XROrigin3D in Godot – Complete Guide

Exploring the wonders of virtual and augmented reality can seem daunting at first, but with tools like Godot 4, it’s accessible to enthusiasts and developers alike. In this series, we will dive into the XROrigin3D class, a pivotal component in crafting immersive AR/VR experiences in your games. By understanding and utilizing XROrigin3D, you’ll be able to create dynamic spaces that bridge the gap between the physical and digital worlds.

What is XROrigin3D?

The XROrigin3D class in Godot 4 serves as a critical anchor point for any AR/VR project. It maps the physical location of your tracking space center to the corresponding virtual space in your game. Think of it as the stage from where your virtual experience begins—a point of reference that keeps your virtual and physical realities aligned.

What is XROrigin3D Used For?

The XROrigin3D node is the foundation of your spatial tracking in AR/VR. All camera, controller, and anchor nodes used for tracking purposes should be direct children of this node to function correctly. This node is where you make adjustments when the player needs to move within the virtual world, while remaining stationary in the real one.

Why Learn About XROrigin3D?

Understanding how to implement and manipulate the XROrigin3D node is crucial for any AR/VR developer. It ensures that user movement translates effectively and intuitively within the virtual space. Whether you’re moving through game levels, teleporting, or driving a virtual car, properly using XROrigin3D ensures a seamless and immersive experience for players. Let’s get started on making your virtual worlds come alive!

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Setting Up XROrigin3D

To begin working with the XROrigin3D class, we must first create an AR/VR project in Godot 4 and set the scene. Start by adding an XROrigin3D node to your main scene as a root node:

var xr_origin = XROrigin3D.new()
add_child(xr_origin)

This will instantiate the XROrigin3D node and add it to your scene. From here, you can begin structuring the rest of your AR/VR environment around this node.

Once you have your XROrigin3D node in place, you’ll need to add a ARVRCamera node as its child:

var camera = ARVRCamera.new()
xr_origin.add_child(camera)

The ARVRCamera will be your viewport into the virtual world, tracking the player’s head movements.

Adjusting Player View

In AR/VR, it’s typical for the player’s view to need adjustment. Whether it’s to adapt to their height or re-center their position, it’s a straightforward process using the script attached to the XROrigin3D node:

# Adjust the origin to account for the player's height
xr_origin.set_world_scale(1.0) # Set the world scale to 1:1
xr_origin.set_floor_offset(-player_height)

In the code snippet above, we set the world scale and adjust the floor offset to compensate for the player’s height, ensuring that the virtual ground aligns with the real-world floor.

Next, you need to provide the capability for the player to reset their view which repositions the XROrigin3D node to the current location of the player:

func reset_view():
    xr_origin.request_reset()

This function triggers a reset, which can be bound to a button press or a specific event in your game.

Handling Controller Input

In many AR/VR experiences, interaction with the virtual world is done through controllers. To track controllers properly, we add them as children of the XROrigin3D node:

var left_controller = ARVRController.new()
left_controller.set_controller_id(1) # ID for the left controller
xr_origin.add_child(left_controller)

var right_controller = ARVRController.new()
right_controller.set_controller_id(2) # ID for the right controller
xr_origin.add_child(right_controller)

These snippets create and assign ARVRController nodes to track the left and right controllers using their respective IDs.

To handle button presses or axis movement on the controllers, you can connect signals from these nodes and implement appropriate functions:

# Connect a signal from the right controller
right_controller.connect("button_pressed", self, "_on_button_pressed")

func _on_button_pressed(button_index):
    print("Button", button_index, "pressed on the right controller.")

This example prints a message to the console whenever a button is pressed on the right controller.

Integrating UI Elements

Augmented Reality often involves overlaying 2D UI elements onto the world. With Godot 4, this can be done using the `Control` nodes as children of the `ARVRCamera` within the `XROrigin3D`:

var ui_element = Button.new()
ui_element.text = "Press Me"
ui_element.rect_min_size = Vector2(200, 50)
camera.add_child(ui_element)

This code simply adds a button to your AR viewing space. You can set up the button as you would in a regular 2D project.

Following these examples, you now have a basic setup for an AR/VR scene using the XROrigin3D class in Godot 4. These snippets are stepping stones to constructing a more complex and immersive experience, paving the way for creative exploration in the expanding realm of AR/VR gaming. Keep experimenting and fine-tuning these fundamentals to harness the full power of XROrigin3D in your virtual worlds.

