对上一个文章JS配合canvas实现贪吃蛇小游戏做了一个大更新，可以手指控制可以键盘控制，APP端控制方向极为丝滑，代码可以直接copy使用。
请忽略上面样式，哈哈哈哈哈，主要看功能
代码里面我做了注释，有什么不清楚的大家一起探讨。
直接上代码
<!--
* @Descripttion:
* @Author: zhangJunQing
* @Date: 2021-04-25
* @LastEditors: zhangJunQing 1
-->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>canvas贪吃蛇游戏</title>
<style>
* {
margin: 0;
padding: 0;
}
html,
body {
overflow: hidden;
width: 100%;
height: 100%;
}
#canvas {
position: relative;
/* background: black; */
background-size: 100vw 100vh;
background-image: url('https://tse1-mm.cn.bing.net/th/id/OIP.pIeqT6_ue0kmKhnO9gR5egHaEW?w=rectSize5&h=180&c=7&o=5&dpr=1.25&pid=1.7');
}
.divBox {
border: none;
position: absolute;
display: flex;
flex-direction: column;
top: 0;
left: 0;
z-index: 888;
width: 100%;
height: 100%;
}
span {
font-size: 20%;
position: absolute;
}
.samllBig {
width: 100vw;
margin-top: 20%;
height: 50%;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
}
.samllBigChild {
width: 50%;
margin-top: 12%;
display: flex;
justify-content: space-between;
}
.samllBigChild button {
display: inline-block;
border: none;
background: rgb(143, 139, 179);
color: black;
font-weight: bold;
line-height: 100%;
padding: 6%;
width: 30%;
text-align: center;
transition: all 1s;
}
input {
width: 30%;
height: 20%;
line-height: 20%;
border: none;
background: rgb(143, 139, 179);
color: black;
font-weight: bold;
text-align: center;
transition: all 1s;
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
<div class="divBox">
<span></span>
<div class="samllBig">
<input type="text" placeholder="请输入刚开始小方块个数">
<div class="samllBigChild">
<button class="button1">APP模式</button>
<button class="button2">PC模式</button>
</div>
</div>
</div>
<!-- <button class="but">因为打开的窗口大小不是小方块的倍数，所以可能存在误差</button> -->
<script>
let canvas = document.getElementById('canvas')
let btn = document.getElementsByTagName('button')[0]
let btn1 = document.getElementsByTagName('button')[1]
let input = document.getElementsByTagName('input')[0]
let span = document.getElementsByTagName('span')[0]
let smSetInterValTime = 100
let SnackNum = null
let EatNum = 0
span.innerHTML = EatNum * 10 + '分;当前速度' + (100 - smSetInterValTime)
window.onload = () => {
canvas.width = document.documentElement.clientWidth
canvas.height = document.documentElement.clientHeight
}
window.addEventListener('resize', () => {
window.onload()
})
//每个蛇身体的大小
let rectSize = 15
//迟到的食物个数
let ctx = canvas.getContext('2d')
//蛇头
let SnackTop = null
//蛇身体
let SnackList = null
//蛇整体
let SnackFonlyList = null
//食物数组
let EatList = null
//存放上次状态的数组
let list = null
//定时器id
let timeID = null;
//坐标
var x1, y1, x2, y2;
//颜色数组
let colorList = null
//初始化
let init = function () {
// 吃掉的食物个数
EatNum = 0
//定时器毫秒数
smSetInterValTime = 100
if (input.value && input.value != undefined && input.value != '' && input.value != null) {
if (input.value <= 3 || input.value > 20) {
alert('请输入大于3小于等于20')
return
}
SnackNum = input.value
//吃掉一个食物 更改一次分数 速度 默认为 0
span.innerHTML = EatNum * 10 + '分;当前速度' + (100 - smSetInterValTime)
} else {
alert('请输入数量')
return
}
x1 = rectSize; y1 = rectSize; x2 = rectSize; y2 = rectSize;
list = []
SnackTop = []
SnackList = []
SnackFonlyList = [...SnackTop, ...SnackList]
EatList = []
colorList = ["#33B5E5", "#0099CC", "#AA66CC", "#9933CC", "#99CC00", "#669900", "#FFBB33", "#FF8800", "#FF4444", "#CC0000"]
getSanck()
//将整个数组颠倒，才能是我们整个蛇身的顺序
SnackList = SnackList.reverse()
btn.style.opacity = 0
btn1.style.opacity = 0
input.style.opacity = 0
//输入框制空
input.value = ''
// btn1.style.opacity = 0
setTimeout(function () {
requestAnimation()
btn.innerHTML = 'APP重开'
btn1.innerHTML = 'PC重开'
timeID = setInterval(requestAnimation, smSetInterValTime)
