three.js/examples/jsm/nodes/accessors/BatchNode.js

import Node, { addNodeClass } from '../core/Node.js';
import { normalLocal } from './NormalNode.js';
import { positionLocal } from './PositionNode.js';
import { nodeProxy, vec3, mat3, mat4, int, ivec2, float } from '../shadernode/ShaderNode.js';
import { textureLoad } from './TextureNode.js';
import { textureSize } from './TextureSizeNode.js';
import { Float32BufferAttribute } from 'three';
import { bufferAttribute } from './BufferAttributeNode.js';
import { tangentLocal } from './TangentNode.js';

class BatchNode extends Node {

	constructor( batchMesh ) {

		super( 'void' );

		this.batchMesh = batchMesh;


		this.instanceColorNode = null;

		this.batchingIdNode = null;

	}

	setup( builder ) {

		// POSITION

		if ( this.batchingIdNode === null ) {

			const batchingAttribute = this.batchMesh.geometry.getAttribute( 'batchId' );
			const array = new Float32Array( batchingAttribute.array );

			const buffer = new Float32BufferAttribute( array, 1 );

			this.batchingIdNode = bufferAttribute( buffer, 'float' ).toVar();

		}

		const matriceTexture = this.batchMesh._matricesTexture;

		const size = textureSize( textureLoad( matriceTexture ), 0 );
		const j = float( int( this.batchingIdNode ) ).mul( 4 ).toVar();

		const x = int( j.mod( size ) );
		const y = int( j ).div( int( size ) );
		const batchingMatrix = mat4(
			textureLoad( matriceTexture, ivec2( x, y ) ),
			textureLoad( matriceTexture, ivec2( x.add( 1 ), y ) ),
			textureLoad( matriceTexture, ivec2( x.add( 2 ), y ) ),
			textureLoad( matriceTexture, ivec2( x.add( 3 ), y ) )
		);


		const bm = mat3(
			batchingMatrix[ 0 ].xyz,
			batchingMatrix[ 1 ].xyz,
			batchingMatrix[ 2 ].xyz
		 );

		positionLocal.assign( batchingMatrix.mul( positionLocal ) );

		const transformedNormal = normalLocal.div( vec3( bm[ 0 ].dot( bm[ 0 ] ), bm[ 1 ].dot( bm[ 1 ] ), bm[ 2 ].dot( bm[ 2 ] ) ) );

		const batchingNormal = bm.mul( transformedNormal ).xyz;

		normalLocal.assign( batchingNormal );

		if ( builder.hasGeometryAttribute( 'tangent' ) ) {

			tangentLocal.mulAssign( bm );

		}

	}

}

export default BatchNode;

export const batch = nodeProxy( BatchNode );

addNodeClass( 'batch', BatchNode );