+  }),
+  explosionBig: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png",
+    spriteX: 0,
+    spriteY: 320,
+    numFrames: 8,
+    spriteWidth: 80,
+    spriteHeight: 40,
+    cols: 4,
+    rows: 2,
+    timePerFrame: 30,
+  }),
+  explosionSmall: game.graphics.Sprite({
+    sheetSrc: "assets/images/centipede-assets.png",
+    spriteX: 320,
+    spriteY: 320,
+    numFrames: 6,
+    spriteWidth: 40,
+    spriteHeight: 40,
+    cols: 3,
+    rows: 2,
+    timePerFrame: 30,
+  }),
+  regularMushrooms: [3,2,1,0].map(i => 
+    game.graphics.Sprite({
+      sheetSrc: "assets/images/centipede-assets.png",
+      spriteX: 320 + i*40,
+      spriteY: 0,
+      numFrames: 1,
+      spriteWidth: 40,
+      spriteHeight: 40,
+      timePerFrame: 0,
+    })
+  ),
+  poisonMushrooms: [3,2,1,0].map(i => 
+    game.graphics.Sprite({
+      sheetSrc: "assets/images/centipede-assets.png",
+      spriteX: 320 + i*40,
+      spriteY: 40,
+      numFrames: 1,
+      spriteWidth: 40,
+      spriteHeight: 40,
+      timePerFrame: 0,
+    })
+  )
+};
\ No newline at end of file