allow rotation-vector to have 4 components

- upadte documentation for rotation vector
- update method dealing with rotation vector to deal with 4 components
- virtual rotation-vector sensor reports all four components
- improve SensorManager documentation layout

Whent he 4-th component of the rotation-vector is present, we can save
a square-root when computing the quaternion or rotation matrix from it.

Change-Id: Ia84d278dd5f0909fab1c5ba050f8df2679e2c7c8

1 files changed, 1 insertions, 0 deletions

diff --git a/services/sensorservice/RotationVectorSensor.cpp b/services/sensorservice/RotationVectorSensor.cpp
index eecf260..50cd6be 100644
--- a/services/sensorservice/RotationVectorSensor.cpp
+++ b/services/sensorservice/RotationVectorSensor.cpp
@@ -125,6 +125,7 @@ bool RotationVectorSensor::process(sensors_event_t* outEvent,
         outEvent->data[0] = qx;
         outEvent->data[1] = qy;
         outEvent->data[2] = qz;
+        outEvent->data[3] = qw;
         outEvent->sensor = '_rov';
         outEvent->type = SENSOR_TYPE_ROTATION_VECTOR;
         return true;