@tool
class_name PlayerCamera extends Node

const CAMERA_PIXELS_PER_UNIT = 1.0
const CAMERA_PIXEL_SCALE = 1.0

@export var camera:Camera3D = null
@export var target:Node3D = null
@export var offset:Vector3 = Vector3(0, 0, 12)

func _process(delta: float) -> void:
	if !camera || !target:
		return

	# I tried a few things but this is most consistent for both backbuffer and
	# framebuffer viewports.
	var viewportHeight = get_viewport().get_visible_rect().size.y;
	var unitScale = CAMERA_PIXEL_SCALE * CAMERA_PIXELS_PER_UNIT;

	var z:float = (
		tan((deg_to_rad(180) - deg_to_rad(camera.fov)) / 2.0) *
		(viewportHeight / 2.0)
	) / unitScale;
	
	var look = target.global_position;
	var position = offset + look;

	camera.look_at_from_position(
		Vector3(position.x, position.y + z, position.z),
		look
	);

	pass