// Created on: 2013-08-27
// Created by: Denis BOGOLEPOV
// Copyright (c) 2013 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#include <Standard_Assert.hxx>

#ifdef HAVE_TBB
  // On Windows, function TryEnterCriticalSection has appeared in Windows NT
  // and is surrounded by #ifdef in MS VC++ 7.1 headers.
  // Thus to use it we need to define appropriate macro saying that we wil
  // run on Windows NT 4.0 at least
  #if ((defined(_WIN32) || defined(__WIN32__)) && !defined(_WIN32_WINNT))
    #define _WIN32_WINNT 0x0501
  #endif

  #include <tbb/tbb.h>
#endif

#include <OpenGl_SceneGeometry.hxx>

//! Use this macro to output BVH profiling info
//#define BVH_PRINT_INFO

#ifdef BVH_PRINT_INFO
  #include <OSD_Timer.hxx>
#endif

namespace
{
  //! Useful constant for null floating-point 4D vector.
  static const BVH_Vec4f ZERO_VEC_4F;
};

// =======================================================================
// function : OpenGl_RaytraceMaterial
// purpose  : Creates new default material
// =======================================================================
OpenGl_RaytraceMaterial::OpenGl_RaytraceMaterial()
: Ambient      (ZERO_VEC_4F),
  Diffuse      (ZERO_VEC_4F),
  Specular     (ZERO_VEC_4F),
  Emission     (ZERO_VEC_4F),
  Reflection   (ZERO_VEC_4F),
  Refraction   (ZERO_VEC_4F),
  Transparency (ZERO_VEC_4F)
{ }

// =======================================================================
// function : OpenGl_RaytraceMaterial
// purpose  : Creates new material with specified properties
// =======================================================================
OpenGl_RaytraceMaterial::OpenGl_RaytraceMaterial (const BVH_Vec4f& theAmbient,
                                                  const BVH_Vec4f& theDiffuse,
                                                  const BVH_Vec4f& theSpecular)
: Ambient      (theAmbient),
  Diffuse      (theDiffuse),
  Specular     (theSpecular),
  Emission     (ZERO_VEC_4F),
  Reflection   (ZERO_VEC_4F),
  Refraction   (ZERO_VEC_4F),
  Transparency (ZERO_VEC_4F)
{
  //
}

// =======================================================================
// function : OpenGl_RaytraceMaterial
// purpose  : Creates new material with specified properties
// =======================================================================
OpenGl_RaytraceMaterial::OpenGl_RaytraceMaterial (const BVH_Vec4f& theAmbient,
                                                  const BVH_Vec4f& theDiffuse,
                                                  const BVH_Vec4f& theSpecular,
                                                  const BVH_Vec4f& theEmission,
                                                  const BVH_Vec4f& theTranspar)
: Ambient      (theAmbient),
  Diffuse      (theDiffuse),
  Specular     (theSpecular),
  Emission     (theEmission),
  Reflection   (ZERO_VEC_4F),
  Refraction   (ZERO_VEC_4F),
  Transparency (theTranspar)
{
  //
}

// =======================================================================
// function : OpenGl_RaytraceMaterial
// purpose  : Creates new material with specified properties
// =======================================================================
OpenGl_RaytraceMaterial::OpenGl_RaytraceMaterial (const BVH_Vec4f& theAmbient,
                                                  const BVH_Vec4f& theDiffuse,
                                                  const BVH_Vec4f& theSpecular,
                                                  const BVH_Vec4f& theEmission,
                                                  const BVH_Vec4f& theTranspar,
                                                  const BVH_Vec4f& theReflection,
                                                  const BVH_Vec4f& theRefraction)
: Ambient      (theAmbient),
  Diffuse      (theDiffuse),
  Specular     (theSpecular),
  Emission     (theEmission),
  Reflection   (theReflection),
  Refraction   (theRefraction),
  Transparency (theTranspar)
{
  //
}

// =======================================================================
// function : OpenGl_LightSource
// purpose  : Creates new light source
// =======================================================================
OpenGl_RaytraceLight::OpenGl_RaytraceLight (const BVH_Vec4f& theDiffuse,
                                            const BVH_Vec4f& thePosition)
: Diffuse (theDiffuse),
  Position (thePosition)
{
  //
}

// =======================================================================
// function : Clear
// purpose  : Clears ray-tracing geometry
// =======================================================================
void OpenGl_RaytraceGeometry::Clear()
{
  BVH_Geometry<Standard_ShortReal, 4>::BVH_Geometry::Clear();

  std::vector<OpenGl_RaytraceLight,
    NCollection_StdAllocator<OpenGl_RaytraceLight> > anEmptySources;

