// Created on: 2015-06-18
// Created by: Anton POLETAEV
// Copyright (c) 2015 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_TransformPers_HeaderFile
#define _Graphic3d_TransformPers_HeaderFile

#include "Aspect_TypeOfTriedronPosition.hxx"
#include "BVH_Box.hxx"
#include "Graphic3d_Camera.hxx"
#include "Graphic3d_TransformUtils.hxx"
#include "Graphic3d_TransModeFlags.hxx"
#include "NCollection_Vec2.hxx"
#include "Standard_TypeDef.hxx"
#include "NCollection_Vec3.hxx"
#include "NCollection_Vec4.hxx"
#include "NCollection_Mat4.hxx"

//! Transformation Persistence definition.
//!
//! Transformation Persistence defines a mutable Local Coordinate system which depends on camera
//! position, so that visual appearance of the object becomes partially immutable while camera
//! moves. Object visually preserves particular property such as size, placement, rotation or their
//! combination.
//!
//! Graphic3d_TMF_ZoomPers, Graphic3d_TMF_RotatePers and Graphic3d_TMF_ZoomRotatePers define Local
//! Coordinate system having origin in specified anchor point defined in World Coordinate system,
//! while Graphic3d_TMF_TriedronPers and Graphic3d_TMF_2d define origin as 2D offset from screen
//! corner in pixels.
//!
//! Graphic3d_TMF_2d, Graphic3d_TMF_TriedronPers and Graphic3d_TMF_ZoomPers defines Local Coordinate
//! system where length units are pixels. Beware that Graphic3d_RenderingParams::ResolutionRatio()
//! will be ignored! For other Persistence flags, normal (world) length units will apply.
//!
//! Graphic3d_TMF_AxialPers and Graphic3d_TMF_AxialZoomPers defines persistence in the axial scale,
//! i.e., keeps the object visual coherence when the camera's axial scale is changed.
//! Meant to be used by objects such as Manipulators and trihedrons.
//! WARNING: Graphic3d_TMF_None is not permitted for defining instance of this class - NULL handle
//! should be used for this purpose!
class Graphic3d_TransformPers : public Standard_Transient
{
  DEFINE_STANDARD_RTTIEXT(Graphic3d_TransformPers, Standard_Transient)
public:
  //! Return true if specified mode is zoom/rotate transformation persistence.
  static bool IsZoomOrRotate(Graphic3d_TransModeFlags theMode)
  {
    return (theMode & (Graphic3d_TMF_ZoomPers | Graphic3d_TMF_RotatePers)) != 0;
  }

  //! Return true if specified mode is 2d/trihedron transformation persistence.
  static bool IsTrihedronOr2d(Graphic3d_TransModeFlags theMode)
  {
    return (theMode & (Graphic3d_TMF_TriedronPers | Graphic3d_TMF_2d)) != 0;
  }

  //! Return true if specified mode is orthographic projection transformation persistence.
  static bool IsOrthoPers(Graphic3d_TransModeFlags theMode)
  {
    return (theMode & Graphic3d_TMF_OrthoPers) != 0;
  }

  //! Return true if specified mode is axial transformation persistence.
  static bool IsAxial(Graphic3d_TransModeFlags theMode)
  {
    return (theMode & Graphic3d_TMF_AxialScalePers) != 0;
  }

public:
  //! Set transformation persistence.
  Graphic3d_TransformPers(const Graphic3d_TransModeFlags theMode)
      : myMode(theMode)
  {
    if (IsZoomOrRotate(theMode) || IsAxial(theMode))
    {
      SetPersistence(theMode, gp_Pnt(0.0, 0.0, 0.0));
    }
    else if (IsTrihedronOr2d(theMode))
    {
      SetPersistence(theMode, Aspect_TOTP_LEFT_LOWER, NCollection_Vec2<int>(0, 0));
    }
    else if (theMode == Graphic3d_TMF_CameraPers)
    {
      myMode = theMode;
    }
    else
    {
      throw Standard_ProgramError(
        "Graphic3d_TransformPers::SetPersistence(), wrong persistence mode.");
    }
  }

  //! Set Zoom/Rotate transformation persistence with an anchor 3D point.
  //! Anchor point defines the origin of Local Coordinate system within World Coordinate system.
  //! Throws an exception if persistence mode is not Graphic3d_TMF_ZoomPers,
  //! Graphic3d_TMF_ZoomRotatePers or Graphic3d_TMF_RotatePers.
  Graphic3d_TransformPers(const Graphic3d_TransModeFlags theMode, const gp_Pnt& thePnt)
      : myMode(Graphic3d_TMF_None)
  {
    SetPersistence(theMode, thePnt);
  }

