RedCore/scripts/ball.gd

class_name Ball
extends CharacterBody2D
## A ball that bounces off everything, speeds up slightly on each bounce and falls under
## light gravity.

## Emitted for every contact, so the game can react to what the ball touched.
signal hit(ball: Ball, other: Node)

## A superball destroys one indestructible block, then turns back into a normal ball.
var superball := false:
	set(value):
		superball = value
		queue_redraw()


func throw() -> void:
	var angle := deg_to_rad(randf_range(-Params.THROW_ANGLE, Params.THROW_ANGLE))
	velocity = Vector2(sin(angle), -cos(angle)) * Params.INITIAL_SPEED


func _physics_process(delta: float) -> void:
	velocity.y += Params.BALL_GRAVITY * delta
	var motion := velocity * delta
	for i in 4:
		var collision := move_and_collide(motion)
		if collision == null:
			break
		var other := collision.get_collider() as Node
		var normal := collision.get_normal()
		var bounce: float = other.get_meta("bounce", 1.0)
		velocity = velocity.bounce(normal) * Params.BALL_BOUNCE * bounce
		motion = collision.get_remainder().bounce(normal)
		hit.emit(self, other)
		if is_queued_for_deletion():
			return
	_kick_power_ups()


## Power-ups are 1/1000 of a ball's mass: they get knocked away and the ball doesn't notice.
func _kick_power_ups() -> void:
	for power_up: PowerUp in get_tree().get_nodes_in_group("power_ups"):
		var offset := power_up.global_position - global_position
		var dist := offset.length()
		if dist == 0.0 or dist > Params.BALL_RADIUS + PowerUp.RADIUS:
			continue
		var normal := offset / dist
		var approach := (power_up.linear_velocity - velocity).dot(normal)
		if approach < 0.0:
			power_up.linear_velocity -= 2.0 * approach * normal
			hit.emit(self, power_up)


func _draw() -> void:
	draw_circle(Vector2.ZERO, Params.BALL_RADIUS, Params.COLOR_ORANGE if superball else Params.COLOR_GREY, true, -1.0, true)