javascript实现贪吃蛇经典游戏
js面向对象编程之贪吃蛇,供大家参考,具体内容如下
首先:面向对象编程,我们要找到项目中具体的对象,此处为(食物(food),蛇(snake),游戏本身(game))也可不把游戏本身作为对象,逻辑体现出来即可。
接着分析每个对象的具体的属性及方法:
1)food 对象:属性有:位置,大小,颜色;方法有:渲染在页面,随机不同位置生成;
2)snake对象:属性有:位置,大小,总节数(计分方便),颜色;方法有:渲染在页面,移动(移动过程中判断其它)。
3)game对象:游戏逻辑的编写;
ok 开敲:
1)简单的静态页面编写(地图)
(1)html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="css/index.css" > <script src="js/food.js"></script> <script src="js/snake.js"></script> <script src="js/game.js"></script> <script src="js/main.js"></script> <title>贪吃蛇</title> </head> <body> <div class="map"></div> </body> </html>
(2)css(如果用边框来作为限制的边界,那么box-sizing属性是必不可少的(以免食物和蛇头坐标之间存在误差))
* { margin: 0; padding: 0; } .map { position: relative; height: 600px; width: 800px; border: 1px solid #333; margin: 0 auto; /* 盒子模型去除边框 */ box-sizing: border-box; }
2)food对象编写(细节处含注释)
//cwen加载页面所有元素 window.addEventListener('load', function() { //cwen自调用函数,开启一个新的作用域,避免命名冲突 (function() { //cwen定义全局变量 //实物数组 var elements = []; //cwen实物 function Food(options) { options = options || {}; this.x = options.x || 0; this.y = options.y || 0; this.width = options.width || 20; this.height = options.height || 20; this.color = options.color || 'yellow'; } //cwen随机数函数 function getRandom(min, max) { return Math.floor(Math.random() * (max - min + 1)) + min; } //cwen渲染 Food.prototype.render = function(map) { //删除之前的食物 remove(); //todo动态创建div实物 var div = document.createElement('div'); map.appendChild(div); //把div添加给数组 elements.push(div); //todo随机设置x,y的值(实物的位置)-----在map中生成随机位置 // ! 值 = Math.floor(Math.random() * 可能值得总数 + 第一个可能的值) this.x = getRandom(0, map.offsetWidth / this.width - 1) * this.width; this.y = getRandom(0, map.offsetHeight / this.height - 1) * this.height; div.style.position = 'absolute'; div.style.left = this.x + 'px'; div.style.top = this.y + 'px'; div.style.width = this.width + 'px'; div.style.height = this.height + 'px'; div.style.backgroundColor = this.color; } function remove() { //为了删除干净,从索引最大的开始循环删除 for (var i = elements.length - 1; i >= 0; i--) { //删除遍历到的div elements[i].parentNode.removeChild(elements[i]); //删除数组中的元素1)第几个开始,2)要删除个数 elements.splice(i, 1); } } //把Food开放出去 window.Food = Food; })() //cwen测试 // var map = document.querySelector('.map'); // var options = { x: 20, y: 20, width: 30, height: 30, color: 'green' }; // //todo不传值默认为自定义food // var food = new Food(); // food.render(map); })
3)snake对象编写()
window.addEventListener('load', function() { (function() { //记录蛇的每一节 var elements = []; //cwen立即执行函数,开启新的作用于,避免命名冲突 function Snake(options) { options = options || {}; //对象(蛇)每节的大小 this.width = options.width || 20; this.height = options.height || 20; //cwen蛇的总节数(计分) this.mark = options.mark || 0; //对象的移动方向 this.direction = options.direction || 'right'; //对象的身体(蛇节) this.kont = [{ x: 3, y: 2, color: 'red' }, { x: 2, y: 2, color: 'black' }, { x: 1, y: 2, color: 'black' }]; } //cwen渲染对象 Snake.prototype.render = function(map) { //移除之前的蛇 remove(); //循环输出对象的身体(蛇节) for (var i = 0, len = this.kont.length; i < len; i++) { var obj = this.kont[i]; var div = document.createElement('div'); map.appendChild(div); //将蛇节添加入数组 elements.push(div); //添加样式 div.style.position = 'absolute'; div.style.width = this.width + 'px'; div.style.height = this.height + 'px'; div.style.left = obj.x * this.width + 'px'; div.style.top = obj.y * this.height + 'px'; div.style.backgroundColor = obj.color; } } //cwen控制蛇移动的方法 //todo传参food,map 在game中调用move方法也要传入相应参数 Snake.prototype.move = function(food, map) { //控制蛇节的移动(当前蛇节到下一个蛇节的位置) for (var i = this.kont.length - 1; i > 0; i--) { this.kont[i].x = this.kont[i - 1].x; this.kont[i].y = this.kont[i - 1].y; } //判断并控制蛇头移动,判断蛇头移动方向 var head = this.kont[0]; switch (this.direction) { case 'right': head.x += 1; break; case 'left': head.x -= 1; break; case 'top': head.y -= 1; break; case 'bottom': head.y += 1; break; } //蛇头碰到食物时处理 // cwen判断蛇头是否和食物坐标重合 var headX = head.x * this.width; var headY = head.y * this.height; if (headX == food.x && headY == food.y) { //1,增加蛇节(找到最后一根蛇节,然后添加给创建的蛇数组) var last = this.kont[this.kont.length - 1]; this.kont.push({ x: last.x, y: last.y, color: last.color }); //cwen求出蛇节的总个数(计分) var mark = this.mark++; //2,重新渲染食物 food.render(map); } } //删除之前的蛇 function remove() { for (var i = elements.length - 1; i >= 0; i--) { elements[i].parentNode.removeChild(elements[i]); elements.splice(i, 1); } } //把Snake构造函数暴露出去 window.Snake = Snake; })() //测试 // var map = document.querySelector('.map'); // var snake = new Snake(); // snake.render(map); })
