Bounce and friction

extends Node

const RADIUS: float = 34.0

const MATERIALS: Array = [
	{bounce = 0.0, friction = 1.0, label = 'bounce 0.0', color = '#fc7f7f'},
	{bounce = 0.5, friction = 0.5, label = 'bounce 0.5', color = '#8da5f3'},
	{bounce = 0.95, friction = 0.1, label = 'bounce 0.95', color = '#8eef97'},
]


func _ready() -> void:
	_add_background()

	var view: Vector2 = get_viewport().get_visible_rect().size

	_add_floor(Vector2(view.x * 0.5, view.y - 30), Vector2(view.x, 60))

	for i in MATERIALS.size():
		var entry: Dictionary = MATERIALS[i]
		var at: Vector2 = Vector2(view.x * (i + 1) / (MATERIALS.size() + 1), view.y * 0.15)

		_add_ball(at, entry)
		_add_label(entry.label, at + Vector2(-46, -70))

	print('same drop height, three PhysicsMaterial values')


func _add_ball(at: Vector2, entry: Dictionary) -> void:
	var material: PhysicsMaterial = PhysicsMaterial.new()
	material.bounce = entry.bounce
	material.friction = entry.friction

	var circle: CircleShape2D = CircleShape2D.new()
	circle.radius = RADIUS

	var collision: CollisionShape2D = CollisionShape2D.new()
	collision.shape = circle

	var ball: RigidBody2D = RigidBody2D.new()
	ball.position = at
	ball.physics_material_override = material
	ball.add_child(_make_circle(RADIUS, Color(entry.color)))
	ball.add_child(collision)
	add_child(ball)


func _add_floor(center: Vector2, size: Vector2) -> void:
	var material: PhysicsMaterial = PhysicsMaterial.new()
	material.bounce = 0.4

	var shape: RectangleShape2D = RectangleShape2D.new()
	shape.size = size

	var collision: CollisionShape2D = CollisionShape2D.new()
	collision.shape = shape

	var rect: Polygon2D = Polygon2D.new()
	rect.polygon = PackedVector2Array([-size * 0.5, Vector2(size.x, -size.y) * 0.5, size * 0.5, Vector2(-size.x, size.y) * 0.5])
	rect.color = Color('#2a2f3d')

	var body: StaticBody2D = StaticBody2D.new()
	body.position = center
	body.physics_material_override = material
	body.add_child(rect)
	body.add_child(collision)
	add_child(body)


func _add_label(text: String, at: Vector2) -> void:
	var label: Label = Label.new()
	label.text = text
	label.position = at
	label.add_theme_color_override('font_color', Color('#999999'))
	add_child(label)


func _make_circle(radius: float, color: Color) -> Polygon2D:
	var points: PackedVector2Array = PackedVector2Array()

	for i in 24:
		points.append(Vector2(cos(TAU * i / 24.0), sin(TAU * i / 24.0)) * radius)

	var circle: Polygon2D = Polygon2D.new()
	circle.polygon = points
	circle.color = color

	return circle


func _add_background() -> void:
	var background: ColorRect = ColorRect.new()
	background.color = Color('#12141a')
	add_child(background)
	background.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)