three.js/src/core/InstancedBufferAttribute.js

import { BufferAttribute } from './BufferAttribute.js';

function InstancedBufferAttribute( array, itemSize, normalized, meshPerAttribute ) {

	if ( typeof ( normalized ) === 'number' ) {

		meshPerAttribute = normalized;

		normalized = false;

		console.error( 'THREE.InstancedBufferAttribute: The constructor now expects normalized as the third argument.' );

	}

	BufferAttribute.call( this, array, itemSize, normalized );

	this.meshPerAttribute = meshPerAttribute || 1;

}

InstancedBufferAttribute.prototype = Object.assign( Object.create( BufferAttribute.prototype ), {

	constructor: InstancedBufferAttribute,

	isInstancedBufferAttribute: true,

	copy: function ( source ) {

		BufferAttribute.prototype.copy.call( this, source );

		this.meshPerAttribute = source.meshPerAttribute;

		return this;

	},

	toJSON: function ()	{

		const data = BufferAttribute.prototype.toJSON.call( this );

		data.meshPerAttribute = this.meshPerAttribute;

		data.isInstancedBufferAttribute = true;

		return data;

	}

} );



export { InstancedBufferAttribute };