threejs-lighting

// AmbientLight(color, intensity)
const ambient = new THREE.AmbientLight(0xffffff, 0.5);
scene.add(ambient);
 
// Modify at runtime
ambient.color.set(0xffffcc);
ambient.intensity = 0.3;

// HemisphereLight(skyColor, groundColor, intensity)
const hemi = new THREE.HemisphereLight(0x87ceeb, 0x8b4513, 0.6);
hemi.position.set(0, 50, 0);
scene.add(hemi);
 
// Properties
hemi.color; // Sky color
hemi.groundColor; // Ground color
hemi.intensity;

// DirectionalLight(color, intensity)
const dirLight = new THREE.DirectionalLight(0xffffff, 1);
dirLight.position.set(5, 10, 5);
 
// Light points at target (default: 0, 0, 0)
dirLight.target.position.set(0, 0, 0);
scene.add(dirLight.target);
 
scene.add(dirLight);

dirLight.castShadow = true;
 
// Shadow map size (higher = sharper, more expensive)
dirLight.shadow.mapSize.width = 2048;
dirLight.shadow.mapSize.height = 2048;
 
// Shadow camera (orthographic)
dirLight.shadow.camera.near = 0.5;
dirLight.shadow.camera.far = 50;
dirLight.shadow.camera.left = -10;
dirLight.shadow.camera.right = 10;
dirLight.shadow.camera.top = 10;
dirLight.shadow.camera.bottom = -10;
 
// Shadow softness
dirLight.shadow.radius = 4; // Blur radius (PCFSoftShadowMap only)
 
// Shadow bias (fixes shadow acne)
dirLight.shadow.bias = -0.0001;
dirLight.shadow.normalBias = 0.02;
 
// Helper to visualize shadow camera
const helper = new THREE.CameraHelper(dirLight.shadow.camera);
scene.add(helper);

// PointLight(color, intensity, distance, decay)
const pointLight = new THREE.PointLight(0xffffff, 1, 100, 2);
pointLight.position.set(0, 5, 0);
scene.add(pointLight);
 
// Properties
pointLight.distance; // Maximum range (0 = infinite)
pointLight.decay; // Light falloff (physically correct = 2)

pointLight.castShadow = true;
pointLight.shadow.mapSize.width = 1024;
pointLight.shadow.mapSize.height = 1024;
 
// Shadow camera (perspective - 6 directions for cube map)
pointLight.shadow.camera.near = 0.5;
pointLight.shadow.camera.far = 50;
 
pointLight.shadow.bias = -0.005;

// SpotLight(color, intensity, distance, angle, penumbra, decay)
const spotLight = new THREE.SpotLight(0xffffff, 1, 100, Math.PI / 6, 0.5, 2);
spotLight.position.set(0, 10, 0);
 
// Target (light points at this)
spotLight.target.position.set(0, 0, 0);
scene.add(spotLight.target);
 
scene.add(spotLight);
 
// Properties
spotLight.angle; // Cone angle (radians, max Math.PI/2)
spotLight.penumbra; // Soft edge (0-1)
spotLight.distance; // Range
spotLight.decay; // Falloff

spotLight.castShadow = true;
spotLight.shadow.mapSize.width = 1024;
spotLight.shadow.mapSize.height = 1024;
 
// Shadow camera (perspective)
spotLight.shadow.camera.near = 0.5;
spotLight.shadow.camera.far = 50;
spotLight.shadow.camera.fov = 30;
 
spotLight.shadow.bias = -0.0001;
 
// Focus (affects shadow projection)
spotLight.shadow.focus = 1;

import { RectAreaLightHelper } from "three/examples/jsm/helpers/RectAreaLightHelper.js";
import { RectAreaLightUniformsLib } from "three/examples/jsm/lights/RectAreaLightUniformsLib.js";
 
// Must initialize uniforms first
RectAreaLightUniformsLib.init();
 
// RectAreaLight(color, intensity, width, height)
const rectLight = new THREE.RectAreaLight(0xffffff, 5, 4, 2);
rectLight.position.set(0, 5, 0);
rectLight.lookAt(0, 0, 0);
scene.add(rectLight);
 
// Helper
const helper = new RectAreaLightHelper(rectLight);
rectLight.add(helper);
 
// Note: Only works with MeshStandardMaterial and MeshPhysicalMaterial
// Does not cast shadows natively

// 1. Enable on renderer
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;
 
// Shadow map types:
// THREE.BasicShadowMap - fastest, low quality
// THREE.PCFShadowMap - default, filtered
// THREE.PCFSoftShadowMap - softer edges
// THREE.VSMShadowMap - variance shadow map
 
// 2. Enable on light
light.castShadow = true;
 
// 3. Enable on objects
mesh.castShadow = true;
mesh.receiveShadow = true;
 
// Ground plane
floor.receiveShadow = true;
floor.castShadow = false; // Usually false for floors

// Tight shadow camera frustum
const d = 10;
dirLight.shadow.camera.left = -d;
dirLight.shadow.camera.right = d;
dirLight.shadow.camera.top = d;
dirLight.shadow.camera.bottom = -d;
dirLight.shadow.camera.near = 0.5;
dirLight.shadow.camera.far = 30;
 
// Fix shadow acne
dirLight.shadow.bias = -0.0001; // Depth bias
dirLight.shadow.normalBias = 0.02; // Bias along normal
 
