/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkTexturedSphereSource.cxx,v $
  Language:  C++
  Date:      $Date: 2002/12/17 02:05:39 $
  Version:   $Revision: 1.28 $

  Copyright (c) 1993-2002 Ken Martin, Will Schroeder, Bill Lorensen 
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#include "vtkTexturedSphereSource.h"

#include "vtkCellArray.h"
#include "vtkFloatArray.h"
#include "vtkMath.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPoints.h"
#include "vtkPolyData.h"

vtkCxxRevisionMacro(vtkTexturedSphereSource, "$Revision: 1.28 $");
vtkStandardNewMacro(vtkTexturedSphereSource);

// Construct sphere with radius=0.5 and default resolution 8 in both Phi
// and Theta directions.
vtkTexturedSphereSource::vtkTexturedSphereSource(int res)
{
  res = res < 4 ? 4 : res;
  this->Radius = 0.5;
  this->ThetaResolution = res;
  this->PhiResolution = res;
  this->Theta = 0.0;
  this->Phi = 0.0;
}

void vtkTexturedSphereSource::Execute()
{
  int i, j;
  int numPts;
  int numPolys;
  vtkPoints *newPoints; 
  vtkFloatArray *newNormals;
  vtkFloatArray *newTCoords;
  vtkCellArray *newPolys;
  float x[3], deltaPhi, deltaTheta, phi, theta, radius, norm;
  vtkIdType pts[3];
  vtkPolyData *output = this->GetOutput();
  float tc[2];
  
  //
  // Set things up; allocate memory
  //

  numPts = (this->PhiResolution + 1) * (this->ThetaResolution + 1);
  // creating triangles
  numPolys = this->PhiResolution * 2 * this->ThetaResolution;

  newPoints = vtkPoints::New();
  newPoints->Allocate(numPts);
  newNormals = vtkFloatArray::New();
  newNormals->SetNumberOfComponents(3);
  newNormals->Allocate(3*numPts);
  newTCoords = vtkFloatArray::New();
  newTCoords->SetNumberOfComponents(2);
  newTCoords->Allocate(2*numPts);
  newPolys = vtkCellArray::New();
  newPolys->Allocate(newPolys->EstimateSize(numPolys,3));
  //
  // Create sphere
  //
  // Create intermediate points
  deltaPhi = vtkMath::Pi() / this->PhiResolution;
  deltaTheta = 2.0 * vtkMath::Pi() / this->ThetaResolution;
  for (i=0; i <= this->ThetaResolution; i++)
    {
    theta = i * deltaTheta;
    tc[0] = theta/(2.0*3.1415926);
    for (j=0; j <= this->PhiResolution; j++)
      {
      phi = j * deltaPhi;
      radius = this->Radius * sin((double)phi);
      x[0] = radius * cos((double)theta);
      x[1] = radius * sin((double)theta);
      x[2] = this->Radius * cos((double)phi);
      newPoints->InsertNextPoint(x);

      if ( (norm = vtkMath::Norm(x)) == 0.0 )
        {
        norm = 1.0;
        }
      x[0] /= norm; x[1] /= norm; x[2] /= norm; 
      newNormals->InsertNextTuple(x);

      tc[1] = 1.0 - phi/3.1415926;
      newTCoords->InsertNextTuple(tc);
      }
    }
  //
  // Generate mesh connectivity
  //
  // bands inbetween poles
  for (i=0; i < this->ThetaResolution; i++)
    {
    for (j=0; j < this->PhiResolution; j++)
      {
      pts[0] = (this->PhiResolution+1)*i + j;
      pts[1] = pts[0] + 1;
      pts[2] = ((this->PhiResolution+1)*(i+1)+j) + 1;
      newPolys->InsertNextCell(3,pts);

      pts[1] = pts[2];
      pts[2] = pts[1] - 1;
      newPolys->InsertNextCell(3,pts);
      }
    }
//
// Update ourselves and release memeory
//
  output->SetPoints(newPoints);
  newPoints->Delete();

  output->GetPointData()->SetNormals(newNormals);
  newNormals->Delete();

  output->GetPointData()->SetTCoords(newTCoords);
  newTCoords->Delete();

  output->SetPolys(newPolys);
  newPolys->Delete();
}

void vtkTexturedSphereSource::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  os << indent << "Theta Resolution: " << this->ThetaResolution << "\n";
  os << indent << "Phi Resolution: " << this->PhiResolution << "\n";
  os << indent << "Theta: " << this->Theta << "\n";
  os << indent << "Phi: " << this->Phi << "\n";
  os << indent << "Radius: " << this->Radius << "\n";
}
