//_______________________________________________________________
//
// This macro creates a 3D spiral using TPolyMarker3D.
// In the loop it takes snapshots of the growing picture.
// With the help of the program "gifsicle" it assembles
// the snapshot into a movie which may be viewed by
// "gifview" or by a browser like mozilla.
// Information on "gifsicle" can be found here:
// http://www.lcdf.org/~eddietwo/gifsicle/
//
//  Author: Otto Schaile
//________________________________________________________________
{
   gROOT->Reset();

   gStyle->SetTitleSize(0.03, "x");
   gStyle->SetTitleOffset(1.5, "x");
   gStyle->SetTitleSize(0.03, "y");
   gStyle->SetTitleOffset(1.5, "y");
   gStyle->SetTitleSize(0.03, "z");
   gStyle->SetTitleOffset(1.5, "z");
   gStyle->SetTitleColor(kBlue, "x");
   gStyle->SetTitleColor(kBlue, "y");
   gStyle->SetTitleColor(kBlue, "z");

   Int_t ppc=30;
   Int_t ncircles = 5;

   // create and open a canvas
   TCanvas * cc = new TCanvas( "cc", "Spiral", 300, 10, 700, 700 );
   cc->SetFillColor(1);

   // create view with axis
   Double_t rx0 = 0, rx1 = 5, ry0 = 0, ry1 = 5, rz0 = 0, rz1 = 5;
   Double_t rmin[3], rmax[3];
   rmin[0] = rx0;
   rmin[1] = ry0;
   rmin[2] = rz0;
   rmax[0] = rx1;
   rmax[1] = ry1;
   rmax[2] = rz1;

   TView3D *view = new TView3D(1, rmin, rmax);
   view->ShowAxis();
   TAxis3D *axis = TAxis3D::GetPadAxis(); // Get pointer to axis
   if (axis) {
      axis->SetLabelSize(0.02);    
      axis->SetLabelOffset(-0.02, "z"); 
      axis->SetLabelColor(kBlue);  
      axis->SetAxisColor(kBlue); 

      axis->SetXTitle("East");
      axis->SetYTitle("North");
      axis->SetZTitle("Altitude");
   }
   // draw a box around
   TPolyLine3D *pl3d; 

   pl3d = new TPolyLine3D(2);
   pl3d->SetPoint(0,rx0, ry1, rz0); 
   pl3d->SetPoint(1,rx1, ry1, rz0);
   pl3d->SetLineColor(kBlue);
   pl3d->Draw();

   pl3d = new TPolyLine3D(2);
   pl3d->SetPoint(0,rx0, ry1, rz1); 
   pl3d->SetPoint(1,rx1, ry1, rz1);
   pl3d->SetLineColor(kBlue);
   pl3d->Draw();

   pl3d = new TPolyLine3D(2);
   pl3d->SetPoint(0,rx1, ry0, rz0); 
   pl3d->SetPoint(1,rx1, ry1, rz0);
   pl3d->SetLineColor(kBlue);
   pl3d->Draw();

   pl3d = new TPolyLine3D(2);
   pl3d->SetPoint(0,rx1, ry0, rz1); 
   pl3d->SetPoint(1,rx1, ry1, rz1);
   pl3d->SetLineColor(kBlue);
   pl3d->Draw();

   pl3d = new TPolyLine3D(2);
   pl3d->SetPoint(0,rx1, ry0, rz0); 
   pl3d->SetPoint(1,rx1, ry0, rz1);
   pl3d->SetLineColor(kBlue);
   pl3d->Draw();

   pl3d = new TPolyLine3D(2);
   pl3d->SetPoint(0,rx1, ry1, rz0); 
   pl3d->SetPoint(1,rx1, ry1, rz1);
   pl3d->SetLineColor(kBlue);
   pl3d->Draw();

   // draw a grid on x-y plane z = 0
   Double_t gr = rx0 + 1;
   while (gr < rx1) {
      pl3d = new TPolyLine3D(2);
      pl3d->SetPoint(0, gr, ry0, rz0); 
      pl3d->SetPoint(1, gr, ry1, rz0);
      pl3d->SetLineColor(kBlue);
      pl3d->Draw();
      gr += 1;
   }   
   gr = ry0 + 1;
   while (gr < ry1) {
      pl3d = new TPolyLine3D(2);
      pl3d->SetPoint(0, rx0, gr, rz0); 
      pl3d->SetPoint(1, rx1, gr, rz0);
      pl3d->SetLineColor(kBlue);
      pl3d->Draw();
      gr += 1;
   }   
  // create a PolyMarker3D
   TPolyMarker3D *pm3d;

   Double_t dphi = 2. * TMath::Pi() / ppc;
   Double_t dr = 0.01;
   Double_t dx = 0.015;
   Double_t dz = 0.0004;
   Double_t phi = 0;
   Double_t x0 = 0.1 * (rx1 - rx0);
   Double_t y0 = 0.5 * (ry1 - ry0);
   Double_t r = dr;
   Double_t z = rz0;
   Double_t x, y; 
   TString pname;
   TList * mlist = new TList();
   Int_t n = 0;
//   for( Int_t i = 0; i < ppc * ncircles; i++ ) {
//    for( Int_t i = 0; i < 1; i++ ) {
   while (z <= rz1) {
      pm3d = new TPolyMarker3D(1);
      mlist->AddFirst(pm3d);
      pm3d->SetPoint( 0, x0, y0, z );
      pm3d->SetMarkerSize(0.5);
      pm3d->SetMarkerStyle( 3 );
      pm3d->SetMarkerColor( 6 );
      pm3d->Draw();

      pm3d = new TPolyMarker3D(1);
      mlist->AddFirst(pm3d);
      x = x0 + r * TMath::Cos(phi);
      y = y0 + r * TMath::Sin(phi);
      pm3d->SetPoint( 0, x, y, z );
      pm3d->SetMarkerSize(0.5);
      pm3d->SetMarkerStyle( 8 );
      pm3d->SetMarkerColor( 2 + 3 * (n%2) );
      pm3d->Draw();
      if ( !(n%4) ) {
// take snapshot every 2nd picture only
      	cc->Modified();
      	cc->Update();
      	pname = "spiral_";
      	pname += Form("%03d", n);
      	pname += ".gif";
      	cc->SaveAs(pname.Data());
      }
//       gSystem->Sleep(20);
      x0 +=   dx;
      z += dz * n;
      r += dr;
      phi += dphi;
      n++;
	}
   TIter next(mlist);
   while (pm3d = (TPolyMarker3D*)next()){
      delete pm3d;
      if ( !(n%4) ) {
// take snapshot every 2nd picture only
      	cc->Modified();
      	cc->Update();
      	pname = "spiral_";
      	pname += Form("%03d", n);
      	pname += ".gif";
      	cc->SaveAs(pname.Data());
      }
      n++;
   }

//  assemble the movie
   gSystem->Exec("gifsicle -O2 --delay=5 --loop=5 spiral_*.gif > spanim.gif");
   gSystem->Exec("rm -f spiral_*.gif");
   gSystem->Exec("gifview -a spanim.gif");
}