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BubbleCollisions - 4th step.html
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BubbleCollisions - 4th step.html
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<!DOCTYPE html>
<html lang="en">
<!------分------割------线------>
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="Author" content="Bruce Zhu">
<title>Bubble Collisions - 泡泡碰撞</title>
</head>
<style>
html,body {
margin: 0;
padding: 0;
}
canvas {
box-shadow: 0 0 40px black;
margin: 50px auto;
}
div {
width: 800px;
height: 600px;
margin: 0 auto;
}
</style>
<!------分------割------线------>
<body>
<div>
<canvas id="bubble" width="800px" height="600px">对不起！您的浏览器不支持Canvas</canvas>
</div>
</body>
<script type="text/javascript">
// 获取画布对象
var canvas = document.getElementById('bubble');
var ctx = canvas.getContext('2d');
// 蓝色泡泡的图片
var blueBubbleImg = new Image();
blueBubbleImg.src = "蓝泡.png";
// 红色泡泡的图片
var redBubbleImg = new Image();
redBubbleImg.src = "红泡.png";
// 创建泡泡对象
var bubble = function(x, y, bubbleWidth, bubbleHeight, whichBubble) {
this.x = x;
this.y = y;
this.r = bubbleHeight/2;
this.speedX;
this.speedY;
this.bubbleWidth = bubbleWidth;
this.bubbleHeight = bubbleHeight;
this.whichBubble = whichBubble;
this.draw = function () {
// 保存当前环境状态
ctx.save();
ctx.drawImage(this.whichBubble, this.x, this.y, this.bubbleWidth, this.bubbleHeight);
}
this.move = function() {
this.x += this.speedX;
this.y += this.speedY;
if(this.x < 0 || this.x > canvas.width - this.r*2) {
this.speedX = -this.speedX;
}
if(this.y < 0 || this.y > canvas.height - this.r*2) {
this.speedY = -this.speedY;
}
// 调用draw方法重绘
this.draw();
}
}
// 自定义蓝色泡泡的随机函数
function blueRandom(min,max) {
return parseInt(Math.random()*(max - min) + min);
}
// 初始化红球的大小
var redWidth = redHeight = 50;
// 初始化红色泡泡出现的位置
var centerX = (canvas.width - redWidth)/2;
var centerY = (canvas.height - redHeight)/2;
// 实例化红色泡泡对象
var redBubble = new bubble(centerX, centerY, redWidth, redHeight, redBubbleImg);
// 在画布上绘制初始状态的泡泡
redBubbleImg.onload = function () {
redBubble.draw();
}
// 实例化多个蓝色泡泡对象
var blueBubbles = [];
// 将红色泡泡放入对象数组中判断是否会被覆盖
blueBubbles[0] = redBubble;
// 设置生成蓝色泡泡的数量
var blueBubblesNum = 20
for (let i = 1; i <= blueBubblesNum; i++) {
// 设置蓝色泡泡的宽高
let blueBubbleHeight = blueBubbleWidth = blueRandom(30, 70);
// 初始化蓝色泡泡出现的位置
let randomX = blueRandom(0, canvas.width - blueBubbleWidth);
let randomY = blueRandom(0, canvas.height - blueBubbleHeight);
// 初始化蓝色泡泡的速度
let blueVx = blueRandom(0, 2);
let blueVy = blueRandom(0, 2);
// 如果将会碰壁，舍弃掉
if(blueBubbleCover(randomX, randomY, blueBubbleWidth, blueBubbleHeight)){
i--;
continue;
}
// 这才是真的实例化对象 = =!