// Shadow map size (balance quality vs performance)
// 512 - low quality
// 1024 - medium quality
// 2048 - high quality
// 4096 - very high quality (expensive)

import { ContactShadows } from "three/examples/jsm/objects/ContactShadows.js";
 
const contactShadows = new ContactShadows({
  resolution: 512,
  blur: 2,
  opacity: 0.5,
  scale: 10,
  position: [0, 0, 0],
});
scene.add(contactShadows);

import { RectAreaLightHelper } from "three/examples/jsm/helpers/RectAreaLightHelper.js";
 
// DirectionalLight helper
const dirHelper = new THREE.DirectionalLightHelper(dirLight, 5);
scene.add(dirHelper);
 
// PointLight helper
const pointHelper = new THREE.PointLightHelper(pointLight, 1);
scene.add(pointHelper);
 
// SpotLight helper
const spotHelper = new THREE.SpotLightHelper(spotLight);
scene.add(spotHelper);
 
// Hemisphere helper
const hemiHelper = new THREE.HemisphereLightHelper(hemiLight, 5);
scene.add(hemiHelper);
 
// RectAreaLight helper
const rectHelper = new RectAreaLightHelper(rectLight);
rectLight.add(rectHelper);
 
// Update helpers when light changes
dirHelper.update();
spotHelper.update();

import { RGBELoader } from "three/examples/jsm/loaders/RGBELoader.js";
 
const rgbeLoader = new RGBELoader();
rgbeLoader.load("environment.hdr", (texture) => {
  texture.mapping = THREE.EquirectangularReflectionMapping;
 
  // Set as scene environment (affects all PBR materials)
  scene.environment = texture;
 
  // Optional: also use as background
  scene.background = texture;
  scene.backgroundBlurriness = 0; // 0-1, blur the background
  scene.backgroundIntensity = 1;
});
 
// PMREMGenerator for better reflections
const pmremGenerator = new THREE.PMREMGenerator(renderer);
pmremGenerator.compileEquirectangularShader();
 
rgbeLoader.load("environment.hdr", (texture) => {
  const envMap = pmremGenerator.fromEquirectangular(texture).texture;
  scene.environment = envMap;
  texture.dispose();
  pmremGenerator.dispose();
});

const cubeLoader = new THREE.CubeTextureLoader();
const envMap = cubeLoader.load([
  "px.jpg",
  "nx.jpg",
  "py.jpg",
  "ny.jpg",
  "pz.jpg",
  "nz.jpg",
]);
 
scene.environment = envMap;
scene.background = envMap;

import { LightProbeGenerator } from "three/examples/jsm/lights/LightProbeGenerator.js";
 
// Generate from cube texture
const lightProbe = new THREE.LightProbe();
scene.add(lightProbe);
 
lightProbe.copy(LightProbeGenerator.fromCubeTexture(cubeTexture));
 
// Or from render target
const cubeCamera = new THREE.CubeCamera(
  0.1,
  100,
  new THREE.WebGLCubeRenderTarget(256),
);
cubeCamera.update(renderer, scene);
lightProbe.copy(
  LightProbeGenerator.fromCubeRenderTarget(renderer, cubeCamera.renderTarget),
);

// Key light (main light)
const keyLight = new THREE.DirectionalLight(0xffffff, 1);
keyLight.position.set(5, 5, 5);
scene.add(keyLight);
 
// Fill light (softer, opposite side)
const fillLight = new THREE.DirectionalLight(0xffffff, 0.5);
fillLight.position.set(-5, 3, 5);
scene.add(fillLight);
 
// Back light (rim lighting)
const backLight = new THREE.DirectionalLight(0xffffff, 0.3);
backLight.position.set(0, 5, -5);
scene.add(backLight);
 
// Ambient fill
const ambient = new THREE.AmbientLight(0x404040, 0.3);
scene.add(ambient);

// Sun
const sun = new THREE.DirectionalLight(0xffffcc, 1.5);
sun.position.set(50, 100, 50);
sun.castShadow = true;
scene.add(sun);
 
// Sky ambient
const hemi = new THREE.HemisphereLight(0x87ceeb, 0x8b4513, 0.6);
scene.add(hemi);

// Multiple area lights
RectAreaLightUniformsLib.init();
 
const light1 = new THREE.RectAreaLight(0xffffff, 5, 2, 2);
light1.position.set(3, 3, 3);
light1.lookAt(0, 0, 0);
scene.add(light1);
 
const light2 = new THREE.RectAreaLight(0xffffff, 3, 2, 2);
light2.position.set(-3, 3, 3);
light2.lookAt(0, 0, 0);
scene.add(light2);
 
// Ambient fill
const ambient = new THREE.AmbientLight(0x404040, 0.2);
scene.add(ambient);

const clock = new THREE.Clock();
 
function animate() {
  const time = clock.getElapsedTime();
 
  // Orbit light around scene
  light.position.x = Math.cos(time) * 5;
  light.position.z = Math.sin(time) * 5;
 
  // Pulsing intensity
  light.intensity = 1 + Math.sin(time * 2) * 0.5;
 
  // Color cycling
  light.color.setHSL((time * 0.1) % 1, 1, 0.5);
 
  // Update helpers if using
  lightHelper.update();
}

// Light layers
light.layers.set(1); // Light only affects layer 1
mesh.layers.enable(1); // Mesh is on layer 1
otherMesh.layers.disable(1); // Other mesh not affected
 
// Selective shadows
mesh.castShadow = true;
mesh.receiveShadow = true;
decorMesh.castShadow = false; // Small objects often don't need to cast