DirectionalLight parallel to the camera - step by step?

three3d · July 24, 2023, 8:06am

This is my first post.
So hello to all Three.js enthusiasts.
I was very intrigued by the possibility of presenting my 3D CAD models on websites.
I’m glad that I’ve learned a lot :), but I have a question about the directional light.
I can’t find a simple and complete example of how to implement a directional light parallel to the camera STEP BY STEP in the project so that it works also when moving the camera (and at the same time the camera target).
Here is a simple example of a scene and moving the camera left/right (only along the X axis for simplicity). The light is sticked to the camera, but the target of the light does not move with the target of the camera and stays at 0,0,0:

is it possible to get a result like this (dynamic view, not static!):

Chaser_Code · July 24, 2023, 8:55am

sun.target.updateMatrixWorld();

three3d · July 24, 2023, 9:21am

ok but where in the script should i put it?
and maybe i should change something else?

EDIT: i added my whole script

import * as THREE from 'three';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { RoomEnvironment } from 'three/addons/environments/RoomEnvironment.js';	
let camera, controls, scene, renderer;
let cam=[], ctar=[];

init();
animate();

function init() {

cam=[0, 55, 25];
ctar=[cam[0], 0, 5];


	scene = new THREE.Scene();
	scene.background = new THREE.Color( 0xffffff ); //0xd1d1d1

	renderer = new THREE.WebGLRenderer( { antialias: true } );
	renderer.setPixelRatio( window.devicePixelRatio );
	renderer.setSize( window.innerWidth, window.innerHeight );
	renderer.useLegacyLights = false;
	renderer.shadowMap.enabled = true;	
	renderer.toneMappingExposure = 1;
	renderer.outputEncoding = THREE.sRGBEncoding;
	document.body.appendChild( renderer.domElement );

	camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 1000 );
	camera.position.set( cam[0], cam[1], cam[2] );

	// controls
	controls = new OrbitControls( camera, renderer.domElement );
	controls.listenToKeyEvents( window ); // optional
	controls.enableDamping = true;
	controls.dampingFactor = 0.05;
	controls.screenSpacePanning = false;
	controls.minDistance = 1;
	controls.maxDistance = 100;
	controls.target.set(ctar[0], ctar[1], ctar[2]);	// camera target	
	
	// lights
	const dirLight = new THREE.DirectionalLight( 0xffffff, 3 );
	dirLight.position.set(0, 10, 45);
	dirLight.shadow.mapSize.set( 4096, 4096 );
	dirLight.penumbra = 0.5;
	dirLight.shadow.bias = -0.0005;
	dirLight.shadow.camera.left =	-50;
	dirLight.shadow.camera.right = 	50;
	dirLight.shadow.camera.top = 	50;
	dirLight.shadow.camera.bottom = -50;
	dirLight.shadowCameraNear = 1;
	dirLight.shadowCameraFar = 500;
	dirLight.castShadow = true;

		camera.add( dirLight );
		
		scene.add( camera );
		let cameraHelper = new THREE.CameraHelper(camera);
		scene.add (cameraHelper);

	const ambientLight = new THREE.AmbientLight( 0xffffff, 1 );
	scene.add( ambientLight );

	///////////////// MODELs //////////////////////

	// PLANE
	const pgeo = new THREE.PlaneGeometry(40, 40);
	const pmat = new THREE.MeshPhongMaterial({ color: '0xf0f0f0' });
	const plane = new THREE.Mesh(pgeo, pmat);
	
	plane.material.side = THREE.DoubleSide;
	plane.rotateX(-Math.PI / 2);
	plane.position.set( 0,-0.003,0);
	plane.receiveShadow = true;
	scene.add( plane );

	// GRIDs
	const helper1 = new THREE.GridHelper( 20, 20, 'gray', 'gray' );
	helper1.position.y=-0.002;scene.add( helper1 );
	const helper2 = new THREE.GridHelper( 40, 8, 'silver', 'silver' );
	helper2.position.y=-0.001;scene.add( helper2 );
	
	// Axes
	const axesHelper = new THREE.AxesHelper( 25 );
	scene.add( axesHelper );

	// CYLINDERs
	const geometry = new THREE.CylinderGeometry( 0.5, 0.5, 10, 8 ); 
	const material = new THREE.MeshPhongMaterial( {color: 0xFFD966} );		
	for (let ii = 0; ii < 3; ii++) {		
	for (let i = 0; i < 3; i++) {
		const mesh = new THREE.Mesh( geometry, material );
			mesh.position.set( -10+i*10, 5 , -10+ii*10);
			mesh.receiveShadow = true;
			mesh.castShadow = true;	
		mesh.updateMatrix();
		mesh.matrixAutoUpdate = false;	
		scene.add( mesh );
	}}
	window.addEventListener( 'resize', onWindowResize );
}
function onWindowResize() {
	camera.aspect = window.innerWidth / window.innerHeight;
	camera.updateProjectionMatrix();
	renderer.setSize( window.innerWidth, window.innerHeight );
}
function animate() {
	requestAnimationFrame( animate );
	controls.update();
	render();
}
function render() {
	renderer.render( scene, camera );
}

