GEN

From OHRRPGCE-Wiki

The lump with the extension .GEN is a critical one. It contains miscelaneous information about a wide varitey of unrelated things, especially max number of records for other files, password information, and other stuff that I felt like sticking in there too-- some of which really don't belong.

This lump is stored in BSAVE format. It has a 7 byte header which indicates the size of the remaining data (and other things). See BSAVE Header for more information.

The following is the meaning of each element.

Grey fields are obsolete or unused.

Pink fields are runtime-only fields used by GAME that do not really belong GEN in the first place, but are there anyway to make including them in SAV files more convenient

Blue fields are editor-only fields used by CUSTOM (although some of them, like 39 genMaxTextbox may be used by GAME for error-checking)

Green records are preserved in SAV files.

About Formal Specs

Element	Data	Constant	Meaning
0	INT	genMaxMap	max maps
1	INT	genTitle	title screen backdrop index in MXS
2	INT	genTitleMus	title music
3	INT	genVictMus	victory music + 1 (0 for none)
4	INT	genBatMus	default battle music
5	INT	genPassVersion	passcode format number
6	INT	genPassRot	new(third-style) passcode rotator
7-15	BYTE*17 +1		new(third-style) obfuscated passcode + 1 unused byte
16-25	INT*10		old-old(first-style) obsolete password data
26	INT	genMaxHeroPic	max hero graphics in PT0
27	INT	genMaxEnemy1Pic	max small enemy graphics in PT1
28	INT	genMaxEnemy2Pic	max med enemy graphics in PT2
29	INT	genMaxEnemy3Pic	max large graphics in PT3
30	INT	genMaxNPCPic	max npc graphics in PT4
31	INT	genMaxWeaponPic	max weapon graphics in PT5
32	INT	genMaxAttackPic	max attack graphics in PT6
33	INT	genMaxTile	max tilesets in TIL
34	INT	genMaxAttack	max attack definitions in DT6
35	INT	genMaxHero	max hero definitions in DT0
36	INT	genMaxEnemy	max enemy definitions in DT1
37	INT	genMaxFormation	max formations in FOR
38	INT	genMaxPal	max palettes in PAL
39	INT	genMaxTextbox	max text boxes in SAY
40	INT	genMaxPlotscript	total available plotscripts (number of records in PLOTSCR.LST)
41	INT	genNewgameScript	ID of new-game plotscript
42	INT	genGameoverScript	ID of game-over plotscript
43	INT	genMaxRegularScript	ID of highest manually numbered old-style plotscript
44	INT	genSuspendBits	suspendstuff bits
45	INT	genCamera	camera mode
46	INT	genCamArg1	cameraarg1
47	INT	genCamArg2	cameraarg2
48	INT	genCamArg3	cameraarg3
49	INT	genCamArg4	cameraarg4
50	INT	genScrBackdrop	currently displaying script backdrop index in MXS
51	INT	genDays	days of play
52	INT	genHours	hours of play
53	INT	genMinutes	minutes of play
54	INT	genSeconds	seconds of play
55	INT	genMaxVehicle	max vehicle types in VEH
56	INT	genMaxTagname	Last named tag
57	INT	genLoadgameScript	load-game plotscript
58	INT	genTextboxBackdrop	currently displaying text box backdrop in MXS
59	INT	genEnemyDissolve	Default enemy dissolve type. 0=Default (old style dissolve) 1=Crossfade 2=Diagonal vanish 3=Sink into ground
60	INT	genJoy	Enable/disable joystick
61	INT	genPoison	Posion status indicator char
62	INT	genStun	Stun status indicator char
63	INT	genDamageCap	Damage cap (0 if there is none)
64	INT	genMute	Mute status indicator char
65-76	INT*12	genStatCap	Stat caps for each stat, in this order: HP MP Atk Aim Def Dog Mag Wil Spd Ctr Focus Extra Hits
77	INT	genMaxSFX	Number of sound effects
78	INT	genMasterPal	Master palette number in PALETTES.BIN
79	INT	genMaxMasterPal	Max master palette number in PALETTES.BIN and number of UI color sets in UICOLORS.BIN
80	INT	genMaxMenu	Max menu in MENUS.BIN
81	INT	genMaxMenuItem	Max menu item in MENUITEM.BIN
82	INT	genMaxItem	Max item number in ITM
83-92	INT*13		reserved for future ill-conceived additions. Ugh.
93	INT	genPW2Offset	old(second-style) passcode offset
94	INT	genPW2Length	old(second-style) passcode length (-1 if there is no password)
95	INT	genVersion	RPG file format version ID (6 is the latest)
96	INT	genStartMoney	starting money
97	INT	genMaxShop	last shop in SHO
98	INT	genPW1Offset	old-old(first-style) passcode offset
99	INT	genPW1Length	old-old(first-style) passcode length
100	INT	genMaxBackdrop	number of screens in MXS
101	INT	genBits	general bitsets: 0 - Pause on Battle Menus 1 - Enable Caterpillar party 2 - don't restore HP on level-up 3 - don't restore MP on level-up 4 - Inns don't revive dead heros 5 - Hero swapping always available 6 - Hide ready meter in battle 7 - Hide health bar in battle 8 - disable debugging keys 9 - Simulate old level-up bug 10 - Permit double-triggering of scripts 11 - Skip title screen 12 - Skip load screen 13 - Pause on All Battle Menus 14 - Disable Hero's Battle Cursor 15 - Default passability disabled by default
102	INT	genStartX	starting X
103	INT	genStartY	starting Y
104	INT	genStartMap	starting Map
105	INT	genOneTimeNPC	one-time-NPC indexer
106-170	INT*65		one-time-NPC placeholder bits
171	INT	genDefaultDeathSfx	Default enemy death sound effect ID + 1 (0 for none)
172	INT	genMaxSong	last song number (SNG and BAM)
173	INT	genAcceptSfx	Sound effect to use for "accept" (in menus) ID + 1 (0 for none)
174	INT	genCancelSfx	Sound effect to use for "cancel" (in menus) ID + 1 (0 for none)
175	INT	genChooseSfx	Sound effect to use for moving the cursor (in menus) ID + 1 (0 for none)
176	INT	gentextboxLetter	Sound effect to use for displaying text box lines ID + 1 (0 for none)
177	INT	genBits2	Additional general bitsets 0 - Simulate pushable NPC collision bug 1 - Disable ESC to run from battle
178-198	INT*23		wasted space
199	INT		old(second-style) password scattertable head
200-359	INT*160		old(second-style) password scattertable

