Javascript 帆布';fps无意中加速?
我正在根据在线教程的内容处理canvas元素,并构建了以下页面 这是我的标记:Javascript 帆布';fps无意中加速?,javascript,canvas,frame-rate,Javascript,Canvas,Frame Rate,我正在根据在线教程的内容处理canvas元素,并构建了以下页面 这是我的标记: <!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8" /> <title>Canvas Game</title> <link rel="stylesheet" href="style.css">
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>Canvas Game</title>
<link rel="stylesheet" href="style.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<script src="script.js"></script>
</head>
<body>
<header>
<h1>Cool Canvas Bouncing Effect!</h1>
<p>Which would you like to see bounce around?</p>
<input id="beachBallButton" type="button" value="Beach Ball" />
<input id="avatarButton" type="button" value="Avatar" />
</header>
<br />
<canvas id="myCanvas" width="600" height="400">
Your browser does not support canvas!
</canvas>
</body>
</html>
帆布游戏
酷帆布反弹效果!
你想看哪一个
您的浏览器不支持画布!
下面是我的JavaScript:
$(document).ready(function() {
const FPS;
var x = 0;
var y = 0;
var xDirection = 1;
var yDirection = 1;
var image = new Image();
image.src = null;
var canvas = document.getElementById('myCanvas');
var ctx = canvas.getContext('2d');
$('#avatarButton').click(function() {
x = 0;
y = 0;
FPS = 30;
image.src = 'avatar.png';
setInterval(draw, 1000 / FPS);
function draw() {
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.fillRect(0,0,canvas.width,canvas.height);
ctx.drawImage(image, x, y);
x += 1 * xDirection;
y += 1 * yDirection;
if (x >= 500)
{
x = 500;
xDirection = -1;
}
else if (x <= 0)
{
x = 0;
xDirection = 1;
}
if (y >= 300)
{
y = 300;
yDirection = -1;
}
else if (y <= 0)
{
y = 0;
yDirection = 1;
}
}
});
$('#beachBallButton').click(function() {
x = 0;
y = 0;
FPS = 60;
image.src = 'beachball.png';
setInterval(draw, 1000 / FPS);
function draw() {
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.fillRect(0,0,canvas.width,canvas.height);
ctx.drawImage(image, x, y);
x += 5 * xDirection;
y += 5 * yDirection;
if (x >= 450)
{
x = 450;
xDirection = -1;
}
else if (x <= 0)
{
x = 0;
xDirection = 1;
}
if (y >= 250)
{
y = 250;
yDirection = -1;
}
else if (y <= 0)
{
y = 0;
yDirection = 1;
}
}
});
});
$(文档).ready(函数(){
常数FPS;
var x=0;
var y=0;
var xDirection=1;
var yDirection=1;
var image=新图像();
image.src=null;
var canvas=document.getElementById('myCanvas');
var ctx=canvas.getContext('2d');
$(“#虚拟按钮”)。单击(函数(){
x=0;
y=0;
FPS=30;
image.src='avatar.png';
设定间隔(绘图,1000/FPS);
函数绘图(){
clearRect(0,0,canvas.width,canvas.height);
ctx.fillRect(0,0,canvas.width,canvas.height);
ctx.drawImage(图像,x,y);
x+=1*x方向;
y+=1*y方向;
如果(x>=500)
{
x=500;
xDirection=-1;
}
否则如果(x=300)
{
y=300;
y方向=-1;
}
否则,如果(y=450)
{
x=450;
xDirection=-1;
}
否则,如果(x=250)
{
y=250;
y方向=-1;
}
否则,如果(yMMM..const FPS;这是一个工作示例=>
只是对Alejandro所说的进行了一些“补充”(这是正确的),JS中没有常量。因此,您需要在开始时“声明”var FPS
此外,您必须设置一个“intervalID”变量,这是调用它时返回的变量。但是,在每次setInterval调用之前,您需要调用它(请注意,第一次调用时没有什么需要清除的)
哇,我怎么会错过尝试将常数指定为变量的机会呢。我从在线教程中改编了这篇文章,所以以前没有问题。xD谢谢!谢谢你对setInterval
的清晰解释,这真的很有帮助!Np朋友,很高兴听到它有帮助:)
var myInterval;
/* ... */
clearInterval(myInterval)
myInterval = setInterval(draw,1000/FPS)