I am trying to do what the title says.
When a user clicks on a face of the cube, that face will change colour.
This is my code snippet:
// create a cube
var cubeGeometry = new THREE.BoxGeometry(20, 20, 20);
var cubeMaterial = new THREE.MeshLambertMaterial({color: 0xffff00 }); //0xF7F7F7 = gray
cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
cube.userData.originalColor = 0xffff00;
function onDocumentMouseClick(event) //if we detect a click event
{
// the following line would stop any other event handler from firing
// (such as the mouse's TrackballControls)
event.preventDefault();
// update the mouse variable
mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;
var vector = new THREE.Vector3( ( event.clientX / window.innerWidth ) * 2 - 1, - ( event.clientY / window.innerHeight ) * 2 + 1, 0.5 );
vector.unproject( camera );
raycaster.set( camera.position, vector.sub( camera.position ).normalize() );
var intersects = raycaster.intersectObject( cube );
if ( intersects.length > 0 )
{
var index = Math.floor( intersects[0].faceIndex / 2 );
switch (index)
{
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
}
}
}
This code is incomplete.
My problems are these:
I don't know if this strategy is correct and works
I don't know what code to use inside the different cases, in order to paint that side of the cube.
First, consider breaking the cube's faces into draw groups. This answer delves into how to do that.
The idea is that all of the cube's faces will have the same color, but not the same material. This will allow you to change the material's colors individually, and as such you will individually change the color of the cube faces.
When you get a response back from the Raycaster, look for the faceIndex property. This will tell you the index of the face that was intersected. Find which draw group that index belongs to, and you can then reference that group's material index, and thus change the color of the material.
I have a rotating sphere on which I have a div attached the example can be viewed here: https://jsfiddle.net/ao5wdm04/
I calculate the x and y values and place the div using a translate3d transform and that works quite well.
My question is how to can get the values for the rotateX, rotateY and rotateZ or rotate3d transforms so the div "tangents" the sphere surface. I know the cube mesh faces the sphere center so I assume the rotation vector of the outward facing normal vector in relation to the camera would contain the values I need. But I'm not quite sure how to obtain these.
Update
By using Euler angles I'm almost achieving the desired effect, shown here: https://jsfiddle.net/ao5wdm04/1/ but the rotation is not large enough.
Disclaimer: I know nothing about three.js. I've just done a bit of OpenGL.
Your euler angles are coming from a model-view-projected origin (lines 74-80). I can't see the logic behind this.
If your div is on the sphere surface, then it should be oriented by the normal of the sphere at the location of the div. Fortunately, you already have these angles. They are named rotation.
If you replace the euler angles in lines 82-84 with the rotation angles used to position the div, then in my browser the div appears edge on when it is at the edge of the circle, and face on when it is at the centre. It kind of looks like it is moving in a circle, edge on to the screen. Is this the effect you want?
My modification to the linked code:
82 var rotX = (rotation.x * (180/ Math.PI));
83 var rotY = (rotation.y * (180/ Math.PI));
84 var rotZ = 0;
EDIT
Ah, ok. The rotation variable is just that of the camera. It governs the tangent at the equator. You also need to modify the orientation to account for latitude.
Make rotY equal to negative your latitude. Then make sure that this rotation happens before the equatorial rotation. Rotations are not commutative.
In summary, changes from the code at https://jsfiddle.net/ao5wdm04/1/ are as follows:
27 var lat = 45 * Math.PI / 180;
...
82 var rotX = (rotation.x * (180/ Math.PI));
83 var rotY = - 45;
...
88 document.getElementById('face').style.webkitTransform = 'translate3d(' + x + 'px,' + y + 'px,0px) rotateY('+rotX+'deg) rotateX('+rotY+'deg)';
I don't know how the latitude should propagate between the init and render functions. As I said, I'm not familiar with the language.
For details about transformation and rotation in openGL or any other graphics please go through here.
