#include "TROOT.h"
#include "TClass.h"
#include "TObject.h"
#include "TNamed.h"
#include "TMath.h"
#include "TRandom.h"
#include "TRandom3.h"
#include "TRotation.h"
#include "TVector3.h"
#include "TGeoManager.h"
#include "TGeoMatrix.h"
#include "TGeoMedium.h"
#include "TGeoVolume.h"
#include "TGeoNode.h"
#include "TGeoShape.h"
#include "TGeoBBox.h"
#include "TGeoCompositeShape.h"

void test_DistFromInside()
{
  gSystem->Load("libGeom");
  TGeoManager *mgr = new TGeoManager( "box" , "Simple geometry" );
  TGeoMaterial *matVacuum = new TGeoMaterial("Vacuum", 0,0,0);
  TGeoMedium *med = new TGeoMedium("Vacuum",1, matVacuum);
  TGeoVolume *top = mgr->MakeBox( "top" , med , 100 , 100 , 100 );
  mgr->SetTopVolume( top );
  
  TGeoVolume *boxvol = mgr->MakeBox("box", med, 20, 20, 20);
  boxvol->SetLineColor( kRed );
  boxvol->SetTransparency( 80 );
  top->AddNode( boxvol, 0);
  
  TGeoBBox * box = boxvol->GetShape();
  
  mgr->CloseGeometry();
  TEveManager::Create();
  
  TGeoNode* node = gGeoManager->GetTopNode();
  TEveGeoTopNode* en = new TEveGeoTopNode(gGeoManager, node);
  en->SetVisLevel(4);
  en->GetNode()->GetVolume()->SetVisibility(kFALSE);
  
  gEve->AddGlobalElement(en);
  
  Double_t pt[3] = { 0. , 0. , -20.};
  double theta = 45./180*3.14;
  double phi   = 45./180*3.14;
  
  Double_t dir[3] = { sin(theta)*cos(phi) , sin(theta)*sin(phi), cos(theta)};
  Double_t opposite_dir[3] = { -dir[0], -dir[1], -dir[2]};
  
  double dist1 =  box->DistFromInside( pt , dir , 1);
  double dist2 =  box->DistFromInside( pt , opposite_dir , 1);
  cout << "positive dir: " << dist1 << " negative dir: " << dist2 << endl;
  
  gEve->Redraw3D(kTRUE);
  en->ExpandIntoListTreesRecursively();
}