mostly working, need netcode, en passant, and castling

Piece.gd

@@ -0,0 +1,140 @@
+extends Area2D
+
+enum TEAM {WHITE, BLACK, NEUTRAL}
+enum KIND {KING, QUEEN, ROOK, BISHOP, KNIGHT, PAWN}
+
+@export var dragging: bool = false
+@export var grid_size: Vector2i = Vector2i(1, 1)
+@export var grid_pos: Vector2i = Vector2i(0, 0)
+@export var kind: KIND = KIND.PAWN
+@export var team: TEAM = TEAM.NEUTRAL
+
+signal moved(piece: Area2D, old_pos: Vector2i, new_pos: Vector2i)
+
+# Called when the node enters the scene tree for the first time.
+func _ready():
+	position = grid_to_pos(grid_pos)
+	setup()
+
+func setup():
+	pass
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+func _process(delta):
+	pass
+
+func _on_input_event(viewport, event, shape_idx):
+	if event.is_pressed():
+		dragging = true
+		position = viewport.get_mouse_position();
+	
+func _unhandled_input(event):
+	if dragging and event is InputEventMouseButton and not event.pressed:
+		dragging = false
+		
+		var grid_x = floor(position.x / grid_size.x)
+		var grid_y = floor(position.y / grid_size.y)
+		
+		if check_move(Vector2i(grid_x, grid_y)):
+			moved.emit(self, grid_pos, Vector2i(grid_x, grid_y))
+			grid_pos = Vector2i(grid_x, grid_y)
+
+		position = grid_to_pos(grid_pos)
+
+	if self.dragging and event is InputEventMouseMotion:
+		position += event.relative
+
+func make_black():
+	team = TEAM.BLACK
+
+func make_white():
+	team = TEAM.WHITE
+
+func make_neutral():
+	team = TEAM.NEUTRAL
+
+func is_black() -> bool:
+	return team == TEAM.BLACK
+
+func is_white() -> bool:
+	return team == TEAM.WHITE
+
+func is_pawn() -> bool:
+	return kind == KIND.PAWN
+
+func is_king() -> bool:
+	return kind == KIND.KING
+	
+func grid_to_pos(grid_p: Vector2i) -> Vector2:
+	var new_x = grid_p.x * grid_size.x + grid_size.x / 2
+	var new_y = grid_p.y * grid_size.y + grid_size.y / 2
+	return Vector2(new_x, new_y)
+
+func get_board_state() -> Dictionary:
+	return get_parent().board_state
+
+func path_empty(destination: Vector2i) -> bool:
+	var board_state = get_board_state()
+	
+	var dx = destination.x - grid_pos.x
+	var dy = destination.y - grid_pos.y
+	
+	if dx == 0:
+		if dy < 0:
+			for y in range(destination.y + 1, grid_pos.y):
+				if board_state.has(Vector2i(grid_pos.x, y)):
+					return false
+		elif dy > 0:
+			for y in range(grid_pos.y + 1, destination.y):
+				if board_state.has(Vector2i(grid_pos.x, y)):
+					return false
+		else:
+			# no movement
+			return false
+	elif dy == 0:
+		if dx < 0:
+			for x in range(destination.x + 1, grid_pos.x):
+				if board_state.has(Vector2i(x, grid_pos.y)):
+					return false
+		elif dx > 0:
+			for x in range(grid_pos.x + 1, destination.x):
+				if board_state.has(Vector2i(x, grid_pos.y)):
+					return false
+		else:
+			# impossible
+			return false
+	elif abs(dx) == abs(dy):
+		if dx < 0:
+			if dy < 0:
+				for d in range(1, abs(dx)):
+					if board_state.has(Vector2i(grid_pos.x - d, grid_pos.y - d)):
+						return false
+			elif dy > 0:
+				for d in range(1, abs(dx)):
+					if board_state.has(Vector2i(grid_pos.x - d, grid_pos.y + d)):
+						return false
+			else:
+				# impossible
+				return false
+		elif dx > 0:
+			if dy < 0:
+				for d in range(1, abs(dx)):
+					if board_state.has(Vector2i(grid_pos.x + d, grid_pos.y - d)):
+						return false
+			elif dy > 0:
+				for d in range(1, abs(dx)):
+					if board_state.has(Vector2i(grid_pos.x + d, grid_pos.y + d)):
+						return false
+			else:
+				# impossible
+				return false
+		else:
+			# impossible
+			return false
+	else:
+		# not a legal move
+		return false
+	return true
+
+func check_move(destination: Vector2i) -> bool:
+	return true