Basic -
There is basically 2 kind of transformations in 3D world-
Translation
Rotation
A small example on this things are given here.
If u go through all of them, I think u have a clear concept on the 3D transformation system.
If u can understand those, u can easily simulate that :) because u need to do this 2 things for each move at the same time.
Try this code-
var camera, scene, renderer, raycaster, geometry, material, mesh, box;
var rotation = {
x: 0,
y: 0
};
var distance = 500;
init();
animate();
function init() {
raycaster = new THREE.Raycaster(); ;
scene = new THREE.Scene();
camera = new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 1, 10000);
camera.position.z = distance;
camera.position.y = 100;
scene.add(camera);
geometry = new THREE.SphereGeometry(100, 50, 50, 50);
material = new THREE.MeshNormalMaterial();
mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
var transform = new THREE.Matrix4().getInverse(scene.matrix);
var lat = 0 * Math.PI / 180;
var lon = 90 * Math.PI / 180;
var r = 100;
var p = new THREE.Vector3(-r * Math.cos(lat) * Math.cos(lon),
r * Math.sin(lat),
r * Math.cos(lat) * Math.sin(lon)
);
p.applyMatrix4(transform);
var geometry = new THREE.CubeGeometry(10, 10, 10);
box = new THREE.Mesh(geometry, new THREE.MeshBasicMaterial({
color: 0xff0000,
}));
box.position.set(p.x, p.y, p.z);
box.lookAt(mesh.position);
//scene.add(box);
box.updateMatrix();
renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
}
function animate() {
requestAnimationFrame(animate);
render();
}
function render() {
rotation.x += 0.01;
camera.position.x = distance * Math.sin(rotation.x) * Math.cos(rotation.y);
camera.position.y = distance * Math.sin(rotation.y);
camera.position.z = distance * Math.cos(rotation.x) * Math.cos(rotation.y);
camera.lookAt(mesh.position);
var w = window.innerWidth;
var h = window.innerHeight;
var mat = new THREE.Matrix4();
var v = new THREE.Vector3();
mat.copy(scene.matrix);
mat.multiply(box.matrix);
v.set(0, 0, 0);
v.applyMatrix4(mat);
v.project(camera);
var euler = new THREE.Euler().setFromVector3(v);
var rotX = (rotation.x * (180/ Math.PI));
var rotY = (rotation.y * (180/ Math.PI));
var rotZ = 0;
var x = (w * (v.x + 1) / 2) - 12.5; //compensate the box size
var y = (h - h * (v.y + 1) / 2) - 12.5;
document.getElementById('face').style.webkitTransform = 'translate3d(' + x + 'px,' + y + 'px,0px) rotateX('+rotY+'deg) rotateY('+rotX+'deg) rotateZ('+rotZ+'deg)';
renderer.render(scene, camera);
}
#face {
position: absolute;
width: 25px;
height: 25px;
border-radius: 50%;
background-color: red;
}
<script src="https://rawgit.com/mrdoob/three.js/master/build/three.min.js"></script>
<div id="face"></div>
I want to aim for objects with cameras' vision (as the user would look at the object, not point at it with mouse).
I'm casting a ray from the camera like this
rotation.x = camera.rotation.x;
rotation.y = camera.rotation.y;
rotation.z = camera.rotation.z;
raycaster.ray.direction.copy( direction ).applyEuler(rotation);
raycaster.ray.origin.copy( camera.position );
var intersections = raycaster.intersectObjects( cubes.children );
This gets me the intersections but it seems to wander off sometimes. So I'd like to add aim (crosshair). That would be somekind on object (mesh) at the end or in the middle of the ray.
How can I add it? When I created a regular line it was in front of the camera so the screen would go black.
