Shops

A shop is a row of items on display and a shopkeeper NPC. When the player stands in front of an item, the shop shows every item's price, plus the name and description of the item in front of them. Pressing A there asks the shopkeeper to sell it. Talking to the shopkeeper opens a menu with To buy, To sell, To check, and To claim:

Option	What happens
To buy	The shopkeeper explains how to buy.
To sell	The player picks an item from their inventory and sells it for coins.
To check	The player leaves an item with the shopkeeper.
To claim	The player takes back an item they left.

Checked items go into one storage space that every shop shares, so the player can check an item in one shop and claim it in another.

The examples on this page are the shop in Koopa Village, from world/area/nok/nok_01/shop.c.

Placing the items in the map

Each item on display needs two objects in the map:

• A model that marks where the item sits. The game hides the model and shows the item 6 units above the model's center.
• A floor collider in front of the item, for the player to stand on.

List the pairs in a ShopItemLocation array, in the same order as the items you'll sell:

ShopItemLocation ItemPositions[] = {
    { .posModelID = MODEL_o213, .triggerColliderID = COLLIDER_o343 },
    { .posModelID = MODEL_o214, .triggerColliderID = COLLIDER_o344 },
    { .posModelID = MODEL_o215, .triggerColliderID = COLLIDER_o345 },
    { .posModelID = MODEL_o216, .triggerColliderID = COLLIDER_o346 },
    { .posModelID = MODEL_o217, .triggerColliderID = COLLIDER_o347 },
    { .posModelID = MODEL_o218, .triggerColliderID = COLLIDER_o348 },
};

List the items for sale

Write a ShopItemData array with each item, its price in coins, and the message the shop shows as its description. End the array with {}:

ShopItemData Inventory[] = {
    { .itemID = ITEM_DIZZY_DIAL,  .price = 10, .descMsg = MSG_ItemShopDesc_DizzyDial },
    { .itemID = ITEM_POW_BLOCK,   .price =  4, .descMsg = MSG_ItemShopDesc_POWBlock },
    { .itemID = ITEM_FIRE_FLOWER, .price =  8, .descMsg = MSG_ItemShopDesc_FireFlower },
    { .itemID = ITEM_HONEY_SYRUP, .price =  8, .descMsg = MSG_ItemShopDesc_HoneySyrup },
    { .itemID = ITEM_VOLT_SHROOM, .price = 15, .descMsg = MSG_ItemShopDesc_VoltShroom },
    { .itemID = ITEM_MUSHROOM,    .price =  4, .descMsg = MSG_ItemShopDesc_Mushroom },
    {}
};

Each item goes at the location in the same position in ItemPositions, so give ItemPositions at least as many entries as Inventory. The game's own descriptions are in msg/24_ShopItemDesc.msg. To sell your own item, see Add an item.

The player can buy each item as many times as they like. Items don't sell out.

Setting what the shop pays for items

When the player sells an item, the shop pays the item's sellValue from registry/items.yaml. To pay a different amount in this shop, list the item in a ShopSellPriceData array, ending with {}:

ShopSellPriceData PriceList[] = {
    { .itemID = ITEM_KOOPASTA,      .sellPrice = 12 },
    { .itemID = ITEM_KOOPA_TEA,     .sellPrice =  4 },
    { .itemID = ITEM_KOOKY_COOKIE,  .sellPrice = 15 },
    { .itemID = ITEM_SPECIAL_SHAKE, .sellPrice = 12 },
    { .itemID = ITEM_BLAND_MEAL,    .sellPrice = 12 },
    { .itemID = ITEM_SUPER_SODA,    .sellPrice =  5 },
    { .itemID = ITEM_LIFE_SHROOM,   .sellPrice = 30 },
    {}
};

If every item can sell for its sellValue, pass nullptr instead of a list.

