async fromCubemapAsync( cubemap, renderTarget = null ) {

		if ( this._hasInitialized === false ) await this._renderer.init();

		return this._fromTexture( cubemap, renderTarget );

	}
Generates a PMREM from an cubemap texture, which can be either LDR
or HDR. The ideal input cube size is 256 x 256,
with the 256 x 256 cubemap output.

@param {Texture} cubemap - The cubemap texture to be converted.
@param {?RenderTarget} [renderTarget=null] - The render target to use.
@return {Promise<RenderTarget>} The resulting PMREM.
@see {@link PMREMGenerator#fromCubemap}