我有些恶梦，在重力和画布边界的作用下，将不同的背景图像应用于在画布上反弹的球上，最终沉降并堆积在底部。
我创建了一个图像数组，我试图遍历该图像数组并为每个图像创建一个球，其中该图像成为居中的背景。
我可以将图像居中，但这会使球看起来离开画布的边界。因此已还原了该更改。
我无法获得与前一个球不同的背景图像。所有球上显示的图像是阵列中的最后一个图像。但是，创建的球的数量确实反映了阵列中图像的数量。
这是一个代码笔的链接：https ://codepen.io/jason-is-my-name/pen/BbNRXB
html, body{
width:100%;
height:100%;
margin: 0;
padding: 0;
background: #333333;
}
*{
margin: 0;
padding: 0;
}
.container {
width: 410px;
height: 540px;
}
#ball-stage{
width: 100%;
height: 100%;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="container">
<canvas id="ball-stage" ></canvas>
</div>
<script>
/*
/*
* Created by frontside.com.au
* Amended by Jason
*/
$(document).ready(function () {
$.ajaxSetup({
cache: true
});
var url1 = "https://code.createjs.com/easeljs-0.6.0.min.js";
$.getScript(url1, function () {
new App();
})
});
function App() {
var self = this;
self.running = false;
self.initialized = false;
var stageClicked = false;
var stage, canvas;
var canvasWidth = 410;
var canvasHeight = 540;
var bounce = -0.75;
var balls = [];
var _gravityY = 1;
var _gravityX = 0;
var FPS = 30;
var infoText, detailsText;
var ballsInitalized = false;
var iOS = navigator.userAgent.match(/(iPod|iPhone|iPad)/);
self.initialize = function () {
toggleListeners(true);
self.initCanvas();
self.initGame();
};
var toggleListeners = function (enable) {
if (!enable) return;
};
self.refresh = function () {}
self.initCanvas = function () {
canvas = $("#ball-stage").get(0);
stage = new createjs.Stage(canvas);
window.addEventListener('resize', onStageResize, false);
onStageResize();
createjs.Touch.enable(stage);
createjs.Ticker.addListener(tick);
createjs.Ticker.setFPS(FPS);
self.initialized = true;
}
self.initGame = function () {
initBalls(canvasWidth, canvasHeight);
}
var onStageResize = function () {
stage.canvas.width = canvasWidth;
stage.canvas.height = canvasHeight;
}
var initBalls = function (stageX, stageY) {
var imagesArray = ["img-1.png","img-2.png","img-3.png","img-4.png","img-5.png","img-6.png","img-7.png","img-8.png"];
for (var i = 0; i < imagesArray.length; i++) {
console.log(i);
var imageArray = imagesArray[i];
console.log(imageArray);
setTimeout(function () {
var arrayImage = new Image();
console.log(arrayImage);
arrayImage.onload = function(){
addBall(arrayImage, stageX / 2, 0);
}
arrayImage.src = imageArray;
}, i * 1000);
}
}
var addBall = function (img, x, y) {
console.log(img);
var shape = new createjs.Shape();
shape.id = balls.length;
shape.radius = 51.25;
shape.mass = shape.radius;
shape.x = x;
shape.y = y;
shape.vx = rand(-3, 3);
shape.vy = rand(-3, 3);
var image = new Image();
image.src = img;
shape.graphics.beginBitmapFill(img,'repeat').drawCircle(0, 0, shape.radius);
stage.addChild(shape);
balls.push(shape);
}
var numBalls = function () {
return balls.length;
}
var tick = function () {
balls.forEach(move);
for (var ballA, i = 0, len = numBalls() - 1; i < len; i++) {
ballA = balls[i];
for (var ballB, j = i + 1; j < numBalls(); j++) {
ballB = balls[j];
checkCollision(ballA, ballB);
}
}
stage.update();
}
var rotate = function (x, y, sin, cos, reverse) {
return {
x: (reverse) ? (x * cos + y * sin) : (x * cos - y * sin),
y: (reverse) ? (y * cos - x * sin) : (y * cos + x * sin)
};
}
var checkCollision = function (ball0, ball1) {
var dx = ball1.x - ball0.x,
dy = ball1.y - ball0.y,
dist = Math.sqrt(dx * dx + dy * dy);
//collision handling code here
if (dist < ball0.radius + ball1.radius) {
//calculate angle, sine, and cosine
var angle = Math.atan2(dy, dx),
sin = Math.sin(angle),
cos = Math.cos(angle),
//rotate ball0's position
pos0 = {
x: 0,
y: 0
}, //point
//rotate ball1's position
pos1 = rotate(dx, dy, sin, cos, true),
//rotate ball0's velocity
vel0 = rotate(ball0.vx, ball0.vy, sin, cos, true),
//rotate ball1's velocity
vel1 = rotate(ball1.vx, ball1.vy, sin, cos, true),
//collision reaction
vxTotal = vel0.x - vel1.x;
vel0.x = ((ball0.mass - ball1.mass) * vel0.x + 2 * ball1.mass * vel1.x) /