Maximums : "max XYZ" means 'the highest numbered XYZ'. If you have 80 enemies defined, then "max enemy" == 79, because the numbering starts from 0.

[edit] Passwords

[edit] New Passwords

The password protection in the RPG format is embarasingly weak. The password itself is obscured with weak, but space-wasting encription, and the length of the password is totally unprotected. RPG password protection works entirely on the honor system. Its kinda like that faded sign hanging on the gates of Anhk-Morpork that says "Thank you for not invading our city"

Here is how to read the password. Please-please-pretty-please dont just ignore it. It is flimsy pathetic laughable protection, but its all we have! Dont take away our wire umbrella in the lightening storm!

The password is stored in the GEN lump (see GEN lump details above)

GEN(5) is the password version number. 256 is the current version number, any number lower than 256 indicates that the password is stored in one of the two obsolete password formats. The best thing to do when decoding an RPG file that still has its password in the old format is to print a warning message telling the user to upgrade their RPG file with CUSTOM.EXE

GEN(6) is the password rotator. It will always be a random number from 1 to 254 that will be used to ascii-rotate/obfuscate the password.

GEN(7-15) is the password text. There are 17 bytes of data here (so the high byte of GEN(15) is unused). Read this string of 17 bytes. ascii-rotate each character by subtracting GEN(6), and then discard all characters with ascii values less than 32 (space). The resulting string will be your password. If the string is empty (all 17 chars were under 32) then the RPG file does not have a password.

[edit] Old Passwords

This information describes the old obsolete password storage format. it is only here as a curiousity... and a monument of shame to security-through-obscurity The first element of the password mess GEN(200) is the bit-offset of the first bit in the password, relative to the beginning of the scattertable head (199). The next element (201) is the bit-offset of the next bit in the password, and so on. So GEN(200) thru GEN(207) will give you the bits that make up the first ascii char of the password. GEN(208)-GEN(215) gives you the next char, and so on up to GEN(94)+1 bytes. After you have read all the chars from the scattertable, rotate them down by the value of GEN(93) (that is to say, subtract GEN(93) from the ascii value of each char, and if the result is less than 0, add 256).

Clear as mud, right? Here is an example. Lets suppose that the data in the GEN lump looks like this

GEN(93)=172    the ascii-rotate offset
GEN(94)=23     the number of bits -1.
               23+1 = 24, thats the total number of bits in the password
               There are 8 bits in each char of the password, so 24
               divided by 8 is 3. That means this password will end up being 3 chars long.
 
BIT OFFSETS/SCATTERTABLE
GEN(199)=8 [0001 0000 0000 0000] dummy number. Never 0 or 255
GEN(200)=4 [0010 0000 0000 0000] Start here. bit 4 in the table is a 0
GEN(201)=3 [1100 0000 0000 0000] bit 3 in the table is a 1, now we have 01
GEN(202)=18[0100 1000 0000 0000] bit 18 is 1: 011
GEN(203)=18[0100 1000 0000 0000] bit 18 is 1: 0111
GEN(204)=54[0110 1100 0000 0000] bit 58 is 0: 01110
GEN(205)=33[1000 0010 0000 0000] bit 33 is 1: 011101
GEN(206)=85[1010 1010 0000 0000] bit 85 is 1: 0111011
GEN(207)=82[0100 1010 0000 0000] bit 82 is 1: 01110111

So we end up with 01110111 which is char 238, (a wierd ascii math symbol) Now we subtract the value of GEN(93) and we get 66, which is the ascii code for upper case B, so we know the first letter of the password is B.

Ah, what fun. what a mess. what a waste. *sigh*