Directional lights meet Wolfram Language behavior

[TiagoCavalcante]

Directional lights in mathics-threejs-backend have been using spherical coordinates since its creation, but Wolfram Language doesn't do this way, it uses cartesian coordinates + ImageScaled coordinates for things like Lighting -> Automatic.

I think we should implement ImageScaled and change directional lights to cartesian coordinates.

@axkr that is why lighting in Symja doesn't look the same way as it does in Wolfram Cloud.

[TiagoCavalcante]

@rocky your thoughts?

[rocky]

@TiagoCavalcante I am always in favor of keeping behavior as compatible with Mathematica.

In some situations like adding better SymPy interaction we may extend things, but keeping the behavior the same is just a good thing to do.

If it wasn't done in the past in my opinion it was probably more because it wasn't thought of or because it was too difficult to do. So if you think we can do it now, we should.

That's my view.

[TiagoCavalcante]

@rocky I believe directional lights were made this way because then we can "unrotate" it by applying some transformations with the camera rotation. The other way to do this is using custom shaders (and this is way faster to rotate the camera with multiple directional lights). It is basically O(n) vs O(0).

[rocky]

Ok - thanks for the explanation. Onward and upward!