After the user[grants permission for face tracking](https://developer.android.com/training/permissions/requesting), your app can retrieve face shape information through ARCore for Jetpack XR. Face shape information can help your app display the user in the virtual world, for example, for a virtual glasses try-on.

## Create an ARCore for Jetpack XR session

Obtain head pose information through an ARCore for Jetpack XR session. See[Understand a Session's lifecycle](https://developer.android.com/develop/xr/jetpack-xr-sdk/work-with-arcore#session-lifecycle)to obtain a[`Session`](https://developer.android.com/reference/kotlin/androidx/xr/runtime/Session).

## Configure the session

Face tracking is not enabled by default on XR sessions. To enable face tracking, configure the session and set the[`FaceTrackingMode.USER`](https://developer.android.com/reference/kotlin/androidx/xr/runtime/Config.FaceTrackingMode#USER())mode:

<br />

```kotlin
val newConfig = session.config.copy(
    faceTracking = Config.FaceTrackingMode.USER,
)
when (val result = session.configure(newConfig)) {
    is SessionConfigureSuccess -> TODO(/* Success! */)
    is SessionConfigureConfigurationNotSupported ->
        TODO(/* Some combinations of configurations are not valid. Handle this failure case. */)
    else ->
        TODO(/* The session could not be configured. See SessionConfigureResult for possible causes. */)
}https://github.com/android/snippets/blob/7bae2021b1c80a8bd422842967ad78dcf4d3756a/xr/src/main/java/com/example/xr/arcore/FaceTracking.kt#L30-L39
```

<br />

| **Note:** Enabling this mode requires the`android.permission.FACE_TRACKING`[runtime permission](https://developer.android.com/training/permissions/requesting)to be granted to your app.

## Retrieve face data

Use[`Face.getUserFace(session)`](https://developer.android.com/reference/kotlin/androidx/xr/arcore/Face#getUserFace(androidx.xr.runtime.Session))to retrieve user face data, which contains the following:

- **Face blendshape values** : A face's possible expressions are a combination of[68 blend shape values](https://developer.android.com/reference/kotlin/androidx/xr/arcore/FaceBlendShapeType). Each blend shape value represents a facial movement or deformation of the face, and the value indicates its intensity, ranging from`0.0`to`1.0`. For an explanation of each blend shape type, see[Understand face blendshape types](https://developer.android.com/develop/xr/jetpack-xr-sdk/arcore/face#blendshape-table).
- **Confidence values for regions** : The face has[three regions](https://developer.android.com/reference/kotlin/androidx/xr/arcore/FaceConfidenceRegion). Confidence values indicate the degree of certainty of accuracy for the given poses, ranging from`0.0`to`1.0`, where`1.0`indicates the highest confidence.

<br />

```kotlin
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]
}https://github.com/android/snippets/blob/7bae2021b1c80a8bd422842967ad78dcf4d3756a/xr/src/main/java/com/example/xr/arcore/FaceTracking.kt#L46-L52
```

<br />

## Understand face blendshape types

The following tables list each[type of face blend shape](https://developer.android.com/reference/kotlin/androidx/xr/arcore/FaceBlendShapeType):