}, 1000)
}
btn1.addEventListener('click', function () {
if (btn1.innerHTML == 'PC模式') {
rectSize = 30
init()
} else {
rectSize = 30
init()
}
})
btn.addEventListener('click', function () {
if (btn.innerHTML == 'APP模式') {
rectSize = 15
init()
} else {
rectSize = 15
init()
}
})
function Snack(x1 = rectSize, y1 = rectSize, x2 = rectSize, y2 = rectSize, color) {
this.x1 = x1;
this.x2 = x2;
this.y1 = y1;
this.y2 = y2;
this.color = color || colorList[Math.floor(Math.random() * 10)]
this.direction = 'x' //X向右 y向下 -x 向左 -y 上
this.paceSoon = rectSize
}
Snack.prototype.RectFun = function () {
ctx.beginPath();
ctx.fillStyle = this.color
ctx.fillRect(this.x1, this.y1, this.x2, this.y2);
ctx.stroke();
}
//动起来的方法，就是一直改变他的x1,y1
Snack.prototype.Update = function () {
if (this.direction == 'x') {
this.x1 += this.paceSoon
} else if (this.direction == 'y') {
this.y1 += this.paceSoon
} else if (this.direction == '-x') {
this.x1 -= this.paceSoon
} else if (this.direction == '-y') {
this.y1 -= this.paceSoon
}
}
//让第一个蛇身跟着蛇头，其他蛇身跟着上一个蛇身，让他们的状态一直改变（也就是属性值改变）
Snack.prototype.directionFun = function (index) {
if (index == 0) {
if (SnackTop[0].direction == 'x') {
this.x1 = SnackTop[0].x1 - rectSize
this.direction = 'x'
this.y1 = SnackTop[0].y1
} else if (SnackTop[0].direction == 'y') {
this.direction = 'y'
this.x1 = SnackTop[0].x1
this.y1 = SnackTop[0].y1 - rectSize
} else if (SnackTop[0].direction == '-x') {
this.direction = '-x'
this.x1 = SnackTop[0].x1 + rectSize
this.y1 = SnackTop[0].y1
} else if (SnackTop[0].direction == '-y') {
this.direction = '-y'
this.y1 = SnackTop[0].y1 + rectSize
this.x1 = SnackTop[0].x1
}
} else {
if (list[index - 1].direction == 'x') {
this.x1 = list[index - 1].x1
this.y1 = list[index - 1].y1
} else if (list[index - 1].direction == 'y') {
this.x1 = list[index - 1].x1
this.y1 = list[index - 1].y1
} else if (list[index - 1].direction == '-x') {
this.x1 = list[index - 1].x1
this.y1 = list[index - 1].y1
} else if (list[index - 1].direction == '-y') {
this.y1 = list[index - 1].y1
this.x1 = list[index - 1].x1
}
}
}
//食物 构造函数
function Eat(x1, y1, x2, y2) {
this.x1 = x1;
this.y1 = y1;
this.x2 = x2;
this.y2 = y2;
this.color = colorList[Math.floor(Math.random() * 10)]
}
//食物 原型方法
Eat.prototype.RectFunE = function () {
ctx.beginPath();
ctx.fillStyle = this.color
ctx.fillRect(this.x1, this.y1, this.x2, this.y2);
ctx.stroke();
}
//生成蛇身体和一个蛇头
function getSanck() {
for (let i = 0; i < SnackNum; i++) {
x1 += rectSize;
SnackList.length != SnackNum - 1 ? SnackList.push(new Snack(x1, y1, x2, y2)) : SnackTop.push(new Snack(x1, y1, x2, y2))
}
}
//生成食物随机数
//利用递归生成一个随机数，并且使蛇方块的大小倍数
function MathRandomFun(min, max) {
let num = Math.floor((max - min) * Math.random() + min)
if (num % rectSize == 0) {
return num
} else {
return MathRandomFun(min, max)
}
}
// 生成n个正方形 和一个食物
function requestAnimation() {
//上一次每一个蛇身的状态
list = JSON.parse(JSON.stringify(SnackList))
// ctx.fillStyle ="rgba(0,0,0,.05)"
// ctx.fillRect(0, 0, canvas.width, canvas.height)
ctx.clearRect(0, 0, canvas.width, canvas.height)
//食物 给生成的食物控制范围
if (EatList.length == 0)
EatList.push(new Eat(MathRandomFun(120, canvas.width - 120), MathRandomFun(150, canvas.height - 90), x2, y2))
EatList.map(item => {
item.RectFunE()
})
//判断舌头和食物的位置信息
//SnackTop 舌头
//EatList 食物
if (SnackTop[0].x1 == EatList[0].x1 && SnackTop[0].y1 == EatList[0].y1) {
//添加蛇身体
EatNum++
//没吃掉是个食物 定时器毫秒-10 页面显示速度+10
switch (EatNum) {
case 10: smSetInterValTime = 80; clearInterval(timeID); timeID = setInterval(requestAnimation, smSetInterValTime); break;
case 20: smSetInterValTime = 70; clearInterval(timeID); timeID = setInterval(requestAnimation, smSetInterValTime); break;
