我创建了三个圆圈，并使其在不使用HTML画布的情况下从墙反弹。现在，我希望两个圆彼此碰撞并以相反的方向移动这些圆。我试图通过检查其位置来检测碰撞，但是它不起作用。我不知道哪里出了问题。 这是我的代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>Bounce Ball</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
.circle{
height: 50px;
width: 50px;
position: absolute;
border-radius: 50%;
}
.container {
height: 300px;
width: 300px;
background-color: skyblue;
position: relative;
}
</style>
</head>
<body>
<div class ="container" id ="container">
<div class="circle" id = "circle1" style="background-color:black;
height: 50px; width: 50px;top:0; left:0"></div>
<div class="circle" id ="circle2" style="background-color:rgb(197, 100,
100);height: 50px; width: 50px;top:200px;left: 150px"></div>
<div class="circle" id ="circle3" style="background-color:brown;height:
50px;width: 50px;top:50px;left: 640px"></div>
</div>
<script>
var container = document.getElementById("container");
container.style.width="700px";
container.style.height = "300px";
var balls = document.getElementsByClassName("circle");
for(var i=0; i <balls.length; i++){
var speed={x:3,y:-3}
setInterval(draw, 50 , balls[i], speed);
}
function draw(ball, speed) {
if(parseInt(ball.style.left) > (parseInt(container.style.width)-
parseInt(ball.style.width)) || (parseInt(ball.style.left) <0) ){
speed.x = -speed.x;
}
ball.style.left = parseInt(ball.style.left) + speed.x + 'px';
if(parseInt(ball.style.top) > (parseInt(container.style.height)-
parseInt(ball.style.height)) || (parseInt(ball.style.top) <0)){
speed.y = -speed.y;
}
ball.style.top = parseInt(ball.style.top) + speed.y + 'px';
//for colliding two circles
for(var i =0 ; i <= balls.length-1; i++){
for(var j = i + 1; j < balls.length; j++){
if(parseInt(balls[i].style.left) +
parseInt(balls[i].style.width) ==
parseInt(balls[j].style.left) ||
parseInt(balls[j].style.left) +
parseInt(balls[j].style.width) ==
parseInt(balls[i].style.left) &&
parseInt(balls[i].style.top) +
parseInt(balls[i].style.height) ==
parseInt(balls[j].style.top) || parseInt(balls[j].style.top)
+ parseInt(balls[j].style.height) ==
parseInt(balls[i].style.top)) {
speed.x = - speed.x;
speed.y = -speed.y;
}
ball[i].style.left = parseInt(ball[i].style.left) +
speed.x + 'px';
ball[j].style.left = parseInt(ball[j].style.left) +
speed.x + 'px';
ball[i].style.top = parseInt(ball[i].style.top) +
speed.y + 'px';
ball[j].style.top = parseInt(ball[j].style.top) +
speed.y + 'px';
}
}
}
</script>
</body>
</html>
答案 0 :(得分：1)
我建议尽可能将其移入javascript变量，这样您就不必为每个参数都查阅HTML。
您有很多错别字，其中speed.x = - speed.x;就是您的意思speed.x = -speed.x;，而且如果没有任何注释或帮助函数来解释正在发生的情况，则很难阅读代码。
我已经修复了您的输入错误，并在下面的代码段中重组了代码。尝试检查开发者控制台typically by pressing F12，因为这将显示行号和严重性等级的代码错误。
在下面的代码段中，我尝试将参数移动到JavaScript中以显示其工作原理，同时仍将一些参数保留在HTML节点上：
//Basic properties
var width = 700;
var height = 300;
//Get container
var container = document.getElementById("container");
// Set dimensions
container.style.width = width + "px";
container.style.height = height + "px";
//Load balls
var balls = Array.prototype.slice.call(document.getElementsByClassName("circle"))
.map(function(ball) {
return {
HTMLNode: ball,
xPos: parseInt(ball.style.left),
yPos: parseInt(ball.style.top),
xAcc: 3,
yAcc: -3,
size: 50
};
});
//Utility functions
function angleBetween(x1, y1, x2, y2) {
return Math.atan2(y2 - y1, x2 - x1);
}
function distanceBetween(x1, y1, x2, y2) {
return Math.abs(y2 - y1) + Math.abs(x2 - x1);
}
//Draw function
function draw() {
//Loop through balls
for (var ballIndex1 = 0; ballIndex1 < balls.length; ballIndex1++) {
var ball1 = balls[ballIndex1];
//Collide with horisontal wall
if (ball1.xPos > width - ball1.size || ball1.xPos < 0) {
ball1.xAcc = -ball1.xAcc;
}
//Collide with vertical wall
if (ball1.yPos > height - ball1.size || ball1.yPos < 0) {
ball1.yAcc = -ball1.yAcc;
}
//Collide with other balls
for (var ballIndex2 = ballIndex1 + 1; ballIndex2 < balls.length; ballIndex2++) {
var ball2 = balls[ballIndex2];
//Test within collision distance
if (distanceBetween(ball1.xPos, ball1.yPos, ball2.xPos, ball2.yPos) > ball1.size) {
continue;
}
//Get angle of collision
var angle = angleBetween(ball1.xPos, ball1.yPos, ball2.xPos, ball2.yPos);
//Apply force to acceleration
ball1.xAcc = -Math.cos(angle) * 3;
ball2.xAcc = -ball1.xAcc;
ball1.yAcc = -Math.sin(angle) * 3;
ball2.yAcc = -ball1.yAcc;
}
//Apply acceleration to position
ball1.yPos += ball1.yAcc;
ball1.xPos += ball1.xAcc;
//Apply to node
ball1.HTMLNode.style.left = ball1.xPos + "px";
ball1.HTMLNode.style.top = ball1.yPos + "px";
}
}
//Start simulation
setInterval(draw, 1000 / 60);.circle {
position: absolute;
border-radius: 50%;
height: 50px;
width: 50px;
}
.container {
height: 300px;
width: 300px;
background-color: skyblue;
position: relative;
}<div class="container" id="container">
<div class="circle" id="circle1" style="background-color:black;
top:0; left:0"></div>
<div class="circle" id="circle2" style="background-color:rgb(197, 100,
100);top:200px;left: 150px"></div>
<div class="circle" id="circle3" style="background-color:brown;top:50px;left: 640px"></div>
</div>