Qt 5.9 | Qt Sensors | Qt Sensors - Grue Sensor Example | gruesensorimpl.cpp Example File

Qt 5.9.9 Reference Documentation

# gruesensorimpl.cpp Example File

grue/plugin/gruesensorimpl.cpp

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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();
      }