case 30: smSetInterValTime = 60; clearInterval(timeID); timeID = setInterval(requestAnimation, smSetInterValTime); break;
case 40: smSetInterValTime = 50; clearInterval(timeID); timeID = setInterval(requestAnimation, smSetInterValTime); break;
case 50: smSetInterValTime = 40; clearInterval(timeID); timeID = setInterval(requestAnimation, smSetInterValTime); break;
case 60: smSetInterValTime = 30; clearInterval(timeID); timeID = setInterval(requestAnimation, smSetInterValTime); break;
}
//吃掉一个食物 更改一次分数 速度
span.innerHTML = EatNum * 10 + '分;当前速度' + (100 - smSetInterValTime)
//定时器速度小于30 闯关成功
if (smSetInterValTime <= 30) {
alert('恭喜您闯关成功')
//取消定时器
clearInterval(timeID)
//重置画布
ctx.clearRect(0, 0, canvas.width, canvas.height)
//按钮 inp显示
btn.style.opacity = 1
btn1.style.opacity = 1
input.style.opacity = 1
return
}
//吃掉食物 身体加1 颜色为吃的食物颜色
SnackList.push(new Snack(list[list.length - 1].x1, list[list.length - 1].y1, x2, y2, EatList[0].color))
EatList.length = 0
}
SnackTop.map(item => {
item.RectFun()
item.Update()
})
SnackList.map((item, index) => {
item.RectFun()
item.directionFun(index)
})
//任意一遍超出界限就是游戏失败
if (SnackTop[0].x1 <= -60 || SnackTop[0].x1 > canvas.width || SnackTop[0].y1 <= -60 || SnackTop[0].y1 > canvas.height) {
clearInterval(timeID)
ctx.clearRect(0, 0, canvas.width, canvas.height)
btn.style.opacity = 1
btn1.style.opacity = 1
input.style.opacity = 1
// btn1.style.opacity = 1
return false
}
}
//添加键盘按下时间 并且不能直接掉头
window.addEventListener('keydown', function (e) {
if (e.keyCode == '39') {
SnackTop[0].direction == '-x' ? '' : SnackTop[0].direction = 'x'
// console.log('右')
} else if (e.keyCode == '40') {
//下 40
SnackTop[0].direction == '-y' ? '' : SnackTop[0].direction = 'y'
// console.log('下')
} else if (e.keyCode == '37') {
//左 37
SnackTop[0].direction == 'x' ? '' : SnackTop[0].direction = '-x'
// console.log('-x')
} else if (e.keyCode == '38') {
//右 39
SnackTop[0].direction == 'y' ? '' : SnackTop[0].direction = '-y'
// console.log('-y')
}
})
var touchSX
var touchSY
var touchMX
var touchMY
//手机端 控制方向
window.addEventListener('touchstart', function (e) {
//记录除此触摸的X
touchSX = e.changedTouches[0].clientX
//记录除此触摸的Y
touchSY = e.changedTouches[0].clientY
})
window.addEventListener('touchmove', function (e) {
//记录滑动中的X
touchMX = e.changedTouches[0].clientX
//记录滑动中的Y
touchMY = e.changedTouches[0].clientY
//计算x轴正方向 x和y的cos值
let xyorx = (touchMX - touchSX) / (Math.sqrt(Math.pow(touchMX - touchSX, 2) + Math.pow(touchSY - touchMY, 2)))
//计算x轴负方向 x和y的cos值
let xyor_x = -(touchMX - touchSX) / (Math.sqrt(Math.pow(touchMX - touchSX, 2) + Math.pow(touchSY - touchMY, 2)))
if (touchMX - touchSX > 0) {
//向右
if (touchMY - touchSY > 0) {
// y 下
if (xyorx >= 0.707 && xyorx <= 1) {
SnackTop[0].direction == '-x' ? '' : SnackTop[0].direction = 'x'
} else {
SnackTop[0].direction == '-y' ? '' : SnackTop[0].direction = 'y'
}
} else {
//-y 向上 touchMY < touchSY
if (xyorx >= 0.707 && xyorx <= 1) {
SnackTop[0].direction == '-x' ? '' : SnackTop[0].direction = 'x'
} else {
SnackTop[0].direction == 'y' ? '' : SnackTop[0].direction = '-y'
}
}
} else {
// //-x
if (touchMY - touchSY > 0) {
// y 下
if (xyor_x >= 0.707 && xyor_x <= 1) {
SnackTop[0].direction == 'x' ? '' : SnackTop[0].direction = '-x'
} else {
SnackTop[0].direction == '-y' ? '' : SnackTop[0].direction = 'y'
}
} else {
//-y 向上 touchMY < touchSY
if (xyor_x >= 0.707 && xyor_x <= 1) {
SnackTop[0].direction == 'x' ? '' : SnackTop[0].direction = '-x'
} else {
SnackTop[0].direction == 'y' ? '' : SnackTop[0].direction = '-y'
}
}
}
})
window.addEventListener('touchend', function (e) {
touchSX = 0
touchSY = 0
touchMX = 0
touchMY = 0
})
</script>
</body>
</html>