Add TiltSensor to QtMobility.sensors 1.3

This has been adapted from the TiltSensor type in QtSensors 5.0
import but the code there has been split into multiple pieces.

There's a C++ class, a generic backend
and a QML interface.

Change-Id: Ic09465a5f76250a02a13938abe4789958137376f
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

4 files changed, 270 insertions, 2 deletions

diff --git a/src/plugins/sensors/generic/generic.pro b/src/plugins/sensors/generic/generic.pro
index d5c9e531..22d7c133 100644
--- a/src/plugins/sensors/generic/generic.pro
+++ b/src/plugins/sensors/generic/generic.pro
@@ -7,12 +7,14 @@ DESTDIR = $$QT.sensors.plugins/sensors
 
 HEADERS += genericorientationsensor.h\
            genericrotationsensor.h\
-           genericalssensor.h
+           genericalssensor.h\
+           generictiltsensor.h
 
 SOURCES += genericorientationsensor.cpp\
            main.cpp\
            genericrotationsensor.cpp\
-           genericalssensor.cpp
+           genericalssensor.cpp\
+           generictiltsensor.cpp
 
 OTHER_FILES = plugin.json
 
diff --git a/src/plugins/sensors/generic/generictiltsensor.cpp b/src/plugins/sensors/generic/generictiltsensor.cpp
new file mode 100644
index 00000000..df07355d
--- /dev/null
+++ b/src/plugins/sensors/generic/generictiltsensor.cpp
@@ -0,0 +1,181 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtSensors module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "generictiltsensor.h"
+#include <QDebug>
+#define _USE_MATH_DEFINES
+#include <qmath.h>
+
+char const * const GenericTiltSensor::id("generic.tilt");
+
+GenericTiltSensor::GenericTiltSensor(QSensor *sensor)
+    : QSensorBackend(sensor)
+    , radAccuracy(M_PI / 180)
+    , pitch(0)
+    , roll(0)
+    , calibratedPitch(0)
+    , calibratedRoll(0)
+{
+    accelerometer = new QAccelerometer(this);
+    accelerometer->addFilter(this);
+    accelerometer->connectToBackend();
+
+    setReading<QTiltReading>(&m_reading);
+    setDataRates(accelerometer);
+}
+
+void GenericTiltSensor::start()
+{
+    accelerometer->setDataRate(sensor()->dataRate());
+    accelerometer->setAlwaysOn(sensor()->isAlwaysOn());
+    accelerometer->start();
+    if (!accelerometer->isActive())
+        sensorStopped();
+    if (accelerometer->isBusy())
+        sensorBusy();
+}
+
+void GenericTiltSensor::stop()
+{
+    accelerometer->stop();
+}
+
+/*
+  Angle between Ground and X
+                |            Ax           |
+  pitch = arctan| ----------------------- |
+                |  sqrt(Ay * Ay + Az * Az)|
+*/
+static inline qreal calcPitch(double Ax, double Ay, double Az)
+{
+    return -qAtan2(Ax, sqrt(Ay * Ay + Az * Az));
+}
+
+/*
+  Angle between Ground and Y
+                |            Ay           |
+   roll = arctan| ----------------------- |
+                |  sqrt(Ax * Ax + Az * Az)|
+*/
+static inline qreal calcRoll(double Ax, double Ay, double Az)
+{
+    return qAtan2(Ay, (sqrt(Ax * Ax + Az * Az)));
+}
+
+void GenericTiltSensor::calibrate()
+{
+    calibratedPitch = pitch;
+    calibratedRoll = roll;
+}
+
+bool GenericTiltSensor::filter(QAccelerometerReading *reading)
+{
+    /*
+      z  y
+      | /
+      |/___ x
+    */
+
+    qreal ax = reading->x();
+    qreal ay = reading->y();
+    qreal az = reading->z();
+#ifdef LOGCALIBRATION
+    qDebug() << "------------ new value -----------";
+    qDebug() << "old _pitch: " << _pitch;
+    qDebug() << "old _roll: " << _roll;
+    qDebug() << "_calibratedPitch: " << _calibratedPitch;
+    qDebug() << "_calibratedRoll: " << _calibratedRoll;
+#endif
+    pitch = calcPitch(ax, ay, az);
+    roll  = calcRoll (ax, ay, az);
