Reference · Engine

Area keywords and the area generator

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A field area is named by three keywords typed at a Chaos Gate. The three word IDs seed a random area; each word may pin some of its attributes; a fixed story area may pin more. WORLD_MAN::SimGenerateCode (0x0019e5c0) does all of it, and tools/areas.py gen reproduces it exactly (checked against the game code run in tools/eemu.py, 0 mismatches over 412 triples). The port is crates/piney-data/src/area.rs (The port). The algorithm and the tables' layout are the same on all four volumes; the differences are under Other volumes.

Tables

All little-endian, in main's .data.

WORDPARAM           0x30 bytes     word_a1..word_c4, 0x00311790 - 0x003150bf
  +0x00  char *  word
  +0x04  s32     ID               unique across slots
  +0x08  s32     pri              higher wins
  +0x0c  s32     fieldType        255 = unset
  +0x10  s32     dungeonSize      0 = unset
  +0x14  s32     weather          255 = unset
  +0x18  s32     ground           255 = unset
  +0x1c  s32     object           255 = unset
  +0x20  s32     areaLevel        255 = unset
  +0x24  s32     enemyOfs         255 = unset
  +0x28  s32     itemOfs          255 = unset
  +0x2c  s32     circleOfs        255 = unset

EVENTAREA_INFO      0x54 bytes     eventAreaInfo 0x00315120, eventAreaInfoNum entries (126)
  +0x00  s32     code             the event area number
  +0x04  char *  wordA            NULL for records with no address
  +0x08  char *  wordB
  +0x0c  char *  wordC
  +0x10  s32     server           0 Δ, 1 Θ, 2 Λ, 3 Σ, 4 Ω
  +0x14  s32     circle           -> circleOfs, 255 = keep
  +0x18  s32     enemy            -> enemyOfs,  255 = keep
  +0x1c  s32     item             -> itemOfs,   255 = keep
  +0x20  s32     model
  +0x24  s32     flag
  +0x28  s32     type             -> fieldType, 255 = keep
  +0x2c  s32     bgnum            -> weather,   255 = keep
  +0x30  s32     dungeonNum
  +0x34  s32[8]  protect

DUNGEON_INFO        8 bytes        dungeonData[11], 0x003150c0
  +0x00  s32     levelMax
  +0x04  s32     roomMax

word_<slot><group>: slot a, b, c is the word's position in the address; group 1-4 splits each slot. Word counts: a 29/25/22/24, b 28/25/24/26, c 28/26/23/25 - 305 in all. dungeonData is (2,5) (2,5) (2,7) (3,7) (3,9) (4,7) (4,9) (4,11) (5,7) (5,9) (5,11).

The algorithm

code = A.ID * 1000000 + B.ID * 1000 + C.ID          also stored in wordparam.ID
seed = code
rand():  randcnt += 1
         seed = ((seed * 109) mod 2^32 + 1021) mod 2^32 mod 0xfffffffe
         return seed

fieldSeed = rand(); dungeonSeed[0..2] = rand() x3

sort [A, B, C] by pri ascending (insertion sort, stable)

base.fieldType   = rand() % 11
base.weather     = clamp(base.fieldType, rand() % 10)
base.dungeonSize = rand() % 10 + 1
base.ground      = rand() % 3
base.object      = rand() % 3
base.areaLevel   = rand() % 5 + 1
base.enemyOfs    = rand() % 20 - 9
base.itemOfs     = rand() % 20 - 9
base.circleOfs   = rand() % 3

m = copy(sorted[0]); merge(m, sorted[1]); merge(m, sorted[2]); merge(base, m)
    merge(dst, src): each field of src that is set overwrites dst's

if a story area on the current server has words (A, B, C):
    its circle, enemy, item, type, bgnum overwrite base where not 255
    area 71 and save flag (saveData+0x5bc0 bit 62): enemyOfs = itemOfs = 119
    area 47 and volumeNum >= 3: enemyOfs = 78, itemOfs = 122
        (INF inline; from MUT on, substitute records instead - see below)

base.weather = clamp(base.fieldType, base.weather)
if base.dungeonSize >= 11: base.dungeonSize = 1
levelMax, roomMax = dungeonData[base.dungeonSize]
timeSym = (A.ID == 131)

clamp(type, w): types 0-4 keep w < 4, types 7-10 keep w < 8, types 5-6 turn 8 into 4 and 9 into 5 and keep w < 4; otherwise 0.

