碰撞检测

目录

• 代码实例
• 与简易拖拽的差异
• 下载源码链接

代码实例

<div id="box" style="background: #334;width: 100px;height: 100px;position: absolute;cursor: move;z-index: 999;"></div><div id="box2" style="background: green;width: 100px;height: 100px;position: absolute;top: 200px;left: 500px;"></div>(function () { var dragging = false var boxX, boxY, mouseX, mouseY, offsetX, offsetY var box = document.getElementById('box') var box2 = document.getElementById('box2') var box2X, box2Y // 鼠标按下的动作 box.onmousedown = down // 鼠标的移动动作 document.onmousemove = move // 释放鼠标的动作 document.onmouseup = up // 鼠标按下后的函数,e为事件对象 function down(e) { dragging = true // 获取元素所在的坐标 boxX = box.offsetLeft boxY = box.offsetTop // 获取元素box2所在的坐标 box2X = box2.offsetLeft box2Y = box2.offsetTop // 获取鼠标所在的坐标 mouseX = parseInt(getMouseXY(e).x) mouseY = parseInt(getMouseXY(e).y) // 鼠标相对元素左和上边缘的坐标 offsetX = mouseX - boxX offsetY = mouseY - boxY } // 鼠标移动调用的函数 function move(e){ if (dragging) { // 获取移动后的元素的坐标 var x = getMouseXY(e).x - offsetX var y = getMouseXY(e).y - offsetY // 计算可移动位置的大小， 保证元素不会超过可移动范围 var width = document.documentElement.clientWidth - box.offsetWidth var height = document.documentElement.clientHeight - box.offsetHeight // min方法保证不会超过右边界，max保证不会超过左边界 x = Math.min(Math.max(0, x), width) y = Math.min(Math.max(0, y), height) // 给元素及时定位 box.style.left = x + 'px' box.style.top = y + 'px' // 碰撞检测 // x坐标值的范围判断，y坐标值的范围判断 var judge_x = (x >= box2X - box2.offsetWidth) && (x <= box2X + box2.offsetWidth) var judge_y = (y >= box2Y - box2.offsetHeight) && (y <= box2Y + box2.offsetHeight) if (judge_x && judge_y) { console.log("碰撞到") } } } // 释放鼠标的函数 function up(e){ dragging = false } // 函数用于获取鼠标的位置 function getMouseXY(e){ var x = 0, y = 0 e = e || window.event if (e.pageX) { x = e.pageX y = e.pageY } else { x = e.clientX + document.body.scrollLeft - document.body.clientLeft y = e.clientY + document.body.scrollTop - document.body.clientTop } return { x: x, y: y } }})()

与简易拖拽的差异

简易拖拽的链接

碰撞检测

// 碰撞检测// x坐标值的范围判断，y坐标值的范围判断var judge_x = (x >= box2X - box2.offsetWidth) && (x <= box2X + box2.offsetWidth)var judge_y = (y >= box2Y - box2.offsetHeight) && (y <= box2Y + box2.offsetHeight)if (judge_x && judge_y) { console.log("碰撞到")}

下载源码链接

星辉的Github

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