You can add a crosshair constructed from simple geometry to your camera like this:
var material = new THREE.LineBasicMaterial({ color: 0xAAFFAA });
// crosshair size
var x = 0.01, y = 0.01;
var geometry = new THREE.Geometry();
// crosshair
geometry.vertices.push(new THREE.Vector3(0, y, 0));
geometry.vertices.push(new THREE.Vector3(0, -y, 0));
geometry.vertices.push(new THREE.Vector3(0, 0, 0));
geometry.vertices.push(new THREE.Vector3(x, 0, 0));
geometry.vertices.push(new THREE.Vector3(-x, 0, 0));
var crosshair = new THREE.Line( geometry, material );
// place it in the center
var crosshairPercentX = 50;
var crosshairPercentY = 50;
var crosshairPositionX = (crosshairPercentX / 100) * 2 - 1;
var crosshairPositionY = (crosshairPercentY / 100) * 2 - 1;
crosshair.position.x = crosshairPositionX * camera.aspect;
crosshair.position.y = crosshairPositionY;
crosshair.position.z = -0.3;
camera.add( crosshair );
scene.add( camera );
Three.js r107
http://jsfiddle.net/5ksydn6u/2/
In case you dont have a special usecase where you need to retrieve the position and rotation from your camera like you are doing, I guess your "wandering off" could be fixed by calling your raycaster with these arguments.:
raycaster.set( camera.getWorldPosition(), camera.getWorldDirection() );
var intersections = raycaster.intersectObjects( cubes.children );
Cast visible ray
Then you can visualize your raycast in 3D space by drawing an arrow with the arrow helper. Do this after your raycast:
scene.remove ( arrow );
arrow = new THREE.ArrowHelper( camera.getWorldDirection(), camera.getWorldPosition(), 100, Math.random() * 0xffffff );
scene.add( arrow );
I've searched around for an example that matches my use case but cannot find one. I'm trying to convert screen mouse co-ordinates into 3D world co-ordinates taking into account the camera.
Solutions I've found all do ray intersection to achieve object picking.
What I am trying to do is position the center of a Three.js object at the co-ordinates that the mouse is currently "over".
My camera is at x:0, y:0, z:500 (although it will move during the simulation) and all my objects are at z = 0 with varying x and y values so I need to know the world X, Y based on assuming a z = 0 for the object that will follow the mouse position.
This question looks like a similar issue but doesn't have a solution: Getting coordinates of the mouse in relation to 3D space in THREE.js
Given the mouse position on screen with a range of "top-left = 0, 0 | bottom-right = window.innerWidth, window.innerHeight", can anyone provide a solution to move a Three.js object to the mouse co-ordinates along z = 0?
You do not need to have any objects in your scene to do this.
You already know the camera position.
Using vector.unproject( camera ) you can get a ray pointing in the direction you want.
You just need to extend that ray, from the camera position, until the z-coordinate of the tip of the ray is zero.
You can do that like so:
var vec = new THREE.Vector3(); // create once and reuse
var pos = new THREE.Vector3(); // create once and reuse
vec.set(
( event.clientX / window.innerWidth ) * 2 - 1,
- ( event.clientY / window.innerHeight ) * 2 + 1,
0.5 );
vec.unproject( camera );
vec.sub( camera.position ).normalize();
var distance = - camera.position.z / vec.z;
pos.copy( camera.position ).add( vec.multiplyScalar( distance ) );
The variable pos is the position of the point in 3D space, "under the mouse", and in the plane z=0.
EDIT: If you need the point "under the mouse" and in the plane z = targetZ, replace the distance computation with:
var distance = ( targetZ - camera.position.z ) / vec.z;
three.js r.98
This worked for me when using an orthographic camera
let vector = new THREE.Vector3();
vector.set(
(event.clientX / window.innerWidth) * 2 - 1,
- (event.clientY / window.innerHeight) * 2 + 1,
0
);
vector.unproject(camera);
WebGL three.js r.89
In r.58 this code works for me:
var planeZ = new THREE.Plane(new THREE.Vector3(0, 0, 1), 0);
var mv = new THREE.Vector3(
(event.clientX / window.innerWidth) * 2 - 1,
-(event.clientY / window.innerHeight) * 2 + 1,
0.5 );
var raycaster = projector.pickingRay(mv, camera);
var pos = raycaster.ray.intersectPlane(planeZ);
console.log("x: " + pos.x + ", y: " + pos.y);
Below is an ES6 class I wrote based on WestLangley's reply, which works perfectly for me in THREE.js r77.