Enhancing Player Mobility

As we delve deeper into the mechanics of AR/VR development, enabling players to move around the virtual space is a significant feature. A common method is teleportation, which allows for instant movement to new locations within the game environment. Here’s how you can achieve teleportation with XROrigin3D:

func teleport_to_position(new_position):
    var current_position = xr_origin.global_transform.origin
    var teleport_vector = new_position - current_position
    xr_origin.global_translate(teleport_vector)

The code snippet above defines a function that teleports the XROrigin3D to a new position specified by `new_position`.

You may also want to provide smooth locomotion options for your players by capturing thumbstick input from the controllers:

# Assuming this code is inside _physics_process or similar
var input_vector = Vector2(0,0) # represents thumbstick axis positions

input_vector.x = left_controller.get_joystick_axis(0) # Get horizontal axis
input_vector.y = left_controller.get_joystick_axis(1) # Get vertical axis

# Apply the movement to the player's position
if input_vector.length() > 0:
    var movement_speed = 2.0
    xr_origin.translate(Vector3(input_vector.x, 0, input_vector.y) * movement_speed * delta)

This checks the axis values of the left controller’s thumbstick and uses them to move the XROrigin3D.

Adding Physics and Collision

Incorporating physics and collision detection to your AR/VR world enhances realism and interaction. For instance, you might want to ensure the player can’t walk through virtual objects. By utilizing Godot’s physics engine alongside XROrigin3D, this is possible.

Here’s how you can set up basic collision for your VR character:

var collision_shape = CapsuleShape.new()
collision_shape.height = 1.8
collision_shape.radius = 0.5

var collision_body = ARVRAnchor.new()
collision_body.shape = collision_shape
xr_origin.add_child(collision_body)

This will create a capsule collision shape, mimicking the player’s physical space, and adds it as a child to the XROrigin3D.

Then, to handle collision events and restrict player movement:

func _physics_process(delta):
    var collision_results = xr_origin.move_and_slide(Vector3(0, 0, 0))

    if collision_results.colliding:
        # Implement logic for when the player is colliding with an object
        print("Collision Detected")

This uses the inbuilt `move_and_slide` method to slide the XROrigin3D node along the collision plane, preventing it from passing through objects.

Syncing with Real-World Anchors

In AR, it can be crucial to synchronize virtual objects with anchors in the real world. These might be QR codes or other notable points that AR devices can detect. Here’s how you can add and track a virtual object with a real-world anchor:

var anchor_id = ARVRServer.find_anchor_by_type("QR_CODE", 0) # Locating a QR code anchor
var anchor = ARVRAnchor.new()
anchor.set_anchor_id(anchor_id)
xr_origin.add_child(anchor)

# Anchor a virtual object to this anchor point
var virtual_object = load("res://my_object.tscn").instance()
anchor.add_child(virtual_object)

The code assigns a virtual object to an anchor point, ensuring the virtual object remains correctly positioned relative to the real-world feature.As you get more comfortable with Godot’s AR/VR capabilities, one area you might explore is enhancing the level of interaction in your virtual environments. This means not just moving around or teleporting but also manipulating objects, engaging with interfaces, and more. Below, you’ll find a set of code examples that build on previous snippets, adding complexity and utility to your AR/VR projects.

Object Interaction – Grabbing and Releasing

Interacting with objects is a staple in the AR/VR experience. These examples illustrate how you might let the player grab objects using a controller:

var grabbed_object = null

func _on_Controller_button_pressed(button_index):
    if button_index == some_button: # Replace with the index of your grab button
        var ray_length = 2.0
        var ray_from = right_controller.global_transform.origin
        var ray_to = ray_from + right_controller.global_transform.basis.z.normalized() * -ray_length
        var space_state = get_world().direct_space_state
        var ray_result = space_state.intersect_ray(ray_from, ray_to)
        
        if ray_result:
            grabbed_object = ray_result.collider
            grabbed_object.set_as_toplevel(true)
            grabbed_object.global_transform = right_controller.global_transform

func _on_Controller_button_released(button_index):
    if grabbed_object != null and button_index == some_button:
        grabbed_object.set_as_toplevel(false)
        grabbed_object = null

In this example, when the player presses a specific button (replace `some_button` with the correct identifier for your setup), a ray is cast from the controller. If the ray hits an object, it becomes the `grabbed_object`, which is then set to move with the controller until the button is released.

