碰撞检测

image-20240127161556531

通过对两个div周围的上下左右进行检查，判断是否碰到

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<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #box {
            width: 200px;
            height: 200px;
            background-color: gainsboro;
            position: absolute;
            left:50%;
            margin-left: -100px;
            top:50%;
            margin-top: -100px;
        }
        #move{
            width: 100px;
            height: 100px;
            background-color: red;
            position: absolute;
        }
    </style>
    <script>
        //鼠标按下，准备移动
        window.onload = function () {
            var box = document.getElementById("box")
            var move = document.getElementById("move")

            move.onmousedown = function(ev) {
                ev = ev || event;
                //移动div的left和top
                var t = ev.clientY - move.offsetTop;
                var l = ev.clientX - move.offsetLeft;
                document.onmousemove = function(ev) {
                    ev = ev || evnet;

                    var left = ev.clientX - l;
                    var top = ev.clientY - t;

                    move.style.left = left + "px";
                    move.style.top = top + "px"

                    //碰撞检测
                    if(left + move.offsetWidth < box.offsetLeft 
                    || left >box.offsetLeft + box.offsetWidth
                    || top + move.offsetHeight < box.offsetTop
                    || top > box.offsetTop + box.offsetHeight
                    ) {
                        console.log('no');
                        box.style.background = 'gainsboro'
                    } else {
                        console.log('yes');
                        box.style.background = 'orange'
                    }   
                }
                
            }
            move.onmouseup = function () {
                document.onmousemove = null;
            }
        }
    </script>
</head>

<body>
    <div id="box"></div>
    <div id="move"></div>
</body>

</html>