# Canvas adapter for the 40250 CWindowManager. The window tree remains native;
# this Control forwards Godot input and draws the native UI command stream.
extends Control

const AssetRoot = preload("res://asset_root.gd")
const UiAssets = preload("res://ui/ui_assets.gd")

const KEY_TO_DIK := {
	KEY_ESCAPE: 0x01, KEY_1: 0x02, KEY_2: 0x03, KEY_3: 0x04,
	KEY_4: 0x05, KEY_5: 0x06, KEY_6: 0x07, KEY_7: 0x08,
	KEY_8: 0x09, KEY_9: 0x0a, KEY_0: 0x0b, KEY_MINUS: 0x0c,
	KEY_EQUAL: 0x0d, KEY_BACKSPACE: 0x0e, KEY_TAB: 0x0f,
	KEY_Q: 0x10, KEY_W: 0x11, KEY_E: 0x12, KEY_R: 0x13,
	KEY_T: 0x14, KEY_Y: 0x15, KEY_U: 0x16, KEY_I: 0x17,
	KEY_O: 0x18, KEY_P: 0x19, KEY_BRACKETLEFT: 0x1a, KEY_BRACKETRIGHT: 0x1b,
	KEY_ENTER: 0x1c, KEY_CTRL: 0x1d, KEY_A: 0x1e, KEY_S: 0x1f,
	KEY_D: 0x20, KEY_F: 0x21, KEY_G: 0x22, KEY_H: 0x23,
	KEY_J: 0x24, KEY_K: 0x25, KEY_L: 0x26, KEY_SEMICOLON: 0x27,
	KEY_APOSTROPHE: 0x28, KEY_QUOTELEFT: 0x29, KEY_SHIFT: 0x2a,
	KEY_BACKSLASH: 0x2b, KEY_Z: 0x2c, KEY_X: 0x2d, KEY_C: 0x2e,
	KEY_V: 0x2f, KEY_B: 0x30, KEY_N: 0x31, KEY_M: 0x32,
	KEY_COMMA: 0x33, KEY_PERIOD: 0x34, KEY_SLASH: 0x35,
	KEY_ALT: 0x38, KEY_SPACE: 0x39,
	KEY_F1: 0x3b, KEY_F2: 0x3c, KEY_F3: 0x3d, KEY_F4: 0x3e,
	KEY_F5: 0x3f, KEY_F6: 0x40, KEY_F7: 0x41, KEY_F8: 0x42,
	KEY_F9: 0x43, KEY_F10: 0x44, KEY_F11: 0x57, KEY_F12: 0x58,
	KEY_HOME: 0xc7, KEY_UP: 0xc8, KEY_PAGEUP: 0xc9,
	KEY_LEFT: 0xcb, KEY_RIGHT: 0xcd, KEY_END: 0xcf,
	KEY_DOWN: 0xd0, KEY_PAGEDOWN: 0xd1, KEY_INSERT: 0xd2,
	KEY_DELETE: 0xd3,
}

# Win32 virtual-key codes of the keys EditLine.OnIMEKeyDown handles (WM_KEYDOWN → OnIMEKeyDown);
# letters and digits use their ASCII code, as VK_A..VK_Z / VK_0..VK_9 do.
const KEY_TO_VK := {
	KEY_BACKSPACE: 0x08, KEY_TAB: 0x09, KEY_ENTER: 0x0d, KEY_KP_ENTER: 0x0d,
	KEY_ESCAPE: 0x1b, KEY_SPACE: 0x20, KEY_END: 0x23, KEY_HOME: 0x24,
	KEY_LEFT: 0x25, KEY_UP: 0x26, KEY_RIGHT: 0x27, KEY_DOWN: 0x28, KEY_DELETE: 0x2e,
}

