JS编写贪吃蛇（面向对象思想）
Posted 孙倩倩
tags:
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效果图：（抱歉，由于本人能力有限，只能暂时放静态图。后期会把动态图更新上去）
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style>
#map {
width: 500px;
height:500px;
position:relative;
background: #ccc;
}
</style>
</head>
<body>
<div id="map"></div>
<script src="Food.js"></script>
<script src="Snake.js"></script>
<script src="Game.js"></script>
<script>
var map = document.getElementById("map");
var game = new Game(map);
game.init();
</script>
</body>
</html>
Food.js内容：
(function(){
function Food(width,height,top,left,background){
this.width = width || 20;
this.height = height || 20;
this.top = top || 0 ;
this.left = left || 0;
this.background = background || "green";
}
var newFood = null;
Food.prototype.init = function(map){
removeFood(map);
newFood = document.createElement("div");
newFood.style.width = this.width + "px";
newFood.style.height = this.height + "px";
newFood.style.background = this.background;
this.top = parseInt(Math.random()*(map.offsetHeight-this.height)/this.height)*this.height;
this.left = parseInt(Math.random()*(map.offsetWidth-this.width)/this.width)*this.width;
newFood.style.top = this.top + "px";
newFood.style.left = this.left + "px";
newFood.style.position = "absolute";
map.appendChild(newFood);
}
function removeFood(map){
if(newFood){
map.removeChild(newFood);
}
}
window.Food = Food;
})();
Snake.js内容：
(function(){
function Snake(width,height,direction){
this.width = width ||20;
this.height = height || 20;
this.direction = direction || "right";
this.body = [
{top:1,left: 3,color: "red"},
{top:1,left: 2,color: "gold"},
{top:1,left: 1,color: "gold"}
]
}
var newSnake = [];
Snake.prototype.init = function(map) {
removeSnake(map);
for (var i = 0; i < this.body.length; i++) {
var snake = document.createElement("div");
snake.style.width =this.width+ "px";
snake.style.height= this.height +"px";
snake.style.background = this.direction;
snake.style.position ="absolute";
snake.style.top = this.body[i].top*this.height +"px";
snake.style.left = this.body[i].left*this.width+ "px";
snake.style.background = this.body[i].color;
map.appendChild(snake);
newSnake.push(snake);
}
}
Snake.prototype.move = function(map,food){
//移动过程中，删除原来的，创建新的；中间加上位置移动
removeSnake(map);
for(var j=this.body.length-1;j>=1;j--){
this.body[j].left = this.body[j-1].left;
this.body[j].top = this.body[j-1].top;
}
switch(this.direction){
case "right":
this.body[0].left +=1;
break;
case "left":
this.body[0].left -=1;
break;
case "top":
this.body[0].top -=1;
break;
case "bottom":
this.body[0].top +=1;
}
//移动过程中，如果蛇头的位置同食物相同，则1、创建新食物 2、蛇身体增加一部分
var last = this.body[this.body.length-1];
var x = this.body[0].left*food.width;
var y = this.body[0].top * food.height;
if(x == food.left && y == food.top){
food.init(map);
var newBo = {
top: last.top,
left:last.left,
color:"gold"
}
this.body.push(newBo);
}
this.init(map);
}
function removeSnake(map){
for(var i=0;i<newSnake.length;){
map.removeChild(newSnake[i]);
newSnake.shift();
}
}
window.Snake = Snake;
})();
Game.js内容：
(function(){
function Game(map){
var food = new Food();
this.food = food;
var snake = new Snake();
this.snake = snake;
this.map = map;
}
Game.prototype.init= function(){
this.snake.init(this.map);
this.food.init(this.map);
snakeMove(this.map,this.food,this.snake);
changeDire(this.snake);
}
function snakeMove(map,food,snake){
//设置定时器，蛇移动
timer = setInterval(function(){
snake.move(map,food);
//判断蛇头位置有没有超出范围
var x = map.offsetWidth/parseInt(food.width) -1;
var y = map.offsetHeight/parseInt(food.height) -1;
if(snake.body[0].left<0 || snake.body[0].left>x){
clearInterval(timer);
alert("Game over");
}
if(snake.body[0].top<0 || snake.body[0].top>y){
clearInterval(timer);
alert("Game over");
}
},200);
}
//根据输入值改变方向
function changeDire(snake){
document.onkeydown = function(event){
event = event || window.event;
var num = event.keyCode;
switch(num){
case 37:snake.direction ="left";break;
case 38:snake.direction = "top";break;
case 39:snake.direction = "right";break;
case 40:snake.direction = "bottom";break;
}
}
}
window.Game = Game;
})();
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