JS事件初试-贪吃蛇小游戏

来源：互联网发布：java软件工程师证书编辑：程序博客网时间：2024/04/29 01:52

1. 获取一个图片当背景

2. 利用数组的push和for循环创建一个蛇身体

3. 然后设置蛇开始移动，开始方向是向右，我设置了一些开始暂停难度选择按钮来决定是否移动

（就是用点击事件打开定时器，然后执行运动函数）

4. 蛇开始移动之后，要先获取蛇头，控制蛇头的运动方向，让蛇尾跟随蛇头（这里用了一个for循环实现）

5. 控制蛇头运动用的键盘事件，运动过程中会撞墙壁和撞蛇尾，都用if语句做一下判断

6. 蛇在移动过程中需要吃食物，用Math.floor和Math.random随机生成了食物，蛇头碰到食物，就在蛇身数组里面加一个div小块

<!DOCTYPE html>

<html lang="en">
<head>
<meta charset="UTF-8">
<title>贪吃蛇最终版</title>
</head>
<style type="text/css">

#wrapper{
width: 1000px;
height: 550px;
border:1px solid black;
margin: 0 auto;
}
#grass{
width: 1000px;
height: 500px;
background: green;
position: relative;
}
#background{
width: 1000px;
height: 500px;
background: green;
position: relative;
}
#button{
float: right;
height: 50px;
line-height: 50px;
}
button{
width: 60px;
height: 45px;
}

.snakeBody{
width: 20px;
height: 20px;
background: red;
position: absolute;
top: 0;
}
.snake-block{
position: absolute;
width: 20px;
height: 20px;
background-color: red;
}
.food-block{
width: 20px;
height: 20px;
background: yellow;
position: absolute;
}

</style>
<body>
<div id="wrapper">
<div id="grass"><img id="background" src="贪吃蛇背景.jpg"></div>
<div id="gameControl">
<div id="button">
<button id="start">开始</button>
<button id="pause">暂停</button>
<button id="through">穿墙</button>
<button id="simple">初级</button>
<button id="middle">中级</button>
<button id="violent">暴走</button>
<button id="supergod">超神</button>
</div>
</div>
</div>
<script type="text/javascript">
//创建蛇
var snakeBody = new Array();//蛇身数组
var ograss = document.getElementById("grass");
for(var i = 3;i>0;i--){
var oDiv = document.createElement("div");
oDiv.className = "snakeBody";
oDiv.style.left= i*20 + "px";
ograss.appendChild(oDiv);
snakeBody.push(oDiv);//向蛇身数组添加蛇身
}
//蛇开始移动
var direction = 'right', //首先开始游戏后，蛇都是向右移动的
oStart = document.getElementById('start'),//设置开始
oSimple = document.getElementById('simple'),//初级
oMiddle = document.getElementById('middle'),//中级
oThrough = document.getElementById('through'),//穿墙
oViolent = document.getElementById('violent'), //暴走
oSuperGod = document.getElementById('supergod'), //超神
timer = null;
oStart.onclick = function(){ //给开始加一个事件
clearInterval(timer);
timer = setInterval(function(){
move(direction);
},300);
}
oSimple.onclick = function(){ //给开始加一个事件
clearInterval(timer);
timer = setInterval(function(){
move(direction);
},200);
}
oThrough.onclick = function(){ //穿墙
clearInterval(timer);
timer = setInterval(function(){
tmove(direction);
},300);
}
oMiddle.onclick = function(){ //中级
clearInterval(timer);
timer = setInterval(function(){
move(direction);
},100);
}
oViolent.onclick = function(){ //暴走
clearInterval(timer);
timer = setInterval(function(){
move(direction);
},30);
}
oSuperGod.onclick = function(){ //超神
clearInterval(timer);
timer = setInterval(function(){
move(direction);
},20);