# The control characters Windows turns these keys into (WM_CHAR); Godot reports them with unicode 0.
const KEY_TO_CHAR := {
	KEY_BACKSPACE: 0x08, KEY_TAB: 0x09, KEY_ENTER: 0x0d, KEY_KP_ENTER: 0x0d, KEY_ESCAPE: 0x1b,
}

# "mem:<id>" → [revision, ImageTexture]: the CGraphicFontTexture glyph pages, refetched when the
# "@<revision>" of a command's name moves on (a glyph was added to the page).
var _memory_textures := {}
var _tex_info_cache := {}
var _color_cache := {}
var _white_color_array := PackedColorArray([Color.WHITE])
var _asset_root_path := ""
var _segments_used := 0

# True when this surface started system.py itself (run_app) and so owns the interpreter's lifetime.
var _owns_app := false

# 40250 WinMain → RunMainScript: start the interpreter, give it the canvas size (app.Create reads it),
# run system.py until it parks in app.Loop(). Returns "" or the error RunApp reported.
func run_app() -> String:
	if not AssetRoot.pack_ready():
		return "no 40250 Client/pack at %s" % AssetRoot.client_path()
	# The exported Godot executable starts in Contents/Resources. 40250 writes mouse.cfg,
	# metin2.cfg and other player settings relative to CWD, so move those writes to user://.
	var data_dir := OS.get_user_data_dir()
	if DirAccess.make_dir_recursive_absolute(data_dir) != OK:
		return "cannot create user data directory at %s" % data_dir
	OS.set_environment("MT_40250_CLIENT", AssetRoot.client_path())
	OS.set_environment("MT_40250_USER_DATA_DIR", data_dir)
	var err: String = Metin2PythonHost.start("")
	if err != "":
		return err
	_sync_size()
	err = Metin2PythonHost.run_main_script("")
	if err != "":
		Metin2PythonHost.stop()
		return err
	_owns_app = true
	return ""

func _exit_tree() -> void:
	for segment in _segments:
		RenderingServer.free_rid(segment)
	_segments.clear()
	for material in _materials:
		RenderingServer.free_rid(material)
	_materials.clear()
	if _mask_shader.is_valid():
		RenderingServer.free_rid(_mask_shader)
		_mask_shader = RID()
	if _owns_app:
		_owns_app = false
		Metin2PythonHost.stop()

func _ready() -> void:
	set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
	mouse_filter = Control.MOUSE_FILTER_STOP
	texture_repeat = CanvasItem.TEXTURE_REPEAT_ENABLED
	_asset_root_path = AssetRoot.path()
	_sync_size()

func _notification(what: int) -> void:
	if what == NOTIFICATION_RESIZED and is_inside_tree():
		_sync_size()

func _sync_size() -> void:
	if ClassDB.class_exists("Metin2PythonHost"):
		# Before the first layout pass a full-rect Control is still 0x0; it will fill the viewport.
		var canvas := size if size.x > 0 and size.y > 0 else get_viewport_rect().size
		Metin2PythonHost.set_ui_size(int(canvas.x), int(canvas.y))

func _process(_delta: float) -> void:
	# app.Exit()/Abort(): Loop() returned and RunApp() finished; 40250 WinMain then ends the process.
	if _owns_app and not Metin2PythonHost.is_app_looping():
		_owns_app = false
		Metin2PythonHost.stop()
		get_tree().quit(0)
		return
	if Metin2PythonHost.is_running():
		var profile_start := Time.get_ticks_usec() if _profile_frame else 0
		Metin2PythonHost.ui_update()
		if profile_start != 0:
			profile_ui_update_ms = float(Time.get_ticks_usec() - profile_start) / 1000.0
		queue_redraw()

