Audiolevels Example

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Data Visualization module of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:GPL$
 ** 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 General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 3 or (at your option) 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.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-3.0.html.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "audiolevelsiodevice.h"
 #include "audiolevels.h"

 #include <QtDataVisualization/qbardataproxy.h>
 #include <QtDataVisualization/qvalue3daxis.h>
 #include <QtDataVisualization/q3dscene.h>
 #include <QtDataVisualization/q3dcamera.h>
 #include <QtDataVisualization/qbar3dseries.h>
 #include <QtDataVisualization/q3dtheme.h>
 #include <QtDataVisualization/qcustom3dlabel.h>

 #include <QtMultimedia/QAudioDeviceInfo>
 #include <QtMultimedia/QAudioInput>

 using namespace QtDataVisualization;

 AudioLevels::AudioLevels(Q3DBars *graph, QObject *parent)
     : QObject(parent),
       m_graph(graph),
       m_device(0),
       m_audioInput(0)
 {
     // Set up the graph
     m_graph->setBarThickness(0.5f);
     m_graph->setBarSpacing(QSizeF(0.0, 1.0));
     m_graph->valueAxis()->setRange(-100.0f, 100.0f);
     m_graph->valueAxis()->setSegmentCount(20);
     m_graph->valueAxis()->setLabelFormat(QStringLiteral("%d%%"));
     m_graph->setShadowQuality(QAbstract3DGraph::ShadowQualityNone);
     m_graph->setSelectionMode(QAbstract3DGraph::SelectionNone);
     m_graph->scene()->activeCamera()->setCameraPosition(-25.0f, 10.0f, 190.0f);
     m_graph->activeTheme()->setType(Q3DTheme::ThemeIsabelle);
     m_graph->activeTheme()->setGridEnabled(true);
     m_graph->activeTheme()->setBackgroundEnabled(false);
     QFont font = m_graph->activeTheme()->font();
     font.setPointSize(10);
     m_graph->activeTheme()->setFont(font);
     QBar3DSeries *series = new QBar3DSeries;
     series->setMesh(QAbstract3DSeries::MeshBar);
     m_graph->addSeries(series);

     QAudioDeviceInfo inputDevice = QAudioDeviceInfo::defaultInputDevice();

     if (inputDevice.supportedSampleRates().size() > 0
             && inputDevice.supportedChannelCounts().size() > 0
             && inputDevice.supportedSampleSizes().size() > 0
             && inputDevice.supportedCodecs().size() > 0) {
         QAudioFormat formatAudio;
         formatAudio.setSampleRate(inputDevice.supportedSampleRates().at(0));
         formatAudio.setChannelCount(inputDevice.supportedChannelCounts().at(0));
         formatAudio.setSampleSize(inputDevice.supportedSampleSizes().at(0));
         formatAudio.setCodec(inputDevice.supportedCodecs().at(0));
         formatAudio.setByteOrder(QAudioFormat::LittleEndian);
         formatAudio.setSampleType(QAudioFormat::UnSignedInt);

         m_audioInput = new QAudioInput(inputDevice, formatAudio, this);
 #ifdef Q_OS_MAC
         // OS X seems to wait for entire buffer to fill before calling writeData, so use smaller buffer
         m_audioInput->setBufferSize(256);
 #else
         m_audioInput->setBufferSize(1024);
 #endif

         m_device = new AudioLevelsIODevice(m_graph->seriesList().at(0)->dataProxy(), this);
         m_device->open(QIODevice::WriteOnly);

         m_audioInput->start(m_device);
     } else {
         // No graph content can be shown, so add a custom warning label
         QCustom3DLabel *titleLabel = new QCustom3DLabel("No valid audio input device found",
                                                         QFont(),
                                                         QVector3D(0.2f, 0.2f, 0.0f),
                                                         QVector3D(1.0f, 1.0f, 0.0f),
                                                         QQuaternion());
         titleLabel->setPositionAbsolute(true);
         titleLabel->setFacingCamera(true);
         m_graph->addCustomItem(titleLabel);
     }
 }

 AudioLevels::~AudioLevels()
 {
     if (m_audioInput)
         m_audioInput->stop();
     if (m_device)
         m_device->close();
 }