Add snippets from Android XR spotlight week that hadn't made it into main (#785)

* Add head tracking snippets

* Add depth map snippets

* Add face tracking snippets

* Add panel move example

* Rebase to January Jetpack release

* Update DepthMaps.kt

Author: devbridie

xr/src/main/AndroidManifest.xml

@@ -14,8 +14,10 @@
      See the License for the specific language governing permissions and
      limitations under the License.
 -->
-<manifest xmlns:tools="http://schemas.android.com/tools"
-    xmlns:android="http://schemas.android.com/apk/res/android">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <uses-permission android:name="android.permission.HEAD_TRACKING" />
 
     <application
         android:label="XR"

xr/src/main/java/com/example/xr/arcore/DepthMaps.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.xr.arcore
+
+import androidx.xr.arcore.DepthMap
+import androidx.xr.runtime.Config
+import androidx.xr.runtime.Session
+import androidx.xr.runtime.SessionConfigureSuccess
+
+private fun configureDepthEstimation(session: Session) {
+    // [START androidxr_arcore_depthmaps_configure]
+    val newConfig = session.config.copy(
+        depthEstimation = Config.DepthEstimationMode.SMOOTH_ONLY,
+    )
+    when (val result = session.configure(newConfig)) {
+        is SessionConfigureSuccess -> TODO(/* Success! */)
+        else ->
+            TODO(/* The session could not be configured. See SessionConfigureResult for possible causes. */)
+    }
+    // [END androidxr_arcore_depthmaps_configure]
+}
+
+@Suppress("UnusedVariable")
+private suspend fun getDepthMap(session: Session) {
+    // [START androidxr_arcore_depthmaps_obtain_depth_map]
+    val depthMap = DepthMap.left(session) ?: return
+    // [END androidxr_arcore_depthmaps_obtain_depth_map]
+
+    // [START androidxr_arcore_depthmaps_calculate_results]
+    depthMap.state.collect { depthMap ->
+        // example coordinates
+        val x = 200
+        val y = 350
+        val index = x + y * depthMap.width
+        val result = depthMap.smoothDepthMap?.get(index)
+        val confidence = depthMap.smoothConfidenceMap?.get(index)
+    }
+    // [END androidxr_arcore_depthmaps_calculate_results]
+}

xr/src/main/java/com/example/xr/arcore/FaceTracking.kt

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.xr.arcore
+
+import androidx.xr.arcore.Face
+import androidx.xr.arcore.FaceBlendShapeType
+import androidx.xr.arcore.FaceConfidenceRegion
+import androidx.xr.runtime.Config
+import androidx.xr.runtime.Session
+import androidx.xr.runtime.SessionConfigureSuccess
+import androidx.xr.runtime.TrackingState
+
+private fun configureFaceTracking(session: Session) {
+    // [START androidxr_arcore_faceTracking_configure]
+    val newConfig = session.config.copy(
+        faceTracking = Config.FaceTrackingMode.USER,
+    )
+    when (val result = session.configure(newConfig)) {
+        is SessionConfigureSuccess -> TODO(/* Success! */)
+        else ->
+            TODO(/* The session could not be configured. See SessionConfigureResult for possible causes. */)
+    }
+    // [END androidxr_arcore_faceTracking_configure]
+}
+
+@Suppress("UnusedVariable")
+private suspend fun getUserFace(session: Session) {
+    // [START androidxr_arcore_faceTracking_getFace]
+    val face = Face.getUserFace(session) ?: return
+    face.state.collect { state ->
+        if (state.trackingState != TrackingState.TRACKING) return@collect
+
+        val confidence = state.getConfidence(FaceConfidenceRegion.FACE_CONFIDENCE_REGION_LOWER)
+        val blendShapeValue = state.blendShapes[FaceBlendShapeType.FACE_BLEND_SHAPE_TYPE_LIPS_TOWARD]
+    }
+    // [END androidxr_arcore_faceTracking_getFace]
+}