1PrBoom compatibility options
2============================
3
4Some of this is a bit dry. You might want to skip to the bottom and read the
5examples.
6
7Internally, PrBoom maintains a "compatibility level" which it uses to
8determine how to behave in various circumstances. The supported levels are
9currently:
10
11Number	Name			Description
120	doom_12_compatibility	Emulate Doom v1.2 game details where possible
131	doom_1666_compatibility	Behave like Doom v1.666 as far as possible
142	doom2_19_compatibility	As compatible as possible for playing original
15				Doom demos
163	ultdoom_compatibility	Ultimate Doom made a few changes
174	finaldoom_compatibility	Compatible with Final Doom & Doom95 - needed
18				for some demos recorded with Final Doom doom2.exe
195 	dosdoom_compatibility	Emulate early dosdoom versions
20				(some TASdoom demos work with this)
216	tasdoom_compatibility	unused
227 	boom_compatibility_compatibility	Emulates Boom's compatibility mode
238	boom_201_compatibility	Emulates Boom v2.01
249	boom_202_compatibility	Emulates Boom v2.02
2510	lxdoom_1_compatibility	Emulates LxDoom v1.4.x
2611	mbf_compatibility	Emulates MBF
2712	prboom_1_compatibility	Emulates PrBoom v2.03beta
2813	prboom_2_compatibility	PrBoom v2.1.0
2914	prboom_3_compatibility	PrBoom v2.1.1-2.2.6
3015	prboom_4_compatibility	PrBoom v2.3.x
3116	prboom_5_compatibility	PrBoom v2.4.0
3217	prboom_6_compatibility	Current PrBoom
33
34You can cycle through the compatibility levels in the game using the TNTCOMP
35cheat. There's also the default_compatibility_level config file option, and
36the -complevel command line parameter.
37
38The numbers are subject to change between versions, so if you're doing
39elaborate stuff with these things you're advised to check this file each
40time you upgrade. Most people should just leave default_compatibility_level
41set to -1 in the config file, which means "use most recent" which has most
42features, most bug fixes, etc.
43
44But some people want to test the behaviour of levels with older versions, and
45will find it helpful to not have to load a dozen games to do so. Some people
46like me play a lot of old levels, so need to be able to enable compatibility
47with some old bugs. And some people may want to record demos for older game
48versions.
49
50When you play a demo, PrBoom sets the compatibility level and settings
51automatically. When you load a savegame, the settings are restored.
52
53When you start a new game, the compatibility level is got from (in order of
54preference):
55- -complevel parameter
56- default_compatibility_level config file param if not -1
57- set to the most recent otherwise
58
59If the compatibility level is MBF or better, the detailed compatibility
60settings are read from the comp_* config file options, as in MBF. Otherwise,
61the settings are put to the defaults for that game version.
62
63You can adjust the compatibility settings during play from the menus
64(Options->Setup->Doom Compatibility).
65
66The sort of people interested in these things will already know the MBF
67options, so I'll just list the changes:
68- comp_floors now also causes the original Doom behaviour of objects stuck in
69a ceiling preventing the floor below lowering.
70- new option comp_moveblock enables the old movement clipping bug which
71allows things to go through walls sometimes (mancubus shots, and key
72grabbing tricks)
73
74PrBoom can also record old demos with some success (demo players see the
75comp_moveblock note above):
76
77prboom -complevel 2 -record test
78
79records a doom v1.9 compatible demo
80
81prboom -complevel 9 -record whatever
82
83records a Boom (v2.02) demo
84
85prboom -complevel 11 -record blah
86
87records an MBF demo.
88
89Of course, demo recording is no more reliable than demo playback; original
90Doom demos will usually but not always work. MBF support should be perfect.
91
92- Colin <cph@moria.org.uk>
93
94