Comment implémenter Snake Game dans le programme WeChat Mini

<!--snake.wxml-->
<view class="control" bindtouchstart="tapStart" bindtouchmove="tapMove" bindtouchend="tapEnd">
<view class="score">
  <view class="title">snake</view>
  <view class="scoredetail">
    <view class="scoredesc">得分</view>
    <view class="scorenumber">{{score}}</view>
  </view>
  <view class="scoredetail">
    <view class="scoredesc">历史最高</view>
    <view class="scorenumber">{{maxscore}}</view>
  </view>
</view>
<view class="ground">
  <view wx:for="{{ground}}" class="rows" wx:for-item="cols">
    <view wx:for="{{cols}}" class="block block_{{item}}" >
    </view>
  </view>
</view>
<modal class="modal" hidden="{{modalHidden}}" no-cancel bindconfirm="modalChange">
 <view> 游戏结束，重新开始吗？ </view>
</modal>
</view>

//snake.js
var app = getApp();
Page({
  data:{
    score: 0,//比分
    maxscore: 0,//最高分
    startx: 0,
    starty: 0,
    endx:0,
    endy:0,//以上四个做方向判断来用
    ground:[],//存储操场每个方块
    rows:28,
    cols:22,//操场大小
    snake:[],//存蛇
    food:[],//存食物
    direction:'',//方向
    modalHidden: true,
    timer:''
  } ,
  onLoad:function(){
    var maxscore = wx.getStorageSync('maxscore');
    if(!maxscore) maxscore = 0
    this.setData({
    maxscore:maxscore
    });
    this.initGround(this.data.rows,this.data.cols);//初始化操场
    this.initSnake(3);//初始化蛇
    this.creatFood();//初始化食物
    this.move();//蛇移动
  },
  //计分器
  storeScore:function(){
   if(this.data.maxscore < this.data.score){
   this.setData({
    maxscore:this.data.score
    })
    wx.setStorageSync(&#39;maxscore&#39;, this.data.maxscore)
   }
 },
 //操场
  initGround:function(rows,cols){
    for(var i=0;i<rows;i++){
      var arr=[];
      this.data.ground.push(arr);
      for(var j=0;j<cols;j++){
        this.data.ground[i].push(0);
      }
    }
  },
  //蛇
  initSnake:function(len){
    for(var i=0;i<len;i++){
      this.data.ground[0][i]=1;
      this.data.snake.push([0,i]);
    }
  },
  //移动函数
  move:function(){
    var that=this;
    this.data.timer=setInterval(function(){
      that.changeDirection(that.data.direction);
      that.setData({
        ground:that.data.ground
      });
    },400);
  },
  tapStart: function(event){
    this.setData({
      startx: event.touches[0].pageX,
      starty: event.touches[0].pageY
      })
  },
  tapMove: function(event){
    this.setData({
      endx: event.touches[0].pageX,
      endy: event.touches[0].pageY
      })
  },
  tapEnd: function(event){
    var heng = (this.data.endx) ? (this.data.endx - this.data.startx) : 0;
    var shu = (this.data.endy) ? (this.data.endy - this.data.starty) : 0;
    if(Math.abs(heng) > 5 || Math.abs(shu) > 5){
      var direction = (Math.abs(heng) > Math.abs(shu)) ? this.computeDir(1, heng):this.computeDir(0, shu);
      switch(direction){
      case &#39;left&#39;:
        if(this.data.direction==&#39;right&#39;)return;
        break;
      case &#39;right&#39;:
        if(this.data.direction==&#39;left&#39;)return;
        break;
      case &#39;top&#39;:
        if(this.data.direction==&#39;bottom&#39;)return;
        break;
      case &#39;bottom&#39;:
        if(this.data.direction==&#39;top&#39;)return;
        break;
      default:
    }
    this.setData({
    startx:0,
    starty:0,
    endx:0,
    endy:0,
    direction:direction
    })
  }
  },
  computeDir: function(heng, num){
  if(heng) return (num > 0) ? &#39;right&#39; : &#39;left&#39;;
  return (num > 0) ? &#39;bottom&#39; : &#39;top&#39;;
  },
  creatFood:function(){
    var x=Math.floor(Math.random()*this.data.rows);
    var y=Math.floor(Math.random()*this.data.cols);
    var ground= this.data.ground;
    ground[x][y]=2;
    this.setData({
      ground:ground,
      food:[x,y]
    });
  },
  changeDirection:function(dir){
    switch(dir){
    case &#39;left&#39;:
      return this.changeLeft();
      break;
    case &#39;right&#39;:
