From f58a2b9cd982a6a761deaa05b3d3e9802df040c3 Mon Sep 17 00:00:00 2001
From: Sunny Goyal <sunnygoyal@google.com>
Date: Thu, 30 Jul 2020 14:40:29 -0700
Subject: [PATCH] Fixing wrong velocity state when there are too few samples

Bug: 160568387
Change-Id: I32b3b7ee1bff5595941fc0c0b37c9f5a28d1a1fa
(cherry picked from commit 48afb6b3b9f5a4d67e36a7c6cc994efeb8b9be38)
---
 .../quickstep/util/MotionPauseDetector.java   | 25 +++++++++++--------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/quickstep/src/com/android/quickstep/util/MotionPauseDetector.java b/quickstep/src/com/android/quickstep/util/MotionPauseDetector.java
index a5d456878a..969fa5067d 100644
--- a/quickstep/src/com/android/quickstep/util/MotionPauseDetector.java
+++ b/quickstep/src/com/android/quickstep/util/MotionPauseDetector.java
@@ -358,18 +358,23 @@ public class MotionPauseDetector {
 
             if (count < 3) {
                 // Too few samples
-                if (count == 2) {
-                    int endPos = pointPos - 1;
-                    if (endPos < 0) {
-                        endPos += HISTORY_SIZE;
-                    }
-                    float denominator = eventTime - mHistoricTimes[endPos];
-                    if (denominator != 0) {
-                        return (eventTime - mHistoricPos[endPos]) / denominator;
-
+                switch (count) {
+                    case 2: {
+                        int endPos = pointPos - 1;
+                        if (endPos < 0) {
+                            endPos += HISTORY_SIZE;
+                        }
+                        float denominator = eventTime - mHistoricTimes[endPos];
+                        if (denominator != 0) {
+                            return (mHistoricPos[pointPos] - mHistoricPos[endPos]) / denominator;
+                        }
                     }
+                    // fall through
+                    case 1:
+                        return 0f;
+                    default:
+                        return null;
                 }
-                return null;
             }
 
             float Sxx = sxi2 - sxi * sxi / count;