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How to use keyboard events to realize character walking in js
- 王林forward
- 2020-03-11 11:07:511866browse
Pictures used:
Rendering pictures:
（ Recommended tutorial: javascript tutorial)
Example code:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
html
{
background-color: deepskyblue;
}
div
{
width: 32px;
height: 32px;
background-image: url("img/Actor01-Braver03.png");
position: absolute;
}
</style>
</head>
<body>
<div></div>
<script>
var key=0;
var bool=false;
var speed=2;//每次行走的距离
var actor;//人物div
const HEIGHT=33;//人物的高
const WIDTH=32;//人物的宽
var arr=[1,3,2,0];//4排图像 代表 下 左 右 上
var num=0;
var jumpBool=false;
var actorSkinSpeed=8;
var jumpSpeed=-15;
init();
function init() {
window.addEventListener("keydown",keyHandler);
window.addEventListener("keyup",keyHandler);
actor=document.querySelector("div");
setInterval(animation,16);
//按键驱动不能实现 实现的是通过按键触发相应动画 实现我们的人物的帧动画 跳转
}
function keyHandler(e) {
bool=e.type==="keydown";
key=e.keyCode;
if(!bool){
num=0;
actor.style.backgroundPositionX=-num*WIDTH+"px";
}
if(key===32 && !jumpBool){//跳跃 空格驱动
jumpBool=true;
}
}
function animation() {
jump();
if(!bool)return;
walk();//单方向行走 实现
changeDirection();//方向确定时 内部行走的实现
}
function jump() {
if(!jumpBool)return;
jumpSpeed+=1;
if(jumpSpeed===15){
jumpBool=false;
jumpSpeed=-15;
return;
}
actor.style.top=actor.offsetTop+jumpSpeed+"px";
}
function changeDirection() {
actorSkinSpeed--;
if(actorSkinSpeed>0) return;
actorSkinSpeed=8;
num++;
if(num>3) num=0;
actor.style.backgroundPositionX=-num*WIDTH+"px";
}
function walk() {
switch (key){
case 37://左 ×1 第二排
actor.style.left=actor.offsetLeft-speed+"px";
actor.style.backgroundPositionY=-arr[0]*HEIGHT+"px";
break;
case 38://上 ×3 第四排
actor.style.top=actor.offsetTop-speed+"px";
actor.style.backgroundPositionY=-arr[1]*HEIGHT+"px";
break;
case 39://右 ×2 第三排
actor.style.left=actor.offsetLeft+speed+"px";
actor.style.backgroundPositionY=-arr[2]*HEIGHT+"px";
break;
case 40://下 ×0 第一排
actor.style.top=actor.offsetTop+speed+"px";
actor.style.backgroundPositionY=-arr[3]*HEIGHT+"px";
break;
}
}
</script>
</body>
</html>Recommended related video tutorial:javascript video tutorial
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