game: add weapon mod system

scenes/player.gd

@@ -29,6 +29,11 @@ func _ready() -> void:
 	if not weapon:
 		weapon = WEAPON_SWORD.instantiate()
 		add_child(weapon)
+		var mod = WeaponModBase.new()
+		mod.mod_property = "attack_damage"
+		mod.mod_value = 10.0
+		mod.mod_type = WeaponModBase.ModType.ADDITIVE
+		weapon.add_mod(mod)
 
 
 func _physics_process(delta: float) -> void:

scenes/weapons/weapon_base.gd

@@ -1,11 +1,19 @@
 class_name WeaponBase
 extends Node2D
 
+enum WeaponTag {
+	CAN_RETURN,
+	CAN_BLEED,
+}
+
 @export var attack_cd: float
 @export var attack_damage: float
 @export var attack_aoe: float
 @export var attack_duration: float
 @export var attack_range: float
+@export var attack_crit_chance: float = 0.05
+@export var tags: Array[String] = []
+@export var modifiers: Array[WeaponModBase] = []
 
 @onready var active_cd_timer: Timer = $ActiveCDTimer
 
@@ -25,6 +33,10 @@ func do_active() -> void:
 	_do_active()
 
 
+func add_mod(mod: WeaponModBase) -> void:
+	modifiers.append(mod)
+
+
 func _do_active() -> void:
 	push_error("%s does not implement do_active" % self)
 
@@ -53,3 +65,14 @@ func find_target_in_radius() -> EnemyBase:
 		):
 			closest = c
 	return closest
+
+
+func get_calculated(key: String) -> Variant:
+	return WeaponModBase.get_calculated(self, key)
+
+
+func has_property(key: String) -> bool:
+	for prop in get_property_list():
+		if prop.name == key:
+			return true
+	return false

scenes/weapons/weapon_mod_base.gd

@@ -0,0 +1,36 @@
+class_name WeaponModBase
+extends Resource
+
+enum ModType { ADDITIVE, MULTIPLICATIVE, ABSOLUTE, BOOL }
+
+@export var name: String = "Unnamed mod"
+@export var description: String = ""
+@export var icon: Texture2D
+@export var mod_property: String
+@export var mod_value: float
+@export var mod_value_bool: bool = false
+@export var mod_type: ModType = ModType.MULTIPLICATIVE
+@export var mod_extra_tags: Array[WeaponBase.WeaponTag] = []
+
+
+static func get_calculated(weapon: WeaponBase, key: String) -> Variant:
+	assert(
+		weapon.has_property(key),
+		"tried calculate property '%s' where base value does not exist on %s" % [key, weapon]
+	)
+	var base_value = weapon.get(key)
+
+	var add = 0.0
+	var mul = 1.0
+	for mod in weapon.modifiers:
+		if mod.mod_property == key:
+			match mod.mod_type:
+				ModType.ADDITIVE:
+					add += mod.mod_value
+				ModType.MULTIPLICATIVE:
+					mul *= mod.mod_value
+				ModType.ABSOLUTE:
+					return mod.mod_value
+				ModType.BOOL:
+					return mod.mod_value_bool
+	return (base_value + add) * mul

scenes/weapons/weapon_mod_base.gd.uid

@@ -0,0 +1 @@
+uid://b1cg1bhnt6xk4

scenes/weapons/weapon_sword.gd

@@ -44,12 +44,13 @@ func _do_active() -> void:
 
 
 func deal_damage(enemy: EnemyBase, damage_mult: float):
-	var crit_chance = _player.player_stats.get_final("crit_chance", _player.modifiers)
-	var damage_dealt = attack_damage * damage_mult
-	var is_crit = randf() >= 1 - crit_chance
+	var weapon_crit = get_calculated("attack_crit_chance")
+	var player_crit = _player.player_stats.get_final("crit_chance", _player.modifiers)
+	var damage = get_calculated("attack_damage")
+	var is_crit = randf() >= 1 - weapon_crit + player_crit
 	if is_crit:
-		damage_dealt *= _player.player_stats.get_final("crit_multiplier", _player.modifiers)
-	enemy.take_damage(damage_dealt, is_crit)
+		damage *= _player.player_stats.get_final("crit_multiplier", _player.modifiers)
+	enemy.take_damage(damage * damage_mult, is_crit)
 
 
 func _on_projectile_hit(projectile: WeaponSwordProjectile, enemy: EnemyBase, damage_mult: float):