Shop

A coin counter for every player and two shop buttons. Players earn coins with one button and spend them on items with the others. An item goes straight into the buyer’s inventory.

Contents

• You need
• Code
• Wire it
• Check it in game
• Change it
• How it works

You need

• A Button that pays out coins (or a Target: see Change it).
• Two Buttons for the shop, one per item.

button1 "Press Count" -> chip earn
button1 Character -> chip earner
button2 "Press Count" -> chip buy1
button2 Character -> chip buyer1
button3 "Press Count" -> chip buy2
button3 Character -> chip buyer2

Code

const EARN = 1                                // coins per press of the earn button
const PRICE_1 = 3                             // price of item 1
const PRICE_2 = 10                            // price of item 2
const ITEM_1 = $BRItemBase/Weapon_Bandage     // item 1
const ITEM_2 = $BRItemBase/Weapon_Pickaxe     // item 2

@left in earn: int
@left in earner: character
@left in buy1: int
@left in buyer1: character
@left in buy2: int
@left in buyer2: character

var coins: Map<string, int>
var lastEarn: int = 0
var last1: int = 0
var last2: int = 0

// true when a button's Press Count went up: a new press, not a release
mod pressed(holding: int, prev: *int) -> bool {
  let up = holding > prev
  prev = holding
  return up
}

mod balance(who: character) -> int {
  let had = coins.get(who.GetUserId())
  return if had.Found then had.Value else 0
}

mod pay(who: character, price: int) -> bool {
  let have = balance(who)
  if have < price {
    who.ShowStatusMessage("You need ${price} coins, you have ${have}")
    return false
  }
  coins.set(who.GetUserId(), have - price)
  who.ShowStatusMessage("Bought! ${have - price} coins left")
  return true
}

on Change(earn) {
  if pressed(earn, lastEarn) {
    let now = balance(earner) + EARN
    coins.set(earner.GetUserId(), now)
    earner.ShowStatusMessage("Coins: ${now}")
  }
}

on Change(buy1) {
  if pressed(buy1, last1) {
    if pay(buyer1, PRICE_1) {
      buyer1.AddInventoryItem(ITEM_1)
    }
  }
}

on Change(buy2) {
  if pressed(buy2, last2) {
    if pay(buyer2, PRICE_2) {
      buyer2.AddInventoryItem(ITEM_2)
    }
  }
}

Wire it

1. Compile the chip and paste it in-game.
2. Wire the earn Button’s Press Count to earn and its Character to earner.
3. Wire the first shop Button’s Press Count and Character to buy1 and buyer1, and the second’s to buy2 and buyer2.
4. Label the shop buttons with their item and price, on a sign or in each Button’s Prompt Custom Label setting.

Check it in game

• Press the first shop button with no coins: “You need 3 coins, you have 0”, and nothing is added to your inventory.
• Press the earn button three times: “Coins: 1”, “Coins: 2”, “Coins: 3”. Letting go gives nothing.
• Press the first shop button: “Bought! 0 coins left”, and a bandage is in your inventory.
• A second player earns and buys: their coins are their own.
• Hold the earn button down while a second player presses it: they still get their coin.
• Die and respawn: your coins are still there.

Change it

• Sell other items: the editor lists every item name after $BRItemBase/. Change ITEM_1 and PRICE_1.
• Earn coins from a Target instead of a button: make earn an exec pin, change its handler to on earn without the pressed check, and wire Just Hit to earn and Character That Just Hit to earner. Or give coins at the end of a course, in a zone’s on ZoneEntered handler.
• Add a third item: two more pins, a last3 var and an on Change(buy3) handler. pressed and pay work for it unchanged.

How it works

Every player’s coins are one entry in a map keyed by GetUserId(), so they survive a respawn and are saved with the bricks. Two mods hold the rules. balance reads a player’s coins, 0 when they have no entry yet. pay checks the price and takes the coins, and its -> bool result tells the handler whether to hand over the item. Each Button’s Character output says who pressed it, so one button serves every player. A Button’s Press Count is how many players hold it right now. The handlers run on every Change of it (Change), and the pressed mod lets one through only when the count went up since the last change: a new press, never a release. Each button keeps its own last count (lastEarn, last1, last2). Held stays on while anyone holds the button, so a second player’s press during that time would not turn it on again, though Press Count and Character both change. AddInventoryItem adds an item to the buyer’s inventory. The item is a constant $BRItemBase/... asset reference, chosen when the chip is compiled.

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