Improve CameraControl dollying through objects

[xeolabs]

With CameraControl followPointer set true, it can be hard to dolly through objects with the mouse scroll wheel, and takes a strong push on the wheel to break through.

CameraControl is designed to slow down as we approach an object, but is slowing down too much.

This can be fixed by ensuring that dollying speed in this case does not fall below a given minimum.

Solution

Increase the default value for CameraControl#dollyMinSpeed from 0.01 to 0.06.

If this is not enough, it can be increased further, eg:

viewer.cameraControl.dollyMinSpeed = 0.08;

Experiment with that here:
https://xeokit.github.io/xeokit-sdk/examples/#CameraControl_orbit_Duplex

[eriadam]

@xeolabs Thanks for the fix attempt.

Would you have any additional information on what this value would be dependent on? Browser, viewport size, js engine, hardware, model size, number of meshes, so forth?

In other words, how to do we make sure it works for every models we render?

[xeolabs]

I'm not sure yet how to dynamically derive a workable value for this yet. It's possible, just needs thinking.

For now, I would just try to find a general magic value that works for all models, then I'll come back to this for the next release.

[xeolabs]

@eriadam this one's going to need more work. I just found a wall it gets stuck on, so will have a second patch for this in 1.5.2 on Monday.