Lighting doesn't work on certain 3D mesh plots

[monfera]

Brain looks like a grey blob with undiscernible features. Cause is that specular reflection isn't active. Besides a plotly.js dependency ignoring the lighting parameters (fixed), there was a problem which resulted in very small triangles being omitted in specular light reflection calculation (also fixed). The triangles were very small - except 2-3 larger ones - because the brain mesh is intricately detailed to yield sufficient anatomical representation of the hemisphere surface, with over 300k points in the mesh.

In this specific case, lighting isn't working and the result is an indistinguishable grey surface.

[monfera]

Found a bug w.r.t. lighting; in the process of working on it. A completely independent issue seems to be that upon some navigation steps, the grid lines can go wild:

[monfera]

We have a fix candidate; will work on the PR Friday. Hopefully no showstoppers.

[monfera]

PRs that fix this issue:
mikolalysenko/normals#2
gl-vis/gl-mesh3d#5
#556 <= this is changed to take advantage of the epsilon config

[monfera]

Internal surface of the hemisphere mesh:

[monfera]

With additional lighting configuration and a crude representation of the brain shape to differentially shade / color the inner grooves vs. the outer surface of the folds: