我正在阅读并尝试完成本教程： http ://www.sitepoint.com/creating-a-simple-windows-8-game-with-javascript-input-and-sound/
昨天，我在这个论坛上写了一个错误，并解决了它，但是今天，我进入了最后一个，又遇到了一个错误。
我的 default.html 文件
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>CatapultGame</title>
<!-- WinJS references -->
<link href="//Microsoft.WinJS.1.0/css/ui-light.css" rel="stylesheet" />
<script src="//Microsoft.WinJS.1.0/js/base.js"></script>
<script src="//Microsoft.WinJS.1.0/js/ui.js"></script>
<!-- CatapultGame references -->
<link href="/css/default.css" rel="stylesheet" />
<script src="/js/default.js"></script>
<script src="js/CreateJS/easeljs-0.6.0.min.js"></script>
<script src="js/CreateJS/preloadjs-0.2.0.min.js"></script>
</head>
<body>
<canvas id="gameCanvas"></canvas>
</body>
</html>
和 default.js 文件：
// For an introduction to the Blank template, see the following documentation:
// http://go.microsoft.com/fwlink/?LinkId=232509
(function () {
"use strict";
var app = WinJS.Application;
var activation = Windows.ApplicationModel.Activation;
WinJS.strictProcessing();
var canvas, context, stage;
var bgImage, p1Image, p2Image, ammoImage, p1Lives, p2Lives, title, endGameImage;
var bgBitmap, p1Bitmap, p2Bitmap, ammoBitmap;
var preload;
// calculate display scale factor - original game assets assume 800x480
var SCALE_X = window.innerWidth / 800;
var SCALE_Y = window.innerHeight / 480;
var MARGIN = 25;
var GROUND_Y = 390 * SCALE_Y;
var LIVES_PER_PLAYER = 3;
var player1Lives = LIVES_PER_PLAYER;
var player2Lives = LIVES_PER_PLAYER;
var isShotFlying = false;
var playerTurn = 1;
var playerFire = false;
var shotVelocity;
var MAX_SHOT_POWER = 10;
var GRAVITY = 0.07;
var isAiming = false;
var aimPower = 1;
var aimStart, aimVector;
var FIRE_SOUND_FILE = "/sounds/CatapultFire.wav";
var HIT_SOUND_FILE = "/sounds/BoulderHit.wav";
var EXPLODE_SOUND_FILE = "/sounds/CatapultExplosion.wav";
var LOSE_SOUND_FILE = "/sounds/Lose.wav";
var AIM_SOUND_FILE = "/sounds/RopeStretch.wav";
var WIN_SOUND_FILE = "/sounds/Win.wav";
app.onactivated = function (args) {
if (args.detail.kind === activation.ActivationKind.launch) {
if (args.detail.previousExecutionState !== activation.ApplicationExecutionState.terminated) {
// TODO: This application has been newly launched. Initialize
// your application here.
} else {
// TODO: This application has been reactivated from suspension.
// Restore application state here.
}
args.setPromise(WinJS.UI.processAll());
}
};
function initialize() {
canvas = document.getElementById("gameCanvas");
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
context = canvas.getContext("2d");
canvas.addEventListener("MSPointerUp", endAim, false);
canvas.addEventListener("MSPointerMove", adjustAim, false);
canvas.addEventListener("MSPointerDown", beginAim, false)
