H3D::TimeSensor Class Reference
[X3D node classes.]

TimeSensor nodes generate events as time passes. More...

#include <H3D/TimeSensor.h>

Inheritance diagram for H3D::TimeSensor:

Inheritance graph

List of all members.

Classes

class  TimeHandler
 The TimeHandler field is specialized to include the handling of the TimeSensor specific fields. More...

Public Types

typedef StartTime CycleInterval
 The CycleInterval has the same conditions for update as the StartTime so use that field class definition.

Public Member Functions

 TimeSensor (Inst< SFNode > _metadata=0, Inst< SFBool > _loop=0, Inst< SFTime > _pauseTime=0, Inst< SFTime > _resumeTime=0, Inst< StartTime > _startTime=0, Inst< StopTime > _stopTime=0, Inst< SFTime > _elapsedTime=0, Inst< SFBool > _isActive=0, Inst< SFBool > _isPaused=0, Inst< TimeHandler > _timeHandler=0, Inst< CycleInterval > _cycleInterval=0, Inst< SFTime > _cycleTime=0, Inst< SFBool > _enabled=0, Inst< SFFloat > _fraction_changed=0, Inst< SFTime > _time=0)
 Constructor.

Public Attributes

auto_ptr< CycleIntervalcycleInterval
 The cycleInterval field defines how long a cycle lasts in seconds.
auto_ptr< SFTimecycleTime
 The cycleTime field sends a time event at startTime and at the beginning of each new cycle with the current time.
auto_ptr< SFBoolenabled
 If the enabled field is TRUE, the TimeSensor node is enabled and may be running, otherwise no field updates are made.
auto_ptr< SFFloatfraction_changed
 The fraction_changed field is the completed fraction of the current cycle, i.e.
auto_ptr< SFTimetime
 The time field sends the absolute time for a given simulation tick( i.e.

Static Public Attributes

static H3DNodeDatabase database
 The H3DNodeDatabase for this node.


Detailed Description

TimeSensor nodes generate events as time passes.

TimeSensor nodes can be used for many purposes including:

The TimeSensor node contains two discrete outputOnly fields: isActive and cycleTime. The isActive outputOnly field sends TRUE when the TimeSensor node begins running, and FALSE when it stops running. The cycleTime outputOnly field sends a time event at startTime and at the beginning of each new cycle (useful for synchronization with other time-based objects). The remaining outputOnly fields generate continuous events. The fraction_changed outputOnly field, an SFFloat in the closed interval [0,1], sends the completed fraction of the current cycle. The time outputOnly field sends the absolute time for a given simulation tick.

If the enabled field is TRUE, the TimeSensor node is enabled and may be running. If a set_enabled FALSE event is received while the TimeSensor node is running, the sensor performs the following actions:

Input events on the fields of the TimeSensor node (e.g., set_startTime) are processed and their corresponding outputOnly fields (e.g., startTime_changed) are sent regardless of the state of the enabled field. The remaining discussion assumes enabled is TRUE.

The "cycle" of a TimeSensor node lasts for cycleInterval seconds. The value of cycleInterval shall be greater than zero.

A cycleTime outputOnly field can be used for synchronization purposes such as sound with animation. The value of a cycleTime event will be equal to the time at the beginning of the current cycle. A cycleTime event is generated at the beginning of every cycle, including the cycle starting at startTime. The first cycleTime event for a TimeSensor node can be used as an alarm (single pulse at a specified time).

When a TimeSensor node becomes active, it generates an isActive = TRUE event and begins generating time, fraction_changed, and cycleTime events which may be routed to other nodes to drive animation or simulated behaviours. The behaviour at read time is described below. The time event sends the absolute time for a given tick of the TimeSensor node (SFTime/MFTime fields and events represent the number of seconds since midnight GMT January 1, 1970).

fraction_changed events output a floating point value in the closed interval [0, 1]. At startTime the value of fraction_changed is 0. After startTime, the value of fraction_changed in any cycle will progress through the range (0.0, 1.0]. At startTime + N cycleInterval, for N = 1, 2, ..., (i.e., at the end of every cycle), the value of fraction_changed is 1.

A TimeSensor node can be set up to be active at read time by specifying loop TRUE (not the default) and stopTime less than or equal to startTime (satisfied by the default values). The time events output absolute times for each tick of the TimeSensor node simulation. The time events shall start at the first simulation tick greater than or equal to startTime. time events end at stopTime, or at startTime + N cycleInterval for some positive integer value of N, or loop forever depending on the values of the other fields. An active TimeSensor node shall stop at the first simulation tick when now = stopTime > startTime.

No guarantees are made with respect to how often a TimeSensor node generates time events, but a TimeSensor node shall generate events at least at every simulation tick. TimeSensor nodes are guaranteed to generate final time and fraction_changed events. If loop is FALSE at the end of the Nth cycleInterval and was TRUE at startTime + M cycleInterval for all 0 < M < N, the final time event will be generated with a value of (startTime + N cycleInterval) or stopTime (if stopTime > startTime), whichever value is less. If loop is TRUE at the completion of every cycle, the final event is generated as evaluated at stopTime (if stopTime > startTime) or never.

An active TimeSensor node ignores set_cycleInterval and set_startTime events. An active TimeSensor node also ignores set_stopTime events for set_stopTime less than or equal to startTime. For example, if a set_startTime event is received while a TimeSensor node is active, that set_startTime event is ignored (the startTime field is not changed, and a startTime_changed event is not generated). If an active TimeSensor node receives a set_stopTime event that is less than the current time, and greater than startTime, it behaves as if the stopTime requested is the current time and sends the final events based on the current time (note that stopTime is set as specified in the field).

A TimeSensor read from a X3D file shall generate isActive TRUE, time and fraction_changed events if the sensor is enabled and all conditions for a TimeSensor to be active are met.


Member Typedef Documentation

typedef StartTime H3D::TimeSensor::CycleInterval

The CycleInterval has the same conditions for update as the StartTime so use that field class definition.


Member Data Documentation

The cycleInterval field defines how long a cycle lasts in seconds.

Access type: inputOutput
Default value: 1

Referenced by H3D::TimeSensor::TimeHandler::activate(), and H3D::TimeSensor::TimeHandler::update().

The cycleTime field sends a time event at startTime and at the beginning of each new cycle with the current time.

Access type: outputOnly

Referenced by H3D::TimeSensor::TimeHandler::activate(), and H3D::TimeSensor::TimeHandler::update().

If the enabled field is TRUE, the TimeSensor node is enabled and may be running, otherwise no field updates are made.

Access type: inputOutput
Default value: TRUE

Referenced by H3D::TimeSensor::TimeHandler::update().

The fraction_changed field is the completed fraction of the current cycle, i.e.

a value in the interval [0-1].

Access type: outputOnly

Referenced by H3D::TimeSensor::TimeHandler::activate(), and H3D::TimeSensor::TimeHandler::update().

The time field sends the absolute time for a given simulation tick( i.e.

for this scene-graph loop).

Access type: outputOnly

Referenced by H3D::TimeSensor::TimeHandler::activate(), and H3D::TimeSensor::TimeHandler::update().


The documentation for this class was generated from the following files:

Generated on Fri Nov 7 10:31:15 2008 for H3D API by  doxygen 1.5.7