Enhanced Player Teleportation

To provide a clearer indication of where the player is about to teleport, you can add a visual teleportation target indicator on the ground:

var teleportation_area = preload("res://TeleportationArea.tscn").instance()
teleportation_area.visible = false
xr_origin.add_child(teleportation_area)

# Update the teleportation area indicator position
func update_teleportation_indicator(is_visible, world_position):
    teleportation_area.visible = is_visible
    teleportation_area.global_transform.origin = world_position

This script will allow you to show or hide a teleportation area indicator and place it at the position in the world where the player is pointing.

func _process(delta):
    var ray_from = right_controller.global_transform.origin
    var ray_to = ray_from + right_controller.global_transform.basis.z.normalized() * -10.0
    var space_state = get_world().direct_space_state
    var ray_result = space_state.intersect_ray(ray_from, ray_to)
    
    if ray_result:
        update_teleportation_indicator(true, ray_result.position)
    else:
        update_teleportation_indicator(false, Vector3())

# Call this function when the player confirms the teleport
func perform_teleportation():
    teleport_to_position(teleportation_area.global_transform.origin)

These additional lines of code allow the teleportation process to include a raycast that updates the position of the teleportation indicator. When the player decides to teleport, the `perform_teleportation` function moves the XROrigin3D to the indicator’s location.

Interacting with UI in VR

When incorporating UI elements in VR, you’ll want to make sure they are interactive. This is a quick setup to allow players to interact with VR buttons:

func _process(delta):
    var ray_length = 3.0
    var ui_layer_mask = 1 << 2 # Assuming UI is on layer 2
    var ray_from = right_controller.global_transform.origin
    var ray_to = ray_from + right_controller.global_transform.basis.z.normalized() * -ray_length
    var space_state = get_world().direct_space_state
    var ray_result = space_state.intersect_ray(ray_from, ray_to, [], ui_layer_mask)

    if ray_result and ray_result.collider is Button:
        var button = ray_result.collider
        if !button.pressed:
            button.emit_signal("pressed")

By using a layer mask to only check for ray collisions with UI elements and identifying if the collider is a `Button`, this snippet emits the `pressed` signal when the ray from the controller intersects with a button, simulating a button press in VR.

Adding Spatial Sound

Lastly, to create a truly immersive AR/VR experience, spatial sound is crucial. Here’s how you can set up a 3D sound that will change as you move around:

var audio_stream_player = AudioStreamPlayer3D.new()
xr_origin.add_child(audio_stream_player)
audio_stream_player.stream = preload("res://sounds/ambient.ogg") # Replace with your audio file path
audio_stream_player.play()

This code adds an `AudioStreamPlayer3D` to your scene and sets an audio stream to play. As the player moves in relation to the `AudioStreamPlayer3D` node, the sound will dynamically change to reflect their position and orientation, enhancing the sense of immersion in your AR/VR game.

Combine these techniques to create a rich and interactable virtual environment that is sure to captivate your players. Remember, each game and application may require modifications of these basic examples, but they give a solid foundation to build upon for your own unique AR/VR experiences.

Continuing Your Journey in Game Development

The fascinating world of AR/VR game development in Godot 4 is vast, and there’s always more to learn. If you’re feeling inspired and eager to expand your skillset further, we warmly invite you to continue your journey with us. Our Godot Game Development Mini-Degree is a perfect next step, offering a comprehensive range of courses that can help elevate your skills from beginner to professional levels.

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Conclusion

Diving into the intricacies of AR/VR development within Godot 4 can truly unlock a universe of possibilities for aspiring game developers—and the journey doesn’t end here. By mastering tools such as the XROrigin3D and leveraging Godot’s robust feature set, you’re well on your way to creating interactive, immersive worlds that resonate with players and stand out in the gaming landscape.

We at Zenva are excited to see what you’ll build with the skills and knowledge gained. Remember, our Godot Game Development Mini-Degree is just a click away, ready to take you to the next level of your development journey. Keep learning, keep creating, and turn your dream projects into reality with Zenva’s quality education. Happy developing!

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