Note that it assumes your render viewport takes up your entire browser viewport.
class CProjectMousePosToXYPlaneHelper
{
constructor()
{
this.m_vPos = new THREE.Vector3();
this.m_vDir = new THREE.Vector3();
}
Compute( nMouseX, nMouseY, Camera, vOutPos )
{
let vPos = this.m_vPos;
let vDir = this.m_vDir;
vPos.set(
-1.0 + 2.0 * nMouseX / window.innerWidth,
-1.0 + 2.0 * nMouseY / window.innerHeight,
0.5
).unproject( Camera );
// Calculate a unit vector from the camera to the projected position
vDir.copy( vPos ).sub( Camera.position ).normalize();
// Project onto z=0
let flDistance = -Camera.position.z / vDir.z;
vOutPos.copy( Camera.position ).add( vDir.multiplyScalar( flDistance ) );
}
}
You can use the class like this:
// Instantiate the helper and output pos once.
let Helper = new CProjectMousePosToXYPlaneHelper();
let vProjectedMousePos = new THREE.Vector3();
...
// In your event handler/tick function, do the projection.
Helper.Compute( e.clientX, e.clientY, Camera, vProjectedMousePos );
vProjectedMousePos now contains the projected mouse position on the z=0 plane.
to get the mouse coordinates of a 3d object use projectVector:
var width = 640, height = 480;
var widthHalf = width / 2, heightHalf = height / 2;
var projector = new THREE.Projector();
var vector = projector.projectVector( object.matrixWorld.getPosition().clone(), camera );
vector.x = ( vector.x * widthHalf ) + widthHalf;
vector.y = - ( vector.y * heightHalf ) + heightHalf;
to get the three.js 3D coordinates that relate to specific mouse coordinates, use the opposite, unprojectVector:
var elem = renderer.domElement,
boundingRect = elem.getBoundingClientRect(),
x = (event.clientX - boundingRect.left) * (elem.width / boundingRect.width),
y = (event.clientY - boundingRect.top) * (elem.height / boundingRect.height);
var vector = new THREE.Vector3(
( x / WIDTH ) * 2 - 1,
- ( y / HEIGHT ) * 2 + 1,
0.5
);
projector.unprojectVector( vector, camera );
var ray = new THREE.Ray( camera.position, vector.subSelf( camera.position ).normalize() );
var intersects = ray.intersectObjects( scene.children );
There is a great example here. However, to use project vector, there must be an object where the user clicked. intersects will be an array of all objects at the location of the mouse, regardless of their depth.
