Parametrized shader and gestures

I implemented some basic swipe actions on the viewfinder, and hooked it up with the blurring shader. Left-right swipes control the size of the Gaussian filter. Vertical swipe basically resets it to the non-blurred state.

Seems like getting multi-touch gestures might be trickier: "Making sense of multitouch"

At this point, it might be also worth it to clean up and optimize the shader, and to implement a kind of a cooler filter.

The fact that we're in RGB in shader is a bit inconvenient. Where does FCam::Frame get converted into RGB? Can I delay it?

Some info on bilateral filtering implementations:

• Real-time bilateral filtering
• Separable bilateral filtering for fast video preprocessing