      return this.changeRight();
      break;
    case &#39;top&#39;:
      return this.changeTop();
      break;
    case &#39;bottom&#39;:
      return this.changeBottom();
      break;
    default:
    }
  },
  changeLeft:function(){
    var arr=this.data.snake;
    var len=this.data.snake.length;
    var snakeHEAD=arr[len-1][1];
    var snakeTAIL=arr[0];
    var ground=this.data.ground;
    ground[snakeTAIL[0]][snakeTAIL[1]]=0; 
    for(var i=0;i<len-1;i++){
        arr[i]=arr[i+1];  
    };
    var x=arr[len-1][0];
    var y=arr[len-1][1]-1;
    arr[len-1]=[x,y];
      this.checkGame(snakeTAIL);
    for(var i=1;i<len;i++){
      ground[arr[i][0]][arr[i][1]]=1;
    } 
  this.setData({
        ground:ground,
      snake:arr
    });
    return true;
  },
  changeRight:function(){
    var arr=this.data.snake;
    var len=this.data.snake.length;
    var snakeHEAD=arr[len-1][1];
    var snakeTAIL=arr[0];
    var ground=this.data.ground;
    ground[snakeTAIL[0]][snakeTAIL[1]]=0; 
    for(var i=0;i<len-1;i++){
        arr[i]=arr[i+1];  
    };
    var x=arr[len-1][0];
    var y=arr[len-1][1]+1;
    arr[len-1]=[x,y];
    this.checkGame(snakeTAIL);
    for(var i=1;i<len;i++){
      ground[arr[i][0]][arr[i][1]]=1;
    } 
    this.setData({
        ground:ground,
      snake:arr
    });
  //  var y=this.data.snake[0][1];
  //  var x=this.data.snake[0][0];
  //   this.data.ground[x][y]=0;
  //   console.log(this.data.ground[x]);
  //   console.log(this.data.snake);
  //   for(var i=0;i<this.data.snake.length-1;i++){
  //     this.data.snake[i]=this.data.snake[i+1];
  //   }
  //   this.data.snake[this.data.snake.length-1][1]++;
  //   for(var j=1;j<this.data.snake.length;j++){
  //     this.data.ground[this.data.snake[j][0]][this.data.snake[j][1]]=1;
  //   }
    return true;
  },
  changeTop:function(){
    var arr=this.data.snake;
    var len=this.data.snake.length;
    var snakeHEAD=arr[len-1][1];
    var snakeTAIL=arr[0];
    var ground=this.data.ground;
    ground[snakeTAIL[0]][snakeTAIL[1]]=0; 
    for(var i=0;i<len-1;i++){
        arr[i]=arr[i+1];  
    };
    var x=arr[len-1][0]-1;
    var y=arr[len-1][1];
    arr[len-1]=[x,y];
      this.checkGame(snakeTAIL);
    for(var i=1;i<len;i++){
      ground[arr[i][0]][arr[i][1]]=1;
    } 
    this.setData({
      ground:ground,
      snake:arr
    });
    return true;
  },
  changeBottom:function(){
    var arr=this.data.snake;
    var len=this.data.snake.length;
    var snakeHEAD=arr[len-1];
    var snakeTAIL=arr[0];
    var ground=this.data.ground;
    ground[snakeTAIL[0]][snakeTAIL[1]]=0; 
    for(var i=0;i<len-1;i++){
        arr[i]=arr[i+1];  
    };
    var x=arr[len-1][0]+1;
    var y=arr[len-1][1];
    arr[len-1]=[x,y];
    this.checkGame(snakeTAIL);
    for(var i=1;i<len;i++){
      ground[arr[i][0]][arr[i][1]]=1;
    } 
    this.setData({
      ground:ground,
      snake:arr
    });
    return true;
  },
  checkGame:function(snakeTAIL){
    var arr=this.data.snake;
    var len=this.data.snake.length;
    var snakeHEAD=arr[len-1];
    if(snakeHEAD[0]<0||snakeHEAD[0]>=this.data.rows||snakeHEAD[1]>=this.data.cols||snakeHEAD[1]<0){
        clearInterval(this.data.timer);
          this.setData({
          modalHidden: false,
            }) 
    }
    for(var i=0;i<len-1;i++){
      if(arr[i][0]==snakeHEAD[0]&&arr[i][1]==snakeHEAD[1]){
        clearInterval(this.data.timer);
          this.setData({
            modalHidden: false,
          })
      }
    }
    if(snakeHEAD[0]==this.data.food[0]&&snakeHEAD[1]==this.data.food[1]){
      arr.unshift(snakeTAIL);
      this.setData({
        score:this.data.score+10
      });
      this.storeScore();
      this.creatFood();
    }
  },
  modalChange:function(){
  this.setData({
      score: 0,
    ground:[],
    snake:[],
      food:[],
      modalHidden: true,
      direction:&#39;&#39;
  })
  this.onLoad();
  }
});