ExternalDeviceMotionFrameSource Class¶

Description¶

External frame source which represents an external device which has motion tracking capability. Usually represents HMD where camera rendering and device tracking are handled in device SDK.

This frame source is one type of motion tracking device, and will output motion data in a ARSession .

You can inherent it to implenment HMD and other device input. You have to make your own implenmentation of motion tracking, EasyAR motion tracking will not directly work on exteranl devices. You need to get image and pose data and input into EasyAR by yourself from hardware other places. EasyAR does not provide the capability to grab data from those devices, it does provide the capability to run EasyAR features after you put data into EasyAR.

Users using personal edition license or trial version Mega services can use EasyAR for 100 seconds per run when custom camera is chosen.

MonoBehaviour Messages¶

protected virtual void Awake()

protected virtual void OnApplicationPause(bool pause)

protected virtual void OnDestroy()

Properties¶

OriginCandidate¶

C#: public MonoBehaviour OriginCandidate { get; set; }

ExternalDeviceFrameSource.Origin candidate. It will be automatically get from the scene or generate if not set.

AvailableCenterMode¶

C#: internal protected override IReadOnlyList< ARSession.ARCenterMode > AvailableCenterMode { }

Provide only when creating a new frame source. It will only be accessed during ARSession.Assemble .

All available center modes.

IsCameraUnderControl¶

C#: internal protected override bool IsCameraUnderControl { }

Provide only when creating a new frame source. It will only be accessed during ARSession.Assemble .

When the value is ture, the session will update camera transform depending on the center mode and render camera images.

When creating a HMD extension, it should be false. You should have full control of the 3D camera in the scene. You should handle camera rendering, especially in VST.

Camera¶

C#: internal protected override Camera Camera { }

Provide only when creating a new frame source. It will only be accessed during ARSession.Assemble .

On desktop or mobile phones, it represents the Camera in the virtual world in reflection of real world camera device, its projection matrix and transform will be set to reflect the real world camera, and it is controlled by EasyAR. On head mounted devices, it is only used to display some diagnostics message in front of your eyes, it is not used for camera image rendering, it is not controled by EasyAR.

OriginType¶

C#: internal protected virtual abstract ExternalDeviceFrameSource.DeviceOriginType OriginType { }

Device origin type.

Origin¶

C#: protected virtual GameObject Origin { get; }

Device origin. You need to define your own origin when ExternalDeviceFrameSource.OriginType is ExternalDeviceFrameSource.DeviceOriginType.Custom . It is not required to re-define origin in other cases.

ReceivedFrameCount¶

C#: public int ReceivedFrameCount { get; }

Received frame count. Usually used for debug. There are usually hardware issues if this value stop to increase, and re-plug may help when using some devices like Nreal.

IsHMD¶

C#: internal protected virtual abstract bool IsHMD { }

Provide only when creating a new frame source. It will only be accessed during ARSession.Assemble .

If the frame source represent head mounted devices. If true, diagnostics will be displayed on a 3D board in from of camera.

Some frame filter may work different on devices.

Display¶

C#: internal protected virtual abstract IDisplay Display { }

Provide only when creating a new frame source. It will only be accessed during ARSession.Assemble .

Provide display system information. You can use Display.DefaultSystemDisplay or Display.DefaultHMDDisplay for default display.

IsAvailable¶

C#: internal protected virtual abstract Optional<bool> IsAvailable { }

Provide only when creating a new frame source. It will only be accessed during ARSession.Assemble .

If the frame source is available.

If the value equals null, FrameSource.CheckAvailability will be called and the value will be accessed after Coroutine finish.

Methods¶

HandleRenderFrameData¶

C#: protected void HandleRenderFrameData(double timestamp, Pose pose, MotionTrackingStatus trackingStatus)

Input render frame data.

Make sure to call every frame after device data ready, do not skip.These data should match the one driving current Unity rendering camera in the same frame.

HandleCameraFrameData¶

C#: protected bool HandleCameraFrameData(double timestamp, Image image, CameraParameters cameraParameters, ExternalDeviceFrameSource.Extrinsics extrinsics, Pose deviceToOriginTransform, MotionTrackingStatus trackingStatus)

Input camera frame data.

Suggest to input 30 or 60 fps data. Acceptable minimum frame rate = 2, but response time of some algorithms will be affected. It can be called in any thread if all your APIs are thread safe. These data should match the one when camera sensor exposure. It is recommended to input the color data into EasyAR Sense as long as it can be obtained, which is helpful for the effect of EasyAR Mega.To get a better performance, you can design the whole data chain to let raw YUV data passthrough directly from shared memory and pass data pointer directly into EasyAR Sense.Be careful with data ownership.

OnSessionStart¶

C#: private override void OnSessionStart( ARSession session)

Provide only when creating a new frame source. It will only be accessed during ARSession.StartSession .

Handle session start if the frame source was assembled into ARSession.Assembly . It is designed for lazy initialization and you can do AR specific initialization work in the method.

OnSessionStop¶

C#: private override void OnSessionStop()

Provide only when creating a new frame source. It will be accessed during ARSession.StopSession or other session stop/break procedure.

Handle session stop if the frame source was assembled into ARSession.Assembly . You can use this method to destroy and resources created in ARSession.StartSession and during the session running and resotre inner state. It is ensured to be called before session destroy. If the frame source was destroyed before session, it will not be called and session will break.

TryAcquireBuffer¶

C#: protected Optional< Buffer > TryAcquireBuffer(int size)

Try acquire buffer from buffer pool.

CheckAvailability¶

C#: private virtual System.Collections.IEnumerator CheckAvailability()

Provide only when creating a new frame source. It will only be accessed during ARSession.Assemble .

Coroutine to check frame source availability when FrameSource.IsAvailable equals null.