Author Topic: Lemmings DAT Anticompressor  (Read 23488 times)

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Offline ccexplore

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Re: Lemmings DAT Anticompressor
« Reply #45 on: September 04, 2005, 04:40:02 AM »
Great!  maindat.txt is now updated with the palette information, so it should have everything someone would need for extracting all the bitmaps out of main.dat.

Offline ccexplore

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Re: Lemmings DAT Anticompressor
« Reply #46 on: September 04, 2005, 05:08:34 AM »
Quote from: Shvegait  link=1125127380/30#31 date=1125608046
DOSBox. I don't think they actually "work", but they at least load up to the level screen, which is enough to see that the letters are in a different font. If I recall correctly, one of the modes doesn't have mouse (clicking) support, one of them will freeze between levels, in one of them the level won't even start (but the graphics will load)... Weird stuff happens for sure.

Actually, I just tried the "PS/2" mode and it seems to work fine in DOSBox, maybe it's an XP/Win98 difference?

I also ran both the "High Performance" and the "PS/2" mode in plain DOS Windows and see the flashing behavior when you're in a level.  This seems to prove my theory that the game tries to do the palette switching trick, so that separate color palettes can be used in separate areas of the screen.  This also explain why they can afford a different green text font and skills panel for those modes.

Of course, the timing is no longer correct for modern PCs, and it just plain confuses DOSBox.

Offline ccexplore

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Re: Lemmings DAT Anticompressor
« Reply #47 on: September 04, 2005, 05:09:38 AM »
Quote from: ccexplore (not logged in)  link=1125127380/45#46 date=1125810514
Actually, I just tried the "PS/2" mode and it seems to work fine in DOSBox

Note that "work fine" means doesn't crash.  The colors are indeed a little messed up, but that's to be expected since palette switching tricks are not emulated correctly by DOSBox.

Offline Mindless

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Re: Lemmings DAT Anticompressor
« Reply #48 on: April 24, 2023, 12:21:26 AM »
Ok, I just checked and they are indeed identical.  main.dat section #5 and cgamain.dat section #3 are the same.

I finally solved the mystery.  It contains the PC speaker sounds that play if you don't have enough memory to load ADLIB.DAT (but ADLIB.DAT is loaded before MAIN.DAT, so the game never works in that case).  Interestingly, I can't find any normal way to get the PC speaker sounds to play.  They don't play normally, even if you don't have an AdLib-capable sound card.  I was only able to get them to play by modifying the game to skip AdLib initialization.  (Of course, maybe this is just a bug in the version of the game that I'm using.  Edit: It was.)

Edit 2:  There are 3 different versions of Lemmings for DOS with the VGALEMMI.EXE files dated 1991-05-10, 1991-05-24, and 1991-07-19.  I was using the version dated 1991-05-24, which has a bug that makes PC speaker sound effects impossible.  Incidentally, it also has the bug where the music starts over at track 1 every time you fail a level.

Edit 3: An easy way to tell which version you have is based on the message when you exit the game.  If it says "Have a nice DOS!" then you have the buggy version.
« Last Edit: July 15, 2023, 08:51:09 PM by Mindless »

Offline jkapp76

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Re: Lemmings DAT Anticompressor
« Reply #49 on: April 24, 2023, 02:58:51 AM »
I'd love to hear PC-speaker music!
...Jeremy Kapp