three.js/examples/jsm/nodes/lighting/EnvironmentNode.js

import LightingNode from './LightingNode.js';
import { cache } from '../core/CacheNode.js';
import { context } from '../core/ContextNode.js';
import { maxMipLevel } from '../utils/MaxMipLevelNode.js';
import { roughness, clearcoatRoughness } from '../core/PropertyNode.js';
import { equirectUV } from '../utils/EquirectUVNode.js';
import { specularMIPLevel } from '../utils/SpecularMIPLevelNode.js';
import { cameraViewMatrix } from '../accessors/CameraNode.js';
import { transformedClearcoatNormalView, transformedNormalView, transformedNormalWorld } from '../accessors/NormalNode.js';
import { positionViewDirection } from '../accessors/PositionNode.js';
import { addNodeClass } from '../core/Node.js';
import { vec2 } from '../shadernode/ShaderNode.js';
import { cubeTexture } from '../accessors/CubeTextureNode.js';
import { reference } from '../accessors/ReferenceNode.js';

const envNodeCache = new WeakMap();

class EnvironmentNode extends LightingNode {

	constructor( envNode = null ) {

		super();

		this.envNode = envNode;

	}

	setup( builder ) {

		let envNode = this.envNode;

		if ( envNode.isTextureNode && envNode.value.isCubeTexture !== true ) {

			let cacheEnvNode = envNodeCache.get( envNode.value );

			if ( cacheEnvNode === undefined ) {

				const texture = envNode.value;
				const renderer = builder.renderer;

				// @TODO: Add dispose logic here
				const cubeRTT = builder.getCubeRenderTarget( 512 ).fromEquirectangularTexture( renderer, texture );

				cacheEnvNode = cubeTexture( cubeRTT.texture );

				envNodeCache.set( envNode.value, cacheEnvNode );

			}

			envNode	= cacheEnvNode;

		}

		//

		const intensity = reference( 'envMapIntensity', 'float', builder.material ); // @TODO: Add materialEnvIntensity in MaterialNode

		const radiance = context( envNode, createRadianceContext( roughness, transformedNormalView ) ).mul( intensity );
		const irradiance = context( envNode, createIrradianceContext( transformedNormalWorld ) ).mul( Math.PI ).mul( intensity );

		const isolateRadiance = cache( radiance );

		//

		builder.context.radiance.addAssign( isolateRadiance );

		builder.context.iblIrradiance.addAssign( irradiance );

		//

		const clearcoatRadiance = builder.context.lightingModel.clearcoatRadiance;

		if ( clearcoatRadiance ) {

			const clearcoatRadianceContext = context( envNode, createRadianceContext( clearcoatRoughness, transformedClearcoatNormalView ) ).mul( intensity );
			const isolateClearcoatRadiance = cache( clearcoatRadianceContext );

			clearcoatRadiance.addAssign( isolateClearcoatRadiance );

		}

	}

}

const createRadianceContext = ( roughnessNode, normalViewNode ) => {

	let reflectVec = null;
	let textureUVNode = null;

	return {
		getUV: ( textureNode ) => {

			let node = null;

			if ( reflectVec === null ) {

				reflectVec = positionViewDirection.negate().reflect( normalViewNode );
				reflectVec = roughnessNode.mul( roughnessNode ).mix( reflectVec, normalViewNode ).normalize();
				reflectVec = reflectVec.transformDirection( cameraViewMatrix );

			}

			if ( textureNode.isCubeTextureNode ) {

				node = reflectVec;

			} else if ( textureNode.isTextureNode ) {

				if ( textureUVNode === null ) {

					// @TODO: Needed PMREM

					textureUVNode = equirectUV( reflectVec );

				}

				node = textureUVNode;

			}

			return node;

		},
		getTextureLevel: () => {

			return roughnessNode;

		},
		getTextureLevelAlgorithm: ( textureNode, levelNode ) => {

			return specularMIPLevel( textureNode, levelNode );

		}
	};

};

const createIrradianceContext = ( normalWorldNode ) => {

	let textureUVNode = null;

	return {
		getUV: ( textureNode ) => {

			let node = null;

			if ( textureNode.isCubeTextureNode ) {

				node = normalWorldNode;

			} else if ( textureNode.isTextureNode ) {

				if ( textureUVNode === null ) {

					// @TODO: Needed PMREM

					textureUVNode = equirectUV( normalWorldNode );
					textureUVNode = vec2( textureUVNode.x, textureUVNode.y.oneMinus() );

				}

				node = textureUVNode;

			}

			return node;

		},
		getTextureLevel: ( textureNode ) => {

			return maxMipLevel( textureNode );

		}
	};

};

export default EnvironmentNode;

addNodeClass( 'EnvironmentNode', EnvironmentNode );