The results land in WORLD_MAN: A, B, C at +0x14c..+0x154, the merged WORDPARAM through the pointer at +0x158 (its ID +0x04 becomes code, +0x0c..+0x2c the nine attributes; word and pri are not written), fieldSeed +0x44, dungeonSeed +0x48, eventAreaNumber +0x120, fieldtype +0x10, bgnum (the weather) +0xc, timeSym +0x134, dungeonLevelNum +0x138, dungeonRoomNum +0x13c. dungeonType[0] (+0x34) is set to 0 and SetDungeonTypeFromField (0x0019cf50, dungeon generation) called before the dungeon counts are set; it reads the story area's flag and saveData.crisis (+0x6772), and writes dungeonType[1] only for field type 4. The RNG is the globals seed (0x00377d20), left at the thirteenth draw, and randcnt (0x00378a80), which goes up by 13 - SimGenerateCode does not reset it; WORLD_MAN::GO does before a generator runs.

Enemies

ccRegisterDifficultyEnemy (0x001b7020, fields and dungeons only) and ccRegisterEnemyList (gcmn.prg:0x0042ed70):

type = 6                                  if ccGame.field > 0 (a story area)
     = FIELD_ATTRIB[fieldType][weather]   otherwise, WORLD_MAN::GetFieldAttrb
rank = 25 * (areaLevel - 1) + 10 + enemyOfs, at least 0
     = the story area's `enemy`           in a story area that sets it
rank += ccGame.floor + 1                  in a dungeon
list = ccEnemyListInfo[server][type]      gcmn 0x005da200, 5 x 7 {int *list; int num}
register list[rank], list[rank+1], list[rank+2]   (ccRegisterEnemyRange = 3),
         staying on the last entry past the end

FIELD_ATTRIB, from running GetFieldAttrb over every input:

The lists (enemyList00 .. enemyList46, 130 entries each) hold indexes into enemyTbl. Each registered row also registers its drained form, and a middle boss (row type 0x40) its base form's drained form as well (battle, "Spawning").

itemOfs feeds AreaItem (gcmn 0x00544c00) the same way: the index into the area's item list is 25 * (areaLevel - 1) + 10 + itemOfs (the story area's item in a story area), plus floor + 1 and rand() % 5, at most 129. The lists by kind, server and element are in field UI.

Lookups

• GetWordParamPtr(part, slot, id) (0x001a2340): the word of slot with that ID, word_<slot>1 to word_<slot>4 in order; NULL for none. GetWordParamPtr(id) (0x001a25d0): any slot, word_a1, word_b1, word_c1, word_a2 ... in order. GetWordParamID(text) (0x001a3370): the ID of the first word, in that order, whose text strcmps equal; -1 for none.
• ccCheckEventAreaNum(a, b, c) (0x001a4290): over eventAreaInfoNum rows, the first with wordA not NULL, server equal to game.server (+0x1c) and the three texts equal to those of words a, b, c (by GetWordParamPtr(id)); its code, else 0.
• ccGetEventAreaInfo(n) (0x001a4220): the first of eventAreaInfoNum rows with code n. WORLD_MAN::GetEventAreaInfo(n) (0x0019d3b0) and GetEventAreaInfo() (0x0019d350, with eventAreaNumber) search a constant 126 rows instead - the same in Infection, whose eventAreaInfoNum is 126.
• WORLD_MAN::IsProtectArea() (0x0019ceb0): 0 when eventAreaNumber is 0 or has no row among the first 126, else protect[1] != 0. 28 of the numbers -1 to 130 are protected. Field generation reads it (field).
• GetWordParamFromEvCode(n, part) (0x001a29a0): the row with code n (first 126), then the word of slot part (groups 1 to 4) whose text strcmps equal to the row's wordA, wordB or wordC; NULL when none does (area 94's Howling). A code with no row, or a row with no address, is read through NULL.

Event instruction 118, area

ccEvAreaCodeAdd (ccEvent::Execute at 0x001b04b8, playing only) takes one signed 16-bit operand n and switches on it unsigned through the jump table at 0x00355f00:

• n 1-13: when game.area (+0x14) is not 0, WORLD_MAN::Quit(); then eventAreaNumber = n. Nothing is generated. Areas 0-12 have no address; area 13 has one (Λ), which this path never uses.
• anything else (0, 14 and up, negative): SimGenerateCode(A, B, C) with the IDs of GetWordParamFromEvCode(n, 0), (n, 1) and (n, 2).

The instruction sets nothing else: not game.server, not game.field. SimGenerateCode matches the words against the story areas on the current game.server, so on the story area's own server eventAreaNumber becomes n and the area's overrides apply; on another it is 0 and the area is the random one the same words make there.

