#62 Desync: dismlmp.lmp

[Graham Burgess]

http://competn.doom2.net/pub/sda/d-h/dis_0942.zip
http://www.doomworld.com/idgames/index.php?id=9787

This Boom 2.02 demo desyncs with current prboom-plus. The same desync occurs with every post-merger version of prboom that I have tried, back to 2.1.0.

The demo plays back OK with prboom 2.02.

[Andrey Budko]

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fixed

Boom's friction and bobbing code was restored. There are too many changes and I am afraid that something could break

[Andrey Budko]

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fixed

Boom's friction and bobbing code was restored. There are too many changes and I am afraid that something could break

[Graham Burgess]

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> Boom's friction and bobbing code was restored. There are too many changes
> and I am afraid that something could break

I have tested this fairly extensively (with my main testset and several collections of Boom-format and other demos), and it appears to work correctly. The case where you would expect to find problems is with Boom-format demos recorded with earlier versions of Prboom, but I only found such demos only on one map:
c215-uv.lmp (in cc2lmps.zip) on cchest2.wad
This plays back with the previous test version, and in the new version desyncs ("correctly") in just the same way that it does with prboom 2.02.

Several other demos on this map are also affected: c215-359.lmp, c2152004.lmp and c2152523.lmp (all in cc2misc.zip).

I don't know how convenient it would be to add a command-line option to force the old behaviour, or if it is worth it for what appears to be a rare case.

Links:
http://competn.doom2.net/pub/sda/b-c/cc2lmps.zip
http://competn.doom2.net/pub/sda/b-c/cc2misc.zip
http://www.doomworld.com/idgames/index.php?id=13024