<head>
<title>贪吃蛇 Snake v2.4</title>
<style>
body{
font-size:9pt
}
table{
border-collapse: collapse
border:solid #333 1px
}
td{
height: 10px
width: 10px
font-size: 0px
}
.filled{
background-color:blue
}
</style>
</head>
<script>
function $(id){return document.getElementById(id)}
/**************************************************************
* javascript贪吃蛇 v2.4 <br />
* author: sunxing007 05/14/2009<br />
* 转载请注明来自http://blog.csdn.net/sunxing007 谢谢！<br />
* v2.4修正了蛇身颜色可以随着蛇前进而移动
**************************************************************/
//贪吃蛇类
var Snake = {
tbl: null,
/**
* body: 蛇身，数组放蛇的每一节，
* 数据结构{x:x0, y:y0, color:color0},
* x,y表示坐标,color表示颜色
**/
body: [],
//当前移动的方向,取值0,1,2,3, 分别表示向上,右,下,左, 按键盘方向键可以改变它
direction: 0,
//定时器
timer: null,
//速度
speed: 250,
//是否已经暂停
paused: true,
//行数
rowCount: 30,
//列数
colCount: 30,
//初始化
init: function(){
var colors = ['red','orange','yellow','green','blue','purple','#ccc']
this.tbl = $("main")
var x = 0
var y = 0
var colorIndex = 0
//产生初始移动方向
this.direction = Math.floor(Math.random()*4)
//构造table
for(var row=0row<this.rowCountrow++){
var tr=this.tbl.insertRow(-1)
for(var col=0col<this.colCountcol++) {
var td=tr.insertCell(-1)
}
}
//产生20个松散节点
for(var i=0i<10i++){
x = Math.floor(Math.random()*this.colCount)
y = Math.floor(Math.random()*this.rowCount)
colorIndex = Math.floor(Math.random()*7)
if(!this.isCellFilled(x,y)){
this.tbl.rows[y].cells[x].style.backgroundColor = colors[colorIndex]
}
}
//产生蛇头
while(true){
x = Math.floor(Math.random()*this.colCount)
y = Math.floor(Math.random()*this.rowCount)
if(!this.isCellFilled(x,y)){
this.tbl.rows[y].cells[x].style.backgroundColor = "black"
this.body.push({x:x,y:y,color:'black'})
break
}
}
this.paused = true
//添加键盘事件
document.onkeydown= function(e){
if (!e)e=window.event
switch(e.keyCode | e.which | e.charCode){
case 13: {
if(Snake.paused){
Snake.move()
Snake.paused = false
}
else{
//如果没有暂停，则停止移动
Snake.pause()
Snake.paused = true
}
break
}
case 37:{//left
//阻止蛇倒退走
if(Snake.direction==1){
break
}
Snake.direction = 3
break
}
case 38:{//up
//快捷键在这里起作用
if(event.ctrlKey){
Snake.speedUp(-20)
break
}
if(Snake.direction==2){//阻止蛇倒退走
break
}
Snake.direction = 0
break
}
case 39:{//right
if(Snake.direction==3){//阻止蛇倒退走
break
}
Snake.direction = 1
break
}
case 40:{//down
if(event.ctrlKey){
Snake.speedUp(20)
break
}
if(Snake.direction==0){//阻止蛇倒退走
break
}
Snake.direction = 2
break
}
}
}
},
//移动
move: function(){
this.timer = setInterval(function(){
Snake.erase()
Snake.moveOneStep()
Snake.paint()
}, this.speed)
},
//移动一节身体
moveOneStep: function(){
if(this.checkNextStep()==-1){
clearInterval(this.timer)
alert("Game over!\nPress Restart to continue.")
