[popey456963]

Imperial (A UK University) are currently making large leaps forward in terms of modelling a room or environment with just a single camera and little computing power. Their basic methodology was:

- Pick "unique" points currently in view

- Track how they move as the camera moves

- Combine this data with the accelerometer to get an accurate movement reading of the phone.

- You can get the depth of any point by comparing two images and knowing the change in user position.

Simple algorithm, but their results were astonishingly good. Snap don't need to model the entire room, they just need to work out where these points are to keep the image appearing still.