From 2cf098846c83bab82272f107ba110f7c47df1763 Mon Sep 17 00:00:00 2001
From: Mathias Agopian <mathias@google.com>
Date: Wed, 19 Jan 2011 14:26:25 -0800
Subject: [PATCH] fix [3369027] Sensor.TYPE_ROTATION_VECTOR is unstable and
 returns NaNs when running slowly

The cut-off frequency of the lowpass filter was too high
for the sampling rate used by DELAY_NORMAL.

Now we use the same filters used for the gravity vector
(cascaded biquad at 1.5 Hz)

Change-Id: I319dc4f449a3abd553d61b196a9ddcf7782f912d
---
 services/sensorservice/RotationVectorSensor.cpp | 4 ++--
 services/sensorservice/RotationVectorSensor.h   | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/services/sensorservice/RotationVectorSensor.cpp b/services/sensorservice/RotationVectorSensor.cpp
index 418e7f8d0..3abfc12bc 100644
--- a/services/sensorservice/RotationVectorSensor.cpp
+++ b/services/sensorservice/RotationVectorSensor.cpp
@@ -34,9 +34,9 @@ static inline T clamp(T v) {
 
 RotationVectorSensor::RotationVectorSensor(sensor_t const* list, size_t count)
     : mSensorDevice(SensorDevice::getInstance()),
-      mALowPass(M_SQRT1_2, 5.0f),
+      mALowPass(M_SQRT1_2, 1.5f),
       mAX(mALowPass), mAY(mALowPass), mAZ(mALowPass),
-      mMLowPass(M_SQRT1_2, 2.5f),
+      mMLowPass(M_SQRT1_2, 1.5f),
       mMX(mMLowPass), mMY(mMLowPass), mMZ(mMLowPass)
 {
     for (size_t i=0 ; i<count ; i++) {
diff --git a/services/sensorservice/RotationVectorSensor.h b/services/sensorservice/RotationVectorSensor.h
index b7c951274..17699f8a4 100644
--- a/services/sensorservice/RotationVectorSensor.h
+++ b/services/sensorservice/RotationVectorSensor.h
@@ -38,9 +38,9 @@ class RotationVectorSensor : public SensorInterface {
     double mAccTime;
     double mMagTime;
     SecondOrderLowPassFilter mALowPass;
-    BiquadFilter mAX, mAY, mAZ;
+    CascadedBiquadFilter mAX, mAY, mAZ;
     SecondOrderLowPassFilter mMLowPass;
-    BiquadFilter mMX, mMY, mMZ;
+    CascadedBiquadFilter mMX, mMY, mMZ;
 
 public:
     RotationVectorSensor(sensor_t const* list, size_t count);