Day 2 of building in public: I lost a day to a bug that wasn't in my code.

Today I was trying to get my renders to stop looking like flat plastic.

I assumed my newest changes had broken something, so I started eliminating suspects. Reverted the latest feature. No change. Turned off the optimization. No change. Rolled everything back 10+ commits, to before any of it existed.

Still broken.

If reverting 10 commits changes nothing, the bug probably isn't in the commits.

Turns out the system responsible for making surfaces look realistic had never actually been switched on in my test setup. Everything silently fell back to a simpler rendering path, so I was testing code that couldn't affect the output.

The fix was one line.

After that, I got my first properly realistic render — and then got a door in the scene to open on command, rotating exactly 90°.

What I'm taking from it:

1. If a change does nothing, first check that the code path is actually running.

2. Write the startup checklist before you need it.

3. Silent fallbacks are some of the most expensive bugs to debug.

I also found another fun one: a generated scene came out completely black because it had zero light sources. It looked exactly like a camera/rendering bug.

Next up: fixing that and pushing the visuals further toward real.

What's the dumbest-in-hindsight bug that ate your week?