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

   Program: ParaView
   Module:    vtkDepthImageProcessingPass.cxx

  Copyright (c) Sandia Corporation, Kitware Inc.
  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.

=========================================================================*/
/*----------------------------------------------------------------------
Acknowledgement:
This algorithm is the result of joint work by Electricité de France,
CNRS, Collège de France and Université J. Fourier as part of the
Ph.D. thesis of Christian BOUCHENY.
------------------------------------------------------------------------*/

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

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

//------------------------------------------------------------------------------
vtkDepthImageProcessingPass::vtkDepthImageProcessingPass()
{
  this->Origin[0] = 0;
  this->Origin[1] = 0;
  this->Width = 0;
  this->Height = 0;
  this->W = 0;
  this->H = 0;
  this->ExtraPixels = 0;
}

//------------------------------------------------------------------------------
vtkDepthImageProcessingPass::~vtkDepthImageProcessingPass() = default;

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

//------------------------------------------------------------------------------
// 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 vtkDepthImageProcessingPass::RenderDelegate(const vtkRenderState* s, int width, int height,
  int newWidth, int newHeight, vtkOpenGLFramebufferObject* fbo, vtkTextureObject* colortarget,
  vtkTextureObject* depthtarget)
{
  assert("pre: s_exists" && s != nullptr);
  assert("pre: fbo_exists" && fbo != nullptr);
  assert("pre: fbo_has_context" && fbo->GetContext() != nullptr);
  assert("pre: colortarget_exists" && colortarget != nullptr);
  assert("pre: colortarget_has_context" && colortarget->GetContext() != nullptr);
  assert("pre: depthtarget_exists" && depthtarget != nullptr);
  assert("pre: depthtarget_has_context" && depthtarget->GetContext() != nullptr);

  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);

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

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

  s2.SetFrameBuffer(fbo);
  fbo->Bind();
  fbo->AddColorAttachment(0, colortarget);

  // 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->ActivateDrawBuffer(0);

  fbo->AddDepthAttachment(depthtarget);
  fbo->StartNonOrtho(newWidth, newHeight);

  // 2. Delegate render in FBO
  // glEnable(GL_DEPTH_TEST);
  vtkOpenGLRenderUtilities::MarkDebugEvent("Start vtkDepthImageProcessingPass delegate render");
  this->DelegatePass->Render(&s2);
  vtkOpenGLRenderUtilities::MarkDebugEvent("End vtkDepthImageProcessingPass delegate render");

  this->NumberOfRenderedProps += this->DelegatePass->GetNumberOfRenderedProps();

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

//------------------------------------------------------------------------------
// Description:
// Read window size from parent
// \pre s_exists: s!=0
//
void vtkDepthImageProcessingPass::ReadWindowSize(const vtkRenderState* s)
{
  assert("pre: s_exists" && s != nullptr);

  vtkOpenGLFramebufferObject* fbo = vtkOpenGLFramebufferObject::SafeDownCast(s->GetFrameBuffer());
  vtkRenderer* r = s->GetRenderer();
  if (fbo == nullptr)
  {
    r->GetTiledSizeAndOrigin(&this->Width, &this->Height, &this->Origin[0], &this->Origin[1]);
  }
  else
  {
    int size[2];
    fbo->GetLastSize(size);
    this->Origin[0] = 0;
    this->Origin[1] = 0;
    this->Width = size[0];
    this->Height = size[1];
  }
}
