three.js 2D mouseclick to 3d co-ordinates using raycaster

问题

I'm trying to draw 2D objects in z=0 plane, now I want to convert screen mouse co-ordinates into 3D world co-ordinates.

I used camera below:

camera = new THREE.OrthographicCamera(SCREEN_WIDTH / - 2, SCREEN_WIDTH / 2,         
SCREEN_HEIGHT / 2, SCREEN_HEIGHT / - 2, NEAR, FAR );
camera.position.set(0,0,500);
camera.lookAt(scene.position);

container = document.getElementById( 'ThreeJS' );
container.appendChild( renderer.domElement );

var floorGeometry = new THREE.PlaneGeometry(1000, 1000, 10, 10);
var  material = new THREE.MeshBasicMaterial({color: 0x000000, opacity: 1});
var floor = new THREE.Mesh(floorGeometry, material);
floor.position.set(0,0,0);
scene.add(floor);
targetList.push(floor);

I tried two ways: 1.the answer of:[question]: Mouse / Canvas X, Y to Three.js World X, Y, Z

var vector = new THREE.Vector3();
vector.set(
( event.clientX / window.innerWidth ) * 2 - 1,
- ( event.clientY / window.innerHeight ) * 2 + 1,
0.5 );
vector.unproject( camera );
var dir = vector.sub( camera.position ).normalize();
var distance = - camera.position.z / dir.z;
var pos = camera.position.clone().add( dir.multiplyScalar( distance ) );

but it does't work for me!the pos is not the correct position in 3D world co-ordinates;To be honestly,I'm not understand this method actually...

2:
mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1;
mouse.y = - ( event.clientY / window.innerHeight ) * 2 + 1;
var raycaster = new THREE.Raycaster();
raycaster.setFromCamera(mouse, camera);
var intersects = raycaster.intersectObjects(targetList);
// if there is one (or more) intersections
if ( intersects.length > 0 )
{
    console.log(intersects[0].point);
    console.log("Hit @ " + toString( intersects[0].point ) );
}

This works right in normal place,but if add "width:300px;height:400px" #test div before #ThreeJS div,it went totally wrong position,WHY,WHY,WHY?

Could someone give me a usable solution?

回答1:

Looks like that your viewport covers only a part of the page and not the whole page like in all those examples of three.js. In this case you need to determine your actual mouse coordinates a bit different: so use event.offsetX instead of clientX. And of course you need your actual <div> dimensions instead of window.innerWidth

var mouse = new THREE.Vector2();
mouse.x = (event.offsetX / SCREEN_WIDTH) * 2 - 1;
mouse.y = - (event.offsetY / SCREEN_HEIGHT) * 2 + 1;

来源：https://stackoverflow.com/questions/34758834/three-js-2d-mouseclick-to-3d-co-ordinates-using-raycaster

标签

three.js

raycasting

mouse-coordinates