#include "TROOT.h"
#include "TStyle.h"
#include "TCanvas.h"
#include "TView.h"
#include "TPolyLine3D.h"
#include "TLatex.h"
void DrawFrame3D(){
  Int_t k2[3][3] = {
    {1,0,0},
    {0,1,0},
    {0,0,1}};
  Double_t xyzsize[3][3] = {
    {1.1,0,0},
    {0,1.3,0},
    {0,0,1.1}};

  TPolyLine3D *l2[3];
  for (Int_t j=0;j<3;j++){
    l2[j] = new TPolyLine3D();
    l2[j]->SetNextPoint(0,0,0);
    l2[j]->SetNextPoint(xyzsize[j][0],xyzsize[j][1],xyzsize[j][2]);
    l2[j]->Draw();
  }
  Double_t arrowsize = 0.1;
  TPolyLine3D *arrow[3];
  for (Int_t j=0;j<3;j++){
    arrow[j] = new TPolyLine3D();
    arrow[j]->SetNextPoint(xyzsize[j][0]+arrowsize*k2[j][0],
			   xyzsize[j][1]+arrowsize*k2[j][1],
			   xyzsize[j][2]+arrowsize*k2[j][2]);
    arrow[j]->SetNextPoint(xyzsize[j][0]+0.3*k2[j][2]*arrowsize,
			   xyzsize[j][1]+0.3*k2[j][0]*arrowsize,
			   xyzsize[j][2]+0.3*k2[j][1]*arrowsize);
    arrow[j]->SetNextPoint(xyzsize[j][0]-0.3*k2[j][2]*arrowsize,
			   xyzsize[j][1]-0.3*k2[j][0]*arrowsize,
			   xyzsize[j][2]-0.3*k2[j][1]*arrowsize);
    arrow[j]->SetNextPoint(xyzsize[j][0]+arrowsize*k2[j][0],
			   xyzsize[j][1]+arrowsize*k2[j][1],
			   xyzsize[j][2]+arrowsize*k2[j][2]);
    arrow[j]->Draw();
  }
}

void rec_solid_angle_off_axis(){
  gROOT->SetStyle("Plain");
  gStyle->SetTextFont(132);
  TCanvas *c1 = new TCanvas("c1","c1",400,400);
  c1->SetTheta(30.);
  c1->SetPhi(-141.);
  DrawFrame3D();
  TView *view = TView::CreateView(1);
  Double_t view_size = 0.55;
  view->SetRange(-view_size*1.0,-view_size*1.0,-view_size*0.5,
		  view_size*1.0, view_size*1.0, view_size*1.5);

  const Int_t nPolyLine3D = 20;
  TPolyLine3D *guide[nPolyLine3D];
  for (Int_t i = 0; i<nPolyLine3D; i++){
    guide[i]=new TPolyLine3D();
  }

  Double_t pi = acos(-1.);
  Int_t    n = 30;

  Double_t theta1 = pi/6.;
  Double_t phi1   = pi/6.;
  Double_t x1 =  1.*tan(theta1);
  Double_t y1 =  1.*tan(phi1);

  Double_t theta2 = pi/3.5;
  Double_t phi2   = pi/4.0;
  Double_t x2 =  1.*tan(theta2);
  Double_t y2 =  1.*tan(phi2);

  guide[1]->SetNextPoint(0,x1,y1);
  guide[1]->SetNextPoint(0,x1,y2);
  guide[1]->SetNextPoint(0,x2,y2);
  guide[1]->SetNextPoint(0,x2,y1);
  guide[1]->SetNextPoint(0,x1,y1);

  guide[2]->SetNextPoint(0,x1,y1);
  guide[2]->SetNextPoint(0,0,y1);
  guide[2]->SetNextPoint(1,0,0);
  guide[2]->SetLineStyle(2);
  guide[3]->SetNextPoint(0,x1,y2);
  guide[3]->SetNextPoint(0,0,y2);
  guide[3]->SetNextPoint(1,0,0);
  guide[3]->SetLineStyle(2);
  guide[4]->SetNextPoint(0,x1,y1);
  guide[4]->SetNextPoint(0,x1,0);
  guide[4]->SetNextPoint(1,0,0);
  guide[4]->SetLineStyle(2);
  guide[5]->SetNextPoint(0,x2,y1);
  guide[5]->SetNextPoint(0,x2,0);
  guide[5]->SetNextPoint(1,0,0);
  guide[5]->SetLineStyle(2);

  for (Int_t i=0;i<=n;i++) {
    Double_t r = 0.3;
    Double_t theta = -i*theta1/n+pi;
    Double_t phi   = -i*phi1/n+pi;
    guide[6]->SetNextPoint(1.0+r*cos(theta),r*sin(theta),0);
    guide[7]->SetNextPoint(1.0+r*cos(phi),0,r*sin(phi));
  }

  for (Int_t i=0;i<=n;i++) {
    Double_t r = 0.6;
    Double_t theta = -i*theta2/n+pi;
    Double_t phi   = -i*phi2/n+pi;
    guide[8]->SetNextPoint(1.0+r*cos(theta),r*sin(theta),0);
    guide[9]->SetNextPoint(1.0+r*cos(phi),0,r*sin(phi));
  }

  Double_t virlen = 0.07;
  guide[10]->SetNextPoint(virlen,0,0);
  guide[10]->SetNextPoint(virlen,virlen,0);
  guide[10]->SetNextPoint(0,virlen,0);
  guide[10]->SetNextPoint(0,virlen,virlen);
  guide[10]->SetNextPoint(0,0,virlen);
  guide[10]->SetNextPoint(virlen,0,virlen);
  guide[10]->SetNextPoint(virlen,0,0);

  for (Int_t i = 0; i<nPolyLine3D; i++){
    guide[i]->Draw();
  }

  Double_t xx[3],xxt[3];
  TLatex Tl;
  Tl.SetTextSize(0.05);
  xx[0]=0.00; xx[1]=1.3; xx[2]=0.07; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{x}");
  xx[0]=0.12; xx[1]=0.00; xx[2]=1.15; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{y}");
  xx[0]=1.18; xx[1]=0.0; xx[2]=0.10; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{z}");
  xx[0]=0.70; xx[1]=0.10; xx[2]=0.0; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#alpha}_{1}");
  xx[0]=0.69; xx[1]=0.0; xx[2]=0.09; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#beta}_{1}");
  xx[0]=0.43; xx[1]=0.20; xx[2]=0.0; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#alpha}_{2}");
  xx[0]=0.42; xx[1]=0.0; xx[2]=0.22; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#beta}_{2}");
  xx[0]=1.00; xx[1]=0.0; xx[2]=-0.10; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"P");
}