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

  Program:   Visualization Toolkit

  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 "vtkOpenGLCamera.h"

#include "vtkMatrix4x4.h"
#include "vtkMatrix3x3.h"
#include "vtkObjectFactory.h"
#include "vtkRenderer.h"
#include "vtkOutputWindow.h"
#include "vtkOpenGLRenderWindow.h"
#include "vtkOpenGLError.h"

#include <cmath>

vtkStandardNewMacro(vtkOpenGLCamera);


vtkOpenGLCamera::vtkOpenGLCamera()
{
  this->WCDCMatrix = vtkMatrix4x4::New();
  this->WCVCMatrix = vtkMatrix4x4::New();
  this->NormalMatrix = vtkMatrix3x3::New();
  this->VCDCMatrix = vtkMatrix4x4::New();
  this->LastRenderer = nullptr;
}

vtkOpenGLCamera::~vtkOpenGLCamera()
{
  this->WCDCMatrix->Delete();
  this->WCVCMatrix->Delete();
  this->NormalMatrix->Delete();
  this->VCDCMatrix->Delete();
}

// Implement base class method.
void vtkOpenGLCamera::Render(vtkRenderer *ren)
{
  vtkOpenGLClearErrorMacro();

  int lowerLeft[2];
  int usize, vsize;

  vtkOpenGLRenderWindow *win = vtkOpenGLRenderWindow::SafeDownCast(ren->GetRenderWindow());

  // find out if we should stereo render
  this->Stereo = (ren->GetRenderWindow())->GetStereoRender();
  ren->GetTiledSizeAndOrigin(&usize, &vsize, lowerLeft, lowerLeft+1);

  // if were on a stereo renderer draw to special parts of screen
  if (this->Stereo)
  {
    unsigned int dfbo = win->GetDefaultFrameBufferId();
    if (dfbo)
    {
      // If the render window is using an FBO to render into, we ensure that
      // it's selected.
      glBindFramebuffer(GL_FRAMEBUFFER, dfbo);
    }
    switch ((ren->GetRenderWindow())->GetStereoType())
    {
      case VTK_STEREO_CRYSTAL_EYES:
        if (this->LeftEye)
        {
          if (ren->GetRenderWindow()->GetDoubleBuffer())
          {
            glDrawBuffer(static_cast<GLenum>(win->GetBackLeftBuffer()));
            glReadBuffer(static_cast<GLenum>(win->GetBackLeftBuffer()));
          }
          else
          {
            glDrawBuffer(static_cast<GLenum>(win->GetFrontLeftBuffer()));
            glReadBuffer(static_cast<GLenum>(win->GetFrontLeftBuffer()));
          }
        }
        else
        {
           if (ren->GetRenderWindow()->GetDoubleBuffer())
           {
            glDrawBuffer(static_cast<GLenum>(win->GetBackRightBuffer()));
            glReadBuffer(static_cast<GLenum>(win->GetBackRightBuffer()));
           }
          else
          {
            glDrawBuffer(static_cast<GLenum>(win->GetFrontRightBuffer()));
            glReadBuffer(static_cast<GLenum>(win->GetFrontRightBuffer()));
          }
        }
        break;
      case VTK_STEREO_LEFT:
        this->LeftEye = 1;
        break;
      case VTK_STEREO_RIGHT:
        this->LeftEye = 0;
        break;
      default:
        break;
    }
  }
  else
  {
    if (ren->GetRenderWindow()->GetDoubleBuffer())
    {
      glDrawBuffer(static_cast<GLenum>(win->GetBackBuffer()));

      // Reading back buffer means back left. see OpenGL spec.
      // because one can write to two buffers at a time but can only read from
      // one buffer at a time.
      glReadBuffer(static_cast<GLenum>(win->GetBackBuffer()));
    }
    else
    {
      glDrawBuffer(static_cast<GLenum>(win->GetFrontBuffer()));

