Orbit Controls pan on two finger unidirectional touch

Currently Orbit Controls handles touch as:

• one finger: orbit
• two fingers: zoom
• three fingers: pan

It’s a fantastic helper library, but I think panning is terribly hard to discover. I only discovered it by looking through the library, and don’t think I would have discovered it just by playing around with a scene on a touchscreen device.

As a user, I would expect to be able to pan using two fingers moving unidirectionally. I would expect to be able to zoom using two fingers, in a pinching and zoom gesture. I would suggest instead:

• one finger: orbit
• two fingers (pinch/spread): zoom
• two fingers (unidirectional): pan

I haven’t implemented this yet, but I’m thinking to in the next couple of weeks. I couldn’t find a related issue or discussion of this so I’m opening a ticket and see if anyone has pre-existing ideas or concerns around this? I could contribute a PR in the future if it’s a desirable change.