tessellatedNav.C

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/// \file
/// \ingroup tutorial_geom
/// Macro allowing to vizualize tessellations from Wavefront's .obj format.
///
/// \image html geom_visualizeWavefrontObj.png width=500px
/// \macro_code
///
/// \author Andrei Gheata
 
#include <TROOT.h>
#include <TColor.h>
#include <TDatime.h>
#include <TRandom3.h>
#include <TGeoManager.h>
#include <TGeoTessellated.h>
#include <TVirtualGeoConverter.h>
#include <TView.h>
 
//______________________________________________________________________________
int randomColor()
{
   gRandom = new TRandom3();
   TDatime dt;
   gRandom->SetSeed(dt.GetTime());
   int ci = TColor::GetFreeColorIndex();
   TColor *color = new TColor(ci, gRandom->Rndm(), gRandom->Rndm(), gRandom->Rndm());
   return ci;
}
 
//______________________________________________________________________________
void tessellatedNav(const char *dot_obj_file = "", bool check = false)
{
   // Input a file in .obj format (https://en.wikipedia.org/wiki/Wavefront_.obj_file)
   // The file should have a single object inside, only vertex and faces information is used
   TString name = dot_obj_file;
   TString sfile = dot_obj_file;
   if (sfile.IsNull()) {
      sfile = gROOT->GetTutorialsDir();
      sfile += "/geom/teddy.obj";
   }
   name.ReplaceAll(".obj", "");
   gROOT->GetListOfCanvases()->Delete();
   if (gGeoManager)
      delete gGeoManager;
   auto geom = new TGeoManager(name, "Imported from .obj file");
   TGeoMaterial *mat = new TGeoMaterial("Al", 26.98, 13, 2.7);
   TGeoMedium *med = new TGeoMedium("MED", 1, mat);
   TGeoVolume *top = geom->MakeBox("TOP", med, 10, 10, 10);
   geom->SetTopVolume(top);
 
   auto tsl = TGeoTessellated::ImportFromObjFormat(sfile.Data(), check);
   if (!tsl)
      return;
   tsl->ResizeCenter(5.);
 
   TGeoVolume *vol = new TGeoVolume(name, tsl, med);
   vol->SetLineColor(randomColor());
   vol->SetLineWidth(2);
   top->AddNode(vol, 1);
   geom->CloseGeometry();
 
   // Convert to VecGeom tessellated solid
   auto converter = TVirtualGeoConverter::Instance(geom);
   if (!converter) {
      printf("Raytracing a tessellated shape without VecGeom support will just draw a box\n");
   } else {
      converter->ConvertGeometry();
   }
 
   if (gROOT->IsBatch())
      return;
   // Set the view
   top->Draw();
   TView *view = gPad->GetView();
   if (!view)
      return;
   view->Top();
 
   // Raytracing will call VecGeom navigation
   top->Raytrace();
}