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//

// Class Description:
//
// G4VUserVisAction is brought into effect by the command
// /vis/scene/add/userAction. The vis manager instantiates a
// G4CallbackModel when the vis action is registered, and adds
// it to the scene. The pure virtual Draw() method
// is invoked whenever the viewer needs to "visit the kernel", e.g.,
// to remake its graphical database, if any, or simply to refresh the
// screen. It is not intended to be called directly. It is called
// via the operator() which is defined to satisfy the template
// G4CallbackModel<G4VUserVisAction>.
//
// A concrete Draw() method would normally make use of the Draw() methods
// of the vis manager, e.g:
//   G4VVisManager* pVisManager = G4VVisManager::GetConcreteInstance();
//   if (pVisManager) {
//     pVisManager->Draw(G4Box("box",2*cm,2*cm,2*cm),
//                       G4VisAttributes(G4Colour(1,1,0)));
//   ...
// but it can also use pointers fpSceneHandler and pMP that give it
// direct access to the current scene handler and modeling parameters
// for more advanced use.
//
// See the User Guide for Application Developers.

#ifndef G4VUSERVISACTION_HH
#define G4VUSERVISACTION_HH

class G4VGraphicsScene;
class G4ModelingParameters;

class G4VUserVisAction
{
public: // With description
  G4VUserVisAction(): fpSceneHandler(nullptr), fpMP(nullptr) {}
  virtual ~G4VUserVisAction() {}
  void operator()(G4VGraphicsScene& scene, const G4ModelingParameters* pMP) {
    fpSceneHandler = &scene;
    fpMP           = pMP;
    Draw();
  }
protected:
  virtual void Draw() = 0;
  G4VGraphicsScene* fpSceneHandler;
  const G4ModelingParameters* fpMP;
};

#endif