Unity Cross-Platform Development

Developers who wish to target multiple platforms and devices may use the Oculus Integration to build and target platforms that support OpenVR. This page will detail the APIs that are supported for cross-platform development and any differences in functionality from typical Oculus development. This page will not detail the typical usage of these APIs and development process that is described elsewhere in the Unity guide.

Cross-platform development allows developers to write an app that, when targeted separately for either the Oculus or SteamVR platforms, will work out-of-the-box with minimal additional work. Cross-platform support for Input generally supports a 6DOF HMD and controllers, like the Oculus Rift S and Touch, the HTC Vive™ and controllers, and the Windows Mixed Reality headset and motion controllers.

Camera - OVRCameraRig

Follow the same steps described in the Oculus Utilities for Unity guide. If you’re updating an existing app, you will need to delete the existing camera and drag a new camera prefab into the scene to track the OpenVR HMD + controllers.

When adding OVRCameraRig prefab, you must select the tracking origin ‘FloorLevel’, ‘EyeLevel’ is not supported for cross-platform development.

Controller tracked objects must be made children of either LControllerAnchor or RControllerAnchor for cross-platform development.

HMD Tracking - OVRDisplay

The following OVRDisplay APIs are supported for cross-platform development to retrieve the HMD’s velocity of movement relative to the local tracked space.

• OVRDisplay.velocity()
• OVRDisplay.angularvelocity()

Input - OVRInput

Using the OVRInput APIs for Oculus controllers is described in the OVRInput guide. For cross-platform development the following APIs are supported.

Individual Buttons - Get(), GetUp(), GetDown() are supported for the buttons listed below, where Get() returns the current state of the control (true if pressed), GetUp() returns if the control was released in the frame (true if released), and GetDown() returns if the control is pressed in the frame (true if pressed). Mapping for Oculus Controllers are provided on the OVRInput page.

• Button.PrimaryIndexTrigger
• Button.SecondaryIndexTrigger
• Button.PrimaryHandTrigger
• Button.SecondaryHandTrigger
• Button.PrimaryThumbstick
• Button.SecondaryThumbstick
• Button.Two
• Button.Four
• Axis1D.PrimaryIndexTrigger
• Axis1D.PrimaryHandTrigger
• Axis1D.SecondaryIndexTrigger
• Axis1D.SecondaryHandTrigger
• Axis2D.PrimaryThumbstick
• Axis2D.SecondaryThumbstick

Both the Oculus Touch controllers and the Vive controllers are treated by these APIs as “Touch” to preserve backward compatibility with existing apps. Left XR controller = LTouch, right XR controller = RTouch. Button/control states can be requested for the following -

• Controller.LTouch
• Controller.RTouch
• Controller.Touch

We encourage developers to specify a Touch controller as the 2nd argument for cross-platform usage, i.e. either LTouch or RTouch, and then have the first argument be a “primary” binding. You are not required to specify a Touch controller as the 2nd argument, but it’s often easier. For example -

• OVRInput.Get(Button.PrimaryHandTrigger, Controller.LTouch) would return true when the “grip” or “hand” trigger of the left XR controller is held down.
• OVRInput.GetDown(Button.Two, Controller.LTouch) would return true when the left XR controller’s “top button” is pressed during a frame. This represents the Y-button on Oculus Touch, and the 3-bar button at the top of Vive controller. If RTouch was specified, this would represent the B-button for Touch.
• OVRInput.Get(Axis1D.PrimaryIndexTrigger. Controller.RTouch) would return the axis value, from 0 to 1.0, which represents how far the right XR controller index trigger is pressed down.

Controller Position and Velocity - The following OVRInput APIs are supported for cross-platform development to retrieve the controller’s position in space and velocity of movement relative to the local tracked space.

• GetLocalControllerPosition()
• GetLocalControllerRotation()
• GetLocalControllerVelocity()
• GetLocalControllerAngularVelocity()

Button Mapping for Supported OpenVR Controllers

HTC Vive Controller

The OVRInput APIs described above map to the following buttons on the HTC Vive controller -

• Button.Two maps to the ‘Menu Button’, #1 on the image above.
• Axis2D.PrimaryThumbstick maps to the capacitive ‘Trackpad’, #2 on the image above.
• Button.PrimaryThumbstick maps to a press of the ‘Trackpad’, #2 on the image above.
• Axis1D.PrimaryIndexTrigger maps to the ‘Trigger’, #7 on the image above.
• Axis1D.PrimaryHandTrigger maps to the ‘Grip Button’, #8 on the image above.

Microsoft Mixed Reality Motion Controller

The OVRInput APIs described above map to the following buttons on the Microsoft Mixed Reality motion controller, which can be found on Microsoft’s Motion controllers page (see controller image under “Hardware details”).

• Button.Two maps to the ‘Menu’.
• Axis2D.PrimaryThumbstick maps to the ‘Thumbstick’.
• Button.PrimaryThumbstick maps to a press of the ‘Touchpad’.
• Axis1D.PrimaryIndexTrigger maps to ‘Trigger’.
• Axis1D.PrimaryHandTrigger maps to ‘Grab’.

Haptics - SetControllerVibration()

Cross-platform haptics support is enabled through the SetControllerVibration API. The OVRHpatics and OVRHapticsClip APIs are not supported for cross-platform development.

Usage of the API is described in the OVRInput guide, with cross-platform devices supporting amplitudes of any increment between 0-1, inclusive, and frequencies of 1.0. For example -

• OVRInput.SetControllerVibration(1.0f, 0.5f, Controller.RTouch) plays haptics at half of the peak amplitude, for the right XR controller. Playback will continue at this amplitude until a new vibration is set (or set to 0). Note - all vibration will time out after 2 seconds.
• OVRInput.SetControllerVibration(1.0f, 0.0f, Controller.RTouch) ends haptic playback on the right XR controller.

Boundary / Play Area - OVRBoundary

OVRBoundary allows developers to retrieve and set information for the user’s play area as described in the OVRBoundary guide. The following APIs are supported for cross-platform development.

• GetDimensions()
• GetGeometry()
• SetVisible()
• GetVisible()
• GetConfigured()

Overlays OVROverlay

Information about adding an overlay using OVROverlay is described in the VR Compositor Layers guide. At this time, only Quad world-locked overlays are supported for cross-platform development.

To use a cross-platform overlay, add a quad gameobject to the scene, delete the mesh renderer and collider components, add an OVROverlay component to the quad, and specify a texture to display.

Cross-Platform Avatars

Oculus Avatars support cross-platform development in Unity. See the Unity CrossPlatform Sample Scene guide for information about using cross-platform Avatars.

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