added some bucket features and two modes

scripts/droplet.gd

@@ -1,7 +1,49 @@
 class_name Droplet extends RigidBody2D
 
-func _ready():
-	pass # Replace with function body.
+# bounce mode seems to settle with a consistent surface, but is erratic
+# stick mode seems to make sand castles, but is very calm
+enum Mode { BOUNCE, STICK }
+const mode: Mode = Mode.BOUNCE
 
-func _process(delta):
+func _ready():
+	var mat = PhysicsMaterial.new()
+	mat.bounce = .1 if mode == Mode.BOUNCE else 0
+	mat.friction = 0.0
+	physics_material_override = mat
+	
+	# setup body entered signal, seems to also matter for STICK mode
+	contact_monitor = true
+	max_contacts_reported = 10
+	body_entered.connect(_on_body_entered)
+
+func _physics_process(delta):
 	pass
+	
+func _integrate_forces(state):
+	if mode == Mode.STICK:
+		var v = state.linear_velocity
+		var contacts = state.get_contact_count()
+		for i in range(contacts):
+			var body = state.get_contact_collider_object(i)
+			var normal = state.get_contact_local_normal(i)
+			var self_damp = .9
+			var other_damp = 1 - self_damp
+			v = v.bounce(normal) * self_damp
+			state.linear_velocity = v # self bounce
+			if body is RigidBody2D: # other body
+				body.apply_central_impulse(normal * v.length() * (other_damp/contacts))
+
+func _on_body_entered(body):
+	if mode == Mode.BOUNCE:
+		# trying to elicit stronger response from rigidBody that was struck
+		# ends up being kind of erratic
+		# at damp_factor .75: settles laterally, but erratic past half-full
+		# at damp_factor of .5, it's pretty calm, but then can't overfill (expected?)
+		var vel = get_linear_velocity()
+		const damp_factor = 0.7
+		var normal = (body.global_position - global_position).normalized()
+		# reflect velocity across collision direction
+		var bounced = vel.bounce(normal) # reflection
+		set_linear_velocity(bounced * damp_factor)
+		if body is RigidBody2D:
+			body.apply_central_impulse(-bounced * damp_factor)

scripts/model.gd

@@ -1,15 +1,19 @@
 class_name Model extends Node2D
 
-const PERIOD: int = 300
+const PERIOD: int = 20 # smaller makes droplets faster
 var CURRENT_TIME: int = 0
+var last_droplet: int = 0
 
 func _ready():
 	pass # Replace with function body.
 
 func _process(delta: float):
 	CURRENT_TIME += delta * 100 	
-	if CURRENT_TIME % 100 == 0:
-		print("Current time: ", str(CURRENT_TIME))
+	if CURRENT_TIME - last_droplet > PERIOD:
+		last_droplet = CURRENT_TIME
+		# print("new droplet at time: ", str(CURRENT_TIME))
 		var droplet = preload("res://scenes/droplet.tscn").instantiate()
-		droplet.global_position = Vector2(100, 100)
+		var shape = droplet.get_node("CollisionShape2D")
+		shape.shape.radius = 5
+		droplet.global_position = Vector2(450, 100)		
 		add_child(droplet)