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    原生js实现贪食蛇小游戏的思路详解

    栏目:Linux/apache问题 时间:2019-11-26 16:26

    先不多说先上图

    下面是代码部分(这里你可以根据需要改变蛇头和身体还有食物的图片,然后默认的样式是使用纯颜色的如果没有更改我的背景图片的话------改这些图开始是想搞笑一下朋友哈哈哈,请不要在意哈),还有操作键是使用 ↑ ↓ ← → )

    <!DOCTYPE html>
    <html>
    <head lang="en">
      <meta charset="UTF-8">
      <title>贪食蛇</title>
      <style>
        .map {
          width: 800px;
          height: 600px;
          background-color: #ccc;
          position: relative;
          left: 50%;
          transform: translate(-50%);
        }
        #dv {
          color: whitesmoke;
          font-weight: 700;
          text-align: center;
          line-height: 50px;
          width: 150px;
          height: 50px;
          position: absolute;
          background-color: orange;
          border-radius: 10px;
          top: 50%;
          left: 50%;
          transform: translate(-50%);
          cursor: pointer;
        }
      </style>
    </head>
    <body>
      <div class="map">
        <div >开始游戏</div>
      </div>
      <script>
        //食物:是一个对象,有宽,有高,有颜色,有横纵坐标
        //自调用函数
        (function () {
          var element = []; //用来保存每个小方块食物的
          function Food(x, y, width, height, color) {
            this.x = x || 0;
            this.y = y || 0;
            this.width = width || 20;
            this.height = height || 20;
            this.color = color || "green";
          }
          //为原型添加初始化的方法(作用:在页面上显示这个食物)
          //因为食物要在地图上显示,所以,需要地图的这个参数(map--就是页面上的.class=map的这个div)
          Food.prototype.init = function (map) {
            //先删除这个小食物
            //外部无法访问,此函数在自调用函数里面
            remove();
            //创建div
            var div = document.createElement("div");
            //把div加到map里面
            map.appendChild(div);
            //获取div的样式
            div.style.width = this.width + "px";
            div.style.height = this.height + "px";
            div.style.backgroundColor = this.color;
            //脱离文档流
            div.style.position = "absolute";
            //横纵坐标先停止----随机产生
            this.x = parseInt(Math.random() * (map.offsetWidth / this.width)) * this.width;
            this.y = parseInt(Math.random() * (map.offsetHeight / this.height)) * this.height;
            div.style.left = this.x + "px";
            div.style.top = this.y + "px";
            //把div加入element数组中
            element.push(div);
            //改变食物的样式---改成自己喜欢的东西
            div.style.backgroundImage = "url(" + "../images/shi.png" + ")";
            div.style.backgroundRepeat = "no-repaet";
            div.style.backgroundSize = "cover";
          };
          //私有函数
          function remove() {
            for (var i = 0; i < element.length; i++) {
              var ele = element[i];
              //找到这个子元素的父级元素,然后删除这个子元素
              ele.parentNode.removeChild(ele);
              //再次把element中的这个子元素删除
              element.splice(i, 1);
            }
          }
          //把Food暴露给window,外部可以使用
          window.Food = Food;
        }());
        //自调用函数---小蛇
        (function () {
          //存放小蛇的每个身体部分
          var element = [];
          //小蛇的构造函数
          function Snake(width, height, driection) {
            this.width = width || 20;
            this.height = height || 20;
            //小蛇的身体
            this.body = [{
                x: 3,
                y: 2,
                color: "red"
              },
              {
                x: 2,
                y: 2,
                color: "orange"
              },
              {
                x: 1,
                y: 2,
                color: "orange"
              }
            ];
            //方向
            this.driection = driection || "right";
          }
          //为原型添加方法---小蛇初始化的方法
          Snake.prototype.init = function (map) {
            //先删除之前的小蛇
            remove();
            //循环遍历创建div
            for (var i = 0; i < this.body.length; i++) {
              //数组中的每个数组元素都是一个对象
              var obj = this.body[i];
              //创建div
              var div = document.createElement("div");
              //把div加入地图map中
              map.appendChild(div);
              //设置div的样式
              div.style.position = "absolute";
              div.style.width = this.width + "px";
              div.style.height = this.height + "px";
              //横纵坐标
              div.style.left = obj.x * this.width + "px";
              div.style.top = obj.y * this.height + "px";
              //背景颜色
              div.style.backgroundColor = obj.color;
              //方向还没定
              //把div加入到element数组中---目的是为了删除
              //把div加入数组中
              element.push(div);
              //更改头部的----变成图片
              if (i == 0) {
                div.style.backgroundImage = "url(" + "../images/tou_03.png" + ")";
                div.style.backgroundRepeat = "no-repaet";
                div.style.backgroundSize = "cover";
              }
              //更改尾巴的样式照片
              if (i != 0) {
                div.style.backgroundImage = "url(" + "../images/shi.png" + ")";
                div.style.backgroundRepeat = "no-repaet";
                div.style.backgroundSize = "cover";
              }
            }
          };
          //为原型添加方法---小蛇动起来
          Snake.prototype.move = function (food, map) {
            var i = this.body.length - 1;
            for (; i > 0; i--) {
              this.body[i].x = this.body[i - 1].x;
              this.body[i].y = this.body[i - 1].y;
            }
            //判断方向---改变小蛇的头的坐标位置
            switch (this.driection) {
              case "left":
                this.body[0].x -= 1;
                break;
              case "right":
