你的位置:首页 > Java教程

[Java教程]贪吃蛇小游戏(含详细思路)


自己写的一个简陋的贪吃蛇游戏,源代码如下:

 1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4   <meta charset="UTF-8"> 5   <title>贪吃蛇小游戏</title> 6   <style> 7 *{margin:0; padding:0;} 8 header { 9   display: block; 10   margin: 0 auto; 11   width: 500px; 12   text-align: center; 13 } 14 header h1 { 15   font-family: Arial; 16   font-weight: bold; 17 } 18 header #newGameButton { 19   display: block; 20   margin: 20px auto; 21   width: 100px; 22   padding: 10px 10px; 23   background-color: #8f7a66; 24   font-family: Arial; 25   color: white; 26   border-radius: 10px; 27   text-decoration: none; 28 } 29 header #newGameButton:hover { 30   background-color: #9f8b77; 31 } 32 header p { 33   font-family: Arial; 34   font-size: 25px; 35   margin: 20px auto; 36 } 37 canvas{ 38   display:block;  39   border:medium double black; 40   margin:4px auto; 41 } 42   </style> 43 </head> 44 <body> 45   <header> 46     <h1>贪吃蛇小游戏</h1> 47     <a href="javascript:newgame();" id="newGameButton">New Game</a> 48     <p>score:<span id="score">0</span></p> 49   </header> 50   <canvas id="canvas"> 51     Your browser doesn't support the <code>canvas</code> element. 52   </canvas> 53   <script> 54   var CANVAS = document.getElementById("canvas"); 55 var CTX = CANVAS.getContext("2d"); 56 var SNAKE = new Array();  //用队列模拟蛇身 57 var DIR = "right";        //用来控制蛇头的方向 58 var SIZE = 20;        //蛇身的宽度 59 var FOODX = 0;      //食物的x坐标 60 var FOODY = 0;      //食物的y坐标 61 var HEADX = 0;    //蛇头的x坐标 62 var HEADY = 0;    //蛇头的y坐标 63 var MAXWIDTH = 200;    //画布的高度 64 var MAXHEIGHT = 200;  //画布的宽度 65 var TIME = 400;      //蛇的速度 66 var SCORE = 0;      //计算玩家分数 67 var interval = null; 68  69 CANVAS.width = MAXWIDTH; 70 CANVAS.height = MAXHEIGHT; 71  72 window.onload = function(){ 73   newgame(); 74 }; 75 document.getElementById("newGameButton").click(function(){ 76   newgame(); 77 }); 78 function newgame(){ 79   SNAKE = [];    //用队列模拟蛇身 80   DIR = "right";  //用来控制蛇头的方向 81   HEADX = 0;    //蛇头的x坐标 82   HEADY = 0;    //蛇头的y坐标 83   SCORE = 0; 84   window.clearInterval(interval); 85   interval = null; 86   //初始化画布 87   CTX.clearRect(0, 0, MAXWIDTH, MAXHEIGHT); 88   //画一条蛇 89   drawSnake(); 90   //放置食物 91   setFood(); 92   //移动蛇 93   interval = window.setInterval(move, TIME); 94  95 } 96 function move(){ 97   switch(DIR){ 98     case "up":HEADY = HEADY-SIZE;break; 99     case "right":HEADX = HEADX+SIZE;break;100     case "down":HEADY = HEADY+SIZE;break;101     case "left":HEADX = HEADX-SIZE;break;102   }103   if(HEADX>MAXWIDTH-SIZE || HEADY>MAXHEIGHT-SIZE || HEADX<0 || HEADY<0){104     alert("你的分数为:"+SCORE+"分,继续努力吧!失败原因:碰壁了.....");105     window.location.reload();106   }107   for(var i=1;i<SNAKE.length;i++){108     if(SNAKE[i][0] == SNAKE[0][0] && SNAKE[i][1] == SNAKE[0][1]){109       alert("你的分数为:"+SCORE+"分,继续努力吧!失败原因:撞到自己了.....");110       window.location.reload();111     }112   }113   if(SNAKE.length == MAXWIDTH *MAXHEIGHT){114     alert("好厉害!