/// <param name="gl">The current WebGL drawing context.</param>
/// <param name="width">The horizontal range of the filter.</param>
/// <param name="height">The vertical range of the filter.</param>
/// <param name="scaleMode">The current scale mode.</param>
/// <param name="resolution">The current resolution.</param>
/// <param name="root">Whether this object is the root element or not.</param>
public extern RenderTarget(IWebGLRenderingContext gl, float width, float height,
ScaleMode scaleMode, Resolution resolution, bool root);
public extern Quad(IWebGLRenderingContext gl);