+#ifdef LOGCALIBRATION
+    qDebug() << "_pitch: " << _pitch;
+    qDebug() << "_roll: " << _roll;
+#endif
+    qreal xrot = roll - calibratedRoll;
+    qreal yrot = pitch - calibratedPitch;
+    //get angle beteen 0 and 180 or 0 -180
+    qreal aG = 1 * sin(xrot);
+    qreal aK = 1 * cos(xrot);
+    xrot = qAtan2(aG, aK);
+    if (xrot > M_PI_2)
+        xrot = M_PI - xrot;
+    else if (xrot < -M_PI_2)
+        xrot = -(M_PI + xrot);
+    aG = 1 * sin(yrot);
+    aK = 1 * cos(yrot);
+    yrot = qAtan2(aG, aK);
+    if (yrot > M_PI_2)
+        yrot = M_PI - yrot;
+    else if (yrot < -M_PI_2)
+        yrot = -(M_PI + yrot);
+
+
+#ifdef LOGCALIBRATION
+    qDebug() << "new xrot: " << xrot;
+    qDebug() << "new yrot: " << yrot;
+    qDebug() << "----------------------------------";
+#endif
+    qreal dxrot = xrot - xRotation;
+    qreal dyrot = yrot - yRotation;
+    if (dxrot < 0) dxrot = -dxrot;
+    if (dyrot < 0) dyrot = -dyrot;
+
+    bool change = false;
+    if (dxrot >= radAccuracy){
+        xRotation = xrot;
+        change = true;
+    }
+    if (dyrot >= radAccuracy){
+        yRotation = yrot;
+        change = true;
+    }
+    if (xRotation != m_reading.xRotation()
+            || yRotation != m_reading.yRotation()
+            || m_reading.timestamp() == 0) {
+        m_reading.setTimestamp(reading->timestamp());
+        m_reading.setXRotation(xRotation);
+        m_reading.setYRotation(yRotation);
+        newReadingAvailable();
+    }
+
+    return false;
+}
diff --git a/src/plugins/sensors/generic/generictiltsensor.h b/src/plugins/sensors/generic/generictiltsensor.h
new file mode 100644
index 00000000..0633662c
--- /dev/null
+++ b/src/plugins/sensors/generic/generictiltsensor.h
@@ -0,0 +1,83 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtSensors module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef GENERICTILTSENSOR_H
+#define GENERICTILTSENSOR_H
+
+#include <qsensorbackend.h>
+#include <qtiltsensor.h>
+#include <qaccelerometer.h>
+
+QT_BEGIN_HEADER
+QT_BEGIN_NAMESPACE
+
+class GenericTiltSensor : public QSensorBackend, public QAccelerometerFilter
+{
+public:
+
+    static char const * const id;
+
+    GenericTiltSensor(QSensor *sensor);
+
+    void start();
+    void stop();
+
+    void calibrate();
+
+    bool filter(QAccelerometerReading *reading);
+
+private:
+    QTiltReading m_reading;
+    QAccelerometer *accelerometer;
+    qreal radAccuracy;
+    qreal pitch;
+    qreal roll;
+    qreal calibratedPitch;
+    qreal calibratedRoll;
+    qreal xRotation;
+    qreal yRotation;
+};
+
+QT_END_NAMESPACE
+QT_END_HEADER
+
+#endif
+
diff --git a/src/plugins/sensors/generic/main.cpp b/src/plugins/sensors/generic/main.cpp
index eb54158d..c4554890 100644
--- a/src/plugins/sensors/generic/main.cpp
+++ b/src/plugins/sensors/generic/main.cpp
@@ -70,6 +70,8 @@ public:
                 QSensorManager::registerBackend(QRotationSensor::type, genericrotationsensor::id, this);
             if (!QSensorManager::isBackendRegistered(QAmbientLightSensor::type, genericalssensor::id))
                 QSensorManager::registerBackend(QAmbientLightSensor::type, genericalssensor::id, this);
+            if (!QSensorManager::isBackendRegistered(QAmbientLightSensor::type, genericalssensor::id))
+                QSensorManager::registerBackend(QAmbientLightSensor::type, genericalssensor::id, this);
         } else {
             if (QSensorManager::isBackendRegistered(QOrientationSensor::type, genericorientationsensor::id))
                 QSensorManager::unregisterBackend(QOrientationSensor::type, genericorientationsensor::id);