[feature] shader from 'puzzle'

[profelis]

Something like https://github.com/andyli/puzzle very usefull thing for lights, post effects, etc

[ncannasse]

While I understand the logic I fail to see how it can be used. The best would be to be able to extend some shader and call super.fragment/super.vertex + add your own vars. But that's hard to get it right,

In h2d I'm adding many activable effects on the same shader base and it seems flexible enough so far