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WebXRInterface

Inherits: XRInterface < RefCounted < Object

XR interface using WebXR.

Description

WebXR is an open standard that allows creating VR and AR applications that run in the web browser.

As such, this interface is only available when running in Web exports.

WebXR supports a wide range of devices, from the very capable (like Valve Index, HTC Vive, Oculus Rift and Quest) down to the much less capable (like Google Cardboard, Oculus Go, GearVR, or plain smartphones).

Since WebXR is based on JavaScript, it makes extensive use of callbacks, which means that WebXRInterface is forced to use signals, where other XR interfaces would instead use functions that return a result immediately. This makes WebXRInterface quite a bit more complicated to initialize than other XR interfaces.

Here’s the minimum code required to start an immersive VR session:

extends Node3D
var webxr_interface
var vr_supported = false
func _ready():
    # We assume this node has a button as a child.
    # This button is for the user to consent to entering immersive VR mode.
    $Button.pressed.connect(self._on_button_pressed)
    webxr_interface = XRServer.find_interface("WebXR")
    if webxr_interface:
        # WebXR uses a lot of asynchronous callbacks, so we connect to various
        # signals in order to receive them.
        webxr_interface.session_supported.connect(self._webxr_session_supported)
        webxr_interface.session_started.connect(self._webxr_session_started)
        webxr_interface.session_ended.connect(self._webxr_session_ended)
        webxr_interface.session_failed.connect(self._webxr_session_failed)
        # This returns immediately - our _webxr_session_supported() method
        # (which we connected to the "session_supported" signal above) will
        # be called sometime later to let us know if it's supported or not.
        webxr_interface.is_session_supported("immersive-vr")
func _webxr_session_supported(session_mode, supported):
    if session_mode == 'immersive-vr':
        vr_supported = supported
func _on_button_pressed():
    if not vr_supported:
        OS.alert("Your browser doesn't support VR")
        return
    # We want an immersive VR session, as opposed to AR ('immersive-ar') or a
    # simple 3DoF viewer ('viewer').
    webxr_interface.session_mode = 'immersive-vr'
    # 'bounded-floor' is room scale, 'local-floor' is a standing or sitting
    # experience (it puts you 1.6m above the ground if you have 3DoF headset),
    # whereas as 'local' puts you down at the XROrigin.
    # This list means it'll first try to request 'bounded-floor', then
    # fallback on 'local-floor' and ultimately 'local', if nothing else is
    # supported.
    webxr_interface.requested_reference_space_types = 'bounded-floor, local-floor, local'
    # In order to use 'local-floor' or 'bounded-floor' we must also
    # mark the features as required or optional.
    webxr_interface.required_features = 'local-floor'
    webxr_interface.optional_features = 'bounded-floor'
    # This will return false if we're unable to even request the session,
    # however, it can still fail asynchronously later in the process, so we
    # only know if it's really succeeded or failed when our
    # _webxr_session_started() or _webxr_session_failed() methods are called.
    if not webxr_interface.initialize():
        OS.alert("Failed to initialize")
        return
func _webxr_session_started():
    $Button.visible = false
    # This tells Godot to start rendering to the headset.
    get_viewport().use_xr = true
    # This will be the reference space type you ultimately got, out of the
    # types that you requested above. This is useful if you want the game to
    # work a little differently in 'bounded-floor' versus 'local-floor'.
    print ("Reference space type: " + webxr_interface.reference_space_type)
func _webxr_session_ended():
    $Button.visible = true
    # If the user exits immersive mode, then we tell Godot to render to the web
    # page again.
    get_viewport().use_xr = false
func _webxr_session_failed(message):
    OS.alert("Failed to initialize: " + message)

There are a couple ways to handle “controller” input:

• Using XRController3D nodes and their XRController3D.button_pressed and XRController3D.button_released signals. This is how controllers are typically handled in XR apps in Godot, however, this will only work with advanced VR controllers like the Oculus Touch or Index controllers, for example.

• Using the select, squeeze and related signals. This method will work for both advanced VR controllers, and non-traditional input sources like a tap on the screen, a spoken voice command or a button press on the device itself.

You can use both methods to allow your game or app to support a wider or narrower set of devices and input methods, or to allow more advanced interactions with more advanced devices.

Tutorials

• How to make a VR game for WebXR with Godot 4

Properties

Methods

Signals

display_refresh_rate_changed ( )

Emitted after the display’s refresh rate has changed.

reference_space_reset ( )

Emitted to indicate that the reference space has been reset or reconfigured.

When (or whether) this is emitted depends on the user’s browser or device, but may include when the user has changed the dimensions of their play space (which you may be able to access via XRInterface.get_play_area) or pressed/held a button to recenter their position.

See WebXR’s XRReferenceSpace reset event for more information.

select ( int input_source_id )

Emitted after one of the input sources has finished its “primary action”.

Use get_input_source_tracker and get_input_source_target_ray_mode to get more information about the input source.

selectend ( int input_source_id )

Emitted when one of the input sources has finished its “primary action”.

Use get_input_source_tracker and get_input_source_target_ray_mode to get more information about the input source.

selectstart ( int input_source_id )

Emitted when one of the input source has started its “primary action”.

Use get_input_source_tracker and get_input_source_target_ray_mode to get more information about the input source.

session_ended ( )

Emitted when the user ends the WebXR session (which can be done using UI from the browser or device).

At this point, you should do get_viewport().use_xr = false to instruct Godot to resume rendering to the screen.

session_failed ( String message )

Emitted by XRInterface.initialize if the session fails to start.

message may optionally contain an error message from WebXR, or an empty string if no message is available.

session_started ( )

Emitted by XRInterface.initialize if the session is successfully started.

