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)
      , lightLevel(QAmbientLightReading::Undefined)
  {
      // 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()
  {
      if (lightLevel == lightSensor->reading()->lightLevel())
          return;

      lightLevel = lightSensor->reading()->lightLevel();

      int chance = 0;
      darkTimer->stop();

      switch (lightSensor->reading()->lightLevel()) {
      case QAmbientLightReading::Dark:
          // It is dark. You are likely to be eaten by a grue.
          chance = 10;
          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
      int chance = m_reading.chanceOfBeingEaten() + 10;

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

      newReadingAvailable();

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