      // Reading front buffer means front left. see OpenGL spec.
      // because one can write to two buffers at a time but can only read from
      // one buffer at a time.
      glReadBuffer(static_cast<GLenum>(win->GetFrontBuffer()));
    }
  }

  glViewport(lowerLeft[0], lowerLeft[1], usize, vsize);
  glEnable(GL_SCISSOR_TEST);
  if (this->UseScissor)
  {
    glScissor(this->ScissorRect.GetX(),this->ScissorRect.GetY(),
              this->ScissorRect.GetWidth(), this->ScissorRect.GetHeight());
    this->UseScissor = false;
  }
  else
  {
    glScissor(lowerLeft[0], lowerLeft[1], usize, vsize);
  }

  if ((ren->GetRenderWindow())->GetErase() && ren->GetErase()
      && !ren->GetIsPicking())
  {
    ren->Clear();
  }

  vtkOpenGLCheckErrorMacro("failed after Render");
}

//----------------------------------------------------------------------------
void vtkOpenGLCamera::UpdateViewport(vtkRenderer *ren)
{
  vtkOpenGLClearErrorMacro();

  int lowerLeft[2];
  int usize, vsize;
  ren->GetTiledSizeAndOrigin(&usize, &vsize, lowerLeft, lowerLeft+1);

  glViewport(lowerLeft[0], lowerLeft[1], usize, vsize);
  glEnable(GL_SCISSOR_TEST);
  if (this->UseScissor)
  {
    glScissor(this->ScissorRect.GetX(),this->ScissorRect.GetY(),
              this->ScissorRect.GetWidth(), this->ScissorRect.GetHeight());
    this->UseScissor = false;
  }
  else
  {
    glScissor(lowerLeft[0], lowerLeft[1], usize, vsize);
  }

  vtkOpenGLCheckErrorMacro("failed after UpdateViewport");
}

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

void vtkOpenGLCamera::GetKeyMatrices(vtkRenderer *ren, vtkMatrix4x4 *&wcvc,
        vtkMatrix3x3 *&normMat, vtkMatrix4x4 *&vcdc, vtkMatrix4x4 *&wcdc)
{
  // has the camera changed?
  if (ren != this->LastRenderer ||
      this->MTime > this->KeyMatrixTime ||
      ren->GetMTime() > this->KeyMatrixTime)
  {
    this->WCVCMatrix->DeepCopy(this->GetModelViewTransformMatrix());

    for(int i = 0; i < 3; ++i)
    {
      for (int j = 0; j < 3; ++j)
      {
        this->NormalMatrix->SetElement(i, j, this->WCVCMatrix->GetElement(i, j));
      }
    }
    this->NormalMatrix->Invert();

    this->WCVCMatrix->Transpose();

    double aspect[2];
    int  lowerLeft[2];
    int usize, vsize;
    ren->GetTiledSizeAndOrigin(&usize, &vsize, lowerLeft, lowerLeft+1);

    ren->ComputeAspect();
    ren->GetAspect(aspect);
    double aspect2[2];
    ren->vtkViewport::ComputeAspect();
    ren->vtkViewport::GetAspect(aspect2);
    double aspectModification = aspect[0] * aspect2[1] / (aspect[1] * aspect2[0]);

    if (usize && vsize)
    {
      this->VCDCMatrix->DeepCopy(this->GetProjectionTransformMatrix(
                         aspectModification * usize / vsize, -1, 1));
      this->VCDCMatrix->Transpose();
    }

    vtkMatrix4x4::Multiply4x4(this->WCVCMatrix, this->VCDCMatrix, this->WCDCMatrix);

    this->KeyMatrixTime.Modified();
    this->LastRenderer = ren;
  }

  wcvc = this->WCVCMatrix;
  normMat = this->NormalMatrix;
  vcdc = this->VCDCMatrix;
  wcdc = this->WCDCMatrix;
}