javascript實現(xiàn)貪吃蛇經(jīng)典游戲
js面向?qū)ο缶幊讨澇陨撸┐蠹覅⒖迹唧w內(nèi)容如下
首先：面向?qū)ο缶幊蹋覀円业巾椖恐芯唧w的對象，此處為（食物（food），蛇（snake），游戲本身（game））也可不把游戲本身作為對象，邏輯體現(xiàn)出來即可。
接著分析每個對象的具體的屬性及方法：1）food 對象：屬性有：位置，大小，顏色；方法有：渲染在頁面，隨機不同位置生成；2）snake對象：屬性有：位置，大小，總節(jié)數(shù)（計分方便），顏色；方法有：渲染在頁面，移動（移動過程中判斷其它）。3）game對象：游戲邏輯的編寫；
ok 開敲：
1）簡單的靜態(tài)頁面編寫（地圖）
（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='http://www.b3g6.com/bcjs/css/index.css' > <script src='http://www.b3g6.com/bcjs/js/food.js'></script> <script src='http://www.b3g6.com/bcjs/js/snake.js'></script> <script src='http://www.b3g6.com/bcjs/js/game.js'></script> <script src='http://www.b3g6.com/bcjs/js/main.js'></script> <title>貪吃蛇</title></head><body> <div class='map'></div></body></html>
(2)css(如果用邊框來作為限制的邊界，那么box-sizing屬性是必不可少的（以免食物和蛇頭坐標(biāo)之間存在誤差）)
* { margin: 0; padding: 0;}.map { position: relative; height: 600px; width: 800px; border: 1px solid #333; margin: 0 auto; /* 盒子模型去除邊框 */ box-sizing: border-box;}
2）food對象編寫（細節(jié)處含注釋）
//cwen加載頁面所有元素window.addEventListener(’load’, function() { //cwen自調(diào)用函數(shù)，開啟一個新的作用域，避免命名沖突 (function() { //cwen定義全局變量 //實物數(shù)組 var elements = []; //cwen實物 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隨機數(shù)函數(shù) function getRandom(min, max) { return Math.floor(Math.random() * (max - min + 1)) + min; } //cwen渲染 Food.prototype.render = function(map) { //刪除之前的食物 remove(); //todo動態(tài)創(chuàng)建div實物 var div = document.createElement(’div’); map.appendChild(div); //把div添加給數(shù)組 elements.push(div); //todo隨機設(shè)置x,y的值（實物的位置）-----在map中生成隨機位置 // ! 值 = Math.floor(Math.random() * 可能值得總數(shù) + 第一個可能的值) 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() { //為了刪除干凈，從索引最大的開始循環(huán)刪除 for (var i = elements.length - 1; i >= 0; i--) { //刪除遍歷到的div elements[i].parentNode.removeChild(elements[i]); //刪除數(shù)組中的元素1）第幾個開始，2）要刪除個數(shù) elements.splice(i, 1); } } //把Food開放出去 window.Food = Food; })() //cwen測試 // var map = document.querySelector(’.map’); // var options = { x: 20, y: 20, width: 30, height: 30, color: ’green’ }; // //todo不傳值默認為自定義food // var food = new Food(); // food.render(map);})
3）snake對象編寫（）
window.addEventListener(’load’, function() { (function() { //記錄蛇的每一節(jié) var elements = []; //cwen立即執(zhí)行函數(shù)，開啟新的作用于，避免命名沖突 function Snake(options) { options = options || {}; //對象（蛇）每節(jié)的大小 this.width = options.width || 20; this.height = options.height || 20; //cwen蛇的總節(jié)數(shù)（計分） this.mark = options.mark || 0; //對象的移動方向 this.direction = options.direction || ’right’; //對象的身體（蛇節(jié)） this.kont = [{ x: 3, y: 2, color: ’red’ }, { x: 2, y: 2, color: ’black’ }, { x: 1, y: 2, color: ’black’ }]; } //cwen渲染對象 Snake.prototype.render = function(map) { //移除之前的蛇 remove(); //循環(huán)輸出對象的身體（蛇節(jié)） for (var i = 0, len = this.kont.length; i < len; i++) { var obj = this.kont[i]; var div = document.createElement(’div’); map.appendChild(div); //將蛇節(jié)添加入數(shù)組 elements.push(div); //添加樣式 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控制蛇移動的方法 //todo傳參food,map 