implement_torque3d_callback.cpp

// Torque3D example of how to intercept a callback in code.
// Callbacks in Torque3D are declared by the DECLARE_CALLBACK macro, and are implemented by IMPLEMENT_CALLBACK.
// Usually they invoke a function in TorqueScript, but there is also an option to invoke a function via a function pointer which
// can be obtained from mAddress in the relevant EngineFunctionInfo.
//
// You must add the following in EngineFunctionInfo:
// 
//    void* getAddress() { return mAddress; }
//


// Our callback function. This will override the console callback
class GuiButtonBase;
void myOnClick(GuiButtonBase *button)
{
   Con::printf("Override onClick\n");
}

// Example function which overrides the GuiButtonBaseCtrl::onClick callback
DefineEngineFunction( TestCallbackAssign, void, (),,"")
{
   // Find a useful export
   EngineExportScope * scope = EngineExportScope::getGlobalScope();
   for (EngineExport *theExport = scope->getExports(); theExport; theExport = theExport->getNextExport())
   {
      if (theExport->getExportKind() == EngineExportKindType)
      {
         EngineTypeInfo *typeInfo = static_cast<EngineTypeInfo*>(theExport);

         if (typeInfo->isClass())
         {
            // We have a class. Look for the callback we need in the class scope
            EngineExportScope * classScope = static_cast<EngineExportScope*>(theExport);
            for (EngineExport *theSubExport = classScope->getExports(); theSubExport; theSubExport = theSubExport->getNextExport())
            {
               if (dStrcmp(theSubExport->getFullyQualifiedExportName().utf8(), "GuiButtonBaseCtrl::onClick") == 0)
               {
                  // Found the function we want. Now all we need to do is assign the address to the myOnClick callback
                  EngineFunctionInfo *function = static_cast<EngineFunctionInfo*>(theSubExport);
                  void **addr = (void**)function->getAddress();
                  *addr = &myOnClick;
               }
            }
         }
      }
   }
}