At this point, it’s safe to do get_viewport().use_xr = true to instruct Godot to start rendering to the XR device.

session_supported ( String session_mode, bool supported )

Emitted by is_session_supported to indicate if the given session_mode is supported or not.

squeeze ( int input_source_id )

Emitted after one of the input sources has finished its “primary squeeze action”.

Use get_input_source_tracker and get_input_source_target_ray_mode to get more information about the input source.

squeezeend ( int input_source_id )

Emitted when one of the input sources has finished its “primary squeeze action”.

Use get_input_source_tracker and get_input_source_target_ray_mode to get more information about the input source.

squeezestart ( int input_source_id )

Emitted when one of the input sources has started its “primary squeeze action”.

Use get_input_source_tracker and get_input_source_target_ray_mode to get more information about the input source.

visibility_state_changed ( )

Emitted when visibility_state has changed.

Enumerations

enum TargetRayMode:

TargetRayMode TARGET_RAY_MODE_UNKNOWN = 0

We don’t know the the target ray mode.

TargetRayMode TARGET_RAY_MODE_GAZE = 1

Target ray originates at the viewer’s eyes and points in the direction they are looking.

TargetRayMode TARGET_RAY_MODE_TRACKED_POINTER = 2

Target ray from a handheld pointer, most likely a VR touch controller.

TargetRayMode TARGET_RAY_MODE_SCREEN = 3

Target ray from touch screen, mouse or other tactile input device.

Property Descriptions

String optional_features

• void set_optional_features ( String value )

• String get_optional_features ( )

A comma-seperated list of optional features used by XRInterface.initialize when setting up the WebXR session.

If a user’s browser or device doesn’t support one of the given features, initialization will continue, but you won’t be able to use the requested feature.

This doesn’t have any effect on the interface when already initialized.

Possible values come from WebXR’s XRReferenceSpaceType. If you want to use a particular reference space type, it must be listed in either required_features or optional_features.

String reference_space_type

• String get_reference_space_type ( )

The reference space type (from the list of requested types set in the requested_reference_space_types property), that was ultimately used by XRInterface.initialize when setting up the WebXR session.

Possible values come from WebXR’s XRReferenceSpaceType. If you want to use a particular reference space type, it must be listed in either required_features or optional_features.

String requested_reference_space_types

• void set_requested_reference_space_types ( String value )

• String get_requested_reference_space_types ( )

A comma-seperated list of reference space types used by XRInterface.initialize when setting up the WebXR session.

The reference space types are requested in order, and the first one supported by the users device or browser will be used. The reference_space_type property contains the reference space type that was ultimately selected.

This doesn’t have any effect on the interface when already initialized.

Possible values come from WebXR’s XRReferenceSpaceType. If you want to use a particular reference space type, it must be listed in either required_features or optional_features.

String required_features

• void set_required_features ( String value )

• String get_required_features ( )

A comma-seperated list of required features used by XRInterface.initialize when setting up the WebXR session.

If a user’s browser or device doesn’t support one of the given features, initialization will fail and session_failed will be emitted.

This doesn’t have any effect on the interface when already initialized.

Possible values come from WebXR’s XRReferenceSpaceType. If you want to use a particular reference space type, it must be listed in either required_features or optional_features.

String session_mode

• void set_session_mode ( String value )

• String get_session_mode ( )

The session mode used by XRInterface.initialize when setting up the WebXR session.

This doesn’t have any effect on the interface when already initialized.

Possible values come from WebXR’s XRSessionMode, including: "immersive-vr", "immersive-ar", and "inline".

String visibility_state

• String get_visibility_state ( )

Indicates if the WebXR session’s imagery is visible to the user.

Possible values come from WebXR’s XRVisibilityState, including "hidden", "visible", and "visible-blurred".

Method Descriptions

Array get_available_display_refresh_rates ( ) const

Returns display refresh rates supported by the current HMD. Only returned if this feature is supported by the web browser and after the interface has been initialized.

float get_display_refresh_rate ( ) const

Returns the display refresh rate for the current HMD. Not supported on all HMDs and browsers. It may not report an accurate value until after using set_display_refresh_rate.

TargetRayMode get_input_source_target_ray_mode ( int input_source_id ) const

Returns the target ray mode for the given input_source_id.

This can help interpret the input coming from that input source. See XRInputSource.targetRayMode for more information.

XRPositionalTracker get_input_source_tracker ( int input_source_id ) const

Gets an XRPositionalTracker for the given input_source_id.

In the context of WebXR, an input source can be an advanced VR controller like the Oculus Touch or Index controllers, or even a tap on the screen, a spoken voice command or a button press on the device itself. When a non-traditional input source is used, interpret the position and orientation of the XRPositionalTracker as a ray pointing at the object the user wishes to interact with.

Use this method to get information about the input source that triggered one of these signals:

• selectstart

• select

• selectend

• squeezestart

• squeeze

• squeezestart

bool is_input_source_active ( int input_source_id ) const

Returns true if there is an active input source with the given input_source_id.

void is_session_supported ( String session_mode )

Checks if the given session_mode is supported by the user’s browser.

Possible values come from WebXR’s XRSessionMode, including: "immersive-vr", "immersive-ar", and "inline".

This method returns nothing, instead it emits the session_supported signal with the result.

void set_display_refresh_rate ( float refresh_rate )

Sets the display refresh rate for the current HMD. Not supported on all HMDs and browsers. It won’t take effect right away until after display_refresh_rate_changed is emitted.