I'm trying to add collision detection in my draggable code which works pretty well I guess ,but when I'm trying to drag the orange rectangle above the green one nothing happens. Is my collision logic right ? Here is what I tried to do.
//HTML code
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link href = "stl.css" rel = "stylesheet" type = "text/css">
</head>
<body>
<div class="item1"></div>
<div class="item2"></div>
<script src = "js.js" type = "text/javascript"></script>
</body>
</html>
I used getBoundingClientRect() to get the position of the rectangles.
//JAVASCRIPT code
const el1 = document.querySelector(".item1");
const el2 = document.querySelector(".item2");
var rect1,rect2;
rect2 = el2.getBoundingClientRect();
el1.addEventListener("mousedown", mousedown);
function mousedown(e) {
window.addEventListener("mousemove", mousemove);
window.addEventListener("mouseup", mouseup);
let prevX = e.clientX; // x cursor position
let prevY = e.clientY;//y cursor position
function mousemove(e) {
let newX = prevX - e.clientX;
let newY = prevY - e.clientY;
rect1 = el1.getBoundingClientRect();
el1.style.left = rect1.left - newX + "px";
el1.style.top = rect1.top - newY + "px";
prevX = e.clientX;
prevY = e.clientY;
//a simple rectangle collision logic funcion
if (rect1.left < rect2.left + rect2.weight &&
rect1.left + rect1.weight > rect2.left &&
rect1.top < rect2.top + rect2.height &&
rect1.height + rect1.top > rect2.top)
{
item2.style.color="#FF0006";
}
}
//function which stops the mousedown event
function mouseup() {
window.removeEventListener("mousemove", mousemove);
window.removeEventListener("mouseup", mouseup);
}
}
I know that item1 require absolute position for draggable action
//CSS code
.item1{
height:50px;
width:50px;
position:absolute;
background:orange;
}
.item2{
height:220px;
width:220px;
position:absolute;
background:green;
top:300px;
left:500px;
z-index:-2;
}
//JAVASCRIPT code
const el1 = document.querySelector(".item1");
const el2 = document.querySelector(".item2");
var rect1,rect2;
rect2 = el2.getBoundingClientRect();
el1.addEventListener("mousedown", mousedown);
function mousedown(e) {
window.addEventListener("mousemove", mousemove);
window.addEventListener("mouseup", mouseup);
let startX = e.clientX; // x cursor position
let startY = e.clientY; //y cursor position
const { left: rectX, top: rectY } = el1.getBoundingClientRect();
function mousemove(e) {
rect1 = el1.getBoundingClientRect();
const diffX = e.clientX - startX;
const diffY = e.clientY - startY;
el1.style.left = (rectX + diffX) + "px";
el1.style.top = (rectY + diffY) + "px";
// https://gamedev.stackexchange.com/questions/586/what-is-the-fastest-way-to-work-out-2d-bounding-box-intersection
// function IntersectRect(r1:Rectangle, r2:Rectangle):Boolean {
// return !(r2.left > r1.right
// || r2.right < r1.left
// || r2.top > r1.bottom
// || r2.bottom < r1.top);
// }
//a simple rectangle collision logic funcion
if (rect1.left < rect2.left + rect2.width &&
rect1.left + rect1.width > rect2.left &&
rect1.top < rect2.top + rect2.height &&
rect1.top + rect1.height > rect2.top)
{
el2.style.background ="#FF0006";
} else {
el2.style.background ="black"; // put original color
}
}
//function which stops the mousedown event
function mouseup() {
window.removeEventListener("mousemove", mousemove);
window.removeEventListener("mouseup", mouseup);
}
}//CSS code
.body {
position: relative;
}
.item1{
height:50px;
width:50px;
position:absolute;
background:orange;
}
.item2{
height:120px;
width:120px;
position:absolute;
background:green;
top:300px;
left:500px;
z-index:-2;
}//HTML code
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link href = "stl.css" rel = "stylesheet" type = "text/css">
</head>
<body>
<div class="item1"></div>
<div class="item2"></div>
<script src = "js.js" type = "text/javascript"></script>
</body>
</html>