// This code implementation is the intellectual property of
// the GEANT4 collaboration.
//
// By copying, distributing or modifying the Program (or any work
// based on the Program) you indicate your acceptance of this statement,
// and all its terms.
//
// $Id: G4VoxelNavigation.icc,v 1.4 2000/11/20 18:59:44 gcosmo Exp $
// GEANT4 tag $Name: geant4-03-00 $
//
// 
// class G4VoxelNavigation Inline implementation

inline
G4VoxelNavigation::G4VoxelNavigation()
  : fVoxelDepth(-1),
    fVoxelAxisStack(kNavigatorVoxelStackMax),
    fVoxelNoSlicesStack(kNavigatorVoxelStackMax),
    fVoxelSliceWidthStack(kNavigatorVoxelStackMax),
    fVoxelNodeNoStack(kNavigatorVoxelStackMax),
    fVoxelHeaderStack(kNavigatorVoxelStackMax),
    fVoxelNode(0)
{
}

inline
G4SmartVoxelNode*
G4VoxelNavigation::VoxelLocate(G4SmartVoxelHeader *pHead,
                               const G4ThreeVector &localPoint)
{
	G4SmartVoxelHeader *targetVoxelHeader=pHead;
	G4SmartVoxelNode *targetVoxelNode=0;
	G4SmartVoxelProxy *sampleProxy;
	EAxis targetHeaderAxis;
	G4double targetHeaderMin,targetHeaderNodeWidth;
	G4int targetHeaderNoSlices,targetNodeNo;
	fVoxelDepth=0;

	while (!targetVoxelNode)
            {
		targetHeaderAxis=targetVoxelHeader->GetAxis();
		targetHeaderNoSlices=targetVoxelHeader->GetNoSlices();
		targetHeaderMin=targetVoxelHeader->GetMinExtent();
		targetHeaderNodeWidth= (targetVoxelHeader->GetMaxExtent()
                                      -targetHeaderMin)/targetHeaderNoSlices;
		targetNodeNo=G4int((localPoint(targetHeaderAxis)
                                    -targetHeaderMin)/targetHeaderNodeWidth);
// Rounding protection
		if (targetNodeNo<0)
			{
			targetNodeNo=0;
			}
		else if (targetNodeNo>=targetHeaderNoSlices)
			{
			targetNodeNo=targetHeaderNoSlices-1;
			}
// Stack info for stepping
		fVoxelAxisStack(fVoxelDepth)=targetHeaderAxis;
		fVoxelNoSlicesStack(fVoxelDepth)=targetHeaderNoSlices;
		fVoxelSliceWidthStack(fVoxelDepth)=targetHeaderNodeWidth;
		fVoxelNodeNoStack(fVoxelDepth)=targetNodeNo;
		fVoxelHeaderStack(fVoxelDepth)=targetVoxelHeader;
		
		sampleProxy=targetVoxelHeader->GetSlice(targetNodeNo);
		if (sampleProxy->IsNode())
			{
			targetVoxelNode=sampleProxy->GetNode();
			}
		else
			{
		        targetVoxelHeader=sampleProxy->GetHeader();
			fVoxelDepth++;
			}
             }
	fVoxelNode=targetVoxelNode;
	return targetVoxelNode;
}

inline
G4bool G4VoxelNavigation::LevelLocate(G4NavigationHistory& history,
			   const G4VPhysicalVolume *blockedVol,
                           const G4int,
                           const G4ThreeVector &globalPoint,
                           const G4ThreeVector* globalDirection,
			   const G4bool  pLocatedOnEdge, 
			   G4ThreeVector &localPoint)
{
  G4SmartVoxelHeader *targetVoxelHeader;
  G4SmartVoxelNode *targetVoxelNode;
  G4VPhysicalVolume *targetPhysical,*samplePhysical;
  G4LogicalVolume *targetLogical;
  G4VSolid *sampleSolid;
  G4ThreeVector samplePoint;
  G4int targetNoDaughters,sampleNo;
  
  targetPhysical=history.GetTopVolume();
  targetLogical=targetPhysical->GetLogicalVolume();
  targetVoxelHeader=targetLogical->GetVoxelHeader();
  //  localPoint=history.GetTopTransform().TransformPoint(globalPoint);
// Find the voxel containing the point
  targetVoxelNode=VoxelLocate(targetVoxelHeader,localPoint);

  targetNoDaughters=targetVoxelNode->GetNoContained();
  if (targetNoDaughters==0) return false;

//
// Search daughters in volume
//
  for (sampleNo=targetNoDaughters-1;sampleNo>=0;sampleNo--)
    {
      samplePhysical=targetLogical->
	GetDaughter(targetVoxelNode->
		    GetVolume(sampleNo));
      if (samplePhysical!=blockedVol)
	{
// Setup volume with mother ptr
	  samplePhysical->Setup(targetPhysical);
	  history.NewLevel(samplePhysical,kNormal,samplePhysical->GetCopyNo());
	  sampleSolid=samplePhysical->GetLogicalVolume()->GetSolid();
	  samplePoint=history.GetTopTransform().TransformPoint(globalPoint);

	  if( G4AuxiliaryNavServices::
	      CheckPointOnSurface(sampleSolid, samplePoint, globalDirection, 
				  history.GetTopTransform(), pLocatedOnEdge) 
	    )
	    {
	      // Enter this daughter
	      //      blockedVol=0;
	      localPoint=samplePoint;
	      return true;
	    }
	  else
	    {
	      history.BackLevel();
	    }
	}
    }
  return false;
}