blueBubbles[i] = new bubble(randomX, randomY, blueBubbleWidth, blueBubbleHeight, blueBubbleImg);
blueBubbles[i].speedX = blueVx;
blueBubbles[i].speedY = blueVy;
}
// 在画布上绘制初始状态的泡泡
blueBubbleImg.onload = function () {
blueBubbleDraw();
}
// 循环绘制蓝色泡泡
function blueBubbleDraw() {
for (let i = 1; i <= blueBubblesNum; i++) {
if (blueBubbles.hasOwnProperty(i)) {
blueBubbles[i].draw();
blueBubbles[i].move();
}
}
}
// 判断绘制的蓝色泡泡是否重叠 PS：详细介绍请看图解
function blueBubbleCover(randomX, randomY, blueBubbleWidth, blueBubbleHeight) {
for (index in blueBubbles) {
if (blueBubbles.hasOwnProperty(index)) {
if(blueBubbles[index].x <= randomX
&& blueBubbles[index].x + blueBubbles[index].bubbleWidth >= randomX
&& blueBubbles[index].y <= randomY
&& blueBubbles[index].y + blueBubbles[index].bubbleHeight >= randomY){
return true
} else if(blueBubbles[index].x <= randomX
&& blueBubbles[index].x + blueBubbles[index].bubbleWidth >= randomX
&& blueBubbles[index].y >= randomY
&& blueBubbles[index].y <= randomY + blueBubbleHeight){
return true
} else if(blueBubbles[index].x >= randomX
&& blueBubbles[index].x <= randomX + blueBubbleWidth
&& blueBubbles[index].y <= randomY
&& blueBubbles[index].y + blueBubbles[index].bubbleHeight >= randomY){
return true
} else if(blueBubbles[index].x >= randomX
&& blueBubbles[index].x <= randomX + blueBubbleWidth
&& blueBubbles[index].y >= randomY
&& blueBubbles[index].y <= randomY + blueBubbleHeight){
return true
}
}
}
}
// 碰撞函数
function Crash(obj1, obj2) {
let x = obj1.x - obj2.x;
let y = obj1.y - obj2.y;
let distance = Math.sqrt(x*x + y*y);
// 判断是否与红球发生碰撞
if(distance < obj1.r + obj2.r) {
obj2.speedX = -obj2.speedX;
obj2.speedY = -obj2.speedY;
}
}
// 给画布设置监听事件，触发阶段默认为false冒泡阶段
canvas.addEventListener("mousemove", onMouseMove, false);
// 记录鼠标移动到的位置，初始化的值为正中心
var mouseX = centerX;
var mouseY = centerY;
// 保存碰壁瞬间状态的泡泡坐标，如果当泡泡触碰到了墙壁，则redBubble.x/y的值取这一状态的
var mouseTouchBorderX, mouseTouchBorderY;
function onMouseMove(evt){
// offset获取到canvas层中鼠标的位置，然后减去红色泡泡自身高度
mouseX = evt.offsetX - redBubble.bubbleWidth/2;
mouseY = evt.offsetY - redBubble.bubbleHeight/2;
}
// 刷新泡泡
function drawBubble() {
// 清空画布
ctx.clearRect(0, 0, canvas.width, canvas.height);
// 如果红泡泡没有碰壁的话，则执行以下条件语句
if(!redBubbleTouchBorder()){
// 更新泡泡的坐标
redBubble.x = mouseX;
redBubble.y = mouseY;
// 暂时保存这一状态的泡泡坐标，如果碰壁的话，此处不执行
mouseTouchBorderX = mouseX;
mouseTouchBorderY = mouseY;
}
for (let i = 1; i <= blueBubblesNum; i++) {
Crash(redBubble, blueBubbles[i]);
}
// 重新绘制
redBubble.draw();
blueBubbleDraw();
}
// 判断红泡泡是否触壁，判断触壁要用mouseX/Y而不能用redBubble.x/y，因为mouseX/Y是变化的。
function redBubbleTouchBorder() {
// 碰壁分为两种情况：
// 第一种是横轴左右碰壁，第二种是纵轴上下碰壁
if(mouseX + redBubble.bubbleWidth > canvas.width || mouseX < 0){
// 小球即使碰壁，那么横轴方向上就不能越界了
redBubble.x = mouseTouchBorderX;
// 这两个条件句是为了解决红色泡泡碰壁后不能拖动小球的情况
// 如果既碰到了横轴方向的壁，又碰到了纵轴方向的壁，那么Y轴是不可以再继续移动的
if(mouseY + redBubble.bubbleHeight > canvas.height || mouseY < 0){
// 红色泡泡Y坐标等于碰壁时的Y坐标
redBubble.y = mouseTouchBorderY;
// 记录
mouseTouchBorderX = redBubble.x;
mouseTouchBorderY = redBubble.y;
} else {
// 如果只是碰到了横轴方向的壁，那么Y轴是可以继续移动的
redBubble.y = mouseY;
// 记录
mouseTouchBorderX = redBubble.x;
mouseTouchBorderY = mouseY;
}
return true;
} else if(mouseY + redBubble.bubbleHeight > canvas.height || mouseY < 0){
redBubble.x = mouseX;
redBubble.y = mouseTouchBorderY;
// Y轴碰壁，不能变化，但X轴依然可以随鼠标变化
mouseTouchBorderX = mouseX;
mouseTouchBorderY = redBubble.y;
return true;
} else {
return false;
}
}
// 设置刷新时间，60帧/s的帧率是比较细腻的，所以用1s/60
setInterval(drawBubble, 1000/60);
</script>
<!------分------割------线------>
</html>