### Upper region blendshapes

|         Name          |                                                                                                                                          Reference Images                                                                                                                                          ||
|-----------------------|---------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|
| `BROW_LOWERER_L`      | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`BROW_LOWERER_L = 0.0`      | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/browLowererL_front.png)`BROW_LOWERER_L = 1.0`          |
| `BROW_LOWERER_R`      | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`BROW_LOWERER_R = 0.0`      | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/browLowererR_front.png)`BROW_LOWERER_R = 1.0`          |
| `EYES_CLOSED_L`       | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_CLOSED_L = 0.0`       | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesClosedL_front.png)`EYES_CLOSED_L = 1.0`            |
| `EYES_CLOSED_R`       | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_CLOSED_R = 0.0`       | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesClosedR_front.png)`EYES_CLOSED_R = 1.0`            |
| `EYES_LOOK_DOWN_L`    | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_DOWN_L = 0.0`    | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookDownL_front.png)`EYES_LOOK_DOWN_L = 1.0`       |
| `EYES_LOOK_DOWN_R`    | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_DOWN_R = 0.0`    | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookDownR_front.png)`EYES_LOOK_DOWN_R = 1.0`       |
| `EYES_LOOK_LEFT_L`    | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_LEFT_L = 0.0`    | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookLeftL_front.png)`EYES_LOOK_LEFT_L = 1.0`       |
| `EYES_LOOK_LEFT_R`    | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_LEFT_R = 0.0`    | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookLeftR_front.png)`EYES_LOOK_LEFT_R = 1.0`       |
| `EYES_LOOK_RIGHT_L`   | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_RIGHT_L = 0.0`   | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookRightL_front.png)`EYES_LOOK_RIGHT_L = 1.0`     |
| `EYES_LOOK_RIGHT_R`   | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_RIGHT_R = 0.0`   | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookRightR_front.png)`EYES_LOOK_RIGHT_R = 1.0`     |
| `EYES_LOOK_UP_L`      | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_UP_L = 0.0`      | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookUpL_front.png)`EYES_LOOK_UP_L = 1.0`           |
| `EYES_LOOK_UP_R`      | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`EYES_LOOK_UP_R = 0.0`      | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/eyesLookUpR_front.png)`EYES_LOOK_UP_R = 1.0`           |
| `INNER_BROW_RAISER_L` | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`INNER_BROW_RAISER_L = 0.0` | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/innerBrowRaiserL_front.png)`INNER_BROW_RAISER_L = 1.0` |
| `INNER_BROW_RAISER_R` | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`INNER_BROW_RAISER_R = 0.0` | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/innerBrowRaiserR_front.png)`INNER_BROW_RAISER_R = 1.0` |
| `LID_TIGHTENER_L`     | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LID_TIGHTENER_L = 0.0`     | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lidTightenerL_front.png)`LID_TIGHTENER_L = 1.0`        |
| `LID_TIGHTENER_R`     | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LID_TIGHTENER_R = 0.0`     | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lidTightenerR_front.png)`LID_TIGHTENER_R = 1.0`        |
| `OUTER_BROW_RAISER_L` | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`OUTER_BROW_RAISER_L = 0.0` | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/outerBrowRaiserL_front.png)`OUTER_BROW_RAISER_L = 1.0` |
| `OUTER_BROW_RAISER_R` | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`OUTER_BROW_RAISER_R = 0.0` | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/outerBrowRaiserR_front.png)`OUTER_BROW_RAISER_R = 1.0` |
| `UPPER_LID_RAISER_L`  | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`UPPER_LID_RAISER_L = 0.0`  | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/upperLidRaiserL_front.png)`UPPER_LID_RAISER_L = 1.0`   |
| `UPPER_LID_RAISER_R`  | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`UPPER_LID_RAISER_R = 0.0`  | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/upperLidRaiserR_front.png)`UPPER_LID_RAISER_R = 1.0`   |

