save/load current game

src/Main.gd

@@ -3,8 +3,56 @@ extends Control
 onready var taquin = $HSplitContainer/Taquin
 
 func _ready():
+	load_game()
 	print("Starting state: ", taquin.current_state_name())
 
+func _notification(what):
+	if what == MainLoop.NOTIFICATION_WM_QUIT_REQUEST:
+		save_game()
+		get_tree().quit() # default behavior
+
+# https://docs.godotengine.org/en/3.2/tutorials/io/saving_games.html
+func save_game():
+	var save_game = File.new()
+	save_game.open("user://savegame.save", File.WRITE)
+	var save_nodes = get_tree().get_nodes_in_group("Persist")
+	for node in save_nodes:
+		# Check the node has a save function
+		if !node.has_method("save"):
+			print("persistent node '%s' is missing a save() function, skipped" % node.name)
+			continue
+
+		# Call the node's save function
+		var node_data = node.call("save")
+		
+		# Augment data with origin
+		node_data["path"] = node.get_path()
+
+		# Store the save dictionary as a new line in the save file
+		save_game.store_line(to_json(node_data))
+	save_game.close()
+
+func load_game():
+	var save_game = File.new()
+	if not save_game.file_exists("user://savegame.save"):
+		return # Error! We don't have a save to load.
+
+	# Load the file line by line and process that dictionary to restore
+	# the object it represents.
+	save_game.open("user://savegame.save", File.READ)
+	while save_game.get_position() < save_game.get_len():
+		# Get the saved dictionary from the next line in the save file
+		var node_data = parse_json(save_game.get_line())
+
+		# Call the node's save function
+		var node = get_node(node_data["path"])
+		node.call("load", node_data)
+
+	save_game.close()
+
+#
+# Signals
+#
 func _on_Taquin_state_changed(previous, new):
 	print("Taquin state: ", Taquin.State.keys()[previous], " -> ", Taquin.State.keys()[new])
 	match new:

src/Main.tscn

@@ -34,7 +34,9 @@ __meta__ = {
 "_edit_use_anchors_": false
 }
 
-[node name="Taquin" parent="HSplitContainer" instance=ExtResource( 2 )]
+[node name="Taquin" parent="HSplitContainer" groups=[
+"Persist",
+] instance=ExtResource( 2 )]
 margin_right = 540.0
 margin_bottom = 560.0
 rows = 4

src/Taquin.gd

@@ -75,27 +75,12 @@ func _ready() -> void:
 	padding = compute_padding(piece_size)
 	print("piece size: ", piece_size)
 	print("padding: ", padding)
-
-	for c in range(columns):
-		var pieces_row: Array = []
-		for r in range(rows):
-			var piece = Piece.instance()
-
-			piece.size = piece_size
-			piece.position = position_for_index(Vector2(c, r), piece.size)
-			piece.order = 1 + c + r * columns
-			piece.taquin_index = Vector2(c, r)
-			piece.piece_scale = Vector2((float(piece_size) / width), (float(piece_size) / height))
-			piece.taquin_position = Vector2(float(piece.position.x) / width, float(piece.position.y) / height)
-
-			if r == rows - 1 && c == columns - 1:
-				piece.visible = false
-				missing_piece = piece
-
-			$Background.add_child(piece)
-			pieces_row.append(piece)
-
-		pieces.append(pieces_row)
+	var pieces_order: Array = []
+	for order in range(1, rows * columns + 1):
+		pieces_order.append(order)
+	var hidden_piece = rows * columns # Last piece is hidden
+	
+	init(pieces_order, hidden_piece)
 
 	shuffle(difficulty)
 
@@ -326,6 +311,80 @@ func transition_to(state):
 			$Timer.stop()
 	emit_signal("state_changed", previous_state, current_state)
 
+func save() -> Dictionary:
+	var serialized_pieces = []
+	for c in range(columns):
+		for r in range(rows):
+			var piece: Piece = pieces[c][r]
+			serialized_pieces.append(piece.order)
+	return {
+		"rows": rows,
+		"columns": columns,
+		"pieces": serialized_pieces,
+		"hidden_piece": serialized_pieces.size(),
+	}
+
+func load(saved_state) -> void:
+	if not saved_state.has_all(["rows", "columns", "pieces", "hidden_piece"]):
+		return
+	rows = saved_state["rows"]
+	columns = saved_state["columns"]
+	init(saved_state["pieces"], saved_state["hidden_piece"])
+
+func init(pieces_order: Array, hidden_piece: int) -> void:
+	var piece_size: int = compute_piece_size()
+	padding = compute_padding(piece_size)
+	print("piece size: ", piece_size)
+	print("padding: ", padding)
+
+	if pieces.size() > 0:
+		for c in range(columns):
+			for r in range(rows):
+				var piece: Piece = pieces[c][r]
+				$Background.remove_child(piece)
+				piece.queue_free()
+		pieces.clear()
+
+	for c in range(columns):
+		var pieces_row: Array = []
+		for r in range(rows):
+			var piece = Piece.instance()
+			# Uniforms
+			piece.size = piece_size
+			piece.piece_scale = Vector2((float(piece_size) / width), (float(piece_size) / height))
+
+			# order start from top-left (1) and iterate over every row
+			# eg. 1 2 3
+			#     4 5 6
+			#     7 8 9
+			piece.order = pieces_order[r + c * rows]
+			print("piece at ", c, ", ", r, " -> order: ", piece.order)
+
+			# place inside the taquin as indices (i, j)
+			piece.taquin_index = Vector2(c, r)
+			# place inside the taquin as coordinates (x, y)
+			piece.position = position_for_index(piece.taquin_index, piece.size)
+			
+			# position inside the original taquin as normalized coordinates (x, y) (domain: [0, 1])
+			# used for offsetting the texture on pieces
+			var original_index = Vector2((piece.order - 1) % columns, (piece.order - 1) / columns)
+			var original_position = position_for_index(original_index, piece.size)
+			piece.taquin_position = Vector2(float(original_position.x) / width, float(original_position.y) / height)
+
+			if piece.order == hidden_piece:
+				piece.visible = false
+				missing_piece = piece
+
+			$Background.add_child(piece)
+			pieces_row.append(piece)
+
+		pieces.append(pieces_row)
+
+	shuffle(difficulty)
+
+#
+# Signals
+#
 func _on_Timer_timeout():
 	transition_to(State.GAME_OVER)