//
// ********************************************************************
// * DISCLAIMER                                                       *
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// * The following disclaimer summarizes all the specific disclaimers *
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// *                                                                  *
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//
//
// $Id: G4VoxelNavigation.icc,v 1.10 2002/05/15 10:21:48 gcosmo Exp $
// GEANT4 tag $Name: geant4-05-01 $
//
// 
// class G4VoxelNavigation Inline implementation
// ********************************************************************

// ********************************************************************
// VoxelLocate
// ********************************************************************
//
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;
}

// ********************************************************************
// LevelLocate
// ********************************************************************
//
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;
  
  targetPhysical = history.GetTopVolume();
  targetLogical = targetPhysical->GetLogicalVolume();
  targetVoxelHeader = targetLogical->GetVoxelHeader();

  // Find the voxel containing the point
  //
  targetVoxelNode = VoxelLocate(targetVoxelHeader,localPoint);

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

  //
  // Search daughters in volume
  //

  for ( register int sampleNo=targetNoDaughters-1; sampleNo>=0; sampleNo-- )
  {
    samplePhysical = targetLogical->
                     GetDaughter(targetVoxelNode->GetVolume(sampleNo));
    if ( samplePhysical!=blockedVol )
    {
      // Setup volume with mother pointer
      //
      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
        //
        localPoint = samplePoint;
        return true;
      }
      else
      {
        history.BackLevel();
      }
    }
  }
  return false;
}