func _gui_input(event: InputEvent) -> void:
	if not Metin2PythonHost.is_running():
		return
	if event is InputEventMouseMotion:
		Metin2PythonHost.ui_mouse_move(int(event.position.x), int(event.position.y))
	elif event is InputEventMouseButton:
		if event.button_index >= MOUSE_BUTTON_LEFT and event.button_index <= MOUSE_BUTTON_MIDDLE:
			Metin2PythonHost.ui_mouse_button(event.button_index, event.pressed,
					int(event.position.x), int(event.position.y))
		elif event.pressed:
			if event.button_index == MOUSE_BUTTON_WHEEL_UP:
				var factor: float = event.factor if event.factor > 0.0 else 1.0
				Metin2PythonHost.ui_mouse_wheel(int(round(120.0 * factor)))
			elif event.button_index == MOUSE_BUTTON_WHEEL_DOWN:
				var factor: float = event.factor if event.factor > 0.0 else 1.0
				Metin2PythonHost.ui_mouse_wheel(-int(round(120.0 * factor)))
	elif event is InputEventPanGesture:
		# macOS trackpad two-finger scroll: scrolling up has negative delta.y, zooming in
		var delta: int = -int(round(event.delta.y * 30.0))
		if delta != 0:
			Metin2PythonHost.ui_mouse_wheel(delta)
	elif event is InputEventMagnifyGesture:
		# macOS trackpad pinch to zoom: factor > 1.0 is zoom in
		var delta: int = int(round((event.factor - 1.0) * 600.0))
		if delta != 0:
			Metin2PythonHost.ui_mouse_wheel(delta)

func _unhandled_key_input(event: InputEvent) -> void:
	if event is InputEventKey and Metin2PythonHost.is_running():
		var code: int = event.physical_keycode
		var dik: int = KEY_TO_DIK.get(code, 0)
		if dik == 0 and event.keycode != 0:
			dik = KEY_TO_DIK.get(event.keycode, 0)
		if dik != 0:
			Metin2PythonHost.ui_key(dik, event.pressed)
		if event.pressed:
			_ime_key(event)

# 40250 gets every key press twice more through the window procedure: WM_KEYDOWN (a VK code, for
# OnIMEKeyDown) and then WM_CHAR (the typed character, for CPythonIME). Held keys repeat both.
func _ime_key(event: InputEventKey) -> void:
	var keycode: int = event.keycode
	var vk: int = KEY_TO_VK.get(keycode, 0)
	if vk == 0 and ((keycode >= KEY_A and keycode <= KEY_Z) or (keycode >= KEY_0 and keycode <= KEY_9)):
		vk = keycode
	if vk != 0:
		Metin2PythonHost.ui_ime_key(vk)
	var ch: int = event.unicode
	if ch == 0:
		ch = KEY_TO_CHAR.get(keycode, 0)
	if ch != 0:
		Metin2PythonHost.ui_char(ch)

# The command stream is drawn into pooled child canvas items in order: a run of plain commands
# shares one item; a masked image (CPythonMiniMap's terrain tiles under minimap_image_filter.dds)
# gets its own item carrying the mask shader, since a canvas item has a single material.
const MASK_SHADER := """
shader_type canvas_item;
render_mode blend_mix;
uniform sampler2D mask_texture : repeat_disable, filter_linear;
uniform vec4 uv_rect;  // su, sv, eu, ev of the image
uniform vec2 m0;       // mask coordinates at the image's TL, TR and BL corners
uniform vec2 m1;
uniform vec2 m2;
void fragment() {
	vec2 ab = (UV - uv_rect.xy) / max(uv_rect.zw - uv_rect.xy, vec2(1e-6));
	vec4 mask = texture(mask_texture, m0 + (m1 - m0) * ab.x + (m2 - m0) * ab.y);
	vec4 image = texture(TEXTURE, UV) * COLOR;
	COLOR = vec4(image.rgb * mask.rgb, mask.a * COLOR.a);
}
"""

var _segments: Array[RID] = []
var _materials: Array[RID] = []
var _mask_shader := RID()
var _white: ImageTexture
var _profile_frame := OS.has_environment("MT_PROFILE_FRAME")
var profile_ui_update_ms := 0.0
var profile_draw_ms := 0.0