}

//蛇移动方法撞墙版
function move(dir){
var snakeHead = snakeBody[0]; //获取蛇头，让蛇头移动
for(var i=snakeBody.length-1; i>0; i--){ //让蛇尾跟随蛇头
snakeBody[i].style.left = snakeBody[i-1].offsetLeft + "px";
snakeBody[i].style.top = snakeBody[i-1].offsetTop + "px"; // 父级是grass
}
switch(dir){
case "left":
snakeHead.style.left = snakeHead.offsetLeft - 20 + "px";
break;
case "up":
snakeHead.style.top = snakeHead.offsetTop - 20 + "px";
break;
case "right":
snakeHead.style.left = snakeHead.offsetLeft + 20 + "px";
break;
case "down":
snakeHead.style.top = snakeHead.offsetTop + 20 + "px";
break;
}
//蛇撞墙/身体
if(snakeHead.offsetLeft == -20 || snakeHead.offsetTop == -20 || snakeHead.offsetLeft == 1000 || snakeHead.offsetTop == 500)
{
alert("GG");
clearInterval(timer);
location.reload();
}
//蛇吃身体
for(var i = 1; i < snakeBody.length; i++){
if(snakeHead.offsetLeft == snakeBody[i].offsetLeft && snakeHead.offsetTop == snakeBody[i].offsetTop){
alert('你撞自己了');
clearInterval(timer);
location.reload();
}
}
//蛇吃食物
if(snakeHead.offsetLeft == food.offsetLeft && snakeHead.offsetTop == food.offsetTop){
food.className = "snake-block";
if("direction" == "right"){
food.style.left = snakeBody[snakeBody.length - 1].offsetLeft - 20 + "px";
}else if("direction" == "down"){
food.style.top = snakeBody[snakeBody.length - 1].offsetTop - 20 + "px";
}else if("direction" == "left"){
food.style.left = snakeBody[snakeBody.length - 1].offsetLeft + 20 + "px";
}else if("direction" == "up"){
food.style.top = snakeBody[snakeBody.length - 1].offsetTop + 20 + "px";
}
snakeBody.push(food);//蛇吃到食物
food = createFood();//重新生成食物
}
document.onkeydown = function(e){
e = e || window.event;
var keyCode = e.which || e.keyCode;
if(keyCode == 37 ){//左
if(direction != 'right'){
direction = 'left';
move(direction);
}
}else if(keyCode == 38){//上
if(direction != 'down'){
direction = 'up';
move(direction);
}
}else if(keyCode == 39){//右
if(direction != 'left'){
direction = 'right';
move(direction);
}
}else if(keyCode == 40){//下
if(direction != 'up'){
direction = 'down';
move(direction);
}
}
};

}
//穿墙版
function tmove(dir){
var snakeHead = snakeBody[0]; //获取蛇头，让蛇头移动
for(var i=snakeBody.length-1; i>0; i--){ //让蛇尾跟随蛇头
snakeBody[i].style.left = snakeBody[i-1].offsetLeft + "px";
snakeBody[i].style.top = snakeBody[i-1].offsetTop + "px"; // 父级是grass
}
switch(dir){
case "left":
snakeHead.style.left = snakeHead.offsetLeft - 20 + "px";
break;
case "up":
snakeHead.style.top = snakeHead.offsetTop - 20 + "px";
break;
case "right":
snakeHead.style.left = snakeHead.offsetLeft + 20 + "px";
break;
case "down":
snakeHead.style.top = snakeHead.offsetTop + 20 + "px";
break;
}
//蛇穿墙
if(snakeHead.offsetLeft == 1000){
snakeHead.style.left = 0;
}else if (snakeHead.offsetTop == 500) {
snakeHead.style.top = 0;
}else if (snakeHead.offsetLeft < 0) {
snakeHead.style.left = 980 + "px";
}else if(snakeHead.offsetTop < 0){
snakeHead.style.top = 480 + "px";
}
//蛇吃身体
for(var i = 1; i < snakeBody.length; i++){
if(snakeHead.offsetLeft == snakeBody[i].offsetLeft && snakeHead.offsetTop == snakeBody[i].offsetTop){
alert('你撞自己了');
clearInterval(timer);
location.reload();
}
}
//蛇吃食物
if(snakeHead.offsetLeft == food.offsetLeft && snakeHead.offsetTop == food.offsetTop){
food.className = "snake-block";
if("direction" == "right"){
food.style.left = snakeBody[snakeBody.length - 1].offsetLeft - 20 + "px";
}else if("direction" == "down"){
food.style.top = snakeBody[snakeBody.length - 1].offsetTop - 20 + "px";
}else if("direction" == "left"){
food.style.left = snakeBody[snakeBody.length - 1].offsetLeft + 20 + "px";
}else if("direction" == "up"){
food.style.top = snakeBody[snakeBody.length - 1].offsetTop + 20 + "px";
}
snakeBody.push(food);//蛇吃到食物
food = createFood();//重新生成食物
}
document.onkeydown = function(e){
e = e || window.event;
var keyCode = e.which || e.keyCode;
if(keyCode == 37 ){//左
if(direction != 'right'){
direction = 'left';
tmove(direction);
}
}else if(keyCode == 38){//上
if(direction != 'down'){
direction = 'up';
tmove(direction);
}
}else if(keyCode == 39){//右
if(direction != 'left'){
direction = 'right';
tmove(direction);
}
}else if(keyCode == 40){//下
if(direction != 'up'){
direction = 'down';
tmove(direction);
}
}
};

}

//蛇暂停移动
var oPause = document.getElementById('pause');
oPause.onclick = function(){
clearInterval(timer);
}
//生成食物
var food = createFood();
function createFood(){
var oFood = document.createElement("div");
oFood.className = "food-block";
while(!bFound){
var bFound = true;//一个标识，表示是否找到食物合适的位置
iLeft = Math.floor(Math.random() * 1000);
iLeft = iLeft - iLeft%20 ;//随机产生食物的位置
iTop = Math.floor(Math.random() * 500);
iTop = iTop - iTop%20;
for(var i = 0;i < snakeBody.length; i++){
if(snakeBody[i].offsetLeft == iLeft && snakeBody[i].offsetTop == iTop){
bFound = false;//表示食物与蛇身重合
break;
}
}
oFood.style.left = iLeft + "px";
oFood.style.top = iTop + "px";
ograss.appendChild(oFood);
}
return oFood;
}
</script>
</body>

</html>

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