Shop

originally posted by joebarnin

Click here for a default purchasable items template.

How to NOT show the shop

The shop shows by default at mission start. If you don't want it then add this spawnarg and value to your map's worldspawn:

"shop_skip"   "1"

The Shop Entity

To define the available items in the shop of your map place an atdm:shop entity somewhere (a blue room maybe).

Once added to the map, you can define the shop items and starting equipment by adding spawnargs to this entity.

Items for Sale

The spawnarg syntax for shop items for sale goes like this:

"shopItem_N_D_item"  "ITEMCLASSNAME"    // which item
"shopItem_N_D_qty"   "QUANTITY"         // amount for sale

N refers is just an index to enumerate the various shop items. The number D is defining the difficulty level this shop item applies to (which can be 0, 1 or 2, with 0 being the lowest level "Easy"). The value ITEMCLASSNAME is usually a classname, which is referring to the shop item definition in tdm_shopitems.def, e.g. the value atdm:weapon_broadhead would be pointing to the shop item entityDef ShopItem_weapon_broadhead. The second key/value pair defines the amount of items that are for sale, e.g. "10".

Numbering

Unlike many other setup entities, you don't have to use a sequential numbering on atdm:shop. The code is able to handle gaps in the sequences, so you don't have to renumber everything each time you remove a shop item. For instance, it's now possible to do something like this:

"shopItem_1_0_item" "atdm:weapon_broadhead"
"shopItem_1_0_qty" "10"
"shopItem_3_0_item" "atdm:weapon_waterarrow"
"shopItem_3_0_qty" "10"

Note the missing "2" in the indexing. The parser just continues, which should make prefabbing easier and set up more robust against user errors.

Notes

• It's possible to add multiple shop entities to your map, it might be convenient to have a separate shop entity for each difficulty level, in the end it's a matter of taste.
• It's also possible to define these spawnargs on the worldspawn entity - this was the original method (way back in about 2007/2008). It's still supported but I'd rather not do it that way.

Setting up the Shop

Add an atdm:shop entity to your map (probably in the "blue room"). You can add the following lines in the editor, but it might be easier to load up your map file in a text editor, find the adtm:shop entity, and cut and paste.

"shop_gold_start" "700"
"shopItem_1_item" "atdm:playertools_flashbomb"
"shopItem_1_qty" "5"
"shopItem_2_item" "atdm:weapon_waterarrow"
"shopItem_2_0_qty" "5"
"shopItem_2_1_qty" "3"
"shopItem_2_2_qty" "1"
"shopItem_2_cost" "225"
"startingItem_1_item" "atdm:weapon_broadsword"
"startingItem_1_qty" "1"
"startingItem_2_item" "atdm:weapon_blackjack"
"startingItem_2_qty" "1"
"startingItem_3_item" "atdm : playertools_health_potion" (remove the spaces around the colon)
"startingItem_3_0_qty" "2"
"startingItem_3_1_qty" "1"
"startingItem_3_2_qty" "0"

_# : item number, starting from 1. No gaps.
_#_X: X is the skill (difficulty) level this value applies to. So in the above example, the shop contains 5 water arrows at 
easy, 3 at medium, 1 at hard (difficulty goes from 0 (easy) to 2 (hard)). If you leave off a skill, quantity zero is assumed 
(e.g., if there was no "shopItem_2_2_qty", then there would be zero arrows for sale at hard level). Note you can have cost 
vary by difficulty as well. And starting item quantities too.
_item: the "classname" listed in the entitydef (see tdm_shopitems.def).
_qty: how many are for sale (or, if a starting item, how many to start with)
_cost field is optional (otherwise it uses the default cost defined in tdm shopitems.def).

Okay, now you've updated your map with something like this, so get back to the Shop and buy what you want. Start the mission. You should have the appropriate number of items.

tdm-shopitems.def defines the list of the common items that can be purchased (or that can be in the Starting Items list). This file documents the format of ShopItem entityDefs, so if you want to add unique items to your own .def file, you can.

shop.cpp and shop.h are new files that define CShop and CShopItems, classes for dealing with the Shop screen.

player.cpp was updated to create the purchased items

game_local.cpp was modified to handle the Main Menu commands. This was the only way I could figure out to have the shop talk to our code. Apparently the id code behaves differently when your in the main menu.

Preventing the player dropping critical items

There is a cannot drop' option for start items, eg, a spawnarg, "startingitem_15_2_candrop" "0". For use with mission-critical items (like lockpicks) so full start equipment can be shown in the shop without risk the player will drop something crucial.

Limit the Loot from previous Missions

This section is applicable to campaigns or multi-mission setups: the mapper can define how much loot collected in Mission 1 will be usable in the shop before Mission 2. It's possible to define "conversion rates" for the various loot types (e.g. "10 goods are worth 1 gold"), absolute and relative gold losses as well as minimum and maximum values.

The following rules are applied in the specified order.

Conversion Rates

Since the shop doesn't care about goods, jewels or gold, each collected loot type will be converted into a gold value before proceeding. The conversion rates are numeric factors the collected value will be multiplied with to calculate the value in gold. The default conversion rates are defining a 1:1 exchange rate: 1 of each loot type will be worth 1 gold.

"loot_convrate_gold"    "1.0"   // 1:1 conversion rate for gold
"loot_convrate_jewels"  "0.5"   // 2 jewels are worth 1 gold
"loot_convrate_goods"   "0.2"   // 5 goods are worth 1 gold

The shop will only accept full rounded integer numbers, so if any conversion rate will produce decimals the number will be rounded towards the nearest lower integer number (they're "floor"ed).

Gold Loss

After the loot type conversion the gold loss is applied, which can be specified in percent or absolute (even both if that makes sense for your setup). If both are specified, the percentile loss is applied first.

"gold_loss_percent"   "20"    // 20% gold will be deducted
"gold_loss"           "200"   // 200 gold will be subtracted in any case

The default value for both loss spawnargs is "0", i.e. no loss.

Shop Starting Gold

After applying the loss, the starting gold defined on the atdm:shop entity (see above) is added.

Gold Cap

After applying the shop starting gold, the maximum gold value will be enforced (if defined):

"gold_cap"            "350"   // no more than 350 gold in any case

The default gold cap value is "-1" which means "no cap".

Minimum Gold

As final step (to ensure that the player has at least a minimum amount of gold to purchase the bare minimum equipment) the minimum gold value is ensured. It is applied if the above rules made the player's budget fall below that value.

"gold_min"            "50"    // at least 50 gold

The default value for "gold_min" is "0", so the player can never enter the shop with a negative amount of gold.