func _get_color_array(argb: int) -> PackedColorArray:
	if argb == 0xFFFFFFFF or argb == -1:
		return _white_color_array
	var arr: PackedColorArray = _color_cache.get(argb, PackedColorArray())
	if not arr.is_empty():
		return arr
	var c := Color8((argb >> 16) & 255, (argb >> 8) & 255, argb & 255, (argb >> 24) & 255)
	arr = PackedColorArray([c])
	_color_cache[argb] = arr
	return arr

func _get_tex_draw_info(name: String) -> Array:
	var info: Array = _tex_info_cache.get(name, [])
	if not info.is_empty():
		return info
	var texture: Texture2D = _texture(name)
	if texture == null:
		_tex_info_cache[name] = []
		return []
	var tex_rid: RID = texture.get_rid()
	var is_atlas := false
	var u0 := 0.0
	var v0 := 0.0
	var du := 1.0
	var dv := 1.0
	var default_uv := PackedVector2Array()
	if texture is AtlasTexture:
		var at: AtlasTexture = texture
		if at.atlas != null:
			tex_rid = at.atlas.get_rid()
			var asize: Vector2 = at.atlas.get_size()
			if asize.x > 0 and asize.y > 0:
				is_atlas = true
				var r: Rect2 = at.region
				u0 = r.position.x / asize.x
				v0 = r.position.y / asize.y
				du = r.size.x / asize.x
				dv = r.size.y / asize.y
				default_uv = PackedVector2Array([
					Vector2(u0, v0),
					Vector2(u0 + du, v0),
					Vector2(u0 + du, v0 + dv),
					Vector2(u0, v0 + dv)
				])
	if default_uv.is_empty():
		default_uv = PackedVector2Array([
			Vector2(0, 0),
			Vector2(1, 0),
			Vector2(1, 1),
			Vector2(0, 1)
		])
	info = [tex_rid, is_atlas, u0, v0, du, dv, default_uv, texture]
	_tex_info_cache[name] = info
	return info

func _draw() -> void:
	var profile_start := Time.get_ticks_usec() if _profile_frame else 0
	var fg_used := 0
	var fg_plain := false
	var masked := 0

	for i in _segments_used:
		RenderingServer.canvas_item_clear(_segments[i])
	_segments_used = 0

	if not Metin2PythonHost.is_running():
		return

	var has_3d: bool = Metin2PythonHost.has_3d_draws()

	for command in Metin2PythonHost.ui_render_commands_batched():
		# Skip background UI commands when 3D is active, as the 3D surface renders the background Quad
		if has_3d and bool(command.get(&"behind_3d", false)):
			continue
		var kind: Variant = command[&"kind"]
		if kind == &"glyph_batch":
			var info := _get_tex_draw_info(command[&"text"])
			if info.is_empty():
				continue
			if not fg_plain:
				fg_used = _segment(fg_used, RID())
				fg_plain = true
			RenderingServer.canvas_item_add_triangle_array(_segments[fg_used - 1],
					command[&"indices"], command[&"points"], command[&"colors"],
					command[&"uvs"], PackedInt32Array(), PackedFloat32Array(), info[0])
			continue

		var x1: float = command[&"x1"]
		var y1: float = command[&"y1"]
		var x2: float = command[&"x2"]
		var y2: float = command[&"y2"]
		var cx1: float = command[&"clip_x1"]
		var cy1: float = command[&"clip_y1"]
		var cx2: float = command[&"clip_x2"]
		var cy2: float = command[&"clip_y2"]