The port

crates/piney-data/src/area/: AreaTables::of(volume) holds the twelve word tables, dungeonData, eventAreaInfo (eventAreaInfoNum rows), the substitute records (Mutation on) and volumeNum of each volume, generated from its disc into the build by piney-gen (the keywords' text byte for byte; the port does not read the executable at run time). The four volumes' tables differ: Mutation on adds the substitutes for areas 71 and 47, and Quarantine renames slot b's word 100 from Vengeful to Vindictive. sim_generate_code(tables, a, b, c, server, flag71) returns every field SimGenerateCode writes (AreaCode, with dungeon_type(tables, crisis) for SetDungeonTypeFromField); ev_area(tables, n, server, flag71) is instruction 118 and story_area_code(tables, n, flag71) the same on the area's own server; the lookups above are word, word_by_id, word_by_text, word_id, event_area_info, cc_event_area_info, check_event_area_num, word_from_event and is_protect_area.

Checked by tools/test_area_rs.py: the game's own functions run in tools/eemu.py on a scratch WORLD_MAN against the area_probe example. SimGenerateCode, 1,080 cases - the 112 story areas whose words are all keywords, each typed on all five servers and once more with the crisis byte set; areas 47 and 71 with the save flag and volumeNum 3 and 4; 400 random triples on random servers, about a fifth with the save flag and a third with the crisis byte - comparing A, B, C, fieldSeed, dungeonSeed[3], bgnum, fieldtype, eventAreaNumber, timeSym, the two dungeon counts, dungeonType[0..1], the merged WORDPARAM's ID and nine attributes, seed and randcnt: 0 mismatches. IsProtectArea and GetEventAreaInfo(n) for every n from -1 to 130, GetWordParamFromEvCode for every code and part (378), instruction 118's generation for every code outside 1-13 on every server (555 areas), and GetWordParamID for every keyword and two non-words: 0 mismatches. The harness runs on any volume's disc through PINEY_VOLUME.

Story areas

113 records carry an address: Δ 22, Θ 12, Λ 28, Σ 34, Ω 17. Area 14 is Bursting Passed Over Aqua Field on Δ, code 13026. tools/areas.py events lists them.

model 1 (areas 1-13, 15, 16, 43, 66, 67, 91) makes ccSetupGameCtrl load the area's event music bank for its field instead of the field type's (sound). flag 3 gives its dungeons the E types (dungeon generation).

Notes

The match against story areas compares the word strings, not IDs, and requires the current server to match.

One story area (94, Σ, Howling Hot-blooded 500 Lohan) uses a first word that is not a keyword in any table on the Infection disc. From Mutation on it is Barking, which is.

Other volumes

Every volume has the same 305 keywords by ID and the same 113 story areas with an address, and tools/areas.py reads each executable's own tables (the stripped ones through the names piney-gen syms carries). Each volume's own SimGenerateCode in eemu against areas.generate, over every story area, events 71 and 47 under their special conditions (the save flag set, and volumeNum forced to 3 and 4), and 100 random triples: INF 218 cases, MUT, OUT and QUA 219 each, 0 mismatches. volumeNum is 1, 2, 3, 4.

Substitute records. From Mutation on, the two special cases are no longer inline. ccGetEventAreaInfo and WORLD_MAN::GetEventAreaInfo return a different EVENTAREA_INFO under the same conditions:

Each is a copy of the table's record: area 71's with enemy and item changed, area 47's with only item. So area 47 keeps enemyOfs 42 in Outbreak and Quarantine, where Infection's inline code says 78 - code Infection never runs, its volumeNum being 1. ccRegisterDifficultyEnemy reads a story area's enemy through WORLD_MAN::GetEventAreaInfo, so from Mutation on the rank of these two areas comes from the substitute too (read from the code; not run). areas.py finds the substitutes by reading ccGetEventAreaInfo.

Table changes.

• MUT: keyword ID 304 (b, group 4) Beginning becomes Darkside, and area 125's address with it. Area 94's Howling becomes Barking. Four addresses lose a trailing space. In Σ and Ω areas, 19 unset (255) type and 19 unset bgnum values get a value, and one type changes (area 76, 9 to 7); enemy changes in 18 areas and item in 16, all but one on Σ or Ω; protect changes in 7, dungeonNum in 5 (109-113, 1 to 0). A record for area 126, with no address, is added (127 in all).
• OUT: Evil Eyed becomes Evil-eyed, Sun Colored Sun-colored, Grave Stone Gravestone.
• QUA: Vengeful becomes Vindictive.

Unknown

• What the values of fieldType, weather, ground, object, circleOfs produce in the game.
• EVENTAREA_INFO.model beyond the music bank, .protect beyond protect[1] and the event VM's item pairs, .dungeonNum.