在game中調(diào)用move方法也要傳入相應(yīng)參數(shù) Snake.prototype.move = function(food, map) { //控制蛇節(jié)的移動（當(dāng)前蛇節(jié)到下一個蛇節(jié)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; } //判斷并控制蛇頭移動，判斷蛇頭移動方向 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; } //蛇頭碰到食物時處理 // cwen判斷蛇頭是否和食物坐標(biāo)重合 var headX = head.x * this.width; var headY = head.y * this.height; if (headX == food.x && headY == food.y) { //1,增加蛇節(jié)(找到最后一根蛇節(jié)，然后添加給創(chuàng)建的蛇數(shù)組) var last = this.kont[this.kont.length - 1]; this.kont.push({ x: last.x, y: last.y, color: last.color }); //cwen求出蛇節(jié)的總個數(shù)（計分） var mark = this.mark++; //2，重新渲染食物 food.render(map); } } //刪除之前的蛇 function remove() { for (var i = elements.length - 1; i >= 0; i--) { elements[i].parentNode.removeChild(elements[i]); elements.splice(i, 1); } } //把Snake構(gòu)造函數(shù)暴露出去 window.Snake = Snake; })() //測試 // var map = document.querySelector(’.map’); // var snake = new Snake(); // snake.render(map);})
4）game對象編寫，其中一個為無敵版（含細節(jié)注釋）
window.addEventListener(’load’, function() { (function() { //改變計時器內(nèi)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.把食物和蛇渲染到頁面 this.food.render(this.map); this.snake.render(this.map); // 2.游戲邏輯編寫 //讓蛇動起來 //判斷地圖邊界 // runSnake(); //todo判斷玩法（兩種模式，原理一樣） goInput(); //通過鍵盤控制蛇頭方向 //! keydown(); //蛇頭碰到食物時處理 //在snake.js中判斷 } function goInput() { var it = prompt(’try:n 經(jīng)典玩法請按1n 無敵玩法請輸入(博主最帥)n’) if (it == 1) { runSnake(); keydown(); } else if (it == ’博主最帥’) { runSnake1(); keydown1(); } else { alert(’you input could not be found!!!’); goInput(); } } //讓蛇動起來 function runSnake() { var timeId = setInterval(function() { // var a = mark; that.snake.move(that.food, that.map); that.snake.render(that.map); //判斷地圖邊界 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 ’ + ’得分為 ’ + that.snake.mark); clearInterval(timeId); } else if (headY < 0 || headY >= maxY) { alert(’Game Over ’ + ’成績?yōu)?’ + that.snake.mark); clearInterval(timeId); } }, 150) } //無敵版本蛇運動 function runSnake1() { var timeId1 = setInterval(function() { that.snake.move(that.food, that.map); that.snake.render(that.map); //判斷地圖邊界 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) } //通過鍵盤控制蛇頭方向 function keydown() { document.addEventListener(’keydown’, function(e) { //通過事件對象判斷按了哪個鍵 37left,38top,39right,40bottom // console.log(e.keyCode); //其在走的同時按下反方向無用 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) { //通過事件對象判斷按了哪個鍵 37left,38top,39right,40bottom // console.log(e.keyCode); //無敵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開放 window.Game = Game; })()})
5）main開啟游戲
window.addEventListener(’load’, function() { (function(window, undefind) { //測試 var map = document.querySelector(’.map’); var game = new Game(map); game.start(); })(window, undefined)})
last but not least*建議把所有js文件寫在同一個js文件中，可以大大提高加載速度。注意在每個立即執(zhí)行函數(shù)前加上‘ ；’，以免出錯。
小編還為大家準(zhǔn)備了精彩的專題：javascript經(jīng)典小游戲匯總
以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持好吧啦網(wǎng)。
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