Three.js: Add option to render only single side of surface

[paulmasson]

The current implementation of WebGL has known issues with transparent surfaces, one being noticeable rendering artifacts for closed transparent surfaces. This ticket adds the option of rendering the front side of the surface only, thereby reducing rendering artifacts. Compare these two graphics:

polytopes.dodecahedron().plot(opacity=.5)
polytopes.dodecahedron().plot(opacity=.5,single_side=True)

This option is only meant to be used with closed surfaces, because an open surface will disappear from view from certain angles if both sides are not rendered.

CC: @jplab @EmmanuelCharpentier @egourgoulhon

Component: graphics

Keywords: threejs

Author: Paul Masson

Branch/Commit: 81f6275

Reviewer: Eric Gourgoulhon

Issue created by migration from https://trac.sagemath.org/ticket/28702

[paulmasson]

Branch: u/paulmasson/single_side

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

81f6275

Better and more consistent tests

[sagetrac-git]

Commit: 81f6275

[egourgoulhon]

Reviewer: Eric Gourgoulhon

[egourgoulhon]

comment:4

LGTM. I've tested it on top of #28699 on this notebook.
Thanks for this improvement!

[vbraun]

Changed branch from u/paulmasson/single_side to 81f6275