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

  Program:   Visualization Toolkit
  Module:    vtkRendererCollection.cxx

  Copyright (c) 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 "vtkRendererCollection.h"
#include "vtkRenderWindow.h"
#include "vtkObjectFactory.h"

#include <cstdlib>

vtkStandardNewMacro(vtkRendererCollection);

// Forward the Render() method to each renderer in the list.
void vtkRendererCollection::Render()
{
  vtkRenderer      *ren, *firstRen;
  vtkRenderWindow  *renWin;
  int               numLayers, i;

  vtkCollectionSimpleIterator rsit;
  this->InitTraversal(rsit);
  firstRen = this->GetNextRenderer(rsit);
  if (firstRen == NULL)
    {
    // We cannot determine the number of layers because there are no
    // renderers.  No problem, just return.
    return;
    }
  renWin = firstRen->GetRenderWindow();
  numLayers = renWin->GetNumberOfLayers();

  // Only have the renderers render from back to front.  This is necessary
  // because transparent renderers clear the z-buffer before each render and
  // then overlay their image.
  for (i = 0; i < numLayers; i++)
    {
    for (this->InitTraversal(rsit); (ren = this->GetNextRenderer(rsit)); )
      {
      if (ren->GetLayer() == i)
        {
        ren->Render();
        }
      }
    }

  // Let the user know if they have put a renderer at an unused layer.
  for (this->InitTraversal(rsit); (ren = this->GetNextRenderer(rsit)); )
    {
    if (ren->GetLayer() < 0 || ren->GetLayer() >= numLayers)
      {
      vtkErrorMacro(<< "Invalid layer for renderer: not rendered.");
      }
    }
}

vtkRenderer *vtkRendererCollection::GetFirstRenderer()
{
  if ( this->Top == NULL )
    {
    return NULL;
    }
  else
    {
    return static_cast<vtkRenderer *>(this->Top->Item);
    }
}

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