### Lower region blendshapes

|           Name           |                                                                                                                                              Reference Images                                                                                                                                               ||
|--------------------------|------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `CHEEK_PUFF_L`           | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHEEK_PUFF_L = 0.0`           | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/cheekPuffL_front.png)`CHEEK_PUFF_L = 1.0`                    |
| `CHEEK_PUFF_R`           | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHEEK_PUFF_R = 0.0`           | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/cheekPuffR_front.png)`CHEEK_PUFF_R = 1.0`                    |
| `CHEEK_RAISER_L`         | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHEEK_RAISER_L = 0.0`         | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/cheekRaiserL_front.png)`CHEEK_RAISER_L = 1.0`                |
| `CHEEK_RAISER_R`         | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHEEK_RAISER_R = 0.0`         | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/cheekRaiserR_front.png)`CHEEK_RAISER_R = 1.0`                |
| `CHEEK_SUCK_L`           | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHEEK_SUCK_L = 0.0`           | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/cheekSuckL_front.png)`CHEEK_SUCK_L = 1.0`                    |
| `CHEEK_SUCK_R`           | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHEEK_SUCK_R = 0.0`           | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/cheekSuckR_front.png)`CHEEK_SUCK_R = 1.0`                    |
| `CHIN_RAISER_B`          | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHIN_RAISER_B = 0.0`          | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/chinRaiserB_front.png)`CHIN_RAISER_B = 1.0`                  |
| `CHIN_RAISER_T`          | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`CHIN_RAISER_T = 0.0`          | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/chinRaiserT_front.png)`CHIN_RAISER_T = 1.0`                  |
| `DIMPLER_L`              | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`DIMPLER_L = 0.0`              | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/dimplerL_front.png)`DIMPLER_L = 1.0`                         |
| `DIMPLER_R`              | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`DIMPLER_R = 0.0`              | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/dimplerR_front.png)`DIMPLER_R = 1.0`                         |
| `JAW_DROP`               | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`JAW_DROP = 0.0`               | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/jawDrop_front.png)`JAW_DROP = 1.0`                           |
| `JAW_SIDEWAYS_LEFT`      | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`JAW_SIDEWAYS_LEFT = 0.0`      | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/jawSidewaysLeft_front.png)`JAW_SIDEWAYS_LEFT = 1.0`          |
| `JAW_SIDEWAYS_RIGHT`     | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`JAW_SIDEWAYS_RIGHT = 0.0`     | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/jawSidewaysRight_front.png)`JAW_SIDEWAYS_RIGHT = 1.0`        |
| `JAW_THRUST`             | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_threeQuarters.png)`JAW_THRUST = 0.0`     | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/jawThrust_threeQuarters.png)`JAW_THRUST = 1.0`               |
| `LIP_CORNER_DEPRESSOR_L` | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_CORNER_DEPRESSOR_L = 0.0` | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipCornerDepressorL_front.png)`LIP_CORNER_DEPRESSOR_L = 1.0` |
| `LIP_CORNER_DEPRESSOR_R` | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_CORNER_DEPRESSOR_R = 0.0` | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipCornerDepressorR_front.png)`LIP_CORNER_DEPRESSOR_R = 1.0` |
| `LIP_CORNER_PULLER_L`    | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_CORNER_PULLER_L = 0.0`    | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipCornerPullerL_front.png)`LIP_CORNER_PULLER_L = 1.0`       |
| `LIP_CORNER_PULLER_R`    | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_CORNER_PULLER_R = 0.0`    | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipCornerPullerR_front.png)`LIP_CORNER_PULLER_R = 1.0`       |
| `LIP_FUNNELER_LB`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_FUNNELER_LB = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipFunnelerLB_front.png)`LIP_FUNNELER_LB = 1.0`              |
| `LIP_FUNNELER_LT`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_FUNNELER_LT = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipFunnelerLT_front.png)`LIP_FUNNELER_LT = 1.0`              |
| `LIP_FUNNELER_RB`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_FUNNELER_RB = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipFunnelerRB_front.png)`LIP_FUNNELER_RB = 1.0`              |
| `LIP_FUNNELER_RT`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_FUNNELER_RT = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipFunnelerRT_front.png)`LIP_FUNNELER_RT = 1.0`              |
| `LIP_PRESSOR_L`          | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_PRESSOR_L = 0.0`          | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipPressorL_front.png)`LIP_PRESSOR_L = 1.0`                  |