I had a canvas that was smaller than my full window, and needed to determine the world coordinates of a click:
// get the position of a canvas event in world coords
function getWorldCoords(e) {
// get x,y coords into canvas where click occurred
var rect = canvas.getBoundingClientRect(),
x = e.clientX - rect.left,
y = e.clientY - rect.top;
// convert x,y to clip space; coords from top left, clockwise:
// (-1,1), (1,1), (-1,-1), (1, -1)
var mouse = new THREE.Vector3();
mouse.x = ( (x / canvas.clientWidth ) * 2) - 1;
mouse.y = (-(y / canvas.clientHeight) * 2) + 1;
mouse.z = 0.5; // set to z position of mesh objects
// reverse projection from 3D to screen
mouse.unproject(camera);
// convert from point to a direction
mouse.sub(camera.position).normalize();
// scale the projected ray
var distance = -camera.position.z / mouse.z,
scaled = mouse.multiplyScalar(distance),
coords = camera.position.clone().add(scaled);
return coords;
}
var canvas = renderer.domElement;
canvas.addEventListener('click', getWorldCoords);
Here's an example. Click the same region of the donut before and after sliding and you'll find the coords remain constant (check the browser console):
// three.js boilerplate
var container = document.querySelector('body'),
w = container.clientWidth,
h = container.clientHeight,
scene = new THREE.Scene(),
camera = new THREE.PerspectiveCamera(75, w/h, 0.001, 100),
controls = new THREE.MapControls(camera, container),
renderConfig = {antialias: true, alpha: true},
renderer = new THREE.WebGLRenderer(renderConfig);
controls.panSpeed = 0.4;
camera.position.set(0, 0, -10);
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(w, h);
container.appendChild(renderer.domElement);
window.addEventListener('resize', function() {
w = container.clientWidth;
h = container.clientHeight;
camera.aspect = w/h;
camera.updateProjectionMatrix();
renderer.setSize(w, h);
})
function render() {
requestAnimationFrame(render);
renderer.render(scene, camera);
controls.update();
}
// draw some geometries
var geometry = new THREE.TorusGeometry( 10, 3, 16, 100, );
var material = new THREE.MeshNormalMaterial( { color: 0xffff00, } );
var torus = new THREE.Mesh( geometry, material, );
scene.add( torus );
// convert click coords to world space
// get the position of a canvas event in world coords
function getWorldCoords(e) {
// get x,y coords into canvas where click occurred
var rect = canvas.getBoundingClientRect(),
x = e.clientX - rect.left,
y = e.clientY - rect.top;
// convert x,y to clip space; coords from top left, clockwise:
// (-1,1), (1,1), (-1,-1), (1, -1)
var mouse = new THREE.Vector3();
mouse.x = ( (x / canvas.clientWidth ) * 2) - 1;
mouse.y = (-(y / canvas.clientHeight) * 2) + 1;
mouse.z = 0.0; // set to z position of mesh objects
// reverse projection from 3D to screen
mouse.unproject(camera);
// convert from point to a direction
mouse.sub(camera.position).normalize();
// scale the projected ray
var distance = -camera.position.z / mouse.z,
scaled = mouse.multiplyScalar(distance),
coords = camera.position.clone().add(scaled);
console.log(mouse, coords.x, coords.y, coords.z);
}
var canvas = renderer.domElement;
canvas.addEventListener('click', getWorldCoords);
render();
html,
body {
width: 100%;
height: 100%;
background: #000;
}
body {
margin: 0;
overflow: hidden;
}
canvas {
width: 100%;
height: 100%;
}
<script src='https://cdnjs.cloudflare.com/ajax/libs/three.js/97/three.min.js'></script>
<script src=' https://threejs.org/examples/js/controls/MapControls.js'></script>
ThreeJS is slowly mowing away from Projector.(Un)ProjectVector and the solution with projector.pickingRay() doesn't work anymore, just finished updating my own code.. so the most recent working version should be as follow:
var rayVector = new THREE.Vector3(0, 0, 0.5);
var camera = new THREE.PerspectiveCamera(fov,this.offsetWidth/this.offsetHeight,0.1,farFrustum);
var raycaster = new THREE.Raycaster();
var scene = new THREE.Scene();
//...
function intersectObjects(x, y, planeOnly) {
rayVector.set(((x/this.offsetWidth)*2-1), (1-(y/this.offsetHeight)*2), 1).unproject(camera);
raycaster.set(camera.position, rayVector.sub(camera.position ).normalize());
var intersects = raycaster.intersectObjects(scene.children);
return intersects;
}
For those using #react-three/fiber (aka r3f and react-three-fiber), I found this discussion and it's associated code samples by Matt Rossman helpful. In particular, many examples using the methods above are for simple orthographic views, not for when OrbitControls are in play.