  //! Set 2d/trihedron transformation persistence with a corner and 2D offset.
  //! 2D offset defines the origin of Local Coordinate system as projection of 2D point on screen
  //! plane into World Coordinate system. Throws an exception if persistence mode is not
  //! Graphic3d_TMF_TriedronPers or Graphic3d_TMF_2d. The offset is a positive displacement from the
  //! view corner in pixels.
  Graphic3d_TransformPers(const Graphic3d_TransModeFlags      theMode,
                          const Aspect_TypeOfTriedronPosition theCorner,
                          const NCollection_Vec2<int>& theOffset = NCollection_Vec2<int>(0, 0))
      : myMode(Graphic3d_TMF_None)
  {
    SetPersistence(theMode, theCorner, theOffset);
  }

  //! Return true for Graphic3d_TMF_ZoomPers, Graphic3d_TMF_ZoomRotatePers or
  //! Graphic3d_TMF_RotatePers modes.
  bool IsZoomOrRotate() const { return IsZoomOrRotate(myMode); }

  //! Return true for Graphic3d_TMF_TriedronPers and Graphic3d_TMF_2d modes.
  bool IsTrihedronOr2d() const { return IsTrihedronOr2d(myMode); }

  //! Return true for Graphic3d_TMF_OrthoPers mode.
  bool IsOrthoPers() const { return IsOrthoPers(myMode); }

  //! Return true for Graphic3d_TMF_AxialScalePers modes.
  bool IsAxial() const { return IsAxial(myMode); }

  //! Transformation persistence mode flags.
  Graphic3d_TransModeFlags Mode() const { return myMode; }

  //! Transformation persistence mode flags.
  Graphic3d_TransModeFlags Flags() const { return myMode; }

  //! Set Zoom/Rotate transformation persistence with an anchor 3D point.
  //! Throws an exception if persistence mode is not Graphic3d_TMF_ZoomPers,
  //! Graphic3d_TMF_ZoomRotatePers or Graphic3d_TMF_RotatePers.
  void SetPersistence(const Graphic3d_TransModeFlags theMode, const gp_Pnt& thePnt)
  {
    if (!IsZoomOrRotate(theMode) && !IsAxial(theMode))
    {
      throw Standard_ProgramError(
        "Graphic3d_TransformPers::SetPersistence(), wrong persistence mode.");
    }

    myMode                 = theMode;
    myParams.Params3d.PntX = thePnt.X();
    myParams.Params3d.PntY = thePnt.Y();
    myParams.Params3d.PntZ = thePnt.Z();
  }

  //! Set 2d/trihedron transformation persistence with a corner and 2D offset.
  //! Throws an exception if persistence mode is not Graphic3d_TMF_TriedronPers or Graphic3d_TMF_2d.
  void SetPersistence(const Graphic3d_TransModeFlags      theMode,
                      const Aspect_TypeOfTriedronPosition theCorner,
                      const NCollection_Vec2<int>&        theOffset)
  {
    if (!IsTrihedronOr2d(theMode))
    {
      throw Standard_ProgramError(
        "Graphic3d_TransformPers::SetPersistence(), wrong persistence mode.");
    }

    myMode                    = theMode;
    myParams.Params2d.Corner  = theCorner;
    myParams.Params2d.OffsetX = theOffset.x();
    myParams.Params2d.OffsetY = theOffset.y();
  }

public:
  //! Return the anchor point for zoom/rotate transformation persistence.
  gp_Pnt AnchorPoint() const
  {
    if (!IsZoomOrRotate() && !IsAxial())
    {
      throw Standard_ProgramError(
        "Graphic3d_TransformPers::AnchorPoint(), wrong persistence mode.");
    }

    return gp_Pnt(myParams.Params3d.PntX, myParams.Params3d.PntY, myParams.Params3d.PntZ);
  }

  //! Set the anchor point for zoom/rotate transformation persistence.
  void SetAnchorPoint(const gp_Pnt& thePnt)
  {
    if (!IsZoomOrRotate() && !IsAxial())
    {
      throw Standard_ProgramError(
        "Graphic3d_TransformPers::SetAnchorPoint(), wrong persistence mode.");
    }

    myParams.Params3d.PntX = thePnt.X();
    myParams.Params3d.PntY = thePnt.Y();
    myParams.Params3d.PntZ = thePnt.Z();
  }

