6.4. Defining the Constructor

Implement the constructor for the class. Begin with the macro SO_ENGINE_CONSTRUCTOR(). Then use the macros SO_ENGINE_ADD_INPUT() and SO_ENGINE_ADD_OUTPUT() to add the engine inputs and outputs and to set default values for the outputs. Perform any other class-specific initialization, if needed. For example:

C++

SoOnOff::SoOnOff()
   {
      SO_ENGINE_CONSTRUCTOR(SoOnOff);
      SO_ENGINE_ADD_INPUT(on, ());     // no default value for
                                       // trigger fields
      SO_ENGINE_ADD_INPUT(off, ());    // no default value
      SO_ENGINE_ADD_INPUT(toggle, ()); // no default value
      SO_ENGINE_ADD_OUTPUT(isOn, SoSFBool);
      SO_ENGINE_ADD_OUTPUT(isOff, SoSFBool);
      state = FALSE;             // engine is off by default
   }

Notice that this is where the outputs are bound to a particular field type.

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6.3. Initializing the Engine Class	Home	6.5. Implementing an evaluate() Method