Implement panning in FirstPersonController

[felixpalmer]

Related to #8149

Background

Add panning motions to FirstPersonController, so that camera is moved in the plane normal to the view direction when shift key is held. Also integrates with dragMode. Test behavior here: https://jsfiddle.net/felixp/b5pugcyx/

Change List

• Implementation for panStart, pan & panEnd methods

[coveralls]

coverage: 84.064% (-0.01%) from 84.074%
when pulling d52cace on felix/first-person-pan
into b1e0ba7 on master.

[chrisgervang]

I was playing around with this on mobile today and was wondering if we could use a two finger up/down gesture to control vertical movement. It works well for looking and walking around!

Alternatively, could the controller be reconfigured with a prop to have the scroll (zoom?) action behave as before (move you in the direction you're pointing)?

For use cases I'm familiar with there are two main modes this controller gets used in: a mode to freely move in 3D space to an area of interest, and a mode to walk around that area of interest as a human would for closer inspection.

Desktop has controls for both modes with mouse and keyboard, but mobile would need some way to perform vertical movement

[felixpalmer]

@chrisgervang have you tried it with touchRotate=true and dragmode='pan'?

[chrisgervang]

Oh nice, dragMode: "pan" works great for that. Apps can add a toggle to support mobile well.