                this.body[0].x += 1;
                break;
              case "top":
                this.body[0].y -= 1;
                break;
              case "bottom":
                this.body[0].y += 1;
                break;
            }
            //判断有没有吃到食物
            //小蛇的头的坐标和食物的坐标一致
            var headX = this.body[0].x * this.width;
            var headY = this.body[0].y * this.height;
            //判断小蛇的头和食物坐标是否相同
            if (headX == food.x && headY == food.y) {
              //获取小蛇的最后的尾巴
              var last = this.body[this.body.length - 1];
              //把最后的蛇尾复制一个,重新的加入到小蛇的body中
              this.body.push({
                x: last.x,
                y: last.y,
                color: last.color
              });
              //把食物删除,重新初始化食物
              food.init(map);
            }
          };
          //删除小蛇的私有函数
          function remove() {
            //获取数组
            var i = element.length - 1;
            for (; i >= 0; i--) {
              var ele = element[i];
              //从map地图上删除这个子元素div
              ele.parentNode.removeChild(ele);
              element.splice(i, 1);
            }
          }
          window.Snake = Snake;
        }());
        //自调用函数---游戏对象
        (function () {
          var that = null;
          //游戏的构造函数
          function game(map) {
            this.food = new Food(); //食物对象
            this.snake = new Snake(); //小蛇对象
            this.map = map; //地图
            that = this;
          }
          game.prototype.init = function () {
            //初始化游戏
            //食物初始化
            this.food.init(this.map);
            //小蛇初始化
            this.snake.init(this.map);
            that = this;
            document.getElementById("dv").onclick = function () {
              document.getElementById("dv").style.display = "none";
              //调用小蛇移动的方法
              that.runSnake(that.food, that.map);
              //调用按键的方法
              that.bindKey();
            }.bind(that);
          };
          //添加原型方法---设置小蛇可以自动跑起来
          game.prototype.runSnake = function (food, map) {
            //自动的去移动
            var time = 90;
            var fn = function () {
              //此时this是window
              //移动小蛇
              this.snake.move(food, map);
              //初始化小蛇
              this.snake.init(map);
              //横坐标的最大值
              var maxX = map.offsetWidth / this.snake.width;
              //纵坐标的最大值
              var maxY = map.offsetHeight / this.snake.height;
              //小蛇的头的坐标
              var headX = this.snake.body[0].x;
              var headY = this.snake.body[0].y;
              //判断 横坐标 有没撞墙
              if (headX < 0 || headX >= maxX) {
                //撞墙停止定时器
                clearInterval(timeId);
                alert("游戏结束");
                location.reload();
              }
              //判断 纵坐标 有没撞墙
              if (headY < 0 || headY >= maxY) {
                clearInterval(timeId);
                alert("游戏结束");
                location.reload();
              }
              //判断 小蛇的头部 有没有 撞到自己
              for (let i = 1; i < this.snake.body.length; i++) {
                let x = this.snake.body[i].x;
                let y = this.snake.body[i].y;
                if (headX === x && headY === y) {
                  clearInterval(timeId);
                  alert("游戏结束");
                  location.reload();
                }
              }
              //增加游戏难度,判断 到达一定数量的时候 加速
              switch (true) {
                case 5 <= this.snake.body.length && this.snake.body.length <= 10:
                  clearInterval(timeId);
                  time = 60;
                  timeId = setInterval(fn, time);
                  break;
                case 10 <= this.snake.body.length && this.snake.body.length <= 15:
                  clearInterval(timeId);
                  time = 40;
                  timeId = setInterval(fn, time);
                  break;
                case 15 <= this.snake.body.length:
                  clearInterval(timeId);
                  time = 30;
                  timeId = setInterval(fn, time);
                  break;
              }
              console.log(this.snake.body.length + "--" + "time:" + time);
            }.bind(that);
            //定时器小蛇自运动
            var timeId = setInterval(fn, time);
          };
          //添加原型方法---设置用户按键,改变小蛇移动的方向
          game.prototype.bindKey = function () {
            //获取用户的按键,改变小蛇的移动方向
            document.addEventListener("keydown", function (e) {
              //获取按键的值并进行判断是,改变小蛇移动的方向
              switch (e.keyCode) {
                //没有bind方法时此时的this指向的是documen
                case 37:
                  if (this.snake.driection != "right") {
                    this.snake.driection = "left";
                  }
                  break;
                case 38:
                  if (this.snake.driection != "bottom") {
                    this.snake.driection = "top";
                  }
                  break;
                case 39:
                  if (this.snake.driection != "left") {
                    this.snake.driection = "right";
                  }
                  break;
                case 40:
                  if (this.snake.driection != "top") {
                    this.snake.driection = "bottom";
                  }
                  break;
              }
            }.bind(that), false);
          };
          //把game暴露给window,外部就可以访问game对象
          window.game = game;
        }());
        //初始化游戏对象
        var gm = new game(document.querySelector(".map"));
        //初始化游戏---开始游戏
        gm.init();
      </script>
    </body>
    </html>