three.js/src/core/InstancedBufferGeometry.js

import { BufferGeometry } from './BufferGeometry';

/**
 * @author benaadams / https://twitter.com/ben_a_adams
 */

function InstancedBufferGeometry() {

	BufferGeometry.call( this );

	this.type = 'InstancedBufferGeometry';
	this.maxInstancedCount = undefined;

}

InstancedBufferGeometry.prototype = Object.assign( Object.create( BufferGeometry.prototype ), {

	constructor: InstancedBufferGeometry,

	isInstancedBufferGeometry: true,

	addGroup: function ( start, count, materialIndex ) {

		this.groups.push( {

			start: start,
			count: count,
			materialIndex: materialIndex

		} );

	},

	copy: function ( source ) {

		var index = source.index;

		if ( index !== null ) {

			this.setIndex( index.clone() );

		}

		var attributes = source.attributes;

		for ( var name in attributes ) {

			var attribute = attributes[ name ];
			this.addAttribute( name, attribute.clone() );

		}

		var groups = source.groups;

		for ( var i = 0, l = groups.length; i < l; i ++ ) {

			var group = groups[ i ];
			this.addGroup( group.start, group.count, group.materialIndex );

		}

		return this;

	}

} );

export { InstancedBufferGeometry };