RPG #16 - Scripted puzzle

An old-school RPG is not complete without a bit of puzzling. Whether we’re talking puzzles in a more traditional sense, or those that are a bit less obvious. What they all have in common is that they need to be implemented, and I want to do so using scripting to implement some truly unique puzzles.

As a first test to see if my scripting system (implemented in RPG #6 - Scripting) is up to the task, I want to implement a common puzzle where the player is expected to put some stones in the correct position by rotating them. Some might recognize this as the Spinning Symbol/Rune Tokens puzzles in Skyrim, but then without the eagles, snakes and the whales.

It’s a simple puzzle, but demonstrates a way to make several objects appear to interact with each other. Following is the script associated with each of the rotation stones, which are triggered by the buttons.

extends EntityScript

var properties: Dictionary

var tween: Tween

var current_value: int
var target_value: int

func _ready():
	current_value = int(properties.initial_value)
	target_value = int(properties.target_value)
	set('intro_cave_puzzle', 0)

func _initialize_tween():
	tween = Tween.new()
	tween.connect("tween_completed", self, '_on_tween_completed')

# triggered by a corresponding button
# each use we tween to a new position, cycling 4 positions
func use():
	if !tween.is_active():
		current_value += 1
		if current_value > 4:
			current_value = 1
		# store the position in a variable so that we can read it later
		var varname = 'intro_cave_puzzle_%s' % [properties.targetname]
		set_variable(varname, current_value)
		var new_rotation = Vector3(get_parent().rotation.x, get_parent().rotation.y + PI / 2, get_parent().rotation.z)
		tween.interpolate_property(get_parent(), 'rotation', get_parent().rotation, new_rotation, 2, Tween.TRANS_LINEAR, Tween.EASE_IN_OUT)

# after each tween completes,
# we check if the stones are in the correct position
func _on_tween_completed(object, key):
	var stone1 = get_variable('intro_cave_puzzle_stone1', 0)
	var stone2 = get_variable('intro_cave_puzzle_stone2', 0)
	var stone3 = get_variable('intro_cave_puzzle_stone3', 0)
	var stone4 = get_variable('intro_cave_puzzle_stone4', 0)
	var stone1_is_correct = stone1 == 2
	var stone2_is_correct = stone2 == 3
	var stone3_is_correct = stone3 == 4
	var stone4_is_correct = stone4 == 1
	if stone1_is_correct and stone2_is_correct and stone3_is_correct and stone4_is_correct:
		# all positions are correct, trigger our parent
        # this will cause the door to open

As you can see, the buttons mainly communicate through triggers (provided by Qodot) and variables. So far the scripting system has passed the first test, I will continue to try it out as I implement new dungeons.