Writing the shopkeeper's messages

The shopkeeper says a different message at each step of buying, selling, checking, and claiming. List them in an array indexed by the SHOP_MSG_ constants. The array needs all 23:

s32 ShopMessages[] = {
    [SHOP_MSG_BUY_CONFIRM      ] MSG_Shop_00_NOK01,
    [SHOP_MSG_NOT_ENOUGH_COINS ] MSG_Shop_01_NOK01,
    [SHOP_MSG_NOT_ENOUGH_ROOM  ] MSG_Shop_02_NOK01,
    [SHOP_MSG_BUY_THANK_YOU    ] MSG_Shop_03_NOK01,
    [SHOP_MSG_GREETING         ] MSG_Shop_04_NOK01,
    [SHOP_MSG_INSTRUCTIONS     ] MSG_Shop_05_NOK01,
    [SHOP_MSG_NOTHING_TO_SELL  ] MSG_Shop_06_NOK01,
    [SHOP_MSG_SELL_WHICH       ] MSG_Shop_07_NOK01,
    [SHOP_MSG_SELL_CONFIRM     ] MSG_Shop_08_NOK01,
    [SHOP_MSG_SELL_CANCEL      ] MSG_Shop_09_NOK01,
    [SHOP_MSG_SELL_MORE        ] MSG_Shop_0A_NOK01,
    [SHOP_MSG_SELL_THANKS      ] MSG_Shop_0B_NOK01,
    [SHOP_MSG_NOTHING_TO_CHECK ] MSG_Shop_0C_NOK01,
    [SHOP_MSG_NO_CHECK_ROOM    ] MSG_Shop_0D_NOK01,
    [SHOP_MSG_CHECK_WHICH      ] MSG_Shop_0E_NOK01,
    [SHOP_MSG_CHECK_ACCEPTED   ] MSG_Shop_0F_NOK01,
    [SHOP_MSG_CHECK_MORE       ] MSG_Shop_10_NOK01,
    [SHOP_MSG_NOTHING_TO_CLAIM ] MSG_Shop_11_NOK01,
    [SHOP_MSG_NO_CLAIM_ROOM    ] MSG_Shop_12_NOK01,
    [SHOP_MSG_CLAIM_WHICH      ] MSG_Shop_13_NOK01,
    [SHOP_MSG_CLAIM_ACCEPTED   ] MSG_Shop_14_NOK01,
    [SHOP_MSG_CLAIM_MORE       ] MSG_Shop_15_NOK01,
    [SHOP_MSG_FAREWELL         ] MSG_Shop_16_NOK01,
};

You can reuse another shop's messages. To write your own, copy a set from msg/27_Shops.msg and change the text, keeping each message's tags at the start and end. The messages that come before a choice, such as SHOP_MSG_GREETING and SHOP_MSG_BUY_CONFIRM, end with [Yield][End] so the choice appears in the same box. For how to write messages, see Write messages.

Some messages show values the shop fills in:

Message	[Var 0]	[Var 1]	[Var 2]
SHOP_MSG_BUY_CONFIRM	The item's name	The price	s if the price isn't 1 coin. For a badge, the BP it costs to equip instead.
SHOP_MSG_SELL_CONFIRM	The item's name	What the shop pays	s if it isn't 1 coin
SHOP_MSG_CHECK_WHICH	How many items the player can still check	s if that isn't 1

Making the shopkeeper

The shopkeeper is an ordinary NPC. For how to add one, see NPCs. To open the shop's menu when the player talks to it, run EVS_ShopOwnerDialog from its interact EVT script:

EvtScript EVS_NpcInteract_Koopa_ShopOwner = {
    ExecWait(EVS_ShopOwnerDialog)
    Return
    End
};

EvtScript EVS_NpcInit_Koopa_ShopOwner = {
    Call(BindNpcInteract, NPC_SELF, EVS_NpcInteract_Koopa_ShopOwner)
    Return
    End
};

Then describe the shopkeeper to the shop with a ShopOwner:

ShopOwner Owner = {
    .npcID = NPC_Koopa_ShopOwner,
    .idleAnim = ANIM_Koopa_Idle,
    .talkAnim = ANIM_Koopa_Talk,
    .onBuyEvt = &EVS_OnBuy,
    .shopMsgIDs = ShopMessages,
};

Field	What it sets
.npcID	The shopkeeper NPC's ID.
.idleAnim, .talkAnim	The animations the shopkeeper plays while it listens and while it talks.
.onBuyEvt	Optional. An EVT script that runs after each purchase. See Run an EVT script after a purchase.
.onTalkEvt	Optional. An EVT script that runs when the player closes the shopkeeper's menu.
.shopMsgIDs	The shopkeeper's messages.

Making the shop

Make the shop with MakeShop, then give it its shopkeeper with MakeShopOwner. Call them in that order, because MakeShop clears the shopkeeper:

EvtScript EVS_SetupShop = {
    Call(MakeShop, ItemPositions, Inventory, PriceList, 0)
    Call(MakeShopOwner, Owner)
    Return
    End
};

Run EVS_SetupShop from the map's main EVT script, such as with Exec(EVS_SetupShop) after MakeNpcs. A map has one shop at a time, so call MakeShop once.

The last argument to MakeShop sets which visibility group the items belong to. Pass 0 for a shop outdoors. If the shop is inside a room, pass the building's group, such as ITEM_VIS_GROUP(ITEM_NONE, VIS_GROUP_1), so the items only show while the player is inside. Koopa Village's shop passes ITEM_ENTITY_FLAG_TOSS_LOWER, which has the same value.

Running an EVT script after a purchase

The shopkeeper's .onBuyEvt runs at the end of every purchase conversation, after the shopkeeper finishes talking, whether or not the player bought the item. It gets:

• LVar0: what happened, such as SHOP_BUY_RESULT_OK, SHOP_BUY_RESULT_CANCEL, SHOP_BUY_RESULT_NOT_ENOUGH_COINS, or SHOP_BUY_RESULT_NOT_ENOUGH_ROOM.
• LVar1: the item's ID.
• LVar2: the item's position in Inventory, from 0.

This EVT script sets a game flag when the player buys a Volt Shroom. You define GF_MyShop_BoughtVoltShroom yourself, as described in Game flags:

EvtScript EVS_OnBuy = {
    IfEq(LVar0, SHOP_BUY_RESULT_OK)
        IfEq(LVar1, ITEM_VOLT_SHROOM)
            Set(GF_MyShop_BoughtVoltShroom, true)
        EndIf
    EndIf
    Return
    End
};

Changing what's for sale during the story

The shop's stock is set when the map loads. To sell different items later in the story, write an inventory for each point in the story and pass the one you want to MakeShop. InventoryEarly and InventoryLate are names you choose:

EvtScript EVS_SetupShop = {
    IfLt(GB_StoryProgress, STORY_CH2_STAR_SPIRIT_DEPARTED)
        Set(LVar0, InventoryEarly)
    Else
        Set(LVar0, InventoryLate)
    EndIf
    Call(MakeShop, ItemPositions, LVar0, PriceList, 0)
    Call(MakeShopOwner, Owner)
    Return
    End
};

Check a game flag the same way to change the stock after an event. Give each inventory the same number of items. If one has fewer, the locations it doesn't use still show their marker models, and standing in front of them does nothing.

Limits

• To buy an item that isn't a badge, the player needs a free slot in their 10-slot item inventory. This includes key items. If they have no room, the shopkeeper says SHOP_MSG_NOT_ENOUGH_ROOM.
• Badges skip the room check. Buying a badge from any shop sets GF_MAC01_BoughtBadgeFromRowf, which the base game uses to unlock a letter in the player's house.
• The player can only sell, check, and claim items from their item inventory. Badges and key items never appear in those menus.
• Storage holds 32 items, shared between every shop.
• The items on display ignore the player while a partner is using its ability, unless that partner is Kooper or Bombette.