gruesensorimpl.cpp Example File

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 #include "gruesensorimpl.h"
 #include <QDebug>
 #include <QTimer>

 char const * const gruesensorimpl::id("grue.gruesensor");

 gruesensorimpl::gruesensorimpl(QSensor *sensor)
     : QSensorBackend(sensor)
 {
     // We need a light sensor
     lightSensor = new QAmbientLightSensor(this);
     connect(lightSensor, SIGNAL(readingChanged()), this, SLOT(lightChanged()));
     lightSensor->connectToBackend();

     // We need a timer
     darkTimer = new QTimer(this);
     darkTimer->setInterval(1000);
     connect(darkTimer, SIGNAL(timeout()), this, SLOT(increaseChance()));

     // We use this as our timestamp source
     timer.start();

     // Register our reading instance
     setReading<GrueSensorReading>(&m_reading);

     // Supply metadata
     // We can run as fast as the light sensor does
     setDataRates(lightSensor);
     // Only one output range, 0 to 1 in .1 increments
     addOutputRange(0, 1, 0.1);
     setDescription(QLatin1String("Grue Sensor"));
 }

 void gruesensorimpl::start()
 {
     lightSensor->setDataRate(sensor()->dataRate());
     lightSensor->start();
     // If the light sensor doesn't work we don't work either
     if (!lightSensor->isActive())
         sensorStopped();
     if (lightSensor->isBusy())
         sensorBusy();
 }

 void gruesensorimpl::stop()
 {
     lightSensor->stop();
 }

 void gruesensorimpl::lightChanged()
 {
     qreal chance = 0.0;
     darkTimer->stop();

     switch (lightSensor->reading()->lightLevel()) {
     case QAmbientLightReading::Dark:
         // It is dark. You are likely to be eaten by a grue.
         chance = 0.1;
         darkTimer->start();
         break;
     default:
         break;
     }

     // Only send an update if the value has changed.
     if (chance != m_reading.chanceOfBeingEaten() || m_reading.timestamp() == 0) {
         m_reading.setTimestamp(timer.elapsed());
         m_reading.setChanceOfBeingEaten(chance);

         newReadingAvailable();
     }
 }

 void gruesensorimpl::increaseChance()
 {
     // The longer you stay in the dark, the higher your chance of being eaten
     qreal chance = m_reading.chanceOfBeingEaten() + 0.1;

     m_reading.setTimestamp(timer.elapsed());
     m_reading.setChanceOfBeingEaten(chance);

     newReadingAvailable();

     // No point in using the timer anymore if we've hit 1... you can't get more
     // likely to be eaten than 100%
     if (chance == 1.0)
         darkTimer->stop();
 }