  //! Return the corner for 2d/trihedron transformation persistence.
  Aspect_TypeOfTriedronPosition Corner2d() const
  {
    if (!IsTrihedronOr2d())
    {
      throw Standard_ProgramError("Graphic3d_TransformPers::Corner2d(), wrong persistence mode.");
    }

    return myParams.Params2d.Corner;
  }

  //! Set the corner for 2d/trihedron transformation persistence.
  void SetCorner2d(const Aspect_TypeOfTriedronPosition thePos)
  {
    if (!IsTrihedronOr2d())
    {
      throw Standard_ProgramError(
        "Graphic3d_TransformPers::SetCorner2d(), wrong persistence mode.");
    }

    myParams.Params2d.Corner = thePos;
  }

  //! Return the offset from the corner for 2d/trihedron transformation persistence.
  NCollection_Vec2<int> Offset2d() const
  {
    if (!IsTrihedronOr2d())
    {
      throw Standard_ProgramError("Graphic3d_TransformPers::Offset2d(), wrong persistence mode.");
    }

    return NCollection_Vec2<int>(myParams.Params2d.OffsetX, myParams.Params2d.OffsetY);
  }

  //! Set the offset from the corner for 2d/trihedron transformation persistence.
  void SetOffset2d(const NCollection_Vec2<int>& theOffset)
  {
    if (!IsTrihedronOr2d())
    {
      throw Standard_ProgramError(
        "Graphic3d_TransformPers::SetOffset2d(), wrong persistence mode.");
    }

    myParams.Params2d.OffsetX = theOffset.x();
    myParams.Params2d.OffsetY = theOffset.y();
  }

public:
  //! Find scale value based on the camera position and view dimensions
  //! @param[in] theCamera  camera definition
  //! @param[in] theViewportWidth  the width of viewport.
  //! @param[in] theViewportHeight  the height of viewport.
  virtual double persistentScale(const occ::handle<Graphic3d_Camera>& theCamera,
                                 const int                            theViewportWidth,
                                 const int                            theViewportHeight) const
  {
    (void)theViewportWidth;
    // use total size when tiling is active
    const int aVPSizeY =
      theCamera->Tile().IsValid() ? theCamera->Tile().TotalSize.y() : theViewportHeight;

    gp_Vec aVecToEye(theCamera->Direction());
    gp_Vec aVecToObj(
      theCamera->Eye(),
      gp_Pnt(myParams.Params3d.PntX, myParams.Params3d.PntY, myParams.Params3d.PntZ));
    const double aFocus   = aVecToObj.Dot(aVecToEye);
    const gp_XYZ aViewDim = theCamera->ViewDimensions(aFocus);
    return std::abs(aViewDim.Y()) / double(aVPSizeY);
  }

  //! Create orientation matrix based on camera and view dimensions.
  //! Default implementation locks rotation by nullifying rotation component.
  //! Camera and view dimensions are not used, by default.
  //! @param[in] theCamera  camera definition
  //! @param[in] theViewportWidth  the width of viewport
  //! @param[in] theViewportHeight  the height of viewport
  virtual NCollection_Mat3<double> persistentRotationMatrix(
    const occ::handle<Graphic3d_Camera>& theCamera,
    const int                            theViewportWidth,
    const int                            theViewportHeight) const
  {
    (void)theCamera;
    (void)theViewportWidth;
    (void)theViewportHeight;

    NCollection_Mat3<double> aRotMat;
    return aRotMat;
  }

  //! Apply transformation to bounding box of presentation.
  //! @param[in] theCamera  camera definition
  //! @param[in] theProjection  the projection transformation matrix.
  //! @param[in] theWorldView  the world view transformation matrix.
  //! @param[in] theViewportWidth  the width of viewport (for 2d persistence).
  //! @param[in] theViewportHeight  the height of viewport (for 2d persistence).
  //! @param theBoundingBox [in/out] the bounding box to transform.
  template <class T>
  void Apply(const occ::handle<Graphic3d_Camera>& theCamera,
             const NCollection_Mat4<T>&           theProjection,
             const NCollection_Mat4<T>&           theWorldView,
             const int                            theViewportWidth,
             const int                            theViewportHeight,
             Bnd_Box&                             theBoundingBox) const;

