#include "TCanvas.h"
#include "TGLParametric.h"
#include "TGLUtil.h"
#include "TMath.h"
#include "TStyle.h"


void fun1(TGLVertex3 &vertex, Double_t u, Double_t v)

{
  vertex[0] = TMath::Cos(u)*TMath::Sin(u)*TMath::Cos(v);
  vertex[1] = TMath::Cos(u)*TMath::Cos(u)*TMath::Cos(v);
  vertex[2] = TMath::Cos(u)*TMath::Sin(v);
}


void glparametric()
{
   gStyle->SetCanvasPreferGL(kTRUE);
   TCanvas *c = new TCanvas("surfaces_with_gl","surfaces_with_gl", 100, 10,
                            700, 700);

   TGLParametricEquation *p1 = 
     new TGLParametricEquation("Conchoid",fun1,  
			       0., TMath::Pi(), 0., TMath::TwoPi());
   p1->Draw();
}