Allow TrackballControls to work in a static scene like OrbitControls does

[mkhorton]

Adds _this.update() to mousewheel(), mousemove() and touchmove() events in TrackballControls.

From the documentation, TrackballControls and OrbitControls look like they're drop-in replacements for one another, they both have the same constructor, etc. However, unlike OrbitControls, TrackballControls does not work in a static scene with no animation loop present.

See this Stack Overflow thread for a discussion.

PR would allow TrackballControls to work in static scenes.

[Mugen87]

Current version: https://jsfiddle.net/6dagmj0c/
With your change: https://jsfiddle.net/dp1ry53v/2/

PR would allow TrackballControls to work in static scenes.

Yes, it is necessary to set TrackballControls.staticMoving to true. Otherwise the interaction feels weird.

Can you please also update the JSM version by running node utils/modularize.js (from the project's root directory)? In this way, it's easier to verify the existing examples via: http://raw.githack.com/mkhorton/three.js/patch-1/examples/index.html

[mkhorton]

Thanks @Mugen87, I've run modularize.js and added a note to the TrackballControls docs about setting TrackballControls.staticMoving to true in static scenes.

[Mugen87]

The issue with this change is that it makes the call of TrackballControls.update() obsolete when no damping is used. The official example misc_controls_trackball now works even if the update call is removed from the animation loop.

Hence, the documentation of update() should be changed to something similar like OrbitControls.update(). Besides, it's necessary to check the examples and remove controls.update() when TrackballControls.staticMoving is set to true. Otherwise unnecessary updates are performed which is not good.

This change also needs a note in the migration guide.

[Mugen87]

Let's revisit this change if it's clear what happens to TrackballControls, see #17842, #17857, #17858.

[mkhorton]

Thanks for the update!