“There’s an app for that.” Apparently there is an app for everything, including projection mapping (video mapping/spatial augmented reality).
DynaMapper is an iPad app that enables projection mapping using images and image sprites, via keystoning and mesh warping for rectangular and rounded surfaces.
Obviously, the app requires a projector (and the proper iPad video adapter).
The feature set is pretty spartan. It doesn’t even support video mapping (using video sources). But hey its $4.99.