  //! Apply transformation to bounding box of presentation
  //! @param[in] theCamera  camera definition
  //! @param[in] theProjection  the projection transformation matrix.
  //! @param[in] theWorldView  the world view transformation matrix.
  //! @param[in] theViewportWidth  the width of viewport (for 2d persistence).
  //! @param[in] theViewportHeight  the height of viewport (for 2d persistence).
  //! @param theBoundingBox [in/out] the bounding box to transform.
  template <class T>
  void Apply(const occ::handle<Graphic3d_Camera>& theCamera,
             const NCollection_Mat4<T>&           theProjection,
             const NCollection_Mat4<T>&           theWorldView,
             const int                            theViewportWidth,
             const int                            theViewportHeight,
             BVH_Box<T, 3>&                       theBoundingBox) const;

  //! Compute transformation.
  //! Computed matrix can be applied to model world transformation
  //! of an object to implement effect of transformation persistence.
  //! @param[in] theCamera  camera definition
  //! @param[in] theProjection  the projection transformation matrix.
  //! @param[in] theWorldView  the world view transformation matrix.
  //! @param[in] theViewportWidth  the width of viewport (for 2d persistence).
  //! @param[in] theViewportHeight  the height of viewport (for 2d persistence).
  //! @param[in] theToApplyProjPers  if should apply projection persistence to matrix (for
  //! orthographic persistence).
  //! @return transformation matrix to be applied to model world transformation of an object.
  template <class T>
  NCollection_Mat4<T> Compute(const occ::handle<Graphic3d_Camera>& theCamera,
                              const NCollection_Mat4<T>&           theProjection,
                              const NCollection_Mat4<T>&           theWorldView,
                              const int                            theViewportWidth,
                              const int                            theViewportHeight,
                              const bool theToApplyProjPers = false) const;

  //! Apply transformation persistence on specified matrices.
  //! @param[in] theCamera  camera definition
  //! @param[in] theProjection  projection matrix to modify
  //! @param theWorldView [in/out]  world-view matrix to modify
  //! @param[in] theViewportWidth   viewport width
  //! @param[in] theViewportHeight  viewport height
  //! @param[in] theAnchor  if not NULL, overrides anchor point
  //! @param[in] theToApplyProjPers  if should apply projection persistence to matrix (for
  //! orthographic persistence).
  template <class T>
  void Apply(const occ::handle<Graphic3d_Camera>& theCamera,
             const NCollection_Mat4<T>&           theProjection,
             NCollection_Mat4<T>&                 theWorldView,
             const int                            theViewportWidth,
             const int                            theViewportHeight,
             const gp_Pnt*                        theAnchor          = nullptr,
             const bool                           theToApplyProjPers = true) const;

  //! Perform computations for applying transformation persistence on specified matrices.
  //! @param[in] theCamera  camera definition
  //! @param[in] theViewportWidth   viewport width
  //! @param[in] theViewportHeight  viewport height
  //! @param[in] theAnchor  if not NULL, overrides anchor point
  virtual NCollection_Mat4<double> ComputeApply(occ::handle<Graphic3d_Camera>& theCamera,
                                                const int                      theViewportWidth,
                                                const int                      theViewportHeight,
                                                const gp_Pnt* theAnchor = nullptr) const
  {
    (void)theViewportWidth;
    occ::handle<Graphic3d_Camera> aProxyCamera = theCamera;
    if (IsOrthoPers() && !aProxyCamera->IsOrthographic())
    {
      // clang-format off
      aProxyCamera = new Graphic3d_Camera(*theCamera); // If OrthoPers, copy camera and set to orthographic projection
      // clang-format on
      aProxyCamera->SetProjectionType(Graphic3d_Camera::Projection_Orthographic);
    }

    NCollection_Mat4<double> aWorldView = aProxyCamera->OrientationMatrix();

    // use total size when tiling is active
    const int aVPSizeY =
      aProxyCamera->Tile().IsValid() ? aProxyCamera->Tile().TotalSize.y() : theViewportHeight;

    // a small enough jitter compensation offset
    // to avoid image dragging within single pixel in corner cases
    const double aJitterComp = 0.001;
    if ((myMode & Graphic3d_TMF_TriedronPers) != 0)
    {
      // reset Z focus for trihedron persistence
      const double aFocus = aProxyCamera->IsOrthographic()
                              ? aProxyCamera->Distance()
                              : (aProxyCamera->ZFocusType() == Graphic3d_Camera::FocusType_Relative
                                   ? double(aProxyCamera->ZFocus() * aProxyCamera->Distance())
                                   : double(aProxyCamera->ZFocus()));

