add stones, pickups

scripts/Enemy.gd

@@ -1,5 +1,7 @@
 extends CharacterBody3D
 
+const PICKUP_SCENE := preload("res://scenes/Pickup.tscn")
+
 signal died(points: int)
 signal merged(upgrade: bool)
 
@@ -211,12 +213,34 @@ func _wall_impact_effect() -> void:
 	tw.tween_property(mat, "albedo_color", Color.WHITE, 0.04)
 	tw.tween_property(mat, "albedo_color", COLOR_STUN, 0.12)
 
+func _try_drop_pickup() -> void:
+	var roll := randf()
+	var p_type := ""
+	var p_heal := 0
+	match enemy_type:
+		"slime":
+			if   roll < 0.30: p_type = "health"; p_heal = 15
+			elif roll < 0.40: p_type = "score"
+		"bat":
+			if   roll < 0.20: p_type = "health"; p_heal = 12
+			elif roll < 0.25: p_type = "score"
+		"ogre":
+			if   roll < 0.55: p_type = "health"; p_heal = 35
+			elif roll < 0.80: p_type = "score"
+	if p_type == "":
+		return
+	var pickup := PICKUP_SCENE.instantiate()
+	pickup.setup(p_type, p_heal)
+	get_parent().add_child(pickup)
+	pickup.global_position = global_position
+
 func _die() -> void:
 	if state == State.DEAD:
 		return
 	state = State.DEAD
 	set_physics_process(false)
 	emit_signal("died", score_value)
+	_try_drop_pickup()
 	var tw := create_tween()
 	tw.tween_property(self, "scale", Vector3(2.0, 0.05, 2.0), 0.18)
 	tw.tween_property(self, "scale", Vector3(0.0, 0.0, 0.0), 0.1)