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下面代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Game</title>
</head>
<body>
<div>
<canvas id="gameCanvas"></canvas>
</div>
<button type="button" id="stopbtn">暂停/开始</button>
<span id="txt">分数：0</span>
<script type="text/javascript">
var can = document.getElementById("gameCanvas");
can.width = "600";
can.height = "900";
const ctx = can.getContext("2d");
class Sprite {
constructor(arg) {
this.x = arg.x || 0;
this.y = arg.y || 0;
this.width = arg.width || 10;
this.height = arg.height || 10;
this.color = arg.color || "#ccc";
this.list = [];
this.parentNode = null;
}
append(sprite) {
this.list.push(sprite);
sprite.parentNode = this;
}
remove() {
for (var x in this.parentNode.list) {
if (this.parentNode.list[x] === this) {
this.parentNode.list.splice(x, 1);
}
}
}
move(dt) {
}
collide(other) {
}
update(dt) {
//移动
this.move(dt);
//碰撞检测
if (this.parentNode) {
for (var x in this.parentNode.list) {
var item = this.parentNode.list[x];
if (item !== this) {
if (this.x > item.x - this.width && this.x < item.x + item.width) {
if (this.y > item.y - this.height && this.y < item.y + item.height) {
this.collide(item);
}
}
}
}
}
//绘制
ctx.fillStyle = this.color;
ctx.fillRect(this.x, this.y, this.width, this.height);
this.list.forEach(item => {
item.update(dt);
})
}
}
class enemy extends Sprite {
constructor(arg) {
super(arg);
this.speed = arg.speed || 10;
}
move(dt) {
this.y += dt * this.speed;
if (this.y > 920) {
this.remove();
end();
}
}
}
class bullet extends Sprite {
constructor(arg) {
super(arg);
this.speed = arg.speed || 10;
}
move(dt) {
this.y -= dt * this.speed;
if (this.y < -20) {
this.remove();
}
}
collide(other) {
other.remove();
this.remove();
count();
}
}
class Scene extends Sprite {
constructor(arg) {
super(arg);
this.spaceEnemy = 0.5;
this.inter = null;
this.timeEnemy = this.spaceEnemy;
}
move(dt) {
this.timeEnemy -= dt;
if (this.timeEnemy < 0) {
this.createEnemy();
this.timeEnemy = this.spaceEnemy;
}
}
run() {
this.inter = setInterval(() => {
this.update(0.04);
}, 40)
}
stop() {
clearInterval(this.inter);
this.inter = null;
}
createEnemy() {
sc.append(new enemy({
x: Math.floor(Math.random() * 50) * 10,
y: -50,
width: 30,
height: 20,
color: "#333",
speed: 50 + Math.floor(Math.random() * 60)
}));
}
}
var sc = new Scene({
width: 600,
height: 900
});
document.getElementById('stopbtn').onclick = function() {
if (sc.inter) {
sc.stop()
} else {
sc.run()
}
}
var scoring = 0;
function count(){
scoring += 1;
document.getElementById('txt').innerText = "分数：" + scoring;
}
function end(){
sc.stop()
document.getElementById('txt').innerText = "分数：" + scoring + " ==== 游戏结束";
}
can.onclick = function(event) {
if (sc.inter) {
var bu = new bullet({
x: event.offsetX - 10,
y: event.offsetY - 10,
width: 20,
height: 20,
color: "#6cf",
speed: 320
})
sc.append(bu);
}
}
</script>
</body>
</html>
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