// $Id$

Reve::PointSet*
t0_hits(const char *varexp    = "T0.fX:T0.fY:T0.fZ",
	 const char *selection = "")
{
  // Extracts  T0 hits.


  AliRunLoader* rl =  Alieve::Event::AssertRunLoader();
  rl->LoadHits("T0");

  TTree* ht = rl->GetTreeH("T0", false);

  Int_t nTracks = ht->GetEntries();
  // printf("Found %d tracks. \n",nTracks);
  for (Int_t it = 0; it < nTracks; it++) {
 
    TClonesArray *hits = 0;
    ht->SetBranchAddress("T0",&hits);
 
    ht->GetEvent(it);
 Int_t nHits = hits->GetEntriesFast();
 //  printf("Found %d hits in track %d. \n",nHits,it);

  }
  Reve::PointSet* points = new Reve::PointSet(Form("T0 Hits '%s'", selection));
   points->SetSourceCS(TPointSelectorConsumer::TVT_XYZ);

  TPointSelector ps(ht, points, varexp, selection);
  ps.Select();

  points->SetTitle(Form("N=%d", points->Size()));
  points->SetMarkerSize(.5);
  points->SetMarkerColor((Color_t)3);

  gReve->AddRenderElement(points);
  gReve->Redraw3D();

  return points;
}