javascript实现贪吃蛇小练习
作者：余依忈
这篇文章主要为大家详细介绍了javascript实现贪吃蛇的小练习，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下
本文实例为大家分享了js实现贪吃蛇的具体代码，供大家参考，具体内容如下
游戏思路：
- 创建方块、控制按钮（showBlock）
- 方块移动（点击开始，不断创建并移除前面的方块，用到队列先进先出）
- 控制移动（doUp\doDown\doLeft\doRight，加入用键盘控制）
- 产生食物方块(generateFood)
- 吃到食物变长（当方块位置相同时，吃食物）
- 判断撞墙、撞到自己游戏结束
- 设置积分
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<style>
body {
margin: 0;
padding: 0;
}
.content {
width: 800px;
height: 400px;
background-color: gray;
display: absolute;
}
</style>
<div id="content" class="content">
</div>
<button onclick="start()">开始游戏</button>
<button onclick="doUp()">上</button>
<button onclick="doDown()">下</button>
<button onclick="doLeft()">左</button>
<button onclick="doRight()">右</button>
<div id="score">0</div>
<script>
//定义参数
var snackBlock = {};
snackBlock.top = 20;
snackBlock.left = 20;
var firstDiv = showBlock(snackBlock.left, snackBlock.top, "red");
var snackDivArray = [];//装方块的数组
snackDivArray.push(firstDiv);
var left = 1, right = 2, up = 3, down = 4;
var direction = right;
var food = generateFood();//生成食物
var hasEat = false;
var score = 0;
function generateFood() {
var left = getRandomNum(39);
var top = getRandomNum(19);
var foodBlock = showBlock(left, top, "pink");
foodBlock.left = left;
foodBlock.top = top;
return foodBlock;
}
function getRandomNum(max) {
return Math.round(Math.random() * max) * 20;
}
function start() {
var interval = setInterval(function () {
var newBlock = {};
switch (direction) {
case up:
newBlock.top = snackBlock.top - 20;
newBlock.left = snackBlock.left;
break;
case down:
newBlock.top = snackBlock.top + 20;
newBlock.left = snackBlock.left;
break;
case left:
newBlock.top = snackBlock.top;
newBlock.left = snackBlock.left - 20;
break;
case right:
newBlock.top = snackBlock.top;
newBlock.left = snackBlock.left + 20;
break;
}
var currentLeft = newBlock.left;
var currentTop = newBlock.top;
var eat = false;
//吃食物
if (currentLeft == food.left && currentTop == food.top) {
removeBlock(food);
food = generateFood();
eat = true;
hasEat = true;
score += 10;//吃一个加10分
document.getElementById("score").innerHTML = score;//写入div
}
snackBlock = newBlock;
//是否撞墙
if (currentLeft < 0 || currentLeft >= 800 || currentTop < 0 || currentTop >= 400) {
alert("game over!");
clearInterval(interval);
return;
}
if (eat == false) {
//移除尾巴
removeBlock(snackDivArray.shift(div));
}
//是否撞到自己
snackDivArray.forEach(function (item, index, array) {
if (item.top == currentTop && item.left == currentLeft) {
alert("game over!");
clearInterval(interval);
return;
}
});
//创建新的身体
var div = showBlock(newBlock.left, newBlock.top, "red");
div.left = newBlock.left;
div.top = newBlock.top;
snackDivArray.push(div);
}, 300);
}
//方向控制
function doUp() {
if (direction == down && hasEat) {
return;
}
direction = up;
}
function doDown() {
if (direction == up && hasEat) {
return;
}
direction = down;
}
function doRight() {
if (direction == left && hasEat) {
return;
}
direction = right;
}
function doLeft() {
if (direction == right && hasEat) {
return;
}
direction = left;
}
function showBlock(left, top, color) {//产生方块
var content = document.getElementById("content");
var snackDiv = document.createElement("div");
snackDiv.style.width = "20px";
snackDiv.style.height = "20px";
snackDiv.style.left = left + "px";
snackDiv.style.top = top + "px";
snackDiv.style.background = color;
snackDiv.style.position = "absolute";
content.appendChild(snackDiv);
return snackDiv;
}
function removeBlock(div) {//移除方块
div.parentNode.removeChild(div);
}
//键盘控制方向
document.onkeydown = function (e) {
if (e && e.keyCode == 38) {
doUp();
} else if (e && e.keyCode == 40) {
doDown();
} else if (e && e.keyCode == 37) {
doLeft();
} else if (e && e.keyCode == 39) {
doRight();
}
}
</script>
</body>
</html>
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