Shops

This folder holds The Broken Seal's counters: shops that buy, sell and repair, the artifact counter and the Game Ticket gifts, the sanctum's healing services, the inn, and the item picker that asks which item to drop when an item is found with every bag full.

See also: Windows, the windows and messages the counters are made of; Menus, which share their work block; and Game rules, the items and their counters.

Files

File	What it holds
shop.c	the guide to the shop object: it includes shop_internal.h, then the parts in shop/ in ROM order
shop_internal.h	the object's includes, the shop actions and sanctum services, and the values that differ by edition
shopspr.s	the hand, gem, arrow, price and quantity sprite tiles

The guide's comment says where to start, and each part's second line says what it holds: head -2 shop/*.c lists them. A part includes the private header, so it resolves when opened on its own, but it is compiled only through shop.c. The ROM shows the counters as one object; the parts are ours, cut where one family ends and the next begins. Link order is in games/tbs/objects.tsv, from shop.

The work block's layout, struct ShopRuntime, is in include/shop.h and the prototypes in games/tbs/include/unit/shop/. Scene overlays import these functions by name (games/tbs/src/scene/import/), and code in other banks calls them through the far-call table games/tbs/src/system/far_call/SHOP.S (the ...Far names), so a rename crosses folders.

Words

• work block: struct ShopRuntime, heap slot HEAP_SLOT_MENU, reached as gMenuWork while a counter is open; Shop_InitializeCursorWork sets it up and Shop_ReleaseCursorWork releases it for every counter.
• stock row: a row of sStockTable (artifacts.c), one per shop: up to 24 item ids from column 0, ending with 0; up to 8 artifacts from column 24; and the shop's type in column 32 (SHOP_STOCK_ names the columns).
• artifact: an item a shop sells only while its shared stock counter is not zero (Item_AdjustCounter). A shop adds its row's artifacts to the counters once, on its first visit, and sets flag 0x400 + stockRow to remember it (EventTable_ApplyRowAbilities).
• action: what the player chose at a shop's counter: buy, sell, artifacts or repair (enum ShopAction). service: what the sanctum does for one party member: revive, cure poison, exorcise or remove a curse (enum SanctumService).
• cursor duration: shop->mode, the number of frames for the next hand cursor glide. Shop_PlaceCursor passes it to Shop_SetCursor, and ShopCursor_Advance interpolates until that many frames have elapsed.
• party row: the party members' icons across the window, which the counters select and animate (partyMemberIcons, Shop_PickUnit).
• unk<offset>: a field whose meaning is not known yet.

Prefixes

Prefix	What it acts on
Shop_	the shops' screens, and anything every counter shares
ShopCursor_	the hand cursor
UiMessage_	the shopkeeper's messages: show, wait, choose
EventTable_	the stock rows
Sanctum_	the sanctum's services
Inn_	the inn
Battle_, BattleUnit_, BattleFx_, AudioCommand_, NodeChain_	things the engine names elsewhere

The comment markers are in Matching.

Design

Artifacts are counted, not stocked

A shop's ordinary items are its row of sStockTable, always for sale. Its artifacts work differently: they are not kept per shop at all. Each rare item has one counter for the whole game (Item_AdjustCounter, in ../game/game/inventory.c), and a shop's artifact list is built when it opens from every item of the shop's type whose counter is above zero (shop/run.c). The counters move with the items:

• a shop's first visit adds one to the counter of each artifact in its row, and sets flag 0x400 + stockRow (FLAG_SHOP_ARTIFACTS_STOCKED plus the row) so it never does so again (EventTable_ApplyRowAbilities);
• buying one takes one away, once the purchase is complete;
• a rare item the party drops, discards or sells goes back into circulation, one up on its counter (Inventory_Discard, the item screen).

So an artifact first stocked in one town is then sold by every shop of its type, and a rare item the party gives up turns up for sale again. The flag per row is what keeps a revisited shop from adding its artifacts a second time.

One work block for every counter

Every counter (shop, sanctum, inn, artifact counter) uses the same heap block, HEAP_SLOT_MENU, as struct ShopRuntime: Shop_InitializeCursorWork takes it and Shop_ReleaseCursorWork gives it back. The field menu's screens use the same slot through their own views, so a counter and the field menu are never open together.

How to change a counter

• A shop's stock is its row of sStockTable in artifacts.c; each row's number is the stockRow its scene passes to Shop_Run.
• A value that differs by edition, such as a window moved for longer words, is a named macro chosen in one #if block at the top of shop_internal.h, or of the part that uses it; change that edition's branch.
• Messages are linker symbols (MsgDeal); their text is in the PO catalogs in games/tbs/text.

Limits

• A shop sells at most 24 items and 8 artifacts, the columns of its stock row (SHOP_STOCK_).
• A shop adds its artifacts once, remembered by flag 0x400 + stockRow.

Evidence and open questions

The counters are named for what the player meets at them; the stock row's columns (SHOP_STOCK_) from what artifacts.c reads at each place; the actions and services from the choices their windows offer in the English release.

Still unknown:

• XXX: why rows 16, 17 and 18 are the warrior's shops (shop->warriorShop, shop/run.c) by number rather than by a column of the row.
• XXX: EventTable_ApplyRowAbilities and the other EventTable_ names say less than the functions do; they cross folders.

Source: src/shop