I have array of XY coordinates from which i have to get the respective Z positions. I have created the following code to achieve same.
This function loops through array and calls further function to get the Z value.
function generate_section(){
for(var i=0;i<points.length;i++){
//temporary try to get for the same.
var pts = points[i];
var z = sectioncall(pts.x,pts.y);
console.log(pts,z);
}
}
The following function is a raycaster which cast the ray for the provided x& y value and cast a downward ray.
function sectioncall(x,y){ //grabs the Z value for the provided XY
var top = new THREE.Vector3(x, y , 30 );
var bottom = new THREE.Vector3(x , y , -30 );
var direction = new THREE.Vector3();
direction = direction.subVectors( bottom, top ).normalize();
//start raycaster
var raycaster = new THREE.Raycaster();
raycaster.set( top, direction );
// calculate objects intersecting the picking ray
var intersects = rayCaster.intersectObjects(scene.getObjectByName('MyObj_s').children);
var rpt = intersects[0].point;
//draw a line the way ray caster casting the ray
var geometry = new THREE.Geometry();
geometry.vertices.push( top );
geometry.vertices.push( rpt );
var material = new THREE.LineBasicMaterial( { color : 0xff0000 } );
var line = new THREE.Line( geometry, material );
scene.add( line );
return rpt;
}
With the above code i get the result like this:
but what i want to achive is the result like this:
So that the returning values will be about for respective XY instead of last XY as you see on the console.
You have slightly made a mistake in the code.
it should be
var intersects = raycaster.intersectObjects(scene.getObjectByName('MyObj_s').children);
you misspelled it as rayCaster.
In three.js, I'm using PointerLock controls the make a basic first person shooter.
I use
function onDocumentMouseDown( event ) {
var raycaster = new THREE.Raycaster();
mouse3D.normalize();
controls.getDirection( mouse3D );
raycaster.set( controls.getObject().position, mouse3D );
var intersects = raycaster.intersectObjects( objects );
...
}
to detect a collision with an object, which means you "shot" the object.
Now, I want to visualize the path the bullet took. I was thinking about drawing a line from where the user is looking to, in direction of the raycaster, but I can't figure out how to do this... Anyone who can help me? I'm new to three.js, never thought drawing a line would be this hard.
Update:
I'm trying to draw a line using:
var geometry = new THREE.Geometry();
geometry.vertices.push(...);
geometry.vertices.push(...);
var line = new THREE.Line(geometry, material);
scene.add(line);
but I can't figure out what to put in place of the "..." . How can I detect which point the line should go to? And how to determine which point it starts from? The player is able to move and even jump so the starting point is always different too.
You can use the following (using r83):
// Draw a line from pointA in the given direction at distance 100
var pointA = new THREE.Vector3( 0, 0, 0 );
var direction = new THREE.Vector3( 10, 0, 0 );
direction.normalize();
var distance = 100; // at what distance to determine pointB
var pointB = new THREE.Vector3();
pointB.addVectors ( pointA, direction.multiplyScalar( distance ) );
var geometry = new THREE.Geometry();
geometry.vertices.push( pointA );
geometry.vertices.push( pointB );
var material = new THREE.LineBasicMaterial( { color : 0xff0000 } );
var line = new THREE.Line( geometry, material );
scene.add( line );
Codepen at: https://codepen.io/anon/pen/evNqGy
You can use something like this:
function animate_Line(frame, totalFrames) {
//Calculate how much of the line should be drawn every iteration
var delta = lineDistance/(totalFrames);
var deltaSpeed = delta * frame;
for(var i=0; i<f_Ray_List[0].length; i++) {
for(var j=0; j<f_Ray_List[1].length; j++) {
//Change Offsets
line.geometry.vertices[1].y = line.geometry.vertices[0].y - deltaSpeed;
//Update Rays = true (Make FRT rays draw-able)
line.geometry.verticesNeedUpdate = true;
}
}
}
where frame is the current frame (a counter in your animate function), totalFrames would be the amount of frames that the line would take to be animated. The lineDistance can be calculated by using this:
lineDistance = line.geometry.vertices[0].y - line.vertices[1].y; //Add this line where you create the line object.
and remember to call line.geometry.verticesNeedUpdate = true; in every line individually, so that the line would able to be animated.
Notice that this is only based on Line.y axis. This would not be great at first. I'm currently working on converting this to Polar coordinates instead but I have no idea what is going on hahah.
If I know what direction an object is facing for example (0, 0, 1). What is the easiest way to rotate the object to face a direction vector of (1, 1, 1)?
Edit:
I've tried this, but something is wrong with this logic:
var newDir = new THREE.Vector3(1,1,1);
var objectDir= new THREE.Vector3(0, 0, 1);
objectDir.applyQuaternion(object.quaternion); // rotate this vector to object's facing direction
var pos = new THREE.Vector3();
pos.addVectors(newDir, object.position);
var axis = objectDir.cross(newDir).normalize();
var angle = objectDir.angleTo(pos);
object.rotateOnAxis(axis, angle);
Solved it with lookAt:
var newDir = new THREE.Vector3(1, 1, 1);
var pos = new THREE.Vector3();
pos.addVectors(newDir, object.position);
object.lookAt(pos);
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;
}