Excerpt from this article:
On Thursday, L’Oréal will introduce an app that turns the front-facing iPhone and iPad camera into a makeup mirror that allows customers to virtually try on more than 300 cosmetic products and see immediately different looks or complete makeovers on their own faces.
They can pout, sneer, move in and out of changes in lighting or shadows, and the virtual makeup stays as if it had been painted on. (A recent test confirmed that the virtual makeup will move with expressions, although vigorous head-shaking seemed to dislodge some heavy eye shadow a bit.)
The app, called Makeup Genius, was developed in partnership with Image Metrics, a company known for its facial mapping in movies and video games.