4)game对象编写,其中一个为无敌版(含细节注释)
window.addEventListener('load', function() { (function() { //改变计时器内this指向 var that; function Game(map) { // var options = { x: 20, y: 20, width: 30, height: 30, color: 'green' }; this.food = new Food(); this.snake = new Snake(); this.map = map; that = this; } //cwen渲染 Game.prototype.start = function() { // 1.把食物和蛇渲染到页面 this.food.render(this.map); this.snake.render(this.map); // 2.游戏逻辑编写 //让蛇动起来 //判断地图边界 // runSnake(); //todo判断玩法(两种模式,原理一样) goInput(); //通过键盘控制蛇头方向 //! keydown(); //蛇头碰到食物时处理 //在snake.js中判断 } function goInput() { var it = prompt('try:\n 经典玩法请按1\n 无敌玩法请输入(博主最帅)\n') if (it == 1) { runSnake(); keydown(); } else if (it == '博主最帅') { runSnake1(); keydown1(); } else { alert('you input could not be found!!!'); goInput(); } } //让蛇动起来 function runSnake() { var timeId = setInterval(function() { // var a = mark; that.snake.move(that.food, that.map); that.snake.render(that.map); //判断地图边界 var maxX = (that.map.offsetWidth) / that.snake.width; var maxY = (that.map.offsetHeight) / that.snake.height; var headX = that.snake.kont[0].x; var headY = that.snake.kont[0].y; if (headX < 0 || headX >= maxX) { alert('Game Over ' + '得分为 ' + that.snake.mark); clearInterval(timeId); } else if (headY < 0 || headY >= maxY) { alert('Game Over ' + '成绩为 ' + that.snake.mark); clearInterval(timeId); } }, 150) } //无敌版本蛇运动 function runSnake1() { var timeId1 = setInterval(function() { that.snake.move(that.food, that.map); that.snake.render(that.map); //判断地图边界 var maxX = (that.map.offsetWidth - that.snake.width) / that.snake.width; var maxY = (that.map.offsetHeight - that.snake.height) / that.snake.height; var headX = that.snake.kont[0].x; var headY = that.snake.kont[0].y; if (headX < 0) { that.snake.kont[0].x = (that.map.offsetWidth - that.snake.width) / that.snake.width; } else if (headX > maxX) { that.snake.kont[0].x = 0; } else if (headY < 0) { that.snake.kont[0].y = (that.map.offsetHeight - that.snake.height) / that.snake.height; } else if (headY > maxY) { that.snake.kont[0].y = 0; } }, 50) } //通过键盘控制蛇头方向 function keydown() { document.addEventListener('keydown', function(e) { //通过事件对象判断按了哪个键 37left,38top,39right,40bottom // console.log(e.keyCode); //其在走的同时按下反方向无用 if (e.keyCode == 37 && that.snake.direction != 'right') { that.snake.direction = 'left'; } else if (e.keyCode == 38 && that.snake.direction != 'bottom') { that.snake.direction = 'top'; } else if (e.keyCode == 39 && that.snake.direction != 'left') { that.snake.direction = 'right'; } else if (e.keyCode == 40 && that.snake.direction != 'top') { that.snake.direction = 'bottom'; } }); } function keydown1() { document.addEventListener('keydown', function(e) { //通过事件对象判断按了哪个键 37left,38top,39right,40bottom // console.log(e.keyCode); //无敌版本四面八方任你行 if (e.keyCode == 37) { that.snake.direction = 'left'; } else if (e.keyCode == 38) { that.snake.direction = 'top'; } else if (e.keyCode == 39) { that.snake.direction = 'right'; } else if (e.keyCode == 40) { that.snake.direction = 'bottom'; } }); } //把Game开放 window.Game = Game; })() })
5)main开启游戏
window.addEventListener('load', function() { (function(window, undefind) { //测试 var map = document.querySelector('.map'); var game = new Game(map); game.start(); })(window, undefined) })
last but not least
*建议把所有js文件写在同一个js文件中,可以大大提高加载速度。注意在每个立即执行函数前加上‘ ;',以免出错。
小编还为大家准备了精彩的专题:javascript经典小游戏汇总
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