Lights

import * as THREE from 'three';
import { RGBELoader } from 'three/examples/jsm/loaders/RGBELoader.js';

// 1) Ambient light — flat fill, no direction, no shadows
const ambient = new THREE.AmbientLight(0xffffff, 0.25);
scene.add(ambient);

// 2) Hemisphere light — sky color above, ground color below
const hemi = new THREE.HemisphereLight(0xb1e1ff, 0xb97a20, 0.4);
scene.add(hemi);

// 3) Directional light — parallel rays, like the sun
const sun = new THREE.DirectionalLight(0xffffff, 3);
sun.position.set(5, 10, 7);
sun.castShadow = true;
sun.shadow.mapSize.set(2048, 2048);            // detail of the shadow
sun.shadow.camera.near   = 0.5;
sun.shadow.camera.far    = 50;
sun.shadow.camera.left   = -20;
sun.shadow.camera.right  =  20;
sun.shadow.camera.top    =  20;
sun.shadow.camera.bottom = -20;
sun.shadow.bias = -0.0001;
scene.add(sun);

// 4) Point light — radial bulb
const bulb = new THREE.PointLight(0xffeedd, 5, 20, 2);
bulb.position.set(2, 3, 0);
bulb.castShadow = true;
scene.add(bulb);

// 5) Spot light — cone
const spot = new THREE.SpotLight(0xffffff, 10);
spot.position.set(0, 8, 0);
spot.angle = Math.PI / 6;
spot.penumbra = 0.2;
spot.decay = 2;
spot.distance = 30;
spot.castShadow = true;
scene.add(spot);

// Make the spot follow a target object
const target = new THREE.Object3D();
scene.add(target);
spot.target = target;

// 6) Rectangle area light (PBR realistic; doesn't cast shadows)
import { RectAreaLightHelper } from 'three/examples/jsm/helpers/RectAreaLightHelper.js';
import { RectAreaLightUniformsLib } from 'three/examples/jsm/lights/RectAreaLightUniformsLib.js';
RectAreaLightUniformsLib.init();

const rect = new THREE.RectAreaLight(0xffffff, 10, 4, 1);
rect.position.set(0, 5, 0);
rect.lookAt(0, 0, 0);
scene.add(rect);

// 7) Receive shadows — meshes must opt-in
mesh.castShadow    = true;
mesh.receiveShadow = true;
floor.receiveShadow = true;

renderer.shadowMap.enabled = true;
renderer.shadowMap.type    = THREE.PCFSoftShadowMap;

// 8) Image-based lighting (IBL) — environment maps drive PBR realism
const pmrem = new THREE.PMREMGenerator(renderer);
pmrem.compileEquirectangularShader();
const hdr = await new RGBELoader().loadAsync('/env/studio.hdr');
const envMap = pmrem.fromEquirectangular(hdr).texture;
hdr.dispose(); pmrem.dispose();

scene.environment = envMap;       // every PBR material now reflects this
scene.background  = envMap;       // optional — visible background too

// 9) Tone mapping + exposure — make HDR lighting look right
renderer.outputColorSpace = THREE.SRGBColorSpace;
renderer.toneMapping      = THREE.ACESFilmicToneMapping;
renderer.toneMappingExposure = 1.0;

// 10) Helpers — see where the light is going
scene.add(new THREE.DirectionalLightHelper(sun, 1));
scene.add(new THREE.PointLightHelper(bulb, 0.5));
scene.add(new THREE.SpotLightHelper(spot));
scene.add(new THREE.HemisphereLightHelper(hemi, 1));

// 11) Lighting recipes
//   Outdoor — ambient(0.2) + directional sun(3) + envmap = sky
//   Indoor  — env map(2) + point/spot bulbs(5) + low ambient(0.05)
//   Studio  — three-point: key + fill + rim

// 12) Performance
//   • Each shadow-casting light is one extra render pass per frame
//   • Use 2K shadow maps for the sun, 1K for accent lights
//   • Bake static lighting into lightmaps when possible (offline)

scene.add(new THREE.AmbientLight(0xffffff, 0.3));
const dir = new THREE.DirectionalLight(0xffffff, 1);
dir.position.set(5, 10, 7);
scene.add(dir);