There are no shadows

[charliewhitfield]

I, Voyager platform
All

I, Voyager version and (if applicable) Godot version
v0.0.6 and master branch; Godot 3.2.1

OS/device
Windows 10 (Chrome for HTML5 platforms)

Issue description:
There are no shadows. There should be.

Steps to reproduce
Visit Saturn. When rings are not edge-on they should cast a shadow on Saturn.
Or visit Jupiter. It should be easy to catch Io's shadow, if it existed. (You can make Io 20x bigger in the moons.tsv table to make that more obvious.)

Minimal project
N/A

Other helpful information
I don't know why we don't have them!
OmniLight.shadow_enabled = true
All of our GeometryInstances (worlds and Saturn's rings) have default cast_shadow = 1.
All of our SpatialMaterials (world & ring textures) have default flags_do_not_receive_shadows = false.

I played around with Light.shadow_bias. According to the tutorial, I ought to be able to create "self-shadow" artifacts by setting that too low. But no, I can't even create shadow artifacts...