| `LIP_PRESSOR_R`          | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_PRESSOR_R = 0.0`          | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipPressorR_front.png)`LIP_PRESSOR_R = 1.0`                  |
| `LIP_PUCKER_L`           | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_PUCKER_L = 0.0`           | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipPuckerL_front.png)`LIP_PUCKER_L = 1.0`                    |
| `LIP_PUCKER_R`           | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_PUCKER_R = 0.0`           | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipPuckerR_front.png)`LIP_PUCKER_R = 1.0`                    |
| `LIP_STRETCHER_L`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_STRETCHER_L = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipStretcherL_front.png)`LIP_STRETCHER_L = 1.0`              |
| `LIP_STRETCHER_R`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_STRETCHER_R = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipStretcherR_front.png)`LIP_STRETCHER_R = 1.0`              |
| `LIP_SUCK_LB`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_SUCK_LB = 0.0`            | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipSuckLB_front.png)`LIP_SUCK_LB = 1.0`                      |
| `LIP_SUCK_LT`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_SUCK_LT = 0.0`            | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipSuckLT_front.png)`LIP_SUCK_LT = 1.0`                      |
| `LIP_SUCK_RB`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_SUCK_RB = 0.0`            | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipSuckRB_front.png)`LIP_SUCK_RB = 1.0`                      |
| `LIP_SUCK_RT`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_SUCK_RT = 0.0`            | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipSuckRT_front.png)`LIP_SUCK_RT = 1.0`                      |
| `LIP_TIGHTENER_L`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_TIGHTENER_L = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipTightenerL_front.png)`LIP_TIGHTENER_L = 1.0`              |
| `LIP_TIGHTENER_R`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIP_TIGHTENER_R = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipTightenerR_front.png)`LIP_TIGHTENER_R = 1.0`              |
| `LIPS_TOWARD`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LIPS_TOWARD = 0.0`            | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lipsToward_front.png)`JAW_DROP = 1.0 and LIPS_TOWARD = 1.0`  |
| `LOWER_LIP_DEPRESSOR_L`  | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LOWER_LIP_DEPRESSOR_L = 0.0`  | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lowerLipDepressorL_front.png)`LOWER_LIP_DEPRESSOR_L = 1.0`   |
| `LOWER_LIP_DEPRESSOR_R`  | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`LOWER_LIP_DEPRESSOR_R = 0.0`  | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/lowerLipDepressorR_front.png)`LOWER_LIP_DEPRESSOR_R = 1.0`   |
| `MOUTH_LEFT`             | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`MOUTH_LEFT = 0.0`             | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/mouthLeft_front.png)`MOUTH_LEFT = 1.0`                       |
| `MOUTH_RIGHT`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`MOUTH_RIGHT = 0.0`            | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/mouthRight_front.png)`MOUTH_RIGHT = 1.0`                     |
| `NOSE_WRINKLER_L`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`NOSE_WRINKLER_L = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/noseWrinklerL_front.png)`NOSE_WRINKLER_L = 1.0`              |
| `NOSE_WRINKLER_R`        | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`NOSE_WRINKLER_R = 0.0`        | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/noseWrinklerR_front.png)`NOSE_WRINKLER_R = 1.0`              |
| `UPPER_LIP_RAISER_L`     | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`UPPER_LIP_RAISER_L = 0.0`     | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/upperLipRaiserL_front.png)`UPPER_LIP_RAISER_L = 1.0`         |
| `UPPER_LIP_RAISER_R`     | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)`UPPER_LIP_RAISER_R = 0.0`     | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/upperLipRaiserR_front.png)`UPPER_LIP_RAISER_R = 1.0`         |
| `TONGUE_OUT`             | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)TONGUE_OUT = 0.0               | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/tongueOut.png)TONGUE_OUT = 1.0                               |
| `TONGUE_LEFT`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)TONGUE_LEFT = 0.0              | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/tongueLeft.png)TONGUE_LEFT = 1.0                             |
| `TONGUE_RIGHT`           | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)TONGUE_RIGHT = 0.0             | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/tongueRight.png)TONGUE_RIGHT = 1.0                           |
| `TONGUE_UP`              | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)TONGUE_UP = 0.0                | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/tongueUp.png)TONGUE_UP = 1.0                                 |
| `TONGUE_DOWN`            | ![Neutral face reference image](https://developer.android.com/static/images/develop/xr/openxr/neutral_front.png)TONGUE_DOWN = 0.0              | ![face tracking reference image](https://developer.android.com/static/images/develop/xr/openxr/tongueDown.png)TONGUE_DOWN = 1.0                             |