I've been working on a simple program that involves creating a clickable 3D object in Three.js. I've referenced my code from
When I click directly on the object, it works as expected, but upon examining the resulting array, I noticed that the object is included twice. I'm assuming this happens because the ray intersects it both when entering and exiting.
However, if I click around the object rather than directly on it, raycaster.intersectObjects still returns the object instead of an empty array. Why does this happen? Is it normal for an object to be included twice in the intersect array due to the ray entering and exiting?
You can see a live example of the code here:
https://codepen.io/ettir_deul/pen/PoGLNZx
(open the console to view the intersect array after clicking on the screen)
Below is a snippet of the code:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<script src="libs/three.min.js.r116.1"></script>
</head>
<body>
<div id="threejsCanvas"></div>
<script>
let scene, center, camera, renderer, raycaster;
const mouse = new THREE.Vector2();
const threejsCanvas = document.getElementById("threejsCanvas");
init3d();
function init3d(){
scene = new THREE.Scene();
scene.background = new THREE.Color(0xAAAAEE);
center = new THREE.Vector3(0, 0, 0);
camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 10000);
camera.position.set(center.x, center.y, center.z+1);
camera.lookAt(center);
buttonMesh = new THREE.Mesh(new THREE.BoxGeometry(1, 1, 0.2), new THREE.MeshBasicMaterial({map : null, color: 0x008844, wireframe: false, side: THREE.DoubleSide}));
buttonMesh.position.set(center.x, center.y, center.z);
scene.add(buttonMesh);
buttonMesh.objId = "buttonMesh";
renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
threejsCanvas.appendChild(renderer.domElement);
renderer.render(scene, camera);
raycaster = new THREE.Raycaster();
document.addEventListener('click', onMouseClick, false);
}
function onMouseClick(event){
event.preventDefault();
mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1;
mouse.y = - ( event.clientY / window.innerHeight ) * 2 + 1;
raycaster.setFromCamera(mouse, camera);
const intersects = raycaster.intersectObjects(scene.children);
console.log(intersects);
}
</script>
</body>
</html>