Say hello to Qt Android Sensors based on NDK API

Until Qt 5.9, we had to use JNI way because the NDK sensors API was
introduced in API-16. Starting with Qt 5.9 we can safely use the NDK API
as API_16 is the minimum API supported by Qt.
Using the NDK API instead of JNI boost the performance a lot! The CPU
usage dropped 2 to 4 times, from over 60% using the JNI to less than
20%.

[ChangeLog][Android] Rewrite Qt Android Sensors using NDK
API.

Change-Id: If3e3f1e56973e2a189662912b2a6ebfbd71dee14
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/src/plugins/sensors/android/androidgyroscope.cpp b/src/plugins/sensors/android/androidgyroscope.cpp
new file mode 100644
index 0000000..2a38b5a
--- /dev/null
+++ b/src/plugins/sensors/android/androidgyroscope.cpp
@@ -0,0 +1,64 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 BogDan Vatra <bogdan@kde.org>
+** Contact: https://www.qt.io/licensing/
+**
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "androidgyroscope.h"
+#include <QtCore/qmath.h>
+
+AndroidGyroscope::AndroidGyroscope(int type, QSensor *sensor, QObject *parent)
+    : SensorEventQueue<QGyroscopeReading>(type, sensor, parent)
+{}
+
+void AndroidGyroscope::dataReceived(const ASensorEvent &event)
+{
+    // check https://developer.android.com/reference/android/hardware/SensorEvent.html#sensor.type_gyroscope:
+    const auto &vec = event.vector;
+    qreal x = qRadiansToDegrees(qreal(vec.x));
+    qreal y = qRadiansToDegrees(qreal(vec.y));
+    qreal z = qRadiansToDegrees(qreal(vec.z));
+    if (sensor()->skipDuplicates() && qFuzzyCompare(m_reader.x(), x) &&
+            qFuzzyCompare(m_reader.y(), y) &&
+            qFuzzyCompare(m_reader.z(), z)) {
+        return;
+    }
+    m_reader.setTimestamp(uint64_t(event.timestamp / 1000));
+    m_reader.setX(x);
+    m_reader.setY(y);
+    m_reader.setZ(z);
+    newReadingAvailable();
+}