NAME

       SoSensorManager -

       The SoSensorManager class handles the sensor queues.

       There are two major sensor types in Coin, 'delay' sensors and 'timer' sensors:

SYNOPSIS

       #include <Inventor/sensors/SoSensorManager.h>

   Public Member Functions
       SoSensorManager (void)
       ~SoSensorManager ()
       void insertDelaySensor (SoDelayQueueSensor *s)
       void insertTimerSensor (SoTimerQueueSensor *s)
       void removeDelaySensor (SoDelayQueueSensor *s)
       void removeTimerSensor (SoTimerQueueSensor *s)
       void setChangedCallback (void(*sensorQueueChangedCB)(void *), void *data)
       void rescheduleTimer (SoTimerSensor *s)
       void removeRescheduledTimer (SoTimerQueueSensor *s)
       void processDelayQueue (SbBool isidle)
       void processImmediateQueue (void)
       void processTimerQueue (void)
       SbBool isDelaySensorPending (void)
       SbBool isTimerSensorPending (SbTime &tm)
       void setDelaySensorTimeout (const SbTime &t)
       const SbTime & getDelaySensorTimeout (void)
       int doSelect (int nfds, void *readfds, void *writefds, void *exceptfds, struct timeval *userTimeOut)

Detailed Description

       The SoSensorManager class handles the sensor queues.

       There are two major sensor types in Coin, 'delay' sensors and 'timer' sensors:

       • Delay  sensors  trigger  when  the  application  is otherwise idle. In addition, to avoid starvation in
         applications that are continually busy, the delay-sensor queue also has a timeout which, when  reached,
         will empty the queue anyhow.
       • Timer sensors are set up to trigger at specific, absolute times.
       Each  of  these two types has its own queue, which is handled by the SoSensorManager. The queues are kept
       in sorted order by SoSensorManager, either according to trigger-time (for timer sensors) or  by  priority
       (for delay sensors).
       The  SoSensorManager provides methods for managing these queues, by insertion and removal of sensors, and
       processing (emptying) of the queues.
       The sensor mechanism is crucial in Coin for a  number  of  important  features,  most  notably  automatic
       scheduling redrawal upon changes, and for making it possible to set up animations in the scenegraph which
       does not need any additional book-keeping from the application code.
       SoSensorManager should usually be considered as an internal class in the Coin API. It is only interesting
       for  application  programmers when implementing new windowsystem-specific libraries (like Kongsberg Oil &
       Gas Technologies's SoQt, SoXt, SoGtk, SoWin or Sc21) or wrappers. Then one has to set up  code  to  empty
       the  queues  at the correct intervals. For detailed information on how to do that, we would advise you to
       look at the implementation of said mechanisms in the So*-libraries which SIM provides.
       Please note that before  Coin  2.3.1,  sensors  with  equal  priority  (or  the  same  trigger  time  for
       SoTimerQueue  sensors)  were  processed  LIFO.  This has now been changed to FIFO to be conformant to SGI
       Inventor.
       See Also:
           SoSensor SoTimerQueueSensor SoDelayQueueSensor
           SoTimerSensor SoAlarmSensor
           SoIdleSensor SoDataSensor SoOneShotSensor
           SoPathSensor SoFieldSensor SoNodeSensor

Constructor & Destructor Documentation

   SoSensorManager::SoSensorManager (void)
       Constructor.
   SoSensorManager::~SoSensorManager ()
       Destructor.

