SoGate: The sogate class is used to selectively copy values from input to output. this engine will forward values from the sogate::input field to the sogate::output field when the sogate::enable field is true.

SYNOPSIS

#include <Inventor/engines/SoGate.h>

Inherits SoEngine.

Public Member Functions

virtual SoType getTypeId (void) const

Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and 'downward' casting. virtual const SoFieldData * getFieldData (void) const

virtual const SoEngineOutputData * getOutputData (void) const

SoGate (SoType type)

Static Public Member Functions

static SoType getClassTypeId (void)

static void * createInstance (void)

static void initClass (void)

Public Attributes

SoSFBool enable

SoSFTrigger trigger

SoMField * input

SoEngineOutput * output

Protected Member Functions

virtual void inputChanged (SoField *which)

Static Protected Member Functions

static const SoFieldData ** getInputDataPtr (void)

static const SoEngineOutputData ** getOutputDataPtr (void)

Additional Inherited Members

Detailed Description

The SoGate class is used to selectively copy values from input to output.

This engine will forward values from the SoGate::input field to the SoGate::output field when the SoGate::enable field is TRUE.

Note that this engine's output field deviates a little from the 'standard' output mechanism of the majority of engine classes: the SoGate::output is not a permanent SoEngineOutput instance, but a pointer to a SoEngineOutput instance. The reason for this is that it is necessary to allocate the output field dynamically to make it match what the SoGate::input is connected to since the type of the SoGate::output always should be the same as the type of the SoGate::input.

The file format for this field is a bit special. Note the leading type specification, which is not necessary for most other field types:

Gate {
  type <multivaluefieldtype>
  [...fields...]
}

Constructor & Destructor Documentation

SoGate::SoGate (\fBSoType\fPtype)

Constructor. The type of the input/output is specified in type.

Member Function Documentation

virtual \fBSoType\fP SoGate::getTypeId (void) const\fC [virtual]\fP

Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and 'downward' casting. Usage example:

void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Implements SoBase.

virtual const \fBSoFieldData\fP* SoGate::getFieldData (void) const\fC [virtual]\fP

Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.

Reimplemented from SoFieldContainer.

virtual const \fBSoEngineOutputData\fP* SoGate::getOutputData (void) const\fC [virtual]\fP

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

Implements SoEngine.

void SoGate::inputChanged (\fBSoField\fP *which)\fC [protected]\fP, \fC [virtual]\fP

Called when an input is changed. The default method does nothing, but subclasses may override this method to do The Right Thing when a specific field is changed.

Reimplemented from SoEngine.

Member Data Documentation

\fBSoSFBool\fP SoGate::enable

Set whether or not to forward from input to output field.

\fBSoSFTrigger\fP SoGate::trigger

Copy the current values of the input field once to the output field.

\fBSoMField\fP * SoGate::input

The multivalue input field which we will forward to the output when SoGate::enable is TRUE.

\fBSoEngineOutput\fP * SoGate::output

(SoMField) This is the field output containing the values of SoGate::input.

The type of the field will of course match the type of the input field.

Author

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SoGate (3)