return
}
if(this.checkNextStep()==1){
var _point = this.getNextPos()
var _x = _point.x
var _y = _point.y
var _color = this.getColor(_x,_y)
this.body.unshift({x:_x,y:_y,color:_color})
//因为吃了一个食物，所以再产生一个食物
this.generateDood()
return
}
//window.status = this.toString()
var point = this.getNextPos()
//保留第一节的颜色
var color = this.body[0].color
//颜色向前移动
for(var i=0i<this.body.length-1i++){
this.body[i].color = this.body[i+1].color
}
//蛇尾减一节， 蛇尾加一节，呈现蛇前进的效果
this.body.pop()
this.body.unshift({x:point.x,y:point.y,color:color})
//window.status = this.toString()
},
//探寻下一步将走到什么地方
pause: function(){
clearInterval(Snake.timer)
this.paint()
},
getNextPos: function(){
var x = this.body[0].x
var y = this.body[0].y
var color = this.body[0].color
//向上
if(this.direction==0){
y--
}
//向右
else if(this.direction==1){
x++
}
//向下
else if(this.direction==2){
y++
}
//向左
else{
x--
}
//返回一个坐标
return {x:x,y:y}
},
//检查将要移动到的下一步是什么
checkNextStep: function(){
var point = this.getNextPos()
var x = point.x
var y = point.y
if(x<0||x>=this.colCount||y<0||y>=this.rowCount){
return -1//触边界，游戏结束
}
for(var i=0i<this.body.lengthi++){
if(this.body[i].x==x&&this.body[i].y==y){
return -1//碰到自己的身体,游戏结束
}
}
if(this.isCellFilled(x,y)){
return 1//有东西
}
return 0//空地
},
//擦除蛇身
erase: function(){
for(var i=0i<this.body.lengthi++){
this.eraseDot(this.body[i].x, this.body[i].y)
}
},
//绘制蛇身
paint: function(){
for(var i=0i<this.body.lengthi++){
this.paintDot(this.body[i].x, this.body[i].y,this.body[i].color)
}
},
//擦除一节
eraseDot: function(x,y){
this.tbl.rows[y].cells[x].style.backgroundColor = ""
},
paintDot: function(x,y,color){
this.tbl.rows[y].cells[x].style.backgroundColor = color
},
//得到一个坐标上的颜色
getColor: function(x,y){
return this.tbl.rows[y].cells[x].style.backgroundColor
},
//用于调试
toString: function(){
var str = ""
for(var i=0i<this.body.lengthi++){
str += "x:" + this.body[i].x + " y:" + this.body[i].y + " color:" + this.body[i].color + " - "
}
return str
},
//检查一个坐标点有没有被填充
isCellFilled: function(x,y){
if(this.tbl.rows[y].cells[x].style.backgroundColor == ""){
return false
}
return true
},
//重新开始
restart: function(){
if(this.timer){
clearInterval(this.timer)
}
for(var i=0i<this.rowCounti++){
this.tbl.deleteRow(0)
}
this.body = []
this.init()
this.speed = 250
},
//加速
speedUp: function(time){
if(!this.paused){
if(this.speed+time<10||this.speed+time>2000){
return
}
this.speed +=time
this.pause()
this.move()
}
},
//产生食物。
generateDood: function(){
var colors = ['red','orange','yellow','green','blue','purple','#ccc']
var x = Math.floor(Math.random()*this.colCount)
var y = Math.floor(Math.random()*this.rowCount)
var colorIndex = Math.floor(Math.random()*7)
if(!this.isCellFilled(x,y)){
this.tbl.rows[y].cells[x].style.backgroundColor = colors[colorIndex]
}
}
}
</script>
<body onload="Snake.init()">
/*************************************************************<br />
* javascript贪吃蛇 v2.4<br />
* author: sunxing007 05/14/2009<br />
* 转载请注明来自 <a href="http://blog.csdn.net/sunxing007">http://blog.csdn.net/sunxing007</a>谢谢！<br />
**************************************************************/<br />
<table id="main" border="1" cellspacing="0" cellpadding="0"></table>
<input type="button" id="btn" value="开始/暂停" />点左边按钮或按Enter开始/暂停游戏<br />
<input type="button" id="reset" value="重新开始" /><br />
<input type="button" id="upSpeed" value="加速" />点左边按钮或按Ctrl + ↑加速<br />
<input type="button" id="downSpeed" value="减速" />点左边按钮或按Ctrl + ↓减速
<script>
$('btn').onclick = function(){
if(Snake.paused){
Snake.move()
Snake.paused = false
}
else{
Snake.pause()
Snake.paused = true
}
}
$("reset").onclick = function(){
Snake.restart()
this.blur()
}
$("upSpeed").onclick = function(){
Snake.speedUp(-20)
}
$("downSpeed").onclick = function(){
Snake.speedUp(20)
}
</script>
</body>
</html>
我原来用C语言，借助curses库实现了linux 终端下的贪吃蛇游戏。这个javascript版本的贪吃蛇是http://www.veryhuo.com/game/tanchishe.html 的学习笔记，实现的原理和C版本基本一样。
--------------------
1.怎样表示一条snake
用一个二维数组存snake的各个点(x,y)，同时标记这些点(x,y)为“cover”，这是用于以后检查snake的头是否撞到了snake的body。
//initialize snake
function initSnake() {
var pointer = randomPointer(len-1, len-1, WIDTH/2)
for(var i = 0 i < len i++) {
var x = pointer[0] - i,
y = pointer[1]
snake.push([x,y])
carrier[x][y] = "cover" //标记snake body
}
}
2.用js画出格子
用document.createElent()方法创建出table->tr->td, 然后用document.appendChild()方法追加到id为“snakewrap”的元素上：
//initialize grid
function initGrid() {
var body = document.getElementsByTagName("body")[0]
var table = document.createElement("table"),