Member Function Documentation

   void SoSensorManager::insertDelaySensor (SoDelayQueueSensor *newentry)
       Add a new entry to the queue of delay sensors.
       See Also:
           removeFromQueue()
   void SoSensorManager::insertTimerSensor (SoTimerQueueSensor *newentry)
       Add a new entry to the timer queue of sensors. The queue will be sorted  in  order  of  supposed  trigger
       time.
       See Also:
           removeFromQueue()
   void SoSensorManager::removeDelaySensor (SoDelayQueueSensor *entry)
       Remove an entry from the queue of prioritized sensors.
       See Also:
           addToQueue()
   void SoSensorManager::removeTimerSensor (SoTimerQueueSensor *entry)
       Remove an entry from the queue of timer sensors.
   void SoSensorManager::setChangedCallback (void(*)(void *)func, void *data)
       For setting up a callback function to be invoked whenever any of the sensor queues are changed.
       This  callback  should  typically be responsible for updating the client-side mechanism which is used for
       processing the queues.
   void SoSensorManager::rescheduleTimer (SoTimerSensor *s)
       This API member is considered internal to the library, as it is not likely  to  be  of  interest  to  the
       application programmer.
   void SoSensorManager::removeRescheduledTimer (SoTimerQueueSensor *s)
       This  API  member  is  considered  internal  to the library, as it is not likely to be of interest to the
       application programmer.
   void SoSensorManager::processDelayQueue (SbBoolisidle)
       Trigger all delay queue entries in priority order.
       The isidle flag indicates whether or not the processing  happens  because  the  application  is  idle  or
       because the delay queue timeout was reached.
       A  delay  queue  sensor with priority > 0 can only be triggered once during a call to this function. If a
       delay sensor is rescheduled during processDelayQueue(), it is not processed  until  the  next  time  this
       function is called. This is done to avoid an infinite loop while processing the sensors.
       A delay queue sensor with priority 0 is called an immediate sensor.
       See Also:
           SoDB::setDelaySensorTimeout()
           SoSensorManager::processImmediateQueue()
   void SoSensorManager::processImmediateQueue (void)
       Process all immediate sensors (delay sensors with priority 0).
       Be  aware  that  you  might  risk  an  infinite loop using immediate sensors. Unlike delay queue sensors,
       immediate sensors can be rescheduled and triggered multiple times during immediate queue processing.
       See Also:
           SoDelayQueueSensor::setPriority()
   void SoSensorManager::processTimerQueue (void)
       Trigger all the timers which has expired.
   SbBool SoSensorManager::isDelaySensorPending (void)
       Returns TRUE if at least one delay sensor or  immediate  sensor  is  present  in  the  respective  queue,
       otherwise FALSE.
   SbBool SoSensorManager::isTimerSensorPending (SbTime &tm)
       Returns TRUE if at least one timer sensor is present in the queue, otherwise FALSE.
       If  sensors  are  pending, the time interval until the next one should be triggered will be put in the tm
       variable.
   void SoSensorManager::setDelaySensorTimeout (const SbTime &t)
       Delay sensors are usually triggered only when the system is idle. But when there are  continuous  updates
       to  the  scene  graph,  there's  a  possibility  that  the  delay queue will starve and sensors are never
       triggered. To make sure this won't happen, this is a timeout value for the delay queue. When this timeout
       has been reached, the sensors in the delay queue gets processed before other  sensors  and  events.  This
       method will let the user set this timeout value.
       The default value is 1/12 of a second.
       Specifying a zero time will disable the timeout, opening for potential delay queue starvation.
       See Also:
           getDelaySensorTimeout(), SoDelayQueueSensor
   const SbTime & SoSensorManager::getDelaySensorTimeout (void)
       Returns the timeout value for sensors in the delay queue.
       See Also:
           setDelaySensorTimeout(), SoDelayQueueSensor
   int  SoSensorManager::doSelect  (intnfds,  void  *readfds,  void  *writefds,  void *exceptfds, struct timeval
       *userTimeOut)
       NOTE: THIS METHOD IS OBSOLETED. DON'T USE IT.
       This is a wrapper around the standard select(2) call, which will make sure the sensor queues are  updated
       while waiting for any action to happen on the given file descriptors.
       The void* arguments must be valid pointers to fd_set structures. We've changed this from the original SGI
       Inventor API to avoid messing up the header file with system-specific includes.
       NOTE: THIS METHOD IS OBSOLETED. DON'T USE IT.

Author

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Version 4.0.0a                                   Wed Feb 26 2014                              SoSensorManager(3)