toDataURL(type = "image/png", quality) {
		return this.renderTarget.toDataURL(type, quality);
	}
returns a data URL containing a representation of the last frame rendered
@param {string} [type="image/png"] - A string indicating the image format
@param {number} [quality] - A Number between 0 and 1 indicating the image quality to be used when creating images using file formats that support lossy compression (such as image/jpeg or image/webp). A user agent will use its default quality value if this option is not specified, or if the number is outside the allowed range.
@returns {Promise} A Promise returning a string containing the requested data URL.
@example
renderer.toDataURL().then((dataURL) => console.log(dataURL));