  Sources.swap (anEmptySources);

  std::vector<OpenGl_RaytraceMaterial,
    NCollection_StdAllocator<OpenGl_RaytraceMaterial> > anEmptyMaterials;

  Materials.swap (anEmptyMaterials);
}

#ifdef HAVE_TBB

struct OpenGL_BVHParallelBuilder
{
  BVH_ObjectSet<Standard_ShortReal, 4>* Set;

  OpenGL_BVHParallelBuilder (BVH_ObjectSet<Standard_ShortReal, 4>* theSet)
    : Set (theSet)
  {
    //
  }

  void operator() (const tbb::blocked_range<size_t>& theRange) const
  {
    for (size_t anObjectIdx = theRange.begin(); anObjectIdx != theRange.end(); ++anObjectIdx)
    {
      OpenGl_TriangleSet* aTriangleSet = dynamic_cast<OpenGl_TriangleSet*> (
        Set->Objects().ChangeValue (static_cast<Standard_Integer> (anObjectIdx)).operator->());

      if (aTriangleSet != NULL)
      {
        aTriangleSet->BVH();
      }
    }
  }
};

#endif

// =======================================================================
// function : ProcessAcceleration
// purpose  : Performs post-processing of high-level BVH
// =======================================================================
Standard_Boolean OpenGl_RaytraceGeometry::ProcessAcceleration()
{
#ifdef BVH_PRINT_INFO
    OSD_Timer aTimer;
#endif

  MarkDirty(); // force BVH rebuilding

#ifdef BVH_PRINT_INFO
  aTimer.Reset();
  aTimer.Start();
#endif

#ifdef HAVE_TBB
  // If Intel TBB is available, perform the preliminary
  // construction of bottom-level scene BVHs
  tbb::parallel_for (tbb::blocked_range<size_t> (0, Size()),
    OpenGL_BVHParallelBuilder (this));
#endif

  myBottomLevelTreeDepth = 0;

  for (Standard_Integer anObjectIdx = 0; anObjectIdx < Size(); ++anObjectIdx)
  {
    OpenGl_TriangleSet* aTriangleSet = dynamic_cast<OpenGl_TriangleSet*> (
      myObjects.ChangeValue (anObjectIdx).operator->());

    Standard_ASSERT_RETURN (aTriangleSet != NULL,
      "Error! Failed to get triangulation of OpenGL element", Standard_False);

    Standard_ASSERT_RETURN (!aTriangleSet->BVH().IsNull(),
      "Error! Failed to update bottom-level BVH of OpenGL element", Standard_False);

    myBottomLevelTreeDepth = Max (myBottomLevelTreeDepth, aTriangleSet->BVH()->Depth());
  }

#ifdef BVH_PRINT_INFO
  aTimer.Stop();

  std::cout << "Updating bottom-level BVHs (sec): " <<
    aTimer.ElapsedTime() << std::endl;
#endif

#ifdef BVH_PRINT_INFO
  aTimer.Reset();
  aTimer.Start();
#endif

  NCollection_Handle<BVH_Tree<Standard_ShortReal, 4> > aBVH = BVH();

#ifdef BVH_PRINT_INFO
  aTimer.Stop();

  std::cout << "Updating high-level BVH (sec): " <<
    aTimer.ElapsedTime() << std::endl;
#endif

  Standard_ASSERT_RETURN (!aBVH.IsNull(),
    "Error! Failed to update high-level BVH of ray-tracing scene", Standard_False);

  myHighLevelTreeDepth = aBVH->Depth();

  Standard_Integer aVerticesOffset = 0;
  Standard_Integer aElementsOffset = 0;
  Standard_Integer aBVHNodesOffset = 0;

  for (Standard_Integer aNodeIdx = 0; aNodeIdx < aBVH->Length(); ++aNodeIdx)
  {
    if (!aBVH->IsOuter (aNodeIdx))
      continue;

    Standard_ASSERT_RETURN (aBVH->BegPrimitive (aNodeIdx) == aBVH->EndPrimitive (aNodeIdx),
      "Error! Invalid leaf node in high-level BVH (contains several objects)", Standard_False);

    Standard_Integer anObjectIdx = aBVH->BegPrimitive (aNodeIdx);

    Standard_ASSERT_RETURN (anObjectIdx < myObjects.Size(),
      "Error! Invalid leaf node in high-level BVH (contains out-of-range object)", Standard_False);

    OpenGl_TriangleSet* aTriangleSet = dynamic_cast<OpenGl_TriangleSet*> (
      myObjects.ChangeValue (anObjectIdx).operator->());

