SceneView Android

3D/AR Android View with ARCore and Google Filament

This is a Sceneform replacement in Kotlin

Features

• Use SceneView for 3D only or ArSceneView for 3D and ARCore.
• Everything is accessible at the SceneView/ArSceneView level. For example, no more ArFragment and code like arFragment.arSceneView.scene, arFragment.session.config, etc.
• Just add the <ArSceneView> tag to your layout or call the ArSceneview(context: Context) constructor in your code. Compose is coming next ...
• Requesting the camera permission and installing/updating the Google Play Services for AR is handled automatically in the ArSceneView.
• Support for the latest ARCore features (the upcoming features will be integrated quicker thanks to Kotlin).
• Lifecycle-aware components = Better memory management and performance.
• Resources are loaded using coroutines launched in the LifecycleCoroutineScope of the SceneView/ArSceneView. This means that loading is started when the view is created and cancelled when it is destroyed.
• Multiple instances are now possible.
• Much easier to use. For example, the local and world position, rotation and scale of the Node are now directly accessible without creating Vector3 objects (position.x = 1f, rotation = Rotation(90f, 180f, 0f), scale = Scale(0.5f), etc.).

Dependency

app/build.gradle

• 3D only

dependencies {
    // 3D only
    implementation 'io.github.sceneview:sceneview:0.6.0'
}

API Reference

• 3D and ARCore

dependencies {
    // 3D and ARCore
    implementation 'io.github.sceneview:arsceneview:0.6.0'
}

API Reference

Usage

res/layout/main_fragment.xml

• 3D only

<io.github.sceneview.SceneView
    android:id="@+id/sceneView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

• 3D and ARCore

<io.github.sceneview.ar.ArSceneView
    android:id="@+id/sceneView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

ARCore Geospatial API

• Configure session

arSceneView.configureSession { session, config ->
    // Enable Geospatial Mode.
    config.geospatialMode = Config.GeospatialMode.ENABLED
}

• Create an Anchor

val earth = arSceneView.session?.earth ?: return
if (earth.trackingState == TrackingState.TRACKING) {
    // Place the earth anchor at the same altitude as that of the camera to make it easier to view.
    val altitude = earth.cameraGeospatialPose.altitudeMeters - 1
    // The rotation quaternion of the anchor in the East-Up-South (EUS) coordinate system.
    val qx = 0f
    val qy = 0f
    val qz = 0f
    val qw = 1f
    earthAnchor = earth.createAnchor(latLng.latitude, latLng.longitude, altitude, qx, qy, qz, qw)
}

Camera Permission and ARCore install/update/unavailable

ArSceneView automatically handles the camera permission prompt and the ARCore requirements checks. Everything is proceed when the attached view Activity/Fragment is resumed but you can also add your ArSceneView at any time, the prompt will then occure when first addView(arSceneView) is called.

If you need it, you can add a listener on both ARCore success or failed session creation (including camera permission denied since a session cannot be created without it)

• Camera permission has been granted and latest ARCore Services version are already installed or have been installed during the auto check

sceneView.onArSessionCreated = { arSession: ArSession ->
}

• Handle a fallback in case of camera permission denied or AR unavailable and possibly move to 3D only usage

sceneView.onArSessionFailed = { exception: Exception ->
    // If AR is not available, we add the model directly to the scene for a 3D only usage
    sceneView.addChild(modelNode)
}

The exception contains the failure reason. e.g. SecurityException in case of camera permission denied

Customizing the instructions

• The default instruction nodes have a ViewRenderable with a TextView or ImageView
• The text and images of the instruction nodes can be overridden at the resource level (in the strings.xml file and drawable directory of your project).
• Custom instruction nodes can have an arbitrary number of child nodes with ModelRenderables and ViewRenderables. It is even possible to play animation for a ModelRenderable if it is defined in a .glb file or a video using the VideoNode
• The infoNode can have one of the following values depending on the ARCore features used and the current ARCore state: searchPlaneInfoNode, tapArPlaneInfoNode and augmentedImageInfoNode. Alternatively, it is possible to create your own instruction nodes.
• The SearchPlaneInfoNode displays messages related to the ARCore state. For example, Searching for surfaces..., Too dark. Try moving to a well-lit area, Moving too fast. Slow down, etc.
• The TapArPlaneInfoNode displays a message that helps users to understand how an object can be placed in AR when no objects are currently present in the scene.
• The AugmentedImageInfoNode displays a frame with white corners when no augmented image is currently tracked.

💡 Idea for future: when access to the flashlight is finally available with the ARCore shared CameraManager, it will be great to add a button to the SearchPlaneInfoNode to enable the flashlight when there isn't enough light.

Why have we included the Kotlin-Math library in SceneView?

Earlier versions of OpenGL had a fixed rendering pipeline and provided an API for setting positions of vertices, transformation and projection matrices, etc. However, with the new rendering pipeline it is required to prepare this data before passing it to GLSL shaders and OpenGL doesn't provide any mathematical functions to do that.

It is possible to implement the required functions yourself like in Sceneform or use an existing library. For example, C++ supports operator overloading and benefits from the excellent GLM library that allows to use the same syntax and features as GLSL.

We use the Kotlin-Math library to rely on a well-tested functions and get an advantage of using Kotlin operators for vector, matrix and quaternion operations too.

Migration from Sceneform

You will have a little work to do if you are using the ArFragment in Sceneform. However, there is the Deprecated.kt file to help you with the migration.

Using the migration suggestions

1. Remove the Sceneform import for the class you want to migrate.
2. Import this class from the io.github.sceneview.ar package.
3. Use Alt+Enter/the light bulb icon to view and apply the suggestions for replacing the deprecated method calls.

After the migration you should get cleaner code and all of the benefits described in the Features section 🎉

Requesting the camera permission and installing/updating the Google Play Services for AR

This is handled automatically in the ArSceneView. You can use the ArSceneView.onArSessionFailed property to register a callback to be invoked when the ARCore Session cannot be initialized because ARCore is not available on the device or the camera permission has been denied.

Instructions for AR

The InstructionsController in the BaseArFragment has been replaced with the Instructions in the ArSceneView.

The Instructions use a Node that is a part of the scene instead of a View, as opposed to the InstructionsController. This provides more flexibility for customizing the instructions. The Instructions have the main Node that can be accessed through the Instructions.infoNode property.