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// $Id: G4XXXSGViewer.cc,v 1.4 2006/08/29 16:11:25 allison Exp $
// GEANT4 tag $Name:  $
//
// 
// John Allison  10th March 2006
// A template for a sophisticated graphics driver with a scene graph.
//?? Lines beginning like this require specialisation for your driver.

#ifdef G4VIS_BUILD_XXXSG_DRIVER

#include "G4XXXSGViewer.hh"

#include "G4VSceneHandler.hh"
#include "G4XXXSGSceneHandler.hh"

#include <fstream>

G4XXXSGViewer::G4XXXSGViewer
(G4VSceneHandler& sceneHandler, const G4String& name):
  G4VViewer(sceneHandler, sceneHandler.IncrementViewCount(), name)
{}

G4XXXSGViewer::~G4XXXSGViewer() {}

void G4XXXSGViewer::SetView() {
  //#ifdef G4XXXSGDEBUG
  G4cout << "G4XXXSGViewer::SetView() called." << G4endl;
  //#endif
}

void G4XXXSGViewer::ClearView() {
  //#ifdef G4XXXSGDEBUG
  G4cout << "G4XXXSGViewer::ClearView() called." << G4endl;
  //#endif
}

void G4XXXSGViewer::DrawView() {
  //#ifdef G4XXXSGDEBUG
  G4cout << "G4XXXSGViewer::DrawView() called." << G4endl;
  //#endif

  // First, a view should decide when to re-visit the G4 kernel.
  // Sometimes it might not be necessary, e.g., if the scene is stored
  // in a graphical database (e.g., OpenGL's display lists) and only
  // the viewing angle has changed.  But graphics systems without a
  // graphical database will always need to visit the G4 kernel.

  // The fNeedKernelVisit flag might have been set by the user in
  // /vis/viewer/rebuild, but if not, make decision and set flag only
  // if necessary...
  if (!fNeedKernelVisit) KernelVisitDecision();
  G4bool kernelVisitWasNeeded = fNeedKernelVisit; // Keep (ProcessView resets).

  ProcessView ();  // Clears store and processes scene only if necessary.

  if (kernelVisitWasNeeded) {
    // Some systems, notably OpenGL, can draw while re-building, so
    // there might not be a need to draw from store again here.  But
    // in this case...
    DrawFromStore("G4XXXSGViewer::DrawView");
  } else {
    DrawFromStore("G4XXXSGViewer::DrawView");
  }

  // ...before finally...
  FinishView ();       // Flush streams and/or swap buffers.
}

void G4XXXSGViewer::ShowView() {
  //#ifdef G4XXXSGDEBUG
  G4cout << "G4XXXSGViewer::ShowView() called." << G4endl;
  //#endif
  // This is what you should see...
  DrawFromStore("G4XXXSGViewer::ShowView");
}

void G4XXXSGViewer::KernelVisitDecision () {
  
  // If there's a significant difference with the last view parameters
  // of either the scene handler or this viewer, trigger a rebuild.

  typedef taj::tree<G4String> SceneGraph;
  typedef taj::tree<G4String>::iterator SceneGraphIterator;
  SceneGraph& sceneGraph =
    static_cast<G4XXXSGSceneHandler&>(fSceneHandler).fSceneGraph;
  if (sceneGraph.size() == 3  // I.e., only the root nodes.
      || CompareForKernelVisit(fLastVP)) {
    NeedKernelVisit ();  // Sets fNeedKernelVisit.
  }      
  fLastVP = fVP;
}

G4bool G4XXXSGViewer::CompareForKernelVisit(G4ViewParameters& lastVP)
{
  // Typical comparison.  Taken from OpenGL.
  if (
      (lastVP.GetDrawingStyle ()    != fVP.GetDrawingStyle ())    ||
      (lastVP.IsAuxEdgeVisible ()   != fVP.IsAuxEdgeVisible ())   ||
      (lastVP.GetRepStyle ()        != fVP.GetRepStyle ())        ||
      (lastVP.IsCulling ()          != fVP.IsCulling ())          ||
      (lastVP.IsCullingInvisible () != fVP.IsCullingInvisible ()) ||
      (lastVP.IsDensityCulling ()   != fVP.IsDensityCulling ())   ||
      (lastVP.IsCullingCovered ()   != fVP.IsCullingCovered ())   ||
      // No need to visit kernel if section plane changes.
      // No need to visit kernel if cutaway planes change.
      (lastVP.IsExplode ()          != fVP.IsExplode ())          ||
      (lastVP.GetNoOfSides ()       != fVP.GetNoOfSides ())       ||
      (lastVP.IsMarkerNotHidden ()  != fVP.IsMarkerNotHidden ())  ||
      (lastVP.GetBackgroundColour ()!= fVP.GetBackgroundColour ())
      ) {
    return true;
  }

  if (lastVP.IsDensityCulling () &&
      (lastVP.GetVisibleDensity () != fVP.GetVisibleDensity ()))
    return true;

  if (lastVP.IsExplode () &&
      (lastVP.GetExplodeFactor () != fVP.GetExplodeFactor ()))
    return true;

  return false;
}

void G4XXXSGViewer::DrawFromStore(const G4String& source) {
  typedef taj::tree<G4String> SceneGraph;
  typedef taj::tree<G4String>::preorder_iterator SceneGraphPreIterator;
  SceneGraph& sceneGraph =
    static_cast<G4XXXSGSceneHandler&>(fSceneHandler).fSceneGraph;
  // Write to a file for testing...
  static G4int iCount = 0;
  std::ostringstream oss;
  oss << source << '.' << fName << '.' << iCount++ << ".out";
  G4cout << "Writing " << oss.str() << G4endl;
  std::ofstream ofs(oss.str().c_str());
  for (SceneGraphPreIterator i = sceneGraph.beginPre();
       i != sceneGraph.endPre(); ++i) {
    G4int depth = 0;
    SceneGraphPreIterator j = i;
    while (j != sceneGraph.getRoot()) {j = j.parent(); ++depth;}
    ofs << "\nDepth: " << depth;
    ofs << *i;
  }
  ofs.close();
}

#endif
