// Copyright (c) 2011-2019 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.

#ifndef _Graphic3d_Layer_HeaderFile
#define _Graphic3d_Layer_HeaderFile

#include "Graphic3d_BvhCStructureSet.hxx"
#include "Graphic3d_BvhCStructureSetTrsfPers.hxx"
#include "Graphic3d_DisplayPriority.hxx"
#include "Graphic3d_ZLayerId.hxx"
#include "Graphic3d_ZLayerSettings.hxx"
#include "Graphic3d_RenderingParams.hxx"
#include "NCollection_Array1.hxx"
#include "NCollection_IndexedMap.hxx"

#include <array>

//! Defines index map of structures.

//! Defines array of indexed maps of structures.
typedef std::array<NCollection_IndexedMap<const Graphic3d_CStructure*>,
                   Graphic3d_DisplayPriority_NB>
  Graphic3d_ArrayOfIndexedMapOfStructure;

class Graphic3d_CullingTool;

//! Presentations list sorted within priorities.
class Graphic3d_Layer : public Standard_Transient
{
  DEFINE_STANDARD_RTTIEXT(Graphic3d_Layer, Standard_Transient)
public:
  //! Initializes associated priority list and layer properties
  Standard_EXPORT Graphic3d_Layer(Graphic3d_ZLayerId                theId,
                                  const occ::handle<BVH_Builder3d>& theBuilder);

  //! Destructor.
  Standard_EXPORT ~Graphic3d_Layer() override;

  //! Return layer id.
  Graphic3d_ZLayerId LayerId() const { return myLayerId; }

  //! Returns BVH tree builder for frustum culling.
  const occ::handle<BVH_Builder3d>& FrustumCullingBVHBuilder() const
  {
    return myBVHPrimitivesTrsfPers.Builder();
  }

  //! Assigns BVH tree builder for frustum culling.
  void SetFrustumCullingBVHBuilder(const occ::handle<BVH_Builder3d>& theBuilder)
  {
    myBVHPrimitivesTrsfPers.SetBuilder(theBuilder);
  }

  //! Return true if layer was marked with immediate flag.
  bool IsImmediate() const { return myLayerSettings.IsImmediate(); }

  //! Returns settings of the layer object.
  const Graphic3d_ZLayerSettings& LayerSettings() const { return myLayerSettings; };

  //! Sets settings of the layer object.
  Standard_EXPORT void SetLayerSettings(const Graphic3d_ZLayerSettings& theSettings);

  Standard_EXPORT void Add(const Graphic3d_CStructure* theStruct,
                           Graphic3d_DisplayPriority   thePriority,
                           bool                        isForChangePriority = false);

  //! Remove structure and returns its priority, if the structure is not found, method returns
  //! negative value
  Standard_EXPORT bool Remove(const Graphic3d_CStructure* theStruct,
                              Graphic3d_DisplayPriority&  thePriority,
                              bool                        isForChangePriority = false);

  //! @return the number of structures
  int NbStructures() const { return myNbStructures; }

  //! Number of NOT culled structures in the layer.
  int NbStructuresNotCulled() const { return myNbStructuresNotCulled; }

  //! Returns the number of available priority levels
  int NbPriorities() const { return Graphic3d_DisplayPriority_NB; }

  //! Append layer of acceptable type (with similar number of priorities or less).
  //! Returns false if the list can not be accepted.
  Standard_EXPORT bool Append(const Graphic3d_Layer& theOther);

  //! Returns array of structures.
  const Graphic3d_ArrayOfIndexedMapOfStructure& ArrayOfStructures() const { return myArray; }

  //! Returns structures for specified priority.
  const NCollection_IndexedMap<const Graphic3d_CStructure*>& Structures(
    Graphic3d_DisplayPriority thePriority) const
  {
    return myArray[thePriority];
  }

  //! Marks BVH tree for given priority list as dirty and
  //! marks primitive set for rebuild.
  Standard_EXPORT void InvalidateBVHData();

  //! Marks cached bounding box as obsolete.
  void InvalidateBoundingBox() const
  {
    myIsBoundingBoxNeedsReset[0] = myIsBoundingBoxNeedsReset[1] = true;
  }

