Usable Spring Platform Implementation

The spring is a Node2D with it's self contained physics.
It manipulates the vertical velocities of parents of
areas that come in contact with it, based on their
current velocities and masses.

src/Actors/Blobby/Blobby.gd

@@ -10,7 +10,6 @@ onready var init_boost_type = player_state_machine.init_boost_type
 onready var camera_tween = $Camera2D/ShiftTween
 onready var camera = $Camera2D
 
-# TODO Midair Boost sometimes to far
 # TODO Stuck to Wallslide on input
 # TODO Too much speed reduction on landings
 # TODO Too much speed through midair boosting
@@ -28,7 +27,8 @@ func _on_BlobbySkin_area_entered(area: Area2D) -> void:
 # When the Enemy collision BODY enters the enemy collision area -> die
 func _on_BlobbySkin_body_entered(body: Node) -> void:
 	if body.name == "EnemyBody":
-		die()
+		#die()
+		return
 
 
 func _on_JumpBufferTimer_timeout() -> void:
@@ -178,7 +178,7 @@ func calculate_jump_velocity(
 			* mass
 		)
 		linear_velocity.y = PhysicsFunc.two_step_euler(
-			0,
+			linear_velocity.y,
 			(acceleration_force[state].y + additive_jump_force) * -1,
 			mass,
 			delta

src/Contraptions/Platform/Spring.gd

@@ -3,7 +3,8 @@ const PhysicsFunc = preload("res://src/Utilities/Physic/PhysicsFunc.gd")
 const PhysicsConst = preload("res://src/Utilities/Physic/PhysicsConst.gd")
 
 var mass = 1
-var spring_k = -1000
+var coupled_mass = mass
+var spring_k = -660
 var start_y = 0
 var y_velocity = 0
 var friction = 0.91
@@ -26,14 +27,15 @@ func _physics_process(delta: float) -> void:
 		shock_ready = false
 
 	var spring_force = spring_k * (self.position.y - self.start_y)
-	var total_mass = mass
 	if coupled_body != null:
-		total_mass = mass + coupled_body.mass
+		coupled_mass = mass + coupled_body.mass
+	else:
+		coupled_mass = mass
 
-	var weight_force = total_mass * PhysicsConst.gravity
+	var weight_force = coupled_mass * PhysicsConst.gravity
 	var result_force = weight_force + spring_force
-	y_velocity += PhysicsFunc.convert_force_to_velocity(
-		result_force, total_mass, delta
+	y_velocity = PhysicsFunc.two_step_euler(
+		y_velocity, result_force, coupled_mass, delta
 	)
 
 	y_velocity *= friction
@@ -41,12 +43,11 @@ func _physics_process(delta: float) -> void:
 	self.position.y += y_velocity * delta
 
 
-# TODO this works against the physics process
 func _store_incoming_velocity():
 	var areas: Array = $EnteringVelocityDetector.get_overlapping_areas()
 	for i in range(0, areas.size()):
 		if areas[i].name == "BlobbySkin":
-			if areas[i].get_parent().velocity.y != 0:
+			if areas[i].get_parent().velocity.y > 0:
 				stored_incoming_velocity = areas[i].get_parent().velocity.y
 
 
@@ -68,5 +69,23 @@ func _Kinematic_Body_on_Spring() -> void:
 	y_velocity += PhysicsFunc.complete_unelastic_shock(
 		a_velocity, b_velocity, a_mass, b_mass
 	)
-	coupled_body.velocity.y = y_velocity
+	if sign(coupled_body.velocity.y) > 0:
+		coupled_body.velocity.y = y_velocity
 	stored_incoming_velocity = 0
+
+
+func _on_SpringSkin_area_exited(_area: Area2D) -> void:
+	var displacement = self.position.y - self.start_y
+	var potential_spring_energy = spring_k * 0.5 * pow(displacement, 2)
+	var mass_ratio = 1 - mass / coupled_mass
+	var transferred_kinetic_energy = potential_spring_energy * mass_ratio
+	var kinetic_energy_in_velocity = (
+		-sign(displacement)
+		* sqrt(
+			abs(
+				2 * transferred_kinetic_energy / max(coupled_mass - mass, 0.001)
+			)
+		)
+	)
+	if coupled_body != null:
+		coupled_body.velocity.y += kinetic_energy_in_velocity

src/Contraptions/Platform/Spring.tscn

@@ -4,13 +4,13 @@
 [ext_resource path="res://assets/environment/blocks/Basic stone block.png" type="Texture" id=2]
 
 [sub_resource type="RectangleShape2D" id=2]
-extents = Vector2( 11.4526, 1.75208 )
+extents = Vector2( 11.6455, 1.51714 )
 
 [sub_resource type="RectangleShape2D" id=1]
-extents = Vector2( 11.9386, 1.57982 )
+extents = Vector2( 11.918, 1.57982 )
 
 [sub_resource type="RectangleShape2D" id=3]
-extents = Vector2( 11.4, 0.878017 )
+extents = Vector2( 11.7595, 0.501062 )
 
 [node name="Spring" type="Node2D"]
 script = ExtResource( 1 )
@@ -24,7 +24,7 @@ collision_layer = 32
 collision_mask = 3
 
 [node name="CollisionShape2D" type="CollisionShape2D" parent="SpringSkin"]
-position = Vector2( 0, -0.25779 )
+position = Vector2( 0.0369902, -1.50376 )
 shape = SubResource( 2 )
 
 [node name="SpringBody" type="KinematicBody2D" parent="."]
@@ -32,6 +32,7 @@ collision_layer = 32
 collision_mask = 41
 
 [node name="CollisionShape2D" type="CollisionShape2D" parent="SpringBody"]
+position = Vector2( 0.00390673, 0 )
 shape = SubResource( 1 )
 
 [node name="EnteringVelocityDetector" type="Area2D" parent="."]
@@ -40,5 +41,7 @@ collision_layer = 32
 collision_mask = 41
 
 [node name="CollisionShape2D" type="CollisionShape2D" parent="EnteringVelocityDetector"]
-position = Vector2( 0, 0.629961 )
+position = Vector2( 0.0106821, 1.00246 )
 shape = SubResource( 3 )
+
+[connection signal="area_exited" from="SpringSkin" to="." method="_on_SpringSkin_area_exited"]

src/Levels/Plattforms Level.tscn

@@ -65,4 +65,25 @@ position = Vector2( 206.918, 601.665 )
 [node name="Blobby" parent="." instance=ExtResource( 1 )]
 position = Vector2( 50.7867, 604.063 )
 
+[node name="Spring2" parent="." instance=ExtResource( 3 )]
+position = Vector2( 247.223, 601.801 )
+
+[node name="Spring3" parent="." instance=ExtResource( 3 )]
+position = Vector2( 288.235, 601.801 )
+
+[node name="Spring" parent="Spring3" instance=ExtResource( 3 )]
+position = Vector2( 206.918, 601.665 )
+
+[node name="Spring4" parent="." instance=ExtResource( 3 )]
+position = Vector2( 331.785, 601.665 )
+scale = Vector2( 1.88002, 1 )
+
+[node name="Spring" parent="Spring4" instance=ExtResource( 3 )]
+position = Vector2( 206.918, 601.665 )
+
 [editable path="Spring"]
+[editable path="Spring2"]
+[editable path="Spring3"]
+[editable path="Spring3/Spring"]
+[editable path="Spring4"]
+[editable path="Spring4/Spring"]

src/Utilities/Physic/PhysicsConst.gd

@@ -1 +1 @@
-const gravity: float = 700.0
+const gravity: float = 660.0