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

  Program:   Visualization Toolkit
  Module:    vtkImageProcessingPass.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 "vtk_glew.h"

#include "vtkImageProcessingPass.h"
#include "vtkObjectFactory.h"
#include <cassert>
#include "vtkRenderState.h"
#include "vtkRenderer.h"
#include "vtkOpenGLFramebufferObject.h"
#include "vtkTextureObject.h"
#include "vtkOpenGLRenderWindow.h"

// to be able to dump intermediate passes into png files for debugging.
// only for vtkImageProcessingPass developers.
//#define VTK_IMAGE_PROCESSING_PASS_DEBUG

#include "vtkPixelBufferObject.h"
#include "vtkCamera.h"
#include "vtkMath.h"

vtkCxxSetObjectMacro(vtkImageProcessingPass,DelegatePass,vtkRenderPass);


// ----------------------------------------------------------------------------
vtkImageProcessingPass::vtkImageProcessingPass()
{
  this->DelegatePass=nullptr;
}

// ----------------------------------------------------------------------------
vtkImageProcessingPass::~vtkImageProcessingPass()
{
  if(this->DelegatePass!=nullptr)
  {
      this->DelegatePass->Delete();
  }
}

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

  os << indent << "DelegatePass:";
  if(this->DelegatePass!=nullptr)
  {
    this->DelegatePass->PrintSelf(os,indent);
  }
  else
  {
    os << "(none)" <<endl;
  }
}
// ----------------------------------------------------------------------------
// Description:
// Render delegate with a image of different dimensions than the
// original one.
// \pre s_exists: s!=0
// \pre fbo_exists: fbo!=0
// \pre fbo_has_context: fbo->GetContext()!=0
// \pre target_exists: target!=0
// \pre target_has_context: target->GetContext()!=0
void vtkImageProcessingPass::RenderDelegate(const vtkRenderState *s,
                                            int width,
                                            int height,
                                            int newWidth,
                                            int newHeight,
                                            vtkOpenGLFramebufferObject *fbo,
                                            vtkTextureObject *target)
{
  assert("pre: s_exists" && s!=nullptr);
  assert("pre: fbo_exists" && fbo!=nullptr);
  assert("pre: fbo_has_context" && fbo->GetContext()!=nullptr);
  assert("pre: target_exists" && target!=nullptr);
  assert("pre: target_has_context" && target->GetContext()!=nullptr);

#ifdef VTK_IMAGE_PROCESSING_PASS_DEBUG
  cout << "width=" << width << endl;
  cout << "height=" << height << endl;
  cout << "newWidth=" << newWidth << endl;
  cout << "newHeight=" << newHeight << endl;
#endif

  vtkRenderer *r=s->GetRenderer();
  vtkRenderState s2(r);
  s2.SetPropArrayAndCount(s->GetPropArray(),s->GetPropArrayCount());

  // Adapt camera to new window size
  vtkCamera *savedCamera=r->GetActiveCamera();
  savedCamera->Register(this);
  vtkCamera *newCamera=vtkCamera::New();
  newCamera->DeepCopy(savedCamera);

#ifdef VTK_IMAGE_PROCESSING_PASS_DEBUG
  cout << "old camera params=";
  savedCamera->Print(cout);
  cout << "new camera params=";
  newCamera->Print(cout);
#endif
  r->SetActiveCamera(newCamera);

  if(newCamera->GetParallelProjection())
  {
    newCamera->SetParallelScale(
      newCamera->GetParallelScale()*newHeight/static_cast<double>(height));
  }
  else
  {
    double large;
    double small;
    if(newCamera->GetUseHorizontalViewAngle())
    {
      large=newWidth;
      small=width;
    }
    else
    {
      large=newHeight;
      small=height;
    }
    double angle=vtkMath::RadiansFromDegrees(newCamera->GetViewAngle());

#ifdef VTK_IMAGE_PROCESSING_PASS_DEBUG
    cout << "old angle =" << angle << " rad="<< vtkMath::DegreesFromRadians(angle) << " deg" <<endl;
#endif

    angle = 2.0*atan(tan(angle/2.0)*large/static_cast<double>(small));

#ifdef VTK_IMAGE_PROCESSING_PASS_DEBUG
    cout << "new angle =" << angle << " rad="<< vtkMath::DegreesFromRadians(angle) << " deg" <<endl;
#endif

    newCamera->SetViewAngle(vtkMath::DegreesFromRadians(angle));
  }

  s2.SetFrameBuffer(fbo);

  if(target->GetWidth()!=static_cast<unsigned int>(newWidth) ||
       target->GetHeight()!=static_cast<unsigned int>(newHeight))
  {
    target->Create2D(newWidth,newHeight,4,VTK_UNSIGNED_CHAR,false);
  }

  fbo->AddColorAttachment(
    fbo->GetBothMode(), 0, target);

  // because the same FBO can be used in another pass but with several color
  // buffers, force this pass to use 1, to avoid side effects from the
  // render of the previous frame.
  fbo->ActivateBuffer(0);

  fbo->AddDepthAttachment(fbo->GetBothMode());
  fbo->StartNonOrtho(newWidth,newHeight);
  glViewport(0, 0, newWidth, newHeight);
  glScissor(0, 0, newWidth, newHeight);

  // 2. Delegate render in FBO
  glEnable(GL_DEPTH_TEST);
  this->DelegatePass->Render(&s2);
  this->NumberOfRenderedProps+=
    this->DelegatePass->GetNumberOfRenderedProps();

#ifdef VTK_IMAGE_PROCESSING_PASS_DEBUG
  vtkPixelBufferObject *pbo=target->Download();

  unsigned int dims[2];
  vtkIdType continuousInc[3];

  dims[0]=static_cast<unsigned int>(newWidth);
  dims[1]=static_cast<unsigned int>(newHeight);
  continuousInc[0]=0;
  continuousInc[1]=0;
  continuousInc[2]=0;

  int byteSize=newWidth*newHeight*4*sizeof(float);
  float *buffer=new float[newWidth*newHeight*4];
  pbo->Download2D(VTK_FLOAT,buffer,dims,4,continuousInc);

  vtkImageImport *importer=vtkImageImport::New();
  importer->CopyImportVoidPointer(buffer,static_cast<int>(byteSize));
  importer->SetDataScalarTypeToFloat();
  importer->SetNumberOfScalarComponents(4);
  importer->SetWholeExtent(0,newWidth-1,0,newHeight-1,0,0);
  importer->SetDataExtentToWholeExtent();

  importer->Update();

  vtkPNGWriter *writer=vtkPNGWriter::New();
  writer->SetFileName("ip.png");
  writer->SetInputConnection(importer->GetOutputPort());
  importer->Delete();
  cout << "Writing " << writer->GetFileName() << endl;
  writer->Write();
  cout << "Wrote " << writer->GetFileName() << endl;
  writer->Delete();

  pbo->Delete();
  delete[] buffer;
#endif

  newCamera->Delete();
  r->SetActiveCamera(savedCamera);
  savedCamera->UnRegister(this);
}

// ----------------------------------------------------------------------------
// Description:
// Release graphics resources and ask components to release their own
// resources.
// \pre w_exists: w!=0
void vtkImageProcessingPass::ReleaseGraphicsResources(vtkWindow *w)
{
  assert("pre: w_exists" && w!=nullptr);
  if(this->DelegatePass!=nullptr)
  {
    this->DelegatePass->ReleaseGraphicsResources(w);
  }
}