		# 1) Completely culled by scissor?
		if x2 <= cx1 or x1 >= cx2 or y2 <= cy1 or y1 >= cy2:
			continue

		var argb: int = command[&"argb"]
		var target_segments := _segments

		if kind == &"image":
			var text_name: String = command.get(&"text", "")
			var mask_name: String = command.get(&"mask", "")
			var mask_tex: Texture2D = _texture(mask_name) if not mask_name.is_empty() else null
			if text_name.is_empty() and mask_tex != null:
				text_name = "__white__"

			var info := _get_tex_draw_info(text_name)
			if info.is_empty():
				continue
			var tex_rid: RID = info[0]
			var is_atlas: bool = info[1]
			var u0: float = info[2]
			var v0: float = info[3]
			var du: float = info[4]
			var dv: float = info[5]

			var quad: PackedVector2Array = command[&"quad"]
			var quad_uv: PackedVector2Array = command[&"uv"]

			var needs_clip := x1 < cx1 or x2 > cx2 or y1 < cy1 or y2 > cy2
			var poly_pts: PackedVector2Array
			var poly_uv: PackedVector2Array

			if not needs_clip:
				poly_pts = PackedVector2Array([quad[0], quad[1], quad[3], quad[2]])
				var is_full_uv := quad_uv[0] == Vector2.ZERO and quad_uv[1] == Vector2(1, 0) and quad_uv[2] == Vector2(0, 1) and quad_uv[3] == Vector2.ONE
				if is_full_uv:
					poly_uv = info[6]
				elif is_atlas:
					poly_uv = PackedVector2Array([
						Vector2(u0 + quad_uv[0].x * du, v0 + quad_uv[0].y * dv),
						Vector2(u0 + quad_uv[1].x * du, v0 + quad_uv[1].y * dv),
						Vector2(u0 + quad_uv[3].x * du, v0 + quad_uv[3].y * dv),
						Vector2(u0 + quad_uv[2].x * du, v0 + quad_uv[2].y * dv)
					])
				else:
					poly_uv = PackedVector2Array([quad_uv[0], quad_uv[1], quad_uv[3], quad_uv[2]])
			else:
				var mapped_uv: PackedVector2Array
				if is_atlas:
					mapped_uv = PackedVector2Array([
						Vector2(u0 + quad_uv[0].x * du, v0 + quad_uv[0].y * dv),
						Vector2(u0 + quad_uv[1].x * du, v0 + quad_uv[1].y * dv),
						Vector2(u0 + quad_uv[2].x * du, v0 + quad_uv[2].y * dv),
						Vector2(u0 + quad_uv[3].x * du, v0 + quad_uv[3].y * dv)
					])
				else:
					mapped_uv = quad_uv
				var clip_rect := Rect2(cx1, cy1, cx2 - cx1, cy2 - cy1)
				var clipped := _clip_quad(quad, mapped_uv, clip_rect)
				if clipped[0].size() < 3:
					continue
				poly_pts = clipped[0]
				poly_uv = clipped[1]

			if mask_tex != null:
				var mat_rid := _mask_material(masked, mask_tex, quad_uv, command[&"mask_uv"])
				fg_used = _segment(fg_used, mat_rid)
				fg_plain = false
				masked += 1
			elif not fg_plain:
				fg_used = _segment(fg_used, RID())
				fg_plain = true
			var seg_idx := fg_used - 1
			RenderingServer.canvas_item_add_polygon(target_segments[seg_idx], poly_pts,
					_get_color_array(argb), poly_uv, tex_rid)

		elif kind == &"bar":
			var bx1 := maxf(x1, cx1)
			var by1 := maxf(y1, cy1)
			var bx2 := minf(x2, cx2)
			var by2 := minf(y2, cy2)
			if bx2 > bx1 and by2 > by1:
				if not fg_plain:
					fg_used = _segment(fg_used, RID())
					fg_plain = true
				var seg_idx := fg_used - 1
				var color := Color8((argb >> 16) & 255, (argb >> 8) & 255,
						argb & 255, (argb >> 24) & 255)
				RenderingServer.canvas_item_add_rect(target_segments[seg_idx],
						Rect2(bx1, by1, bx2 - bx1, by2 - by1), color)

