Shader generators are converted to modules

[mvaligursky]

• new base class for shader generators, called ShaderGenerator, implements functionality from now deleted common.js as static functions (so that they can be called from outside of generators too)
• all shader generator (basic, standard, particle, sky, pass-through) extend this class, and generate and export a single instance of it

[willeastcott]

Should these generateKey functions be static? If all functions on these classes were static, no need to create instances. Just export the classes directly.

[mvaligursky]

standard.js contains some members as well .. I'm not sure I'd want to change those and all functions in it to static, instances seems more flexible for the future too.

[slimbuck]

What's the purpose of this extends?

[mvaligursky]

To give all those classes base class / shared type information.

[slimbuck]

I don't see that used anywhere?

The structure of this whole class hierarchy is very non-standard (and for me confusing).

ShaderGenerator isn't a real base class because it defines no base functionality. Rather it is a set of static helper functions.

Then ShaderGeneratorBasic and the rest implement what looks like a consistent set of functions (which presumably program-libraray expects, but never defines).

Ultimately the structure/interface of ShaderGenerator isn't defined anywhere and is left as implicit.

I don't think there needs to be any inheritance here and probably program-library should define what structure a 'generator' takes. Each implementation of generator just implements that interface.

[mvaligursky]

At some point I'm going to add type information to the program-library, and this is the type of the generator. Ideally this would be an interface, but unfortunately JS does not have a concept of this. But this is the only way to assign a single (base) type to multiple classes.

[slimbuck]

If program-library just uses duck typing on generators, why do generators need a class hierarchy?

[mvaligursky]

I added some JSDocs to the program-libray that use the base class type - type safety is where we're going to with the engine changes.

[slimbuck]

Approving under the assumption this mess is cleaned up in future :)