么么哒~");115     window.location.reload();116   }117   moveIn(HEADX, HEADY);//移动一格118 }119 document.onkeydown = function(e) { //改变蛇方向120   var code = e.keyCode - 37;121   switch(code){122     case 1 : DIR = "up";break;//上123     case 2 : DIR = "right";break;//右124     case 3 : DIR = "down";break;//下125     case 0 : DIR = "left";break;//左126   }127 }128 //=============================画一条蛇=======================================================129 function drawSnake(){130   CTX.fillStyle = "black";131   //画蛇头132   CTX.fillRect (HEADX, HEADY, SIZE, SIZE);133   SNAKE.push([HEADX, HEADY]);134   135   //画蛇身136   switch(DIR){137     case "up": 138       drawBody(HEADX, HEADY + SIZE, HEADX, HEADY + 2 * SIZE);139       break;140     case "right": 141       drawBody(HEADX - SIZE, HEADY, HEADX - 2 * SIZE, HEADY);142       break;143     case "down": 144       drawBody(HEADX, HEADY - SIZE, HEADX, HEADY - 2 * SIZE);145       break;146     case "left": 147       drawBody(HEADX + SIZE, HEADY, HEADX + 2 * SIZE, HEADY);148       break;149   }150 }151 function drawBody(x1, y1, x2, y2){152   CTX.fillRect (x1, y1, SIZE, SIZE); 153   CTX.fillRect (x2, y2, SIZE, SIZE); 154   SNAKE.push([x1, y1]);155   SNAKE.push([x2, y2]);156 }157 //===========================放置食物==============================158 function setFood(){159   do{160     FOODX = SIZE * Math.floor(Math.random() * MAXWIDTH / SIZE);161     FOODY = SIZE * Math.floor(Math.random() * MAXHEIGHT / SIZE);162   }while(foodInSnake());163   CTX.fillStyle = "red";164   CTX.fillRect (FOODX, FOODY, SIZE, SIZE);165 }166 function foodInSnake(){167   for (var i = 0; i < SNAKE.length; i++) {168     if(FOODX == SNAKE[i][0] && FOODY == SNAKE[i][1]){169       return true;170     }171   }172   return false;173 }174 //========================================移动一格===========================175 function moveIn(x, y){176   CTX.fillStyle = "black";177   CTX.fillRect(x, y, SIZE, SIZE);//重画蛇头  178   //把新蛇头添加到 SNAKE 数组179   var newSnake = [[x, y]];180   SNAKE = newSnake.concat(SNAKE);181 182   if(false == eatFood()){//如果没吃到食物,减少一格蛇尾  183     var snakeTail = SNAKE.pop();//获得蛇尾位置184     CTX.clearRect(snakeTail[0], snakeTail[1], SIZE, SIZE);//去掉蛇尾  185   }186 }187 function eatFood(){188   if(HEADX == FOODX && HEADY == FOODY){189     CTX.fillStyle = "block";190     CTX.fillRect (FOODX, FOODY, SIZE, SIZE);191 192     setFood();193     SCORE++;194     //$("#score").text(SCORE);195     document.getElementById("score").innerHTML = SCORE;196     return true;197   }198   return false;199 }200 201   </script>202 </html>

查看代码

效果图:

思路:

function newgame(){  重置蛇和分数的数据;  清除interval;  初始化画布;  画一条蛇;  放置食物;  使用定时器(setInterval)使蛇移动(move函数);}function move(){  根据方向改变蛇头下一格将要到达的位置;  判断游戏是否结束,以及显示结束的原因(包含输赢);  蛇移动一格(moveIn函数);}对键盘的方向键作监控,当改变方向时,修改全局变量DIR的值(用于存储方向);function moveIn(){  在蛇头的前一格增加一格作为新的蛇头,并将蛇头的坐标作为第一个元素加入到代表蛇的数组中;  if(没吃到食物){    删除一格蛇尾,在画布中做相应改变;  }}

欢迎各位试玩和纠错~(*^__^*)

 需要注意的是,如果需要在JS中设定canvas中的宽度和高度,和设置其他CSS属性略有不同。CANVAS.width = MAXWIDTH;CANVAS.height = MAXHEIGHT;