Consider a more recent version of three.js

[samreid]

From #5, Density & Buoyancy is using THREE r104 which was released April 2019. Since then, there have been numerous releases. We may have an easier time maintaining something more recent, perhaps before publication we should see if it is easy to use the current version. Or, if there are changes that make upgrading impossible, we should know what they are. @jonathanolson can you please investigate?

[jonathanolson]

Upgrading looks possible, notable items from the migration guide (https://github.com/mrdoob/three.js/wiki/Migration-Guide):

• clearCoat => clearcoat
• BufferGeometry addAttribute => setAttribute
• BufferGeomtery removeAttribute => deleteAttribute
• The default value of MeshStandardMaterial.roughness has changed from 0.5 to 1.
• The default value of MeshStandardMaterial.metalness has changed from 0.5 to 0.
• applyMatrix() has been renamed to applyMatrix4().
• Frustum.setFromMatrix() has been renamed to Frustum.setFromProjectionMatrix().
• MeshPhysicalMaterial.transparency has been renamed to MeshPhysicalMaterial.transmission.
• Scene.dispose() has been removed.
• Geometry generators like BoxGeometry now produce a BufferGeometry.

[jonathanolson]

An hour of porting, and most things are working except the envMap on MeshStandardMaterial is being internally concerted to an PMREM, and it's definitely not accepting the LDR texture provided, even with giving the proper LDR format (THREE.RGBFormat). All appearances of anything with reflection are completely off still:

I can't tell if it's incorrectly interpreting the Canvas texture as RGBE, modifying the alpha channel can't reproduce the same effect.

I've created branches above (just for density/buoyancy, we'd also need to port build-a-molecule).

@kathy-phet it will at least take a few hours to probably find a new way of getting an environment map, and it will probably have a 80% chance of still causing a change of appearance. Thoughts on whether to defer?