I'm trying to create a 2D overlay for my 3D scene. I've thought of three options:

1. Get a 2d context from the existing canvas element and draw on it.
	* Unfortunately, **this won't work** since three.js already got a [webgl context](https://stackoverflow.com/questions/2928558/canvas-3d-drawing-using-both-2d-and-3d-context) from the canvas.
2. Create a second canvas element and position it over the top of the original canvas
	* **I'd like to avoid this solution**; I don't want to worry about passing click events from the overlay canvas to the original canvas
3. Create a billboard (from a particle) that perfectly fits the viewport and give it a canvas texture.

How do I carry out the third option? I'll need the option to resize the canvas. I already know how to use a canvas as a texture thanks to [this](http://stemkoski.github.io/Three.js/Sprite-Text-Labels.html) example.

Also, if the second option is not as hard as I'm thinking it might be, please let me know.