      // scale factor to pixels
      const gp_XYZ aViewDim = aProxyCamera->ViewDimensions(aFocus);
      const double aScale   = std::abs(aViewDim.Y()) / double(aVPSizeY);
      const gp_Dir aForward = aProxyCamera->Direction();
      gp_XYZ       aCenter =
        aProxyCamera->Center().XYZ() + aForward.XYZ() * (aFocus - aProxyCamera->Distance());
      if ((myParams.Params2d.Corner & (Aspect_TOTP_LEFT | Aspect_TOTP_RIGHT)) != 0)
      {
        const double anOffsetX = (double(myParams.Params2d.OffsetX) + aJitterComp) * aScale;
        const gp_Dir aSide     = aForward.Crossed(aProxyCamera->Up());
        const gp_XYZ aDeltaX =
          aSide.XYZ() * (std::abs(aViewDim.X()) * aProxyCamera->NDC2dOffsetX() - anOffsetX);
        if ((myParams.Params2d.Corner & Aspect_TOTP_RIGHT) != 0)
        {
          aCenter += aDeltaX;
        }
        else
        {
          aCenter -= aDeltaX;
        }
      }
      if ((myParams.Params2d.Corner & (Aspect_TOTP_TOP | Aspect_TOTP_BOTTOM)) != 0)
      {
        const double anOffsetY = (double(myParams.Params2d.OffsetY) + aJitterComp) * aScale;
        const gp_XYZ aDeltaY =
          aProxyCamera->Up().XYZ()
          * (std::abs(aViewDim.Y()) * aProxyCamera->NDC2dOffsetY() - anOffsetY);
        if ((myParams.Params2d.Corner & Aspect_TOTP_TOP) != 0)
        {
          aCenter += aDeltaY;
        }
        else
        {
          aCenter -= aDeltaY;
        }
      }
      Graphic3d_TransformUtils::Scale(aWorldView,
                                      1.0 / theCamera->AxialScale().X(),
                                      1.0 / theCamera->AxialScale().Y(),
                                      1.0 / theCamera->AxialScale().Z());
      Graphic3d_TransformUtils::Translate(aWorldView, aCenter.X(), aCenter.Y(), aCenter.Z());
      Graphic3d_TransformUtils::Scale(aWorldView, aScale, aScale, aScale);
    }
    else if ((myMode & Graphic3d_TMF_2d) != 0)
    {
      const double aFocus = aProxyCamera->IsOrthographic()
                              ? aProxyCamera->Distance()
                              : (aProxyCamera->ZFocusType() == Graphic3d_Camera::FocusType_Relative
                                   ? double(aProxyCamera->ZFocus() * aProxyCamera->Distance())
                                   : double(aProxyCamera->ZFocus()));

      // scale factor to pixels
      const gp_XYZ aViewDim = aProxyCamera->ViewDimensions(aFocus);
      const double aScale   = std::abs(aViewDim.Y()) / double(aVPSizeY);
      gp_XYZ       aCenter(0.0, 0.0, -aFocus);
      if ((myParams.Params2d.Corner & (Aspect_TOTP_LEFT | Aspect_TOTP_RIGHT)) != 0)
      {
        aCenter.SetX(-aViewDim.X() * aProxyCamera->NDC2dOffsetX()
                     + (double(myParams.Params2d.OffsetX) + aJitterComp) * aScale);
        if ((myParams.Params2d.Corner & Aspect_TOTP_RIGHT) != 0)
        {
          aCenter.SetX(-aCenter.X());
        }
      }
      if ((myParams.Params2d.Corner & (Aspect_TOTP_TOP | Aspect_TOTP_BOTTOM)) != 0)
      {
        aCenter.SetY(-aViewDim.Y() * aProxyCamera->NDC2dOffsetY()
                     + (double(myParams.Params2d.OffsetY) + aJitterComp) * aScale);
        if ((myParams.Params2d.Corner & Aspect_TOTP_TOP) != 0)
        {
          aCenter.SetY(-aCenter.Y());
        }
      }

      aWorldView.InitIdentity();
      Graphic3d_TransformUtils::Translate(aWorldView, aCenter.X(), aCenter.Y(), aCenter.Z());
      Graphic3d_TransformUtils::Scale(aWorldView, aScale, aScale, aScale);
    }
    else if ((myMode & Graphic3d_TMF_CameraPers) != 0)
    {
      aWorldView.InitIdentity();
    }
    else
    {
      // Compute reference point for transformation in untransformed projection space.
      if (theAnchor != nullptr)
      {
        Graphic3d_TransformUtils::Translate(aWorldView,
                                            theAnchor->X(),
                                            theAnchor->