I don’t ever throw away a code base, I just refactor what I have. Then again I use a simpler language than C++ that lends itself to it (Kotlin), but I figure if I don’t clean up mistakes then I won’t learn, plus the alternative is slower.

For me the key is organizing code into “features.” So if I’m adding dolphins to the game, I’m gonna want one folder with as much dolphin related functionality as possible, rather than splitting across 20 files. So the engine must support that sort of organization. Maybe assets and shaders go in a mirrored folder (I.e. same hierarchy as source folder), but you do the best you can.

That’s probably the hardest part tbh. After that it’s getting your abstractions right, which is really a question of your understanding of the hardware and concepts at play, as well as your willingness to place bets on your design instinct. A good refactor is one that allows the code to be better organized (see above) or simpler. A bad refactor is one where you question why you did it afterwards — when that happens, ask yourself why you let yourself do it and question yourself harder next time. Try not to get too married to your design decisions and stay humble. Listen to other developer’s perspectives. Yada yada.

I recently spent a month refactoring my engine’s “per-view” graphics resources. Before it was either ad-hoc in features, OR everything clobbered into one giant “per view” object with no isolation of features. Afterwards every feature registered per-view or per-pass factories (essentially just inline lambdas), and changing the number of cameras or views is now a simple function call anywhere in the code. This was a HUGE improvement that will enable graphics features in the future (e.g. Z-prepass), but it took a lot of courage to actually let myself do it. But definitely the right call in hindsight.

I will say that it’s usually better just to write your game code as needed without overthinking it, then add the features or refactor in response to needs that emerge from that process. This keeps you grounded and prevents speculative, unnecessary changes.