tbody = document.createElement("tbody")
for(var j = 0 j < HEIGHT j++) {
var col = document.createElement("tr")
for(var i = 0 i < WIDTH i++) {
var row = document.createElement("td")
gridElems[i][j] = col.appendChild(row)
}
tbody.appendChild(col)
}
table.appendChild(tbody)
document.getElementById("snakewrap").appendChild(table)
}
3.生成食物的随机坐标
function randomPointer(startX,startY,endX,endY) {
startX = startX || 0
startY = startY || 0
endX = endX || WIDTH
endY = endY || HEIGHT
var p = [],
x = Math.floor(Math.random()*(endX - startX)) + startX,
y = Math.floor(Math.random()*(endY - startY)) + startY
//如果(x,y)有物体，则重新生成坐标
if(carrier[x][y]) {
return randomPointer(startX,startY,endX,endY)
}
p[0] = x
p[1] = y
return p
}
添加新的食物：
//addObject("food")
function addObject(name) {
var p = randomPointer() //get random position
var x = p[0]
var y = p[1]
carrier[x][y] = name
gridElems[x][y].className = name
}
4.方向键按下动作事件监听：允许左上右下这4个按键来改变snake的运动方向，注意，如果方向相反的话，不生效。
对于键盘上的每一个按键，都有一个key cord,我的这篇博客记录了javascript的key cord,可看到：
left arrow 37
up arrow 38
right arrow 39
down arrow 40
//keyboard event listener
function attachEvents(e) {
e = e || event
directkey = Math.abs(e.keyCode - directkey) != 2 && e.keyCode > 36 && e.keyCode < 41 ? e.keyCode : directkey
return false
}
以前做的一个 部分注释 核心部分由注释 其实就是一个最后一个跟随前面一个位置的算法
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<style type="text/css">
.body{width:600pxmargin:100px autotext-align:center}
#main{height:300pxborder:1px solid #f00position:relative}
#main div{width:20pxheight:20pxbackground-color:greenposition:absolute}
#main div.snake{background-color:#ff0}
.score{font-size:14px}
.score strong{color:Red}
</style>
<script type="text/javascript">
window.onload = function () {
var omain = document.getElementById("main")
var r = 15, c = 30
var asnake = []
var speed = 150
var odiv = document.createElement("div")
asnake.push({ l: Math.floor(Math.random() * c), t: Math.floor(Math.random() * r), div: odiv, d: "l" })
omain.appendChild(odiv)
setPosition(asnake[0])
//设置位置
function setPosition(obj) {
obj.div.style.left = obj.l * 20 + "px"
obj.div.style.top = obj.t * 20 + "px"
}
var aEat = null
var d = "l"
//创建吃的
function createEat() {
var l = Math.floor(Math.random() * c)
var t = Math.floor(Math.random() * r)
var isexist = false
//判断是否存在在设数组里面
for (var i = 0 i < asnake.length i++) {
if (l == asnake[i].l && t == asnake[i].t) {
isexist = true
break
}
}
//如果存在再创建一个蛇
if (isexist) {
createEat()
return
}
var onewdiv = document.createElement("div")
onewdiv.className = "snake"
aEat = { l: l, t: t, div: onewdiv, d: "l" }
omain.appendChild(onewdiv)
setPosition(aEat)
}
createEat()
var obtn = document.getElementById("btn")
var oscore = document.getElementById("score")
var oaddspeed = document.getElementById("addspeed")
var otimer = null
var isitem = true
oaddspeed.onclick = function () {
clearInterval(otimer)
speed = speed < 50 ? 50 : speed - 20
setasnke()
}
obtn.onclick = function () {
if (!isitem) {
clearInterval(otimer)
obtn.value = "继续游戏"
isitem = true
return false
}
obtn.value = "暂停游戏"
setasnke()
isitem = false
}
function setasnke() {
otimer = setInterval(function () {
for (var i = asnake.length - 1 i > 0 i--) {
asnake[i].l = asnake[i - 1].l
asnake[i].t = asnake[i - 1].t
asnake[i].d = asnake[i - 1].d
}
switch (d) {
case "l":
asnake[0].l--
break
case "r":
asnake[0].l++
break
case "t":
asnake[0].t--
break
case "b":
asnake[0].t++
break
}
//判断蛇是否撞墙了
if (asnake[0].l < 0 || asnake[0].l >= c || asnake[0].t < 0 || asnake[0].t >= r) {
alert("你死掉了")
clearInterval(otimer)
return
}
//判断蛇是否撞到自己了
for (var n = 1 n < asnake.length n++) {
if (asnake[0].l == asnake[n].l && asnake[0].t == asnake[n].t) {
alert("你已经死掉了")
clearInterval(otimer)
return
}
}
//判断蛇是否吃到东西了
if (asnake[0].l == aEat.l && asnake[0].t == aEat.t) {
aEat.div.className = ""
oscore.innerHTML = parseInt(oscore.innerHTML) + 1
asnake.push(aEat)
createEat()
}
//重新设置蛇的位置
for (var j = 0 j < asnake.length j++) {
setPosition(asnake[j])
}
}, speed)
}
//键盘改变蛇的方向
document.onkeydown = function (event) {
var oEn = event || window.event
var oCode = oEn.keyCode
switch (oCode) {
case 37:
d = "l"
break
case 38:
d = "t"
break
case 39:
d = "r"
break
case 40:
d = "b"
break
}
}
}
</script>
</head>
<body>
<div class="body">
<input type="button" value="加速" id="addspeed" /> <input type="button" id="btn" value="开始游戏" />  <span class="score">积分：<strong id="score">0</strong></span>
<div id="main">
</div>
</div>
</body>
</html>
