extends SceneTree

## Dev tool: does the cloth actually JITTER when the character is standing still?
##
##   godot --path . --windowed --resolution 900x900 \
##       -s res://debug/idle_jitter_check.gd -- <out_dir>
##
## debug/cloth_settle_check.gd answers this in degrees per frame of LOCAL bone
## rotation, and that number is inflated for a chain: correcting a panel root
## shows up as an equal and opposite delta on its segments, so a hem that has not
## moved at all in world space can report ten degrees. It has misled before.
##
## This renders consecutive frames of a still idle from a fixed camera and saves
## them; comparing neighbouring PNGs gives the only number that matters, which is
## whether anything on screen moved.

var _frames := 0
var _out := "."
var _model: SkinnedPlayerModel = null
var _cam: Camera3D = null
var _shots := 0
const SHOTS := 12


func _initialize() -> void:
	var args := OS.get_cmdline_user_args()
	_out = args[0] if args.size() > 0 else "."
	var scene := Node3D.new()
	root.add_child(scene)
	current_scene = scene

	var env := WorldEnvironment.new()
	var e := Environment.new()
	e.background_mode = Environment.BG_COLOR
	e.background_color = Color(0.05, 0.05, 0.08)
	e.ambient_light_source = Environment.AMBIENT_SOURCE_COLOR
	e.ambient_light_color = Color(1, 1, 1)
	e.ambient_light_energy = 1.3
	env.environment = e
	scene.add_child(env)
	var sun := DirectionalLight3D.new()
	sun.rotation_degrees = Vector3(-40, 35, 0)
	scene.add_child(sun)

	_model = SkinnedPlayerModel.new()
	_model.model_path = "res://assets/characters/skins/taila.glb"
	scene.add_child(_model)
	_cam = Camera3D.new()
	_cam.fov = 28.0
	scene.add_child(_cam)
	_cam.current = true


func _process(_delta: float) -> bool:
	_frames += 1
	if _frames < 10 or not _model.loaded:
		return false
	_model.update_state("ground", 0.0, false)
	_model.set_locomotion(0.0, 0.0, 0.0)
	var hips := 0.95
	if _model.skeleton:
		var h := _model.skeleton.find_bone("DEF-spine")
		if h >= 0:
			hips = _model.skeleton.get_bone_global_pose(h).origin.y
	# NEGATIVE Z is the FRONT. SkinnedPlayerModel spins the imported scene 180
	# degrees (`facing_flip`: glTF forward is +Z, players face -Z), so a camera
	# on +Z looks at the character's BACK. Every tool in here used to sit on +Z,
	# and every "front" judgement made from them was of the back of the skirt.
	_cam.position = Vector3(0.0, hips - 0.08, -0.9)
	_cam.look_at(Vector3(0, hips - 0.14, 0), Vector3.UP)
	# Let the chains settle before recording — the first second is the model
	# dropping into its hanging pose, which is not jitter.
	if _frames > 130 and _shots < SHOTS:
		root.get_texture().get_image().save_png("%s/idle_%02d.png" % [_out, _shots])
		_shots += 1
		if _shots == SHOTS:
			print("saved %d idle frames" % SHOTS)
			return true
	return _frames > 400