3D scene won't render in HTML5 export, unless it has at least one DirectionalLight3D, OmniLight3D and SpotLight3D

[dsnopek]

Godot version

v4.0.alpha.custom_build [ad24789]

System information

Chrome, GLES3

Issue description

It appears as though a 3D scene won't render in an HTML5 export, unless it has at least one DirectionLight3D, one OmniLight3D and one SpotLight3D.

This doesn't affect a 3D scene running with the 'opengl3' driver on the desktop (having only a DirectionalLight3D is enough) - the problem happens only when exported to HTML5.

I can't get 2D to render on HTML5 at all (even though, again, it renders fine with the 'opengl3' driver on my desktop).

Steps to reproduce

1. Create a new project
2. Go to "Project settings..." and turn on "Advanced Settings"
3. In "Rendering" -> "Driver" set the "Driver Name" to "opengl3"
4. Restart the editor
5. Create a new scene with a Node3D as the root
6. Add a MeshInstance3D with a Cube mesh
7. Add a DirectionalLight3D
8. Add a Camera3D that is pointing at the Cube
9. Save the scene, run the project, and use the current scene as the main scene when prompted
10. Verify that you can see the cube when running on the desktop!
11. Export the game to HTML5
12. Use the "Run exported HTML the system's default browser" button in the upper-right (the one that looks like the HTML5 logo, but the normal run button)
13. You'll only see the clear color in the web browser - no cube!
14. Go back to the Godot editor
15. Add an OmniLight3D
16. Add a SpotLight3D
17. Use the "Run exported HTML the system's default browser" button again
18. Now you WILL see the cube in the web browser!

Minimal reproduction project

g4-html5-test.zip

This project include all 3 lights, so it should actually work! However, if you delete any one of the lights, and export again, it won't render the cube.

[dsnopek]

Chatted with @clayjohn about this a bit on RocketChat! He has an idea about what it might be