As always, here’s a thought that’s more about demo-engines than about game-engines; and mostly dealing with graphics stuff.
Some folks add whatever gfx effects/techniques they use to “the engine”. Quote from Plastic:
We’ve also added a couple of new features like <…> wireframe/particle shader.
Now, I don’t have a problem with that, but what strikes me is that for whatever reason our engine doesn’t have any effect/technique in it. Zero shaders, no shadowmaps/PRT/refractions/whatever.
The obvious disadvantage of our approach is that for each demo I basically write the shaders and “effects” from scratch (ok, copying them is also fine). There’s no central place where, for example, a Gaussian blur postprocessing filter or shadowmaps rendering code is stored.
On the other hand, that means (nearly) complete freedom for each demo. In each prod I can tweak whatever I want and implement completely different rendering techniques. For example, in.out.side demo is quite different from Visual Gaming viewer or Xplodar FEM demo, yet they all share the same underlying “engine” (read: bunch of code).
Still, what I’d like to do is have “somewhat stable” stuff gathered in one place. I don’t tweak my basic lighting functions, standard postprocessing effects or shadowmap sampling patterns that often :)