  //! Returns layer bounding box.
  //! @param theViewId             view index to consider View Affinity in structure
  //! @param theCamera             camera definition
  //! @param theWindowWidth        viewport width  (for applying transformation-persistence)
  //! @param theWindowHeight       viewport height (for applying transformation-persistence)
  //! @param theToIncludeAuxiliary consider also auxiliary presentations (with infinite flag or with
  //! trihedron transformation persistence)
  //! @return computed bounding box
  Standard_EXPORT Bnd_Box BoundingBox(int                                  theViewId,
                                      const occ::handle<Graphic3d_Camera>& theCamera,
                                      int                                  theWindowWidth,
                                      int                                  theWindowHeight,
                                      bool theToIncludeAuxiliary) const;

  //! Returns zoom-scale factor.
  Standard_EXPORT double considerZoomPersistenceObjects(
    int                                  theViewId,
    const occ::handle<Graphic3d_Camera>& theCamera,
    int                                  theWindowWidth,
    int                                  theWindowHeight) const;

  //! Update culling state - should be called before rendering.
  //! Traverses through BVH tree to determine which structures are in view volume.
  Standard_EXPORT void UpdateCulling(
    int                                             theViewId,
    const Graphic3d_CullingTool&                    theSelector,
    const Graphic3d_RenderingParams::FrustumCulling theFrustumCullingState);

  //! Returns TRUE if layer is empty or has been discarded entirely by culling test.
  bool IsCulled() const { return myNbStructuresNotCulled == 0; }

  //! Returns number of transform persistence objects.
  int NbOfTransformPersistenceObjects() const { return myBVHPrimitivesTrsfPers.Size(); }

public:
  //! Returns set of Graphic3d_CStructures structures for building BVH tree.
  const Graphic3d_BvhCStructureSet& CullableStructuresBVH() const { return myBVHPrimitives; }

  //! Returns set of transform persistent Graphic3d_CStructures for building BVH tree.
  const Graphic3d_BvhCStructureSetTrsfPers& CullableTrsfPersStructuresBVH() const
  {
    return myBVHPrimitivesTrsfPers;
  }

  //! Returns indexed map of always rendered structures.
  const NCollection_IndexedMap<const Graphic3d_CStructure*>& NonCullableStructures() const
  {
    return myAlwaysRenderedMap;
  }

  //! Dumps the content of me into the stream
  Standard_EXPORT void DumpJson(Standard_OStream& theOStream, int theDepth = -1) const;

protected:
  //! Updates BVH trees if their state has been invalidated.
  Standard_EXPORT void updateBVH() const;

private:
  //! Array of Graphic3d_CStructures by priority rendered in layer.
  Graphic3d_ArrayOfIndexedMapOfStructure myArray;

  //! Overall number of structures rendered in the layer.
  int myNbStructures;

  //! Number of NOT culled structures in the layer.
  int myNbStructuresNotCulled;

  //! Layer setting flags.
  Graphic3d_ZLayerSettings myLayerSettings;

  //! Layer id.
  Graphic3d_ZLayerId myLayerId;

  //! Set of Graphic3d_CStructures structures for building BVH tree.
  mutable Graphic3d_BvhCStructureSet myBVHPrimitives;

  //! Set of transform persistent Graphic3d_CStructures for building BVH tree.
  mutable Graphic3d_BvhCStructureSetTrsfPers myBVHPrimitivesTrsfPers;

  //! Indexed map of always rendered structures.
  mutable NCollection_IndexedMap<const Graphic3d_CStructure*> myAlwaysRenderedMap;

  //! Is needed for implementation of stochastic order of BVH traverse.
  bool myBVHIsLeftChildQueuedFirst;

  //! Defines if the primitive set for BVH is outdated.
  mutable bool myIsBVHPrimitivesNeedsReset;

  //! Defines if the cached bounding box is outdated.
  mutable bool myIsBoundingBoxNeedsReset[2];

  //! Cached layer bounding box.
  mutable Bnd_Box myBoundingBox[2];
};

#endif // _Graphic3d_Layer_HeaderFile