Bug: severe stutter after lapping the 2nd place car

[ArkVogel]

Hi guys, love the work you're doing in rebuilding this game!
I've encountered a bug: the game severely stutters after lapping the 2nd place car. It's reproducible on my end, and happens no matter the car or track. One time it CTD, and one time it happened when getting lapped, though these are not reproducible. I had both SUPERMAN and MAYTE cheats enabled if that helps (it's hard to reproduce the bug without them because you need a lot of laps and a consistent top speed)

[Zizin13]

Interesting, I'll take a look when I get a chance

[Zizin13]

I'm having trouble reproducing this, it may just be because my PC is fast enough that the issue is hidden though. Does it only happen after a long race or does it happen if you lap 2nd place within a couple laps too? You can test this easily by modifying line 4882 of control.c and severely limiting the max speed of the AI cars. Replace the "levels[level]" with whatever speed modifier you want such as:

fMaxEngineSpeed = fMaxEngineSpeed * 10.0f/*levels[level]*/ * 0.01f;// Apply difficulty level scaling to AI maximum speed

[ArkVogel]

That seems to have fixed it. It no longer stutters with or without cheats even on long races. Tested this three times in a row so it's hardly enough, but I'll keep you posted if it happens again.
Keep up the good work!

[Zizin13]

It is not fixed, we can reproduce this after all, will need to figure this out. Created #75

[ArkVogel]

Sorry I haven’t gotten back to you but yes it happened again. Not as frequently as before though.
Side question: is this a project to reverse engineer the game to work on modern hardware or is it a prelude to a full-on remake (a la Carmageddon)? Either way, kudos!

[docfo4r]

Hey there,
I can also confirm the stutter. Easily reproducible on Bonus 5 where you can go left all the time. Once lapping the 2nd car it stutters heavily or CTD. Happens with 16, 8 and 2 cars on the road.
Worth mentioning: It does return to normal once the 2nd place unlaps itself.
Hope that helps!

[docfo4r]

Me again, I was able to get rid of this bug by modifying the ordercars() function in control.c with the help of AI. Especially this if statement:
if (byLapNumber <= byCurrentProgress)
Tested a few times getting lapped and lapping all cars and there are no more freezes or crashes.
You can see the diffs here: master...docfo4r:ROLLER:master

I don't know if this is the way you guys like the code, no need to use this chunk of mine but maybe it helps guiding you in the right direction. Also, don't know exactly how to interact with the repo so I just forked it :)

[Zizin13]

Neat, I added you to the org, you should be able to make pull requests now. For the code, I don't really care about style, Whiplash's original code was all over the place in this respect. Stick to ascii though, no funny unicode characters like those arrows. Because this is a deviation from the original logic it should also be heavily commented to explain that it isn't original, why it was done, and why the original logic caused a bug. We should also confirm that this bug is present in the original game.

[docfo4r]

Thank you!
I will do some more testing first and refactor the fix to stick as close to the source code as possible without any funny characters.
The bug wasn't present in the original game, though.