CARMA95 / Meld Pack difficulty mode bug

If you require any assistance, or you have any technical questions, use this forum.

Moderator: coffeycup

Post Reply
pancirno
pedestrian
Posts: 2
Joined: Mon Jan 29, 2018 7:56 pm

CARMA95 / Meld Pack difficulty mode bug

Post by pancirno » Mon Jan 29, 2018 8:00 pm

Start the game on Hard difficulty. Start the race - it gives you 30 seconds of time correctly. Now, abort race and save the game. Load the same game and start the race again and you get 3 minutes instead - difficulty always resets to easy on loading the game. It makes it impossible to play on harder difficulties with patched Carmageddon. Original DOS version works correctly, starting correct difficulty mode upon loading.

This behaviour shows on Windows 10 - I haven't tested on the other systems.

User avatar
Toshiba-3
アルカリ (単3形)
Posts: 3896
Joined: Thu Jul 24, 1986 12:13 pm
Location: Belgium/France
Contact:

Re: CARMA95 / Meld Pack difficulty mode bug

Post by Toshiba-3 » Mon Jan 29, 2018 9:41 pm

Hello! Yes, that bug has been reported before but we haven't been able to track down the issue so far...
I'd like to solve this for the next update to the Meld Pack.

The only workaround at the moment is editing DATA\GENERAL.TXT and changing each skill-related line so that the easy skill value matches the hard skill one.
Image / carmageddon add-ons at road reaction

pancirno
pedestrian
Posts: 2
Joined: Mon Jan 29, 2018 7:56 pm

Re: CARMA95 / Meld Pack difficulty mode bug

Post by pancirno » Tue Jan 30, 2018 5:23 pm

Just changing GENERAL.TXT won't do the trick - the skill levels are referenced in multiple files, even all the races themselves need to be modified to account for that.

User avatar
Toshiba-3
アルカリ (単3形)
Posts: 3896
Joined: Thu Jul 24, 1986 12:13 pm
Location: Belgium/France
Contact:

Re: CARMA95 / Meld Pack difficulty mode bug

Post by Toshiba-3 » Tue Jan 30, 2018 10:32 pm

Right, my bad, I answered too quickly...
Editing all races TXT files could be a chore, especially as the folder is also filled with unused ones. :crazy:

I just tested with an unmodified CARM95.EXE from the original CD and the problem is also present... I'll have to check in a Win95 VM as well.
Image / carmageddon add-ons at road reaction

User avatar
QTZ
hit n run
Posts: 176
Joined: Sun Jan 12, 2014 6:53 pm
Contact:

Re: CARMA95 / Meld Pack difficulty mode bug

Post by QTZ » Wed Jan 31, 2018 6:25 am

Mastro done such pack for SE version, but unfortunately based on older SE version with other bugs... Maybe one day I will finish to fix it and update for all maps...

User avatar
Toshiba-3
アルカリ (単3形)
Posts: 3896
Joined: Thu Jul 24, 1986 12:13 pm
Location: Belgium/France
Contact:

Re: CARMA95 / Meld Pack difficulty mode bug

Post by Toshiba-3 » Fri Feb 02, 2018 7:23 pm

Ok I spent a lot of time on this.

The culprit is... OPPONENT.TXT. Somehow. Actually the game only allocates enough space in a savefile to save the wasted status of 48 cars. So if we have more cars installed, like MeldPack which has 70, the overflow is written over the entries that follow the 48-cars chunk, in order: credits, rank, skill level, game completed, number of cars, etc. So if you have 51 cars installed, the skill level is corrupted...

The easy way is to create a 'hard mode' savefile with a DOS version then load it in the MeldPack. It seems like saving the progress afterward will retain the skill level despite there being too many cars installed. Can't tell if it remains unaffected as the players gain more cars ingame.

The hard way was to patch the executable. I tried making the savefiles larger (that was easy) and allocating more space to the car chunk (way more complicated, that 48 value got translated into offsets). So Errol suggested preventing the game from trying to write the infos from all the installed cars and just stop at 48. Which was much easier thanks to his help and is a decent solution IMO:
All unstealable cars can be placed toward the end of OPPONENT.TXT. Once the game is beaten they'll be accessible as the game_completed flag overrides the 'stolen' status of opponents' cars anyway.
Problems could only arrise from having less than 48 cars installed, but I tested with a vanilla Carmageddon install (40 cars) and it worked nicely as skill, rank, parts, gained cars, credits were saved.

Here's the patched exec:
http://rr2000.toshiba-3.com/R6/CARMA95- ... ers-48.zip

I haven't updated the MeldPack yet as I prefer to get some feedback first. Also OPPONENT.TXT must be sorted again ofcourse.
Image / carmageddon add-ons at road reaction

User avatar
Harmalarm
motorised death
Posts: 1194
Joined: Tue May 13, 2008 3:56 am
Location: Den Haag, Holland

Re: CARMA95 / Meld Pack difficulty mode bug

Post by Harmalarm » Mon Feb 05, 2018 9:36 am

Wow impressive and tenacious work there :cool:

User avatar
QTZ
hit n run
Posts: 176
Joined: Sun Jan 12, 2014 6:53 pm
Contact:

Re: CARMA95 / Meld Pack difficulty mode bug

Post by QTZ » Wed Mar 07, 2018 12:21 pm

I don't understand how to test this? What mean "Also OPPONENT.TXT must be sorted again ofcourse."?

Also what happened when we start game without save games files? Is game create wrong size one or create proper one?

User avatar
Toshiba-3
アルカリ (単3形)
Posts: 3896
Joined: Thu Jul 24, 1986 12:13 pm
Location: Belgium/France
Contact:

Re: CARMA95 / Meld Pack difficulty mode bug

Post by Toshiba-3 » Thu Mar 08, 2018 10:42 pm

Best way to test is to start a new game and try and get all cars and see if the save file keeps all the info properly I guess.
As I explained the patch prevents the game from writing more than 48 car entries in the savefile, so if a stealable car is placed beyond place 48 in OPPONENT.TXT its status shouldn't be saved. Thus it'd be better to place unappearing and unstealable cars after position #48 as these get all unlocked anyway once the game is completed and the savefile has the 'completed' flag checked.

And it creates a proper savefile. It just prevents the game to write more car status than the savefile can hold.
Image / carmageddon add-ons at road reaction

Post Reply

Who is online

Users browsing this forum: No registered users and 19 guests