Smoother skeleton

app/src/main/java/com/example/jnicpp/bowling/PoseAnalyzer.kt

@@ -5,7 +5,6 @@ import androidx.camera.core.ExperimentalGetImage
 import androidx.camera.core.ImageAnalysis
 import androidx.camera.core.ImageProxy
 import com.google.mlkit.vision.common.InputImage
-import com.google.mlkit.vision.pose.Pose
 import com.google.mlkit.vision.pose.PoseDetection
 import com.google.mlkit.vision.pose.PoseDetector
 import com.google.mlkit.vision.pose.accurate.AccuratePoseDetectorOptions
@@ -39,10 +38,13 @@ class PoseAnalyzer(
      * map it from analysis-image pixels to view pixels, plus the joint
      * angles derived from that same pose (see [PoseAngleCalculator]) so
      * downstream consumers (overlay text, future frame-by-frame logging)
-     * don't need to recompute them from [pose] themselves.
+     * don't need to recompute them from [landmarks] themselves. [landmarks]
+     * is already smoothed across frames (see [PoseLandmarkSmoother]) rather
+     * than raw ML Kit output, so anything drawn straight from it doesn't
+     * need to smooth it again.
      */
     data class PoseFrameResult(
-        val pose: Pose,
+        val landmarks: Map<Int, SmoothedLandmark>,
         val imageWidth: Int,
         val imageHeight: Int,
         val rotationDegrees: Int,
@@ -56,6 +58,12 @@ class PoseAnalyzer(
             .build()
     )
 
+    // One smoother per analyzer instance -- a fresh PoseAnalyzer (see
+    // CameraXController.bindToLifecycle) means a fresh detection stream, so
+    // its smoothing state should start clean rather than lerping in from
+    // whatever pose the previous stream last saw.
+    private val landmarkSmoother = PoseLandmarkSmoother()
+
     // STRATEGY_KEEP_ONLY_LATEST on the ImageAnalysis use case (see
     // CameraXController) already ensures we're never handed a backlog, but
     // this guards against overlapping calls if the detector ever falls
@@ -85,16 +93,17 @@ class PoseAnalyzer(
 
         detector.process(inputImage)
             .addOnSuccessListener { pose ->
+                val landmarks = landmarkSmoother.smooth(pose)
                 onResult(
                     PoseFrameResult(
-                        pose = pose,
+                        landmarks = landmarks,
                         imageWidth = width,
                         imageHeight = height,
                         rotationDegrees = rotationDegrees,
                         isFrontCamera = frontCamera,
                         // Cheap (four atan2 pairs at most), safe to compute
                         // on every frame right alongside the detection result.
-                        angles = PoseAngleCalculator.compute(pose)
+                        angles = PoseAngleCalculator.compute(landmarks)
                     )
                 )
             }