Discussion: https://github.com/pmndrs/react-three-fiber/discussions/857
Simple example using Matt's technique: https://codesandbox.io/s/r3f-mouse-to-world-elh73?file=/src/index.js
More generalizable example: https://codesandbox.io/s/react-three-draggable-cxu37?file=/src/App.js
Here is my take at creating an es6 class out of it. Working with Three.js r83. The method of using rayCaster comes from mrdoob here: Three.js Projector and Ray objects
export default class RaycasterHelper
{
constructor (camera, scene) {
this.camera = camera
this.scene = scene
this.rayCaster = new THREE.Raycaster()
this.tapPos3D = new THREE.Vector3()
this.getIntersectsFromTap = this.getIntersectsFromTap.bind(this)
}
// objects arg below needs to be an array of Three objects in the scene
getIntersectsFromTap (tapX, tapY, objects) {
this.tapPos3D.set((tapX / window.innerWidth) * 2 - 1, -(tapY /
window.innerHeight) * 2 + 1, 0.5) // z = 0.5 important!
this.tapPos3D.unproject(this.camera)
this.rayCaster.set(this.camera.position,
this.tapPos3D.sub(this.camera.position).normalize())
return this.rayCaster.intersectObjects(objects, false)
}
}
You would use it like this if you wanted to check against all your objects in the scene for hits. I made the recursive flag false above because for my uses I did not need it to be.
var helper = new RaycasterHelper(camera, scene)
var intersects = helper.getIntersectsFromTap(tapX, tapY,
this.scene.children)
...
Although the provided answers can be useful in some scenarios, I hardly can imagine those scenarios (maybe games or animations) because they are not precise at all (guessing around target's NDC z?). You can't use those methods to unproject screen coordinates to the world ones if you know target z-plane. But for the most scenarios, you should know this plane.
For example, if you draw sphere by center (known point in model space) and radius - you need to get radius as delta of unprojected mouse coordinates - but you can't! With all due respect #WestLangley's method with targetZ doesn't work, it gives incorrect results (I can provide jsfiddle if needed). Another example - you need to set orbit controls target by mouse double click, but without "real" raycasting with scene objects (when you have nothing to pick).
The solution for me is to just create the virtual plane in target point along z-axis and use raycasting with this plane afterward. Target point can be current orbit controls target or vertex of object you need to draw step by step in existing model space etc. This works perfectly and it is simple (example in typescript):
screenToWorld(v2D: THREE.Vector2, camera: THREE.PerspectiveCamera = null, target: THREE.Vector3 = null): THREE.Vector3 {
const self = this;
const vNdc = self.toNdc(v2D);
return self.ndcToWorld(vNdc, camera, target);
}
//get normalized device cartesian coordinates (NDC) with center (0, 0) and ranging from (-1, -1) to (1, 1)
toNdc(v: THREE.Vector2): THREE.Vector2 {
const self = this;
const canvasEl = self.renderers.WebGL.domElement;
const bounds = canvasEl.getBoundingClientRect();
let x = v.x - bounds.left;
let y = v.y - bounds.top;
x = (x / bounds.width) * 2 - 1;
y = - (y / bounds.height) * 2 + 1;
return new THREE.Vector2(x, y);
}
ndcToWorld(vNdc: THREE.Vector2, camera: THREE.PerspectiveCamera = null, target: THREE.Vector3 = null): THREE.Vector3 {
const self = this;
if (!camera) {
camera = self.camera;
}
if (!target) {
target = self.getTarget();
}
const position = camera.position.clone();
const origin = self.scene.position.clone();
const v3D = target.clone();
self.raycaster.setFromCamera(vNdc, camera);
const normal = new THREE.Vector3(0, 0, 1);
const distance = normal.dot(origin.sub(v3D));
const plane = new THREE.Plane(normal, distance);
self.raycaster.ray.intersectPlane(plane, v3D);
return v3D;
}