<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
canvas {
border: 1px solid #000000;
}
</style>
</head>
<body>
<canvas width="980" height="600" id="canvas"></canvas>
<script>
//初始化变量
var foods = new Array(); //存放食物坐标
var gameover = false; //游戏结束
var gridWidth = 10; //正方形长度
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d"); //构建画布
//食物定时器、蛇定时器、场景、蛇对象
var food_interval, snake_interval, Farm, Snake;
//方格对象
function node(x, y, w) {
var self = this;
self.x = x;
self.y = y;
self.w = w;
//食物初始化
self.foodInit = function() {
ctx.fillStyle = "#FF0000";
ctx.fillRect(self.x, self.y, self.w, self.w);
}
//蛇的初始化
self.snakeInit = function() {
ctx.fillStyle = "#000000";
ctx.strokeStyle = "#FFFFFF";
ctx.fillRect(x, y, w, w);
ctx.strokeRect(x, y, w, w);
}
//判断两个方块是否重合
self.equals = function(node) {
if (self.x == node.x && self.y == node.y) {
return true;
} else {
return false;
}
}
//清除格子 让格子跟背景颜色一样
self.clear = function() {
ctx.fillStyle = "#E8FFFF";
ctx.strokeStyle = "#E8FFFF";
ctx.fillRect(x, y, w, w);
ctx.strokeRect(x, y, w, w);
}
}
//创建场景对象
function farm() {
//保存作用域
var self = this;
ctx.fillStyle = "#E8FFFF"; //填充的场景颜色
ctx.fillRect(0, 0, canvas.width, canvas.height);
//增加食物的方法
self.addFood = function() {
if (gameover) {
return gameOver(); //游戏结束方法
} else {
//计算随机位置
var x = parseInt(canvas.width / gridWidth * Math.random()) * gridWidth;
var y = parseInt(canvas.height / gridWidth * Math.random()) * gridWidth;
//实例化一个方格对象
var food = new node(x, y, gridWidth);
//得到对象之后，要把食物画到界面上面
food.foodInit();
//追加到数组里面
foods.push(food);
}
}
}
//蛇对象
function snake(x, y, len, speed) {
var self = this;
self.init = function() {
self.len = len; //身体长度
self.nodes = new Array(); //蛇的身体数组
self.dir = "R"; //方向
self.speed = speed; //速度
//从右往左，逐格把蛇画出来
var nx = x,
ny = y; //蛇的坐标点
for (var i = 0; i < len; i++) {
//创建一个方格对象
var tmpNode = new node(nx, ny, gridWidth);
//把蛇的身体存放起来
self.nodes[i] = tmpNode;
//存放完了之后，把蛇画出来
tmpNode.snakeInit();
nx -= gridWidth; //往左边画
}
//让蛇动起来定时器
snake_interval = setInterval(self.move, self.speed);
//给蛇绑定方向按键
document.onkeydown = function(e) {
//按键的值
var code = e.keyCode;
//记录一下旧的方向
self.odir = self.dir;
switch (code) {
//一组方向键 一组字母 WASD
case 65:
self.dir = "L";
break;
case 87:
self.dir = "U";
break;
case 68:
self.dir = "R";
break;
case 83:
self.dir = "D";
break;
case 37:
self.dir = "L";
break;
case 38:
self.dir = "U";
break;
case 39:
self.dir = "R";
break;
case 40:
self.dir = "D";
break;
}
}
}
