js实现简单的贪吃蛇游戏
本文实例为大家分享了js实现贪吃蛇游戏的具体代码，供大家参考，具体内容如下
运行截图：
源码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>贪吃蛇小游戏</title>
<style>
body {
margin:0px;
padding:0px;
}
#main {
margin:100px;
}
.btn {
width:100px;
height:40px;
}
.gtitle {
font-size:25px;
font-weight: bold;
}
#gnum {
color:red;
}
</style>
</head>
<body>
<div id="main">
<h1>贪吃蛇</h1>
<input class="btn" type="button" value="开始游戏" id="begin" />
<input class="btn" type="button" value="暂停游戏" id="pause" />
<span class="gtitle">第 <span id="gnum">1</span> 关</span>
<script>
var main = document.getElementById('main');
var showcanvas = true; //是否开启画布格子
/**
* 地图对象的构造方法
* @param atom 原子大小宽和高是一样的 10
* @param xnum 横向原子的数量
* @param ynum 纵向原子的数量
* @constructor
*/
function Map(atom, xnum, ynum){
this.atom = atom; // 20x20
this.xnum = xnum; //
this.ynum = ynum;
this.canvas = null;
//创建画布的方法
this.create = function(){
this.canvas = document.createElement('div');
this.canvas.style.cssText="position:relative;top:40px;border:1px solid darkred; background:#FAFAFA";
this.canvas.style.width = this.atom * this.xnum + 'px'; //画布的宽
this.canvas.style.height = this.atom * this.ynum + 'px'; //画布的高
main.appendChild(this.canvas);
if(showcanvas) {
for(var y=0; y<ynum; y++) {
for (var x = 0; x < xnum; x++) {
var a = document.createElement('div');
a.style.cssText = "border:1px solid yellow";
a.style.width = this.atom + 'px';
a.style.height = this.atom + 'px';
a.style.backgroundColor = "LightSkyBlue";
this.canvas.appendChild(a);
a.style.position = 'absolute';
a.style.left = x * this.atom + 'px';
a.style.top = y*this.atom+'px';
}
}
}
}
}
/**
* 创建食物的构造方法
* @param map 地图对象
* @constructor
*/
function Food(map){
this.width = map.atom;
this.height = map.atom;
this.bgcolor= "rgb("+Math.floor(Math.random()*200)+", "+Math.floor(Math.random()*200)+", " + Math.floor(Math.random() * 200) +")";
this.x = Math.floor(Math.random()*map.xnum);
this.y = Math.floor(Math.random()*map.ynum);
this.flag = document.createElement('div');
this.flag.style.width = this.width + 'px';
this.flag.style.height = this.height + 'px';
this.flag.style.backgroundColor = this.bgcolor;
// this.flag.style.borderRadius = '50%';
this.flag.style.position = 'absolute';
this.flag.style.left = this.x * this.width +'px';
this.flag.style.top = this.y * this.height + 'px';
map.canvas.appendChild(this.flag);
}
function Snake(map) {
//设置宽，高
this.width=map.atom;
this.height = map.atom;
//默认走的方向
this.direction = 'right';
this.body = [
{x:2, y:0}, //蛇头， 第一点 0
{x:1, y:0}, //蛇脖子, 第二点 1
{x:0, y:0} //蛇尾， 第三点 2
//{x:null, y:null, flag:null} 3
];
//显示蛇
this.display = function(){
for(var i=0; i<this.body.length; i++){
if(this.body[i].x !=null) { //当吃到食物时， x==null, 不能新建， 不然会在0,0处理新建一个
var s = document.createElement('div');
// 将节点保存到一个状态变量中， 以便以后删除使用
this.body[i].flag = s;
//设置蛇的样式
s.style.width = this.width + 'px';
s.style.height = this.height + 'px';
s.style.backgroundColor="rgb("+Math.floor(Math.random()*200)+", "+Math.floor(Math.random()*200)+", " + Math.floor(Math.random() * 200) +")";
//s.style.borderRadius = '50%';
//设置位置
s.style.position = 'absolute';