		elif kind == &"gradient_bar":
			var bx1 := maxf(x1, cx1)
			var by1 := maxf(y1, cy1)
			var bx2 := minf(x2, cx2)
			var by2 := minf(y2, cy2)
			if bx2 > bx1 and by2 > by1:
				if not fg_plain:
					fg_used = _segment(fg_used, RID())
					fg_plain = true
				var seg_idx := fg_used - 1
				var color := Color8((argb >> 16) & 255, (argb >> 8) & 255,
						argb & 255, (argb >> 24) & 255)
				var bottom_argb: int = command[&"end_argb"]
				var bottom := Color8((bottom_argb >> 16) & 255, (bottom_argb >> 8) & 255,
						bottom_argb & 255, (bottom_argb >> 24) & 255)
				var top_factor := (by1 - y1) / (y2 - y1) if y2 != y1 else 0.0
				var bottom_factor := (by2 - y1) / (y2 - y1) if y2 != y1 else 1.0
				RenderingServer.canvas_item_add_polygon(target_segments[seg_idx],
					PackedVector2Array([Vector2(bx1, by1), Vector2(bx2, by1),
						Vector2(bx2, by2), Vector2(bx1, by2)]),
					PackedColorArray([color.lerp(bottom, top_factor), color.lerp(bottom, top_factor),
						color.lerp(bottom, bottom_factor), color.lerp(bottom, bottom_factor)]))

		elif kind == &"line":
			var clip_rect := Rect2(cx1, cy1, cx2 - cx1, cy2 - cy1)
			var p1 := Vector2(x1, y1)
			var p2 := Vector2(x2, y2)
			var segment := _clip_line(p1, p2, clip_rect)
			if segment.size() == 2:
				if not fg_plain:
					fg_used = _segment(fg_used, RID())
					fg_plain = true
				var seg_idx := fg_used - 1
				var color := Color8((argb >> 16) & 255, (argb >> 8) & 255,
						argb & 255, (argb >> 24) & 255)
				RenderingServer.canvas_item_add_line(target_segments[seg_idx], segment[0], segment[1], color)

	_segments_used = fg_used
	if profile_start != 0:
		profile_draw_ms = float(Time.get_ticks_usec() - profile_start) / 1000.0

# Opens the next pooled child item (draw order = index) with the given material; returns the count used.
func _segment(used: int, material: RID) -> int:
	var pool := _segments
	var parent_item: RID = get_canvas_item()
	if used == pool.size():
		var item := RenderingServer.canvas_item_create()
		RenderingServer.canvas_item_set_parent(item, parent_item)
		RenderingServer.canvas_item_set_default_texture_repeat(item, RenderingServer.CANVAS_ITEM_TEXTURE_REPEAT_ENABLED)
		pool.push_back(item)
	var item := pool[used]
	RenderingServer.canvas_item_set_draw_index(item, used)
	RenderingServer.canvas_item_set_material(item, material)
	return used + 1

func _mask_material(index: int, mask: Texture2D, uv: PackedVector2Array, mask_uv: PackedVector2Array) -> RID:
	if not _mask_shader.is_valid():
		_mask_shader = RenderingServer.shader_create()
		RenderingServer.shader_set_code(_mask_shader, MASK_SHADER)
	if index == _materials.size():
		var material := RenderingServer.material_create()
		RenderingServer.material_set_shader(material, _mask_shader)
		_materials.push_back(material)
	var material := _materials[index]
	RenderingServer.material_set_param(material, "mask_texture", mask.get_rid())
	RenderingServer.material_set_param(material, "uv_rect", Vector4(uv[0].x, uv[0].y, uv[3].x, uv[3].y))
	RenderingServer.material_set_param(material, "m0", mask_uv[0])
	RenderingServer.material_set_param(material, "m1", mask_uv[1])
	RenderingServer.material_set_param(material, "m2", mask_uv[2])
	return material