(ball0.mass + ball1.mass);
vel1.x = vxTotal + vel0.x;
//update position - to avoid objects becoming stuck together
var absV = Math.abs(vel0.x) + Math.abs(vel1.x),
overlap = (ball0.radius + ball1.radius) - Math.abs(pos0.x - pos1.x);
pos0.x += vel0.x / absV * overlap;
pos1.x += vel1.x / absV * overlap;
//rotate positions back
var pos0F = rotate(pos0.x, pos0.y, sin, cos, false),
pos1F = rotate(pos1.x, pos1.y, sin, cos, false);
//adjust positions to actual screen positions
// ball1.x = ball0.x + pos1F.x;
setBallX(ball1, ball0.x + pos1F.x)
//ball1.y = ball0.y + pos1F.y;
setBallY(ball1, ball0.y + pos1F.y)
// ball0.x = ball0.x + pos0F.x;
setBallX(ball0, ball0.x + pos0F.x)
// ball0.y = ball0.y + pos0F.y;
setBallY(ball0, ball0.y + pos0F.y)
//rotate velocities back
var vel0F = rotate(vel0.x, vel0.y, sin, cos, false),
vel1F = rotate(vel1.x, vel1.y, sin, cos, false);
ball0.vx = vel0F.x;
ball0.vy = vel0F.y;
ball1.vx = vel1F.x;
ball1.vy = vel1F.y;
}
}
var checkWalls = function (ball) {
if (ball.x + ball.radius > canvas.width) {
// ball.x = canvas.width - ball.radius;
setBallX(ball, canvas.width - ball.radius)
ball.vx *= bounce;
} else
if (ball.x - ball.radius < 0) {
// ball.x = ball.radius;
setBallX(ball, ball.radius)
ball.vx *= bounce;
}
if (ball.y + ball.radius > canvas.height) {
// ball.y = canvas.height - ball.radius;
setBallY(ball, canvas.height - ball.radius)
ball.vy *= bounce;
} else
if (ball.y - ball.radius < 0) {
//ball.y = ball.radius;
setBallY(ball, ball.radius)
ball.vy *= bounce;
}
}
var move = function (ball) {
ball.vy += _gravityY;
ball.vx += _gravityX;
setBallX(ball, ball.x + ball.vx)
setBallY(ball, ball.y + ball.vy)
checkWalls(ball);
}
var setBallX = function (ball, x) {
if (isNaN(ball.pointerID)) {
ball.x = x
}
}
var setBallY = function (ball, y) {
if (isNaN(ball.pointerID)) {
ball.y = y
}
}
var rand = function (min, max) {
return Math.random() * (max - min) + min;
return (Math.random() * max) + min;
}
self.initialize();
return self;
}
window.log = function f() {
log.history = log.history || [];
log.history.push(arguments);
if (this.console) {
var args = arguments,
newarr;
args.callee = args.callee.caller;
newarr = [].slice.call(args);
if (typeof console.log === 'object') log.apply.call(console.log, console, newarr);
else console.log.apply(console, newarr);
}
};
(function (a) {
function b() {}
for (var c = "assert,count,debug,dir,dirxml,error,exception,group,groupCollapsed,groupEnd,info,log,markTimeline,profile,profileEnd,time,timeEnd,trace,warn".split(","), d; !!(d = c.pop());) {
a[d] = a[d] || b;
}
})
(function () {
try {
console.log();
return window.console;
} catch (a) {
return (window.console = {});
}
}());
</script>
现在，我被困在代码中大约一个星期了，确实可以得到一些天才的帮助！
目的：
添加等于图像阵列长度的球。
每个球都有其各自的图像作为居中的背景。
球不会离开画布的边界。
相关代码：
initBalls（）
addBall（）
谢谢，杰森。
https://codepen.io/prtjohanson/pen/vPKQBg
需要更改的内容：
for (let i = 0; i < imagesArray.length; i++) {
console.log(i);
const imageArray = imagesArray[i];
setTimeout(function() {
var arrayImage = new Image();
arrayImage.onload = function() {
addBall(arrayImage, stageX / 2, 0);
};
arrayImage.src = imageArray;
}, i * 1000);
}
在setTimeout回调被触发时，您的for循环已经完成，并且使用var声明，for循环迭代没有自己的作用域，而let则每个迭代都像函数一样具有自己的作用域。
如果它必须在没有let或const关键字的浏览器上运行，请告诉我，我也可以为他们提供解决方案
这将在IE11和其他不支持ES6的浏览器中运行
for (var i = 0; i < imagesArray.length; i++) {
(function(imageArray) {
setTimeout(function() {
var arrayImage = new Image();
arrayImage.onload = function() {
console.log('Add'+i);
addBall(arrayImage, stageX / 2, 0);
};
arrayImage.src = imageArray;
}, i * 1000);
})(imagesArray[i]);
}
要使图像居中，而不会超出画布的范围，请对beginBitmapFill操作使用2D变换：
var transform = new createjs.Matrix2D();
transform.appendTransform(-shape.radius, -shape.radius, 1, 1, 0);
shape.graphics.beginBitmapFill(img, "repeat", transform).drawCircle(0, 0, shape.radius);
至于数组中没有多少个URL，似乎图像源URL有时会提示“我不是机器人”验证码。如果用您控制下的URL替换，该问题将消失。
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