s.style.left = this.body[i].x * this.width + 'px';
s.style.top = this.body[i].y * this.height + 'px';
//添加到地图中
map.canvas.appendChild(s);
}
}
}
//让蛇运动起来
this.run = function() {
for(var i=this.body.length-1; i>0; i--) {
this.body[i].x = this.body[i-1].x;
this.body[i].y = this.body[i-1].y;
}
//默认是right left up down
// 根据方向处理蛇头
switch(this.direction) {
case "left": this.body[0].x -=1; break;
case "right": this.body[0].x +=1;break;
case "up": this.body[0].y -=1; break;
case "down": this.body[0].y +=1; break;
}
//判断蛇头吃到食物， xy和食物的XY重合
if(this.body[0].x ==food.x && this.body[0].y == food.y ){
//蛇加一节， 根据最后节点定
this.body.push({x:null, y:null, flag:null});
//判读一下设置级别
if(this.body.length > l.slength) {
l.set();
}
map.canvas.removeChild(food.flag);
food = new Food(map);
}
//判断是否出界， 蛇头
if(this.body[0].x <0 || this.body[0].x > map.xnum-1 || this.body[0].y <0 || this.body[0].y > map.ynum -1) {
clearInterval(timer); //清除定时器
alert("怎么这么不小心撞墙了呢，摸摸头");
//重新开始游戏
restart(map, this)
return false;
}
//判读是否和自己重合
for(var i=4; i<this.body.length; i++){
if(this.body[0].x == this.body[i].x && this.body[0].y == this.body[i].y) {
clearInterval(timer); //清除定时器
alert("呀，怎么喜欢咬自己的肉肉");
//重新开始游戏
restart(map, this)
return false;
}
}
for(var i=0; i<this.body.length; i++){
if(this.body[i].flag != null) { //当吃到食物， flag是等null, 且不能删除
map.canvas.removeChild(this.body[i].flag)
}
}
this.display();
}
}
//重新开始游戏
function restart(map, snake) {
for(var i=0; i<snake.body.length; i++) {
map.canvas.removeChild(snake.body[i].flag);
}
snake.body = [
{x:2, y:0}, //蛇头， 第一点 0
{x:1, y:0}, //蛇脖子, 第二点 1
{x:0, y:0} //蛇尾， 第三点 2
];
snake.direction = 'right';
snake.display();
map.canvas.removeChild(food.flag);
food = new Food(map);
}
//设置级别对象
function Level() {
this.num = 1; //第几级别
this.speed= 300; //毫秒， 每升一关， 数量减少20， 速度就加快了
this.slength = 8; //每个关的长度判断
this.set = function() {
this.num++;
if(this.speed <= 50) {
this.speed = 50;
}else{
this.speed -=50;
}
this.slength += 10; //这个可以自己定义
this.display();
start(); //重新开始， 速度加快
}
this.display = function() {
document.getElementById('gnum').innerHTML = this.num;
}
}
var l = new Level();
l.display();
//创建地图对象
var map = new Map(20, 40, 20);
map.create(); //显示画布
//构造食物对象
var food = new Food(map);
//构造蛇对象
var snake = new Snake(map);
snake.display();
// 组body加键盘事件， 上下左右
window.onkeydown = function(e){
var event = e || window.event;
// console.log(event.keyCode);
switch(event.keyCode) {
case 38:
if(snake.direction != "down") {
snake.direction = "up";
}
break;
case 40:
if(snake.direction != "up") {
snake.direction = "down";
}
break;
case 37:
if(snake.direction != "right") {
snake.direction = "left";
}
break;
case 39:
if(snake.direction != "left") {
snake.direction = "right";
}
break;
}
}
var timer; //变量可以提升
function start() {
clearInterval(timer);
timer = setInterval(function(){
snake.run();
},l.speed);
}
document.getElementById('begin').onclick=function(){
start();
}
document.getElementById('pause').onclick=function() {
clearInterval(timer);
}
</script>
</div>
</body>
</html>
小编还为大家准备了精彩的专题：javascript经典小游戏汇总
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