async readRenderTargetPixelsAsync( renderTarget, x, y, width, height, textureIndex = 0, faceIndex = 0 ) {

		return this.backend.copyTextureToBuffer( renderTarget.textures[ textureIndex ], x, y, width, height, faceIndex );

	}
Reads pixel data from the given render target.

@async
@param {RenderTarget} renderTarget - The render target to read from.
@param {number} x - The `x` coordinate of the copy region's origin.
@param {number} y - The `y` coordinate of the copy region's origin.
@param {number} width - The width of the copy region.
@param {number} height - The height of the copy region.
@param {number} [textureIndex=0] - The texture index of a MRT render target.
@param {number} [faceIndex=0] - The active cube face index.
@return {Promise<TypedArray>} A Promise that resolves when the read has been finished. The resolve provides the read data as a typed array.