• Linux Doom 1.10 is based on Ultimate Doom 1.9, not Final Doom 1.9 (yes, they're actually completely different versions (and so is Doom II 1.9), to the point where some demos will desync when played back with a different version 1.9 EXE, even if identical IWADs are used). The only difference between Ultimate Doom 1.9 and Final Doom 1.9 that I can remember is that teleporters don't set your z-coordinate in Final Doom, causing you to be teleported into the air if departure point is higher than the arrival point.
  
• The sky never changing in Doom II is fixed.
  
• A different sound library was used since the DOS one used a proprietary license. A bunch of sound code got rewritten for the new library, which introduced a new bug into the special sound handling on level 8. In vanilla, the effect is simply that sounds are never cut off as a result of extreme distance (or even from setting the sound volume to zero), instead they become very quiet instead of completely silent. In Linux Doom, sounds actually get louder with distance, unless the sound volume is at maximum, in which case sounds are played at full volume regardless of distance.
  
• Some movement functions use floating point instead of fixed point calculations, which in some cases can cause demo desyncing.
  

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chungy said:
Not definitive but: http://doomwiki.org/wiki/Versions_o...#Source_release

Probably the easiest way to figure out is to look at the Chocolate Doom commit history. You'll have to sort out changes related to registered/Doom 2 and Ultimate Doom compatibility and Final Doom itself.

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Foxpup said:
Linux Doom 1.10 is based on Ultimate Doom 1.9, not Final Doom 1.9 (yes, they're actually completely different versions (and so is Doom II 1.9), to the point where some demos will desync when played back with a different version 1.9 EXE, even if identical IWADs are used). The only difference between Ultimate Doom 1.9 and Final Doom 1.9 that I can remember is that teleporters don't set your z-coordinate in Final Doom, causing you to be teleported into the air if departure point is higher than the arrival point.

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A different sound library was used since the DOS one used a proprietary license. A bunch of sound code got rewritten for the new library, which introduced a new bug into the special sound handling on level 8. In vanilla, the effect is simply that sounds are never cut off as a result of extreme distance (or even from setting the sound volume to zero), instead they become very quiet instead of completely silent. In Linux Doom, sounds actually get louder with distance, unless the sound volume is at maximum, in which case sounds are played at full volume regardless of distance.

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[*]Some movement functions use floating point instead of fixed point calculations, which in some cases can cause demo desyncing.

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fraggle said:
Sound effects do not get louder with distance, I have no idea where you got that from.

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fraggle said:
Also untrue [floating point code]. Where on earth are you getting this stuff?

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Maes said:


I think he's referring to the ApproxDist function overflow. Due to limitations of fixed_t numbers, differences greater than 32K units will wrap around, possibly resulting in such an effect. In practice, I've never noticed it.

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I think he's referring to the FixedDiv function in the source release -indeed, that one uses a cast to float as an intermediate calculation. This is even mentioned on the wiki page.

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In any case, even if the source release is based off Final Doom, a lot of the code needed to properly support it -or even to properly support e.g. correct switch initialization in episode 4 of UD) is missing, so anyone starting from the "bare metal" will have to fill-in for these missing parts.

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fraggle said:

Completely untrue. The LinuxDoom source release is absolutely based on Final Doom it includes all the Final Doom string changes for example.

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fraggle said:

Sound effects do not get louder with distance, I have no idea where you got that from.

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fraggle said:

Also untrue. Where on earth are you getting this stuff?

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Maes said:

I think he's referring to the FixedDiv function in the source release -indeed, that one uses a cast to float as an intermediate calculation. This is even mentioned on the wiki page.

In any case, even if the source release is based off Final Doom, a lot of the code needed to properly support it -or even to properly support e.g. correct switch initialization in episode 4 of UD) is missing, so anyone starting from the "bare metal" will have to fill-in for these missing parts.

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Foxpup said:

It's been a long time since I've played Linux Doom, but I do specifically recall this happening, and wondering what the Hell was wrong with the sound, and the wiki says it happens, so... But just to humour me, start up Linux Doom, warp to level 8 (doesn't matter what game or episode), and tell me what you hear with the sound volume on various settings.

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fraggle said:
Has it been so long that I've forgotten about this? I don't remember doing these.

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