**var stage = new createjs.Stage(canvas);** <<========== HERE IS THE ERROR LINE !!!!
// use preloadJS to get sounds and images loaded before starting
preload = new createjs.PreloadJS();
preload.onComplete = prepareGame;
var manifest = [
{ id: "screenImage", src: "images/Backgrounds/gameplay_screen.png" },
{ id: "redImage", src: "images/Catapults/Red/redIdle/redIdle.png" },
{ id: "blueImage", src: "images/Catapults/Blue/blueIdle/blueIdle.png" },
{ id: "ammoImage", src: "images/Ammo/rock_ammo.png" },
{ id: "winImage", src: "images/Backgrounds/victory.png" },
{ id: "loseImage", src: "images/Backgrounds/defeat.png" },
{ id: "blueFire", src: "images/Catapults/Blue/blueFire/blueCatapultFire.png" },
{ id: "redFire", src: "images/Catapults/Red/redFire/redCatapultFire.png" },
{ id: "hitSound", src: HIT_SOUND_FILE },
{ id: "explodeSound", src: EXPLODE_SOUND_FILE },
{ id: "fireSound", src: FIRE_SOUND_FILE },
{ id: "loseSound", src: LOSE_SOUND_FILE },
{ id: "aimSound", src: AIM_SOUND_FILE },
{ id: "winSound", src: WIN_SOUND_FILE }
];
preload.loadManifest(manifest);
}
function prepareGame()
{
// draw Bg first, others appear on top
bgImage = preload.getResult("screenImage").result;
bgBitmap = new createjs.Bitmap(bgImage);
bgBitmap.scaleX = SCALE_X;
bgBitmap.scaleY = SCALE_Y;
stage.addChild(bgBitmap);
// draw p1 catapult
p1Image = preload.getResult("redImage").result;
p1Bitmap = new createjs.Bitmap(p1Image);
p1Bitmap.scaleX = SCALE_X;
p1Bitmap.scaleY = SCALE_Y;
p1Bitmap.x = MARGIN;
p1Bitmap.y = GROUND_Y - p1Image.height * SCALE_Y;
stage.addChild(p1Bitmap);
// draw p2 catapult and flip
p2Image = preload.getResult("blueImage").result;
p2Bitmap = new createjs.Bitmap(p2Image);
p2Bitmap.regX = p2Image.width;
p2Bitmap.scaleX = -SCALE_X; // flip from right edge
p2Bitmap.scaleY = SCALE_Y;
p2Bitmap.x = canvas.width - MARGIN - (p2Image.width * SCALE_X);
p2Bitmap.y = GROUND_Y - (p2Image.height * SCALE_Y);
stage.addChild(p2Bitmap);
// draw the boulder, and hide for the moment
ammoImage = preload.getResult("ammoImage").result;
ammoBitmap = new createjs.Bitmap(ammoImage);
ammoBitmap.scaleX = SCALE_X;
ammoBitmap.scaleY = SCALE_Y;
ammoBitmap.visible = false; // hide until fired
stage.addChild(ammoBitmap);
// player 1 lives
p1Lives = new createjs.Text("Lives Left : " + player1Lives, "20px sans-serif", "red");
p1Lives.scaleX = SCALE_X;
p1Lives.scaleY = SCALE_Y;
p1Lives.x = MARGIN;
p1Lives.y = MARGIN * SCALE_Y;
stage.addChild(p1Lives);
//player 2 lives
p2Lives = new createjs.Text("Lives Left : " + player2Lives, "20px sans-serif", "red");
p2Lives.scaleX = SCALE_X;
p2Lives.scaleY = SCALE_Y;
p2Lives.x = canvas.width - p2Lives.getMeasuredWidth() * SCALE_X - MARGIN;
p2Lives.y = MARGIN * SCALE_Y;
stage.addChild(p2Lives);
// game title
title = new createjs.Text("Catapult Wars", "30px sans-serif", "black");
title.scaleX = SCALE_X;
title.scaleY = SCALE_Y;
title.x = canvas.width / 2 - (title.getMeasuredWidth() * SCALE_X) / 2
title.y = 30 * SCALE_Y;
stage.addChild(title);
stage.update();
startGame();
}
function startGame()
{
Ticker.setInterval(window.requestAnimationFrame);
Ticker.addListener(gameLoop);
}
function gameLoop()
{
update();
draw();
}
function update() {
if (isShotFlying)
{
// shot in the air
ammoBitmap.x += shotVelocity.x;
ammoBitmap.y += shotVelocity.y;
shotVelocity.y += GRAVITY; //apply gravity to the y(height) values only, obviously
if (ammoBitmap.y + ammoBitmap.image.height >= GROUND_Y ||
ammoBitmap.x <= 0 ||
ammoBitmap.x + ammoBitmap.image.width >= canvas.width)
{
// missed
isShotFlying = false; //stop shot
ammoBitmap.visible = false;
playerTurn = playerTurn % 2 + 1; // invert player ( switch between 1 and 2)
}
else if (playerTurn == 1)
{
if (checkHit(p2Bitmap)) {
// Hit
p2Lives.text = "Lives Left : " + --player2Lives;
processHit();
}
}
else if (playerTurn == 2)
{
if (checkHit(p1Bitmap))
{
// Hit
p1Lives.text = "Lives Left : " + --player1Lives;
processHit();
}
}
}
// No current shot, should either player fire ?
else if (playerTurn == 1)
{
// does the player want to fire ?