Chaser_Code · July 24, 2023, 10:06am

function animate() {
	requestAnimationFrame( animate );
	controls.update();
	dirLight.target.position.copy(camera.position.);
	dirLight.target.position.y=0;
	dirLight.target.updateMatrixWorld();
	render();
}

three3d · July 24, 2023, 10:14am

Black screen

Chaser_Code:

function animate() {
	requestAnimationFrame( animate );
	controls.update();
	//dirLight.target.position.copy(camera.position); //<<< black screen after this
	//dirLight.target.position.y=0;
	//dirLight.target.updateMatrixWorld();
	render();
}

seanwasere · July 24, 2023, 10:47am

check your console for errors.

your dirLight is declared in your init scope.
Move it to the global scope.

let camera, controls, scene, renderer, dirLight;

and change
const dirLight = new THREE.DirectionalLight( 0xffffff, 3 );
to
dirLight = new THREE.DirectionalLight( 0xffffff, 3 );

three3d · July 24, 2023, 11:28am

Chaser_Code and seanwasere YES YES YES !
Thank you for the quick reply. I implemented it successfully.
This allowed me to take another milestone in three.js

Corrected script:

import * as THREE from 'three';

import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { RoomEnvironment } from 'three/addons/environments/RoomEnvironment.js';	

let camera, controls, scene, renderer, dirLight;
let cam=[], ctar=[];

init();
animate();

function init() {

cam=[0, 55, 25];
ctar=[cam[0], 0, 5];

	scene = new THREE.Scene();
	scene.background = new THREE.Color( 0xffffff ); //0xd1d1d1

	renderer = new THREE.WebGLRenderer( { antialias: true } );
	renderer.setPixelRatio( window.devicePixelRatio );
	renderer.setSize( window.innerWidth, window.innerHeight );
	renderer.useLegacyLights = false;
	renderer.shadowMap.enabled = true;	
	renderer.toneMappingExposure = 1;
	renderer.outputEncoding = THREE.sRGBEncoding;
	document.body.appendChild( renderer.domElement );

	camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 1000 );
	camera.position.set( cam[0], cam[1], cam[2] );

	// controls
	controls = new OrbitControls( camera, renderer.domElement );
	controls.listenToKeyEvents( window ); // optional
	controls.enableDamping = true;
	controls.dampingFactor = 0.05;
	controls.screenSpacePanning = false;
	controls.minDistance = 1;
	controls.maxDistance = 100;
	controls.target.set(ctar[0], ctar[1], ctar[2]);	// camera target	
	
	// lights
	dirLight = new THREE.DirectionalLight( 0xffffff, 3 );
	dirLight.position.set(0, 1, 100);
	dirLight.shadow.mapSize.set( 4096, 4096 );
	dirLight.penumbra = 0.5;
	dirLight.shadow.bias = -0.0005;
	dirLight.shadow.camera.left =	-200;
	dirLight.shadow.camera.right = 	200;
	dirLight.shadow.camera.top = 	200;
	dirLight.shadow.camera.bottom = -200;
	dirLight.shadowCameraNear = 1;
	dirLight.shadowCameraFar = 500;
	dirLight.castShadow = true;
	
		camera.add( dirLight );
		
		scene.add( camera );
		let cameraHelper = new THREE.CameraHelper(camera);
		scene.add (cameraHelper);

	const ambientLight = new THREE.AmbientLight( 0xffffff, 1 );
	scene.add( ambientLight );

	///////////////// MODELs //////////////////////

	// PLANE
	const pgeo = new THREE.PlaneGeometry(40, 40);
	const pmat = new THREE.MeshPhongMaterial({ color: '0xf0f0f0' });
	const plane = new THREE.Mesh(pgeo, pmat);
	
	plane.material.side = THREE.DoubleSide;
	plane.rotateX(-Math.PI / 2);
	plane.position.set( 0,-0.003,0);
	plane.receiveShadow = true;
	scene.add( plane );

	// GRIDs
	const helper1 = new THREE.GridHelper( 20, 20, 'gray', 'gray' );
	helper1.position.y=-0.002;scene.add( helper1 );
	const helper2 = new THREE.GridHelper( 40, 8, 'silver', 'silver' );
	helper2.position.y=-0.001;scene.add( helper2 );
	
	// Axes
	const axesHelper = new THREE.AxesHelper( 25 );
	scene.add( axesHelper );

	// CYLINDERs
	const geometry = new THREE.CylinderGeometry( 0.5, 0.5, 10, 8 ); 
	const material = new THREE.MeshPhongMaterial( {color: 0xFFD966} );		
	for (let ii = 0; ii < 3; ii++) {		
	for (let i = 0; i < 3; i++) {
		const mesh = new THREE.Mesh( geometry, material );
			mesh.position.set( -10+i*10, 5 , -10+ii*10);
			mesh.receiveShadow = true;
			mesh.castShadow = true;	
		mesh.updateMatrix();
		mesh.matrixAutoUpdate = false;	
		scene.add( mesh );
	}}
	window.addEventListener( 'resize', onWindowResize );
}

function onWindowResize() {
	camera.aspect = window.innerWidth / window.innerHeight;
	camera.updateProjectionMatrix();
	renderer.setSize( window.innerWidth, window.innerHeight );
}
function animate() {
	requestAnimationFrame( animate );
	controls.update();
	// dirLight.target.position.copy(camera.position);
	dirLight.target.position.copy(controls.target);	// for me it works similarly
	// dirLight.target.position.y=0;
	dirLight.target.updateMatrixWorld();
	render();
}
function render() {
	renderer.render( scene, camera );
}

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DirectionalLight parallel to the camera - step by step?

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