Stage 3D , extra viewpoint of world

I’m unsure if this is possible, but if I don’t ask I’ might never know.
In Stage 3D we basically draw direct onto the canvas,
I’m building a vehicle interface where I wish the user/driver to look at the rear vision mirrors.
I would like this to ideally be a reverse viewpoint of the view behind.
Is this possible?
My “work-around” alternative is to add reflective//shiny surfaces to my “car’s-world” and have these 'reflect the rear scenery. However I fear this will increase processing usage significantly.

TIA.