if (playerFire)
{
playerFire = false;
ammoBitmap.x = p1Bitmap.x + (p1Bitmap.image.width * SCALE_X / 2);
ammoBitmap.y = p1Bitmap.y;
shotVelocity = aimVector;
fireShot();
}
}
else if (playerTurn == 2)
{
// AI automatically fires (randomly on it's turn)
ammoBitmap.x = p2Bitmap.x + (p2Bitmap.image.width * SCALE_X / 2);
ammoBitmap.y = p2Bitmap.y;
shotVelocity = new createjs.Point(
Math.random() * (-4 * SCALE_X) - 3,
Math.random() * (-3 * SCALE_Y) - 1);
fireShot();
}
}
// triggered by MSPointerDown event
function beginAim(event)
{
if (playerTurn == 1)
{
if (!isAiming)
{
aimStart = new createjs.Point(event.x, event.y);
isAiming = true;
}
}
}
// triggered by MSPointerMove event
function adjustAim(event)
{
if (isAiming)
{
var aimCurrent = new createjs.Point(event.x, event.y);
aimVector = calculateAim(aimStart, aimCurrent);
// TODO write text and/or show aiming arrow on screen
Debug.writeln("Aiming..." + aimVector.x + "/" + aimVector.y);
}
}
// triggered by MSPointerUp event
function endAim(event)
{
if (isAiming) {
isAiming = false;
var aimCurrent = new createjs.Point(event.x, event.y);
aimVector = calculateAim(aimStart, aimCurrent);
playerFire = true;
}
}
function calculateAim(start, end)
{
// this only works for player 1
var aim = new createjs.Point(
(end.x - start.x) / 80,
(end.y - start.y) / 80);
aim.x = Math.min(MAX_SHOT_POWER, aim.x); // cap velocity
aim.x = Math.max(0, aim.x); // fire forward only
aim.y = Math.max(-MAX_SHOT_POWER, aim.y);/// cap velocity
aim.y = Math.min(0, aim.y); // fire up only
return aim;
}
function checkHit(target)
{
// EaselJS hit test doesn't factor in scaling
// so use simple bounding box vs center of rock
// get centre of rock
var shotX = ammoBitmap.x + ammoBitmap.image.width / 2;
var shotY = ammoBitmap.y + ammoBitmap.image.height / 2;
// return wether center of rock is in rectangle bounding target player
return (((shotX > target.x) &&
(shotX <= target.x + (target.image.width * SCALE_X)))
&&
((shotY >= target.y) &&
(shotY <= target.y + (target.image.height * SCALE_Y))));
}
function fireShot()
{
playSound(FIRE_SOUND_FILE);
ammoBitmap.visible = true;
isShotFlying = true;
}
function processHit()
{
playSound(EXPLODE_SOUND_FILE);
isShotFlying = false; // stop shot
ammoBitmap.visible = false; // hide shot
playerTurn = playerTurn % 2 + 1; // change player
if ((player1Lives <= 0) || (player2Lives <= 0)) {
endGame();
}
}
function endGame()
{
Ticker.setPaused(true); // stop game loop
// show win/lose graphic
var endGameImage;
if (player1Lives <= 0)
{
playSound(LOSE_SOUND_FILE);
endGameImage = preload.getResult("loseImage").result;
}
else if (player2Lives <= 0)
{
endGameImage = preload.getResult("winImage").result;
playSound(WIN_SOUND_FILE);
}
var endGameBitmap = new createjs.Bitmap(endGameImage);
stage.addChild(endGameBitmap);
endGameBitmap.x = (canvas.width / 2) - (endGameImage.width * SCALE_X / 2);
endGameBitmap.y = (canvas.height / 2) - (endGameImage.height * SCALE_Y / 2);
endGameBitmap.scaleX = SCALE_X;
endGameBitmap.scaleY = SCALE_Y;
stage.update();
}
function draw() {
// EaselJS allows for easy updates
stage.update();
}
function playSound(path)
{
var sound = document.createElement("audio");
sound.src = path;
sound.autoplay = true;
}
app.oncheckpoint = function (args) {
// TODO: This application is about to be suspended. Save any state
// that needs to persist across suspensions here. You might use the
// WinJS.Application.sessionState object, which is automatically
// saved and restored across suspension. If you need to complete an
// asynchronous operation before your application is suspended, call
// args.setPromise().
};
document.addEventListener("DOMContentLoaded", initialize, false);
app.start();
})();
还有一个问题：当我尝试构建这个游戏时，我遇到了这样的错误：
0x800a01bd - JavaScript 运行时错误：对象不支持此操作
在我的代码中的标记位置
谢谢你的帮助 ：）