LatheGeometry: Improve normal generation. (#22927)
LatheGeometry: Improve normal generation. (#22927)

* Update LatheGeometry.js

Two-step approach:
1. pre-compute normals in 2D-domain (all z = 0) for initial "meridian" of vertices as defined in the points[] array
2. rotate pre-computed normals along with vertices for each additional meridian in lathing
Advantages:
* Considerably reduces computational expense of setting up normals.
* perfect normal precision (within limits of numerical accuracy), avoids considerable deviations from precision in low lathe-segment count situations of current approach
* seam-handling obsoleted by design
This is going to be my first pull request. I hope, I'll be able to add screenshots/scetches later in the process.

* Update LatheGeometry.js

Struggling with my 1st PR and now fixing previously ommitted code lines.

* Update LatheGeometry.js

Fixed linting errors
gero3/three.js,makc/three.js.fork,Liuer/three.js,06wj/three.js,jpweeks/three.js,mrdoob/three.js,looeee/three.js,fyoudine/three.js,fyoudine/three.js,aardgoose/three.js,Liuer/three.js,aardgoose/three.js,WestLangley/three.js,donmccurdy/three.js,06wj/three.js,donmccurdy/three.js,WestLangley/three.js,greggman/three.js,mrdoob/three.js,looeee/three.js,makc/three.js.fork,jpweeks/three.js,gero3/three.js,greggman/three.js