使用 ARCore for Jetpack XR 在应用中加入面部跟踪功能

用户授予面部追踪权限后，您的应用可以通过 ARCore for Jetpack XR 检索面部形状信息。面部形状信息可帮助您的应用在虚拟世界中显示用户，例如用于虚拟试戴眼镜。

创建 ARCore for Jetpack XR 会话

通过 ARCore for Jetpack XR 会话获取头部姿态信息。请参阅了解会话的生命周期，以获取 Session。

配置会话

默认情况下，XR 会话中未启用人脸跟踪功能。如需启用人脸跟踪，请配置会话并设置 FaceTrackingMode.USER 模式：

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. */)
}FaceTracking.kt

检索人脸数据

使用 Face.getUserFace(session) 可检索用户面部数据，其中包含以下信息：

面部混合形状值：面部的可能表情是 68 个混合形状值的组合。每个混合形状值都表示一种面部运动或面部变形，该值表示其强度，范围从 0.0 到 1.0。如需了解每种混合形状类型的说明，请参阅了解面部混合形状类型。
各区域的置信度值：面部有三个区域。置信度值表示给定姿势的准确性确定程度，范围为 0.0 到 1.0，其中 1.0 表示置信度最高。

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]
}FaceTracking.kt

了解面部融合变形类型

下表列出了每种面部混合形状：

上半区域混合形状

名称	参考图片
`BROW_LOWERER_L`	`BROW_LOWERER_L = 0.0`	`BROW_LOWERER_L = 1.0`
`BROW_LOWERER_R`	`BROW_LOWERER_R = 0.0`	`BROW_LOWERER_R = 1.0`
`EYES_CLOSED_L`	`EYES_CLOSED_L = 0.0`	`EYES_CLOSED_L = 1.0`
`EYES_CLOSED_R`	`EYES_CLOSED_R = 0.0`	`EYES_CLOSED_R = 1.0`
`EYES_LOOK_DOWN_L`	`EYES_LOOK_DOWN_L = 0.0`	`EYES_LOOK_DOWN_L = 1.0`
`EYES_LOOK_DOWN_R`	`EYES_LOOK_DOWN_R = 0.0`	`EYES_LOOK_DOWN_R = 1.0`
`EYES_LOOK_LEFT_L`	`EYES_LOOK_LEFT_L = 0.0`	`EYES_LOOK_LEFT_L = 1.0`
`EYES_LOOK_LEFT_R`	`EYES_LOOK_LEFT_R = 0.0`	`EYES_LOOK_LEFT_R = 1.0`
`EYES_LOOK_RIGHT_L`	`EYES_LOOK_RIGHT_L = 0.0`	`EYES_LOOK_RIGHT_L = 1.0`
`EYES_LOOK_RIGHT_R`	`EYES_LOOK_RIGHT_R = 0.0`	`EYES_LOOK_RIGHT_R = 1.0`
`EYES_LOOK_UP_L`	`EYES_LOOK_UP_L = 0.0`	`EYES_LOOK_UP_L = 1.0`
`EYES_LOOK_UP_R`	`EYES_LOOK_UP_R = 0.0`	`EYES_LOOK_UP_R = 1.0`
`INNER_BROW_RAISER_L`	`INNER_BROW_RAISER_L = 0.0`	`INNER_BROW_RAISER_L = 1.0`
`INNER_BROW_RAISER_R`	`INNER_BROW_RAISER_R = 0.0`	`INNER_BROW_RAISER_R = 1.0`
`LID_TIGHTENER_L`	`LID_TIGHTENER_L = 0.0`	`LID_TIGHTENER_L = 1.0`
`LID_TIGHTENER_R`	`LID_TIGHTENER_R = 0.0`	`LID_TIGHTENER_R = 1.0`
`OUTER_BROW_RAISER_L`	`OUTER_BROW_RAISER_L = 0.0`	`OUTER_BROW_RAISER_L = 1.0`
`OUTER_BROW_RAISER_R`	`OUTER_BROW_RAISER_R = 0.0`	`OUTER_BROW_RAISER_R = 1.0`
`UPPER_LID_RAISER_L`	`UPPER_LID_RAISER_L = 0.0`	`UPPER_LID_RAISER_L = 1.0`
`UPPER_LID_RAISER_R`	`UPPER_LID_RAISER_R = 0.0`	`UPPER_LID_RAISER_R = 1.0`

下部区域混合形状

名称	参考图片
`CHEEK_PUFF_L`	`CHEEK_PUFF_L = 0.0`	`CHEEK_PUFF_L = 1.0`
`CHEEK_PUFF_R`	`CHEEK_PUFF_R = 0.0`	`CHEEK_PUFF_R = 1.0`
`CHEEK_RAISER_L`	`CHEEK_RAISER_L = 0.0`	`CHEEK_RAISER_L = 1.0`
`CHEEK_RAISER_R`	`CHEEK_RAISER_R = 0.0`	`CHEEK_RAISER_R = 1.0`
`CHEEK_SUCK_L`	`CHEEK_SUCK_L = 0.0`	`CHEEK_SUCK_L = 1.0`
`CHEEK_SUCK_R`	`CHEEK_SUCK_R = 0.0`	`CHEEK_SUCK_R = 1.0`
`CHIN_RAISER_B`	`CHIN_RAISER_B = 0.0`	`CHIN_RAISER_B = 1.0`
`CHIN_RAISER_T`	`CHIN_RAISER_T = 0.0`	`CHIN_RAISER_T = 1.0`
`DIMPLER_L`	`DIMPLER_L = 0.0`	`DIMPLER_L = 1.0`
`DIMPLER_R`	`DIMPLER_R = 0.0`	`DIMPLER_R = 1.0`
`JAW_DROP`	`JAW_DROP = 0.0`	`JAW_DROP = 1.0`
`JAW_SIDEWAYS_LEFT`	`JAW_SIDEWAYS_LEFT = 0.0`	`JAW_SIDEWAYS_LEFT = 1.0`
`JAW_SIDEWAYS_RIGHT`	`JAW_SIDEWAYS_RIGHT = 0.0`	`JAW_SIDEWAYS_RIGHT = 1.0`
`JAW_THRUST`	`JAW_THRUST = 0.0`	`JAW_THRUST = 1.0`
`LIP_CORNER_DEPRESSOR_L`	`LIP_CORNER_DEPRESSOR_L = 0.0`	`LIP_CORNER_DEPRESSOR_L = 1.0`
`LIP_CORNER_DEPRESSOR_R`	`LIP_CORNER_DEPRESSOR_R = 0.0`	`LIP_CORNER_DEPRESSOR_R = 1.0`
`LIP_CORNER_PULLER_L`	`LIP_CORNER_PULLER_L = 0.0`	`LIP_CORNER_PULLER_L = 1.0`
`LIP_CORNER_PULLER_R`	`LIP_CORNER_PULLER_R = 0.0`	`LIP_CORNER_PULLER_R = 1.0`
`LIP_FUNNELER_LB`	`LIP_FUNNELER_LB = 0.0`	`LIP_FUNNELER_LB = 1.0`
`LIP_FUNNELER_LT`	`LIP_FUNNELER_LT = 0.0`	`LIP_FUNNELER_LT = 1.0`
`LIP_FUNNELER_RB`	`LIP_FUNNELER_RB = 0.0`	`LIP_FUNNELER_RB = 1.0`
`LIP_FUNNELER_RT`	`LIP_FUNNELER_RT = 0.0`	`LIP_FUNNELER_RT = 1.0`
`LIP_PRESSOR_L`	`LIP_PRESSOR_L = 0.0`	`LIP_PRESSOR_L = 1.0`
`LIP_PRESSOR_R`	`LIP_PRESSOR_R = 0.0`	`LIP_PRESSOR_R = 1.0`
`LIP_PUCKER_L`	`LIP_PUCKER_L = 0.0`	`LIP_PUCKER_L = 1.0`
`LIP_PUCKER_R`	`LIP_PUCKER_R = 0.0`	`LIP_PUCKER_R = 1.0`
`LIP_STRETCHER_L`	`LIP_STRETCHER_L = 0.0`	`LIP_STRETCHER_L = 1.0`
`LIP_STRETCHER_R`	`LIP_STRETCHER_R = 0.0`	`LIP_STRETCHER_R = 1.0`
`LIP_SUCK_LB`	`LIP_SUCK_LB = 0.0`	`LIP_SUCK_LB = 1.0`
`LIP_SUCK_LT`	`LIP_SUCK_LT = 0.0`	`LIP_SUCK_LT = 1.0`
`LIP_SUCK_RB`	`LIP_SUCK_RB = 0.0`	`LIP_SUCK_RB = 1.0`
`LIP_SUCK_RT`	`LIP_SUCK_RT = 0.0`	`LIP_SUCK_RT = 1.0`
`LIP_TIGHTENER_L`	`LIP_TIGHTENER_L = 0.0`	`LIP_TIGHTENER_L = 1.0`
`LIP_TIGHTENER_R`	`LIP_TIGHTENER_R = 0.0`	`LIP_TIGHTENER_R = 1.0`
`LIPS_TOWARD`	`LIPS_TOWARD = 0.0`	`JAW_DROP = 1.0 and LIPS_TOWARD = 1.0`
`LOWER_LIP_DEPRESSOR_L`	`LOWER_LIP_DEPRESSOR_L = 0.0`	`LOWER_LIP_DEPRESSOR_L = 1.0`
`LOWER_LIP_DEPRESSOR_R`	`LOWER_LIP_DEPRESSOR_R = 0.0`	`LOWER_LIP_DEPRESSOR_R = 1.0`
`MOUTH_LEFT`	`MOUTH_LEFT = 0.0`	`MOUTH_LEFT = 1.0`
`MOUTH_RIGHT`	`MOUTH_RIGHT = 0.0`	`MOUTH_RIGHT = 1.0`
`NOSE_WRINKLER_L`	`NOSE_WRINKLER_L = 0.0`	`NOSE_WRINKLER_L = 1.0`
`NOSE_WRINKLER_R`	`NOSE_WRINKLER_R = 0.0`	`NOSE_WRINKLER_R = 1.0`
`UPPER_LIP_RAISER_L`	`UPPER_LIP_RAISER_L = 0.0`	`UPPER_LIP_RAISER_L = 1.0`
`UPPER_LIP_RAISER_R`	`UPPER_LIP_RAISER_R = 0.0`	`UPPER_LIP_RAISER_R = 1.0`
`TONGUE_OUT`	TONGUE_OUT = 0.0	TONGUE_OUT = 1.0
`TONGUE_LEFT`	TONGUE_LEFT = 0.0	TONGUE_LEFT = 1.0
`TONGUE_RIGHT`	TONGUE_RIGHT = 0.0	TONGUE_RIGHT = 1.0
`TONGUE_UP`	TONGUE_UP = 0.0	TONGUE_UP = 1.0
`TONGUE_DOWN`	TONGUE_DOWN = 0.0	TONGUE_DOWN = 1.0