player: add Economy integration

economy/economy.gd

@@ -0,0 +1,79 @@
+# Economy is a game entity that tracks money.
+
+# How money is minted, how money changes hands, and which
+# money is valid is all controlled by Economy. When an
+# in-game item is purchased, the money does not disappear
+# but rather goes to the Market, an economic entity which
+# can give back to players through investments or other means.
+
+# Economy also tracks GDP, which is the total amount of
+# money that has changed hands so far during the game.
+class_name Economy extends Node
+
+# Participant in the game economy
+@abstract class Participant:
+	var participant_name = "Unnamed participant"
+	var _tokens = PackedInt32Array()
+
+	func balance():
+		return _tokens.size()
+
+	func hold_tokens(tokens):
+		_tokens.append_array(tokens)
+		on_balance_update(balance())
+
+	func pop_tokens(amount):
+		if balance() < amount:
+			return []
+
+		var dropped = []
+		for i in range(amount):
+			dropped.append(_tokens[_tokens.size() - 1])
+			_tokens.remove_at(_tokens.size() - 1)
+		on_balance_update(balance())
+		return dropped
+
+	@abstract func message(string)
+	@abstract func on_balance_update(bal)
+
+class Market extends Participant:
+	func _init():
+		participant_name = "Market"
+	func message(_s):
+		pass
+	func on_balance_update(_bal):
+		pass
+
+const max_money_supply = 1_000_000
+
+var _gdp = 0
+var _market = Market.new()
+var _participants = []
+var _token_ptr = 0
+
+# register a Participant to receive benefits
+func register(p: Participant):
+	_participants.append(p)
+
+func transfer(amount, sender: Participant, recipient: Participant):
+	if sender.balance() < amount:
+		return false
+	recipient.hold_tokens(sender.pop_tokens(amount))
+	_gdp += amount
+
+func mint(amount):
+	var tokens = PackedInt32Array()
+	if _token_ptr + amount > max_money_supply:
+		return false
+	for i in range(amount):
+		tokens.append(_token_ptr)
+		_token_ptr += 1
+	_market.hold_tokens(tokens)
+	return true
+
+func _ready():
+	while true:
+		if len(_participants) > 0:
+			mint(1000)
+			transfer(1000, _market, _participants[0])
+			break

economy/economy.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3 uid="uid://cenj3dcweigwt"]
+
+[ext_resource type="Script" uid="uid://dl1jbgt83gocy" path="res://economy/economy.gd" id="1_n84lp"]
+
+[node name="Economy" type="Node"]
+script = ExtResource("1_n84lp")

main.tscn

@@ -1,10 +1,11 @@
-[gd_scene load_steps=9 format=3 uid="uid://eiaw4xbs3suk"]
+[gd_scene load_steps=10 format=3 uid="uid://eiaw4xbs3suk"]
 
 [ext_resource type="PackedScene" uid="uid://qb8cbljxgnub" path="res://world/killbrick.tscn" id="1_h2yge"]
 [ext_resource type="PackedScene" uid="uid://cfceg80unq0pe" path="res://player/player.tscn" id="1_ig7tw"]
 [ext_resource type="PackedScene" uid="uid://bcmrj6qkemrll" path="res://world/radiohead_cube.tscn" id="2_0xm2m"]
 [ext_resource type="PackedScene" uid="uid://of6tq8gpjxtu" path="res://gears/gear_pickup.tscn" id="3_lquwl"]
 [ext_resource type="PackedScene" uid="uid://bafl8q0r61xrg" path="res://gears/gear.tscn" id="4_7mycd"]
+[ext_resource type="PackedScene" uid="uid://cenj3dcweigwt" path="res://economy/economy.tscn" id="6_7mycd"]
 
 [sub_resource type="BoxShape3D" id="BoxShape3D_7dm0k"]
 size = Vector3(100, 2, 100)
@@ -52,3 +53,5 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -12, 2, -21)
 
 [node name="Gear" parent="GearPickup" instance=ExtResource("4_7mycd")]
 transform = Transform3D(1, 0, 0, 0, -0.012967386, 0.9999159, 0, -0.9999159, -0.012967386, 0, 0.5, 0)
+
+[node name="Economy" parent="." instance=ExtResource("6_7mycd")]

player/player.gd

@@ -10,6 +10,7 @@ const gear_slots = ["1", "2", "3"]
 
 var starting_gear = preload("res://gears/ball.tscn")
 
+var ep = PlayerParticipant.new(self)
 var suspended = false
 var direction = Vector3.ZERO
 var target_velocity = Vector3.ZERO
@@ -27,13 +28,17 @@ func resize_ui():
 	$HUD.position.x = 0
 	$HUD.position.y = size.y - hud_h
 
-func make_hud():
+func make_hud(balance = ep.balance()):
+	if suspended: # TODO: CHANGE TO DEAD!
+		return
+
 	var text = ""
 	for node in $Backpack.get_children():
 		if not node is Gear:
 			continue
 		text += "%s (%s)\n" % [node.gear_name(), node.name]
 	text += "Holding " + $Pivot/Container/Gear.gear_name() + "\n"
+	text += str(balance) + " ₹ (rupees)\n"
 	text += str(health()) + " hp"
 	$HUD.text = text
 
@@ -147,6 +152,18 @@ func equip(gear: Gear):
 	message("Backpack full")
 	return false
 
+# Economy participant definition
+
+class PlayerParticipant extends Economy.Participant:
+	var player: Player
+	func _init(p: Player):
+		player = p
+		participant_name = "Player participant"
+	func message(string):
+		player.message(string)
+	func on_balance_update(bal):
+		player.make_hud(bal)
+
 # Player mechanics
 
 func move_player(x, z):
@@ -217,6 +234,7 @@ func do_gears():
 # Engine callbacks
 
 func _ready():
+	get_tree().current_scene.get_node("Economy").register(ep)
 	get_viewport().size_changed.connect(resize_ui)
 	resize_ui()
 	respawn()