func _white_texture() -> Texture2D:
	if _white == null:
		var image := Image.create(1, 1, false, Image.FORMAT_RGBA8)
		image.fill(Color.WHITE)
		_white = ImageTexture.create_from_image(image)
	return _white

func _texture(name: String) -> Texture2D:
	if name == "__white__":
		return _white_texture()
	if not name.begins_with("mem:"):
		var root := _asset_root_path if not _asset_root_path.is_empty() else AssetRoot.path()
		return UiAssets.load_tex(root, name)
	var at := name.find("@")
	var key := name.substr(0, at) if at >= 0 else name
	var revision := int(name.substr(at + 1)) if at >= 0 else 0
	var entry: Array = _memory_textures.get(key, [])
	if not entry.is_empty() and entry[0] == revision:
		return entry[1]
	var image: Image = Metin2PythonHost.memory_texture(name, -1)
	if image == null:
		_memory_textures.erase(key)
		return null
	var texture: ImageTexture = entry[1] if not entry.is_empty() else null
	if texture != null and texture.get_size() == Vector2(image.get_size()):
		texture.update(image)
	else:
		texture = ImageTexture.create_from_image(image)
	_memory_textures[key] = [revision, texture]
	return texture

# 40250's image quad (TL, TR, BL, BR) clipped to the viewport. The quad is a
# parallelogram, so texture coordinates are an affine function of position and are recomputed for
# the clipped outline. Returns [points, uvs]; empty points when nothing is visible.
# PORT: 40250's SCREEN / COLOR_DODGE / MODULATE blend states (command["blend"]) are not applied yet;
# the canvas draws every quad with normal alpha blending.
func _clip_quad(quad: PackedVector2Array, uv: PackedVector2Array, clip: Rect2) -> Array:
	var outline := PackedVector2Array([quad[0], quad[1], quad[3], quad[2]])
	var edge_u := quad[1] - quad[0]
	var edge_v := quad[2] - quad[0]
	var det := edge_u.cross(edge_v)
	if is_zero_approx(det):
		return [PackedVector2Array(), PackedVector2Array()]
	if clip.has_point(quad[0]) and clip.has_point(quad[1]) \
			and clip.has_point(quad[2]) and clip.has_point(quad[3]):
		return [outline, PackedVector2Array([uv[0], uv[1], uv[3], uv[2]])]
	var rect := PackedVector2Array([clip.position, Vector2(clip.end.x, clip.position.y),
			clip.end, Vector2(clip.position.x, clip.end.y)])
	var pieces := Geometry2D.intersect_polygons(outline, rect)
	if pieces.is_empty():
		return [PackedVector2Array(), PackedVector2Array()]
	var points: PackedVector2Array = pieces[0]
	var uvs := PackedVector2Array()
	for point in points:
		var d := point - quad[0]
		var a := d.cross(edge_v) / det
		var b := edge_u.cross(d) / det
		uvs.push_back(uv[0] + (uv[1] - uv[0]) * a + (uv[2] - uv[0]) * b)
	return [points, uvs]

func _clip_line(a: Vector2, b: Vector2, clip: Rect2) -> PackedVector2Array:
	var delta := b - a
	var p := [-delta.x, delta.x, -delta.y, delta.y]
	var q := [a.x - clip.position.x, clip.end.x - a.x,
			a.y - clip.position.y, clip.end.y - a.y]
	var enter := 0.0
	var leave := 1.0
	for i in range(4):
		if is_zero_approx(p[i]):
			if q[i] < 0.0:
				return PackedVector2Array()
		else:
			var t: float = q[i] / p[i]
			if p[i] < 0.0:
				enter = maxf(enter, t)
			else:
				leave = minf(leave, t)
	if enter > leave:
		return PackedVector2Array()
	return PackedVector2Array([a + delta * enter, a + delta * leave])