    // Note: We overwrite node info record to store parameters
    // of bottom-level BVH and triangulation of OpenGL element

    aBVH->NodeInfoBuffer().at (aNodeIdx) = BVH_Vec4i (
      anObjectIdx + 1 /* to keep leaf flag */, aBVHNodesOffset, aVerticesOffset, aElementsOffset);

    aVerticesOffset += (int)aTriangleSet->Vertices.size();
    aElementsOffset += (int)aTriangleSet->Elements.size();
    aBVHNodesOffset += aTriangleSet->BVH()->Length();
  }

  return Standard_True;
}

// =======================================================================
// function : AccelerationOffset
// purpose  : Returns offset of bottom-level BVH for given leaf node
// =======================================================================
Standard_Integer OpenGl_RaytraceGeometry::AccelerationOffset (Standard_Integer theNodeIdx)
{
  const NCollection_Handle<BVH_Tree<Standard_ShortReal, 4> >& aBVH = BVH();

  if (theNodeIdx >= aBVH->Length() || !aBVH->IsOuter (theNodeIdx))
    return INVALID_OFFSET;

  return aBVH->NodeInfoBuffer().at (theNodeIdx).y();
}

// =======================================================================
// function : VerticesOffset
// purpose  : Returns offset of triangulation vertices for given leaf node
// =======================================================================
Standard_Integer OpenGl_RaytraceGeometry::VerticesOffset (Standard_Integer theNodeIdx)
{
  const NCollection_Handle<BVH_Tree<Standard_ShortReal, 4> >& aBVH = BVH();

  if (theNodeIdx >= aBVH->Length() || !aBVH->IsOuter (theNodeIdx))
    return INVALID_OFFSET;

  return aBVH->NodeInfoBuffer().at (theNodeIdx).z();
}

// =======================================================================
// function : ElementsOffset
// purpose  : Returns offset of triangulation elements for given leaf node
// =======================================================================
Standard_Integer OpenGl_RaytraceGeometry::ElementsOffset (Standard_Integer theNodeIdx)
{
  const NCollection_Handle<BVH_Tree<Standard_ShortReal, 4> >& aBVH = BVH();

  if (theNodeIdx >= aBVH->Length() || !aBVH->IsOuter (theNodeIdx))
    return INVALID_OFFSET;

  return aBVH->NodeInfoBuffer().at (theNodeIdx).w();
}

// =======================================================================
// function : TriangleSet
// purpose  : Returns triangulation data for given leaf node
// =======================================================================
OpenGl_TriangleSet* OpenGl_RaytraceGeometry::TriangleSet (Standard_Integer theNodeIdx)
{
  const NCollection_Handle<BVH_Tree<Standard_ShortReal, 4> >& aBVH = BVH();

  if (theNodeIdx >= aBVH->Length() || !aBVH->IsOuter (theNodeIdx))
    return NULL;

  if (aBVH->NodeInfoBuffer().at (theNodeIdx).x() > myObjects.Size())
    return NULL;

  return dynamic_cast<OpenGl_TriangleSet*> (myObjects.ChangeValue (
    aBVH->NodeInfoBuffer().at (theNodeIdx).x() - 1).operator->());
}

namespace OpenGl_Raytrace
{
  // =======================================================================
  // function : IsRaytracedElement
  // purpose  : Checks to see if the element contains ray-trace geometry
  // =======================================================================
  Standard_Boolean IsRaytracedElement (const OpenGl_ElementNode* theNode)
  {
    OpenGl_PrimitiveArray* anArray = dynamic_cast< OpenGl_PrimitiveArray* > (theNode->elem);
    return anArray != NULL
        && anArray->PArray()->type >= TelPolygonsArrayType;
  }

  // =======================================================================
  // function : IsRaytracedGroup
  // purpose  : Checks to see if the group contains ray-trace geometry
  // =======================================================================
  Standard_Boolean IsRaytracedGroup (const OpenGl_Group *theGroup)
  {
    const OpenGl_ElementNode* aNode;
    for (aNode = theGroup->FirstNode(); aNode != NULL; aNode = aNode->next)
    {
      if (IsRaytracedElement (aNode))
      {
        return Standard_True;
      }
    }
    return Standard_False;
  }

  // =======================================================================
  // function : IsRaytracedStructure
  // purpose  : Checks to see if the structure contains ray-trace geometry
  // =======================================================================
  Standard_Boolean IsRaytracedStructure (const OpenGl_Structure* theStructure)
  {
    for (OpenGl_Structure::GroupIterator aGroupIter (theStructure->DrawGroups());
         aGroupIter.More(); aGroupIter.Next())
    {
      if (aGroupIter.Value()->IsRaytracable())
        return Standard_True;
    }
    for (OpenGl_ListOfStructure::Iterator anIts (theStructure->ConnectedStructures());
         anIts.More(); anIts.Next())
    {
      if (IsRaytracedStructure (anIts.Value()))
        return Standard_True;
    }
    return Standard_False;
  }
}