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

/**
 * This special type of buffer attribute is intended for compute shaders.
 * In earlier three.js versions it was only possible to update attribute data
 * on the CPU via JavaScript and then upload the data to the GPU. With the
 * new material system and renderer it is now possible to use compute shaders
 * to compute the data for an attribute more efficiently on the GPU.
 *
 * The idea is to create an instance of this class and provide it as an input
 * to {@link StorageBufferNode}.
 *
 * Note: This type of buffer attribute can only be used with `WebGPURenderer`.
 *
 * @augments BufferAttribute
 */
class StorageBufferAttribute extends BufferAttribute {

	/**
	 * Constructs a new storage buffer attribute.
	 *
	 * @param {number|TypedArray} count - The item count. It is also valid to pass a typed array as an argument.
	 * The subsequent parameters are then obsolete.
	 * @param {number} itemSize - The item size.
	 * @param {TypedArray.constructor} [typeClass=Float32Array] - A typed array constructor.
	 */
	constructor( count, itemSize, typeClass = Float32Array ) {

		const array = ArrayBuffer.isView( count ) ? count : new typeClass( count * itemSize );

		super( array, itemSize );

		/**
		 * This flag can be used for type testing.
		 *
		 * @type {boolean}
		 * @readonly
		 * @default true
		 */
		this.isStorageBufferAttribute = true;

	}

}

export default StorageBufferAttribute;