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

  Program:   Visualization Toolkit
  Module:    vtkPointFillPass.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 "vtkPointFillPass.h"
#include "vtkObjectFactory.h"
#include <cassert>

#include "vtkCamera.h"
#include "vtkRenderState.h"
#include "vtkRenderer.h"
#include "vtkOpenGLFramebufferObject.h"
#include "vtkOpenGLQuadHelper.h"
#include "vtkOpenGLRenderWindow.h"
#include "vtkOpenGLError.h"
#include "vtkShaderProgram.h"
#include "vtkOpenGLShaderCache.h"
#include "vtkOpenGLRenderWindow.h"
#include "vtkOpenGLState.h"
#include "vtkOpenGLVertexArrayObject.h"
#include "vtkTextureObject.h"
#include "vtkMath.h"

#include "vtkPointFillPassFS.h"
#include "vtkTextureObjectVS.h"

vtkStandardNewMacro(vtkPointFillPass);

// ----------------------------------------------------------------------------
vtkPointFillPass::vtkPointFillPass()
{
  this->FrameBufferObject=nullptr;
  this->Pass1=nullptr;
  this->Pass1Depth=nullptr;
  this->QuadHelper = nullptr;
  this->MinimumCandidateAngle = 1.5*vtkMath::Pi();
  this->CandidatePointRatio = 0.99;
}

// ----------------------------------------------------------------------------
vtkPointFillPass::~vtkPointFillPass()
{
  if(this->FrameBufferObject!=nullptr)
  {
    vtkErrorMacro(<<"FrameBufferObject should have been deleted in ReleaseGraphicsResources().");
  }
   if(this->Pass1!=nullptr)
   {
    vtkErrorMacro(<<"Pass1 should have been deleted in ReleaseGraphicsResources().");
   }
   if(this->Pass1Depth!=nullptr)
   {
    vtkErrorMacro(<<"Pass1Depth should have been deleted in ReleaseGraphicsResources().");
   }
}

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

// ----------------------------------------------------------------------------
// Description:
// Perform rendering according to a render state \p s.
// \pre s_exists: s!=0
void vtkPointFillPass::Render(const vtkRenderState *s)
{
  assert("pre: s_exists" && s!=nullptr);

  vtkOpenGLClearErrorMacro();

  this->NumberOfRenderedProps=0;

  vtkRenderer *r=s->GetRenderer();
  vtkOpenGLRenderWindow *renWin = static_cast<vtkOpenGLRenderWindow *>(r->GetRenderWindow());

  if(this->DelegatePass == nullptr)
  {
    vtkWarningMacro(<<" no delegate.");
    return;
  }

  // 1. Create a new render state with an FBO.

  int width;
  int height;
  int size[2];
  s->GetWindowSize(size);
  width = size[0];
  height = size[1];

  if(this->Pass1==nullptr)
  {
    this->Pass1 = vtkTextureObject::New();
    this->Pass1->SetContext(renWin);
    this->Pass1->Create2D(static_cast<unsigned int>(width),
                          static_cast<unsigned int>(height),4,
                          VTK_UNSIGNED_CHAR,false);
  }
  this->Pass1->Resize(width, height);

  // Depth texture
  if (this->Pass1Depth == nullptr)
  {
    this->Pass1Depth = vtkTextureObject::New();
    this->Pass1Depth->SetContext(renWin);
    this->Pass1Depth->AllocateDepth(
      width, height, vtkTextureObject::Float32);
  }
  this->Pass1Depth->Resize(width, height);

  if(this->FrameBufferObject==nullptr)
  {
    this->FrameBufferObject=vtkOpenGLFramebufferObject::New();
    this->FrameBufferObject->SetContext(renWin);
  }

  this->FrameBufferObject->SaveCurrentBindingsAndBuffers();
  this->RenderDelegate(s,width,height,width,height,this->FrameBufferObject,
                       this->Pass1, this->Pass1Depth);

  this->FrameBufferObject->UnBind();
  this->FrameBufferObject->RestorePreviousBindingsAndBuffers();

  // has something changed that would require us to recreate the shader?
  if (!this->QuadHelper)
  {
    // build the shader source code
    // compile and bind it if needed
    this->QuadHelper = new vtkOpenGLQuadHelper(renWin,
        nullptr,
        vtkPointFillPassFS,
        "");
  }
  else
  {
    renWin->GetShaderCache()->ReadyShaderProgram(this->QuadHelper->Program);
  }

  if (!this->QuadHelper->Program)
  {
    return;
  }

  renWin->GetState()->vtkglDisable(GL_BLEND);
//  glDisable(GL_DEPTH_TEST);

  this->Pass1->Activate();
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  this->QuadHelper->Program->SetUniformi("source",this->Pass1->GetTextureUnit());

  this->Pass1Depth->Activate();
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  this->QuadHelper->Program->SetUniformi("depth",this->Pass1Depth->GetTextureUnit());

  vtkCamera *cam = r->GetActiveCamera();
  double *frange = cam->GetClippingRange();
  this->QuadHelper->Program->SetUniformf("nearC",frange[0]);
  this->QuadHelper->Program->SetUniformf("farC",frange[1]);
  this->QuadHelper->Program->SetUniformf("MinimumCandidateAngle",
    this->MinimumCandidateAngle);
  this->QuadHelper->Program->SetUniformf("CandidatePointRatio",
    this->CandidatePointRatio);
  float offset[2];
  offset[0] = 1.0/width;
  offset[1] = 1.0/height;
  this->QuadHelper->Program->SetUniform2f("pixelToTCoord", offset);

  this->QuadHelper->Render();
  this->Pass1->Deactivate();
  this->Pass1Depth->Deactivate();

  vtkOpenGLCheckErrorMacro("failed after Render");
}

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

  this->Superclass::ReleaseGraphicsResources(w);

  if (this->QuadHelper !=nullptr)
  {
    delete this->QuadHelper;
    this->QuadHelper = nullptr;
  }
  if(this->FrameBufferObject!=nullptr)
  {
    this->FrameBufferObject->Delete();
    this->FrameBufferObject=nullptr;
  }
   if(this->Pass1!=nullptr)
   {
    this->Pass1->Delete();
    this->Pass1=nullptr;
   }
   if(this->Pass1Depth!=nullptr)
   {
    this->Pass1Depth->Delete();
    this->Pass1Depth=nullptr;
   }
}
