Blobby/src/Platforms/Spring/SpringPhysics.gd

98 lines
2.7 KiB
GDScript

extends Node2D
const PhysicsFunc = preload("res://src/Utilities/Physic/PhysicsFunc.gd")
const PhysicsConst = preload("res://src/Utilities/Physic/PhysicsConst.gd")
# onready var slide_friction = 0.5
var mass = 1
var coupled_mass = mass
var spring_k = -400
var start_y = 0
var y_velocity = 0
var friction = 0.91
# TODO Only store velocity coming to the springs orientation
var stored_incoming_velocity = 0
var coupled_body = null
var shock_ready = true
func _ready() -> void:
start_y = self.position.y
# TODO Limit spring deformation
func _physics_process(delta: float) -> void:
var bc = _body_contact()
if !bc:
shock_ready = true
if bc && shock_ready:
_Kinematic_Body_on_Spring()
var spring_force = spring_k * (self.position.y - self.start_y)
if coupled_body != null:
coupled_mass = mass + coupled_body.mass
else:
coupled_mass = mass
var weight_force = coupled_mass * PhysicsConst.gravity
var result_force = weight_force + spring_force
y_velocity = PhysicsFunc.two_step_euler(
y_velocity, result_force, coupled_mass, delta
)
y_velocity *= friction
self.position.y += y_velocity * delta
func _body_contact() -> bool:
var areas: Array = $SpringSkin.get_overlapping_areas()
for i in range(0, areas.size()):
if ["BlobbySkin","EnemySkin"].has(areas[i].name):
coupled_body = areas[i].get_parent()
return true
coupled_body = null
return false
func _Kinematic_Body_on_Spring() -> void:
var a_velocity = stored_incoming_velocity
var a_mass = coupled_body.mass
var b_velocity = y_velocity
var b_mass = mass
y_velocity += PhysicsFunc.complete_unelastic_shock(
a_velocity, b_velocity, a_mass, b_mass
)
stored_incoming_velocity = 0
shock_ready = false
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
func _on_EnteringVelocityDetector_area_entered(area: Area2D) -> void:
if area.name == "BlobbySkin":
if area.get_parent().velocity.y > 0:
stored_incoming_velocity = area.get_parent().velocity.y
func _on_EnteringVelocityDetector_area_exited(area: Area2D) -> void:
if coupled_body == null:
$SpringSound.play()