使用 ARCore for Jetpack XR 在應用程式中加入臉部追蹤功能

使用者授予臉部追蹤權限後，應用程式就能透過 ARCore for Jetpack XR 擷取臉部形狀資訊。臉部形狀資訊可協助應用程式在虛擬世界中顯示使用者，例如虛擬試戴眼鏡。

建立 Jetpack XR 的 ARCore 工作階段

透過 Jetpack XR 工作階段的 ARCore 取得頭部姿勢資訊。請參閱「瞭解工作階段的生命週期」一文，取得 Session。

設定工作階段

XR 工作階段預設不會啟用臉部追蹤功能。如要啟用臉部追蹤功能，請設定工作階段並設定 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

擷取臉孔資料

使用 Face.getUserFace(session) 擷取使用者臉部資料，其中包含下列項目：

臉部混合形狀值：臉部可能出現的表情是68 個混合形狀值的組合。每個混合形狀值代表臉部動作或臉部變形，值則表示強度，範圍從 0.0 到 1.0。如要瞭解各類混合形狀，請參閱「瞭解臉部混合形狀類型」。
區域的信賴度值：臉部有三個區域。信賴度值表示指定姿勢的準確度確定程度，範圍從 0.0 到 1.0，其中 1.0 表示信賴度最高。

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

瞭解臉部混合形狀類型

下表列出每種臉部混合形狀類型：

上區域混合形狀

名稱	參考圖片
`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`

下半部區域混合形狀

名稱	參考圖片
`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