<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<script src="xiaoshu.js"></script>
<style>
#div1 {
602px;
margin: 20px auto;
border: 1px solid #efdede;
}
</style>
</head>
<body>
<div id="div1">
<canvas id="ca" width="600" height="600"></canvas>
</div>
</body>
</html>
<script>
var OC = document.getElementById('ca');
var CG = OC.getContext('2d');
var mx = 0, my = 0;
var iRoat = 0;
var ball = [];
setInterval(function () {
ball.push({
x: 200,
y: 0,
r: 100,
num: 0,
starX: 200,
starY: 0
});
}, 400);
var bollet = [];
var oImg = new Image();
oImg.src = "img/person.png";
oImg.onload = function () {
//画图运动
setInterval(function () {
CG.clearRect(0, 0, OC.width, OC.height);
CG.save();
CG.translate(180, 100);
CG.rotate(iRoat);
CG.translate(-25, -25);
CG.drawImage(oImg, 0, 0, 50, 50);
CG.restore();
CG.beginPath();
CG.arc(200, 100, 100, -90 * Math.PI / 180, 180 * Math.PI / 180, false);
CG.stroke();
CG.beginPath();
CG.arc(180, 100, 80, 180 * Math.PI / 180, 360 * Math.PI / 180, false);
CG.stroke();
CG.beginPath();
CG.arc(260, 100, 10, 0, 360 * Math.PI / 180, true)
CG.stroke();
CG.closePath();
for (var i = 0; i < ball.length; i++) {
CG.beginPath();
CG.moveTo(ball[i].x, ball[i].y);
CG.arc(ball[i].x, ball[i].y, 10, 0, 360 * Math.PI / 180, false);
CG.closePath();
CG.fill();
}
for (var i = 0; i < bollet.length; i++) {
CG.save();
CG.beginPath();
CG.fillStyle = 'red';
CG.moveTo(bollet[i].startX, bollet[i].startY);
CG.arc(bollet[i].startX, bollet[i].startY, 10, 0, 360 * Math.PI / 180, false);
CG.closePath();
CG.fill();
CG.restore();
}
}, 1000 / 60);
//为运动提供数据
setInterval(function () {
for (var i = 0; i < ball.length; i++) {
ball[i].num++;
if (ball[i].num >= 270) {
ball[i].r = 80;
ball[i].starX = 180;
ball[i].starY = 100;
ball[i].x = add(ball[i].starX, mul(Math.sin(ball[i].num * Math.PI / 180), ball[i].r));
ball[i].y = add(-mul(Math.cos(ball[i].num * Math.PI / 180), ball[i].r), ball[i].starY);
if (ball[i].num == 270 + 180) {
alert('游戏结束');
window.location.reload();
}
}
else if (ball[i].num < 270) {
ball[i].x = Math.sin(ball[i].num * Math.PI / 180) * ball[i].r + ball[i].starX;
ball[i].y = ball[i].r - Math.cos(ball[i].num * Math.PI / 180) * ball[i].r + ball[i].starY;
}
}
for (var i = 0; i < bollet.length; i++) {
bollet[i].startX = bollet[i].startX + bollet[i].sX;
bollet[i].startY = bollet[i].startY + bollet[i].sY;
}
for (var i = 0; i < bollet.length; i++) {
for (var j = 0; j < ball.length; j++) {
var a = {
x: Math.abs( bollet[i].startX),
y: Math.abs(bollet[i].startY),
r: 10
};
var b = {
x: Math.abs(ball[j].x),
y: Math.abs(ball[j].y),
r: 10
};
if (afoul(a, b))
{
bollet.splice(i, 1);
ball.splice(j, 1);
break;
}
}
}
}, 30);
}
OC.onmousemove = function (ev) {
var ev = ev || event;
var a = ev.clientX - OC.offsetLeft - 180;
var b = ev.clientY - OC.offsetTop - 100;
var c = Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2));
if (a >= 0 && b <= 0) {
iRoat = Math.asin(a / c);
} else if (a > 0) {
iRoat = Math.acos(a / c) + 90 * Math.PI / 180;
}
if (a <= 0 && b <= 0) {
iRoat = Math.asin(a / c);
} else if (a < 0) {
iRoat = -(Math.asin(b / c) + 90 * Math.PI / 180);
}
}
OC.onmousedown = function (ev) {
var ev = ev || event;
var a = ev.clientX - OC.offsetLeft - 180;
var b = ev.clientY - OC.offsetTop - 100;
var c = Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2));
var iSpeed = 5;
var sX = iSpeed * a / c;
var sY = iSpeed * b / c;
bollet.push({
startX: 180,
startY: 100,
sX: sX,
sY: sY
});
}
//碰撞检测
function afoul(a, b) {
var x = Math.pow((a.x - b.x), 2);
var y = Math.pow((a.y - b.y), 2);
var r = Math.pow((a.r + b.r), 2);
if (Math.sqrt( x + y) <Math.sqrt(r)) {
return true;
}
return false;
}
</script>
用到的处理小数的js xiaoshu.js
//加法
function add(a, b) {
var c, d, e;
try {
c = a.toString().split(".")[1].length;
} catch (f) {
c = 0;
}
try {
d = b.toString().split(".")[1].length;
} catch (f) {
d = 0;
}
return e = Math.pow(10, Math.max(c, d)), (mul(a, e) + mul(b, e)) / e;
}
//减法
function sub(a, b) {
var c, d, e;
try {
c = a.toString().split(".")[1].length;
} catch (f) {
c = 0;
}
try {
d = b.toString().split(".")[1].length;
} catch (f) {
d = 0;
}
return e = Math.pow(10, Math.max(c, d)), (mul(a, e) - mul(b, e)) / e;
}
//乘法
function mul(a, b) {
var c = 0,
d = a.toString(),
e = b.toString();
try {
c += d.split(".")[1].length;
} catch (f) { }
try {
c += e.split(".")[1].length;
} catch (f) { }
return Number(d.replace(".", "")) * Number(e.replace(".", "")) / Math.pow(10, c);
}
//除法
function div(a, b) {
var c, d, e = 0,
f = 0;
try {
e = a.toString().split(".")[1].length;
} catch (g) { }
try {
f = b.toString().split(".")[1].length;
} catch (g) { }
return c = Number(a.toString().replace(".", "")), d = Number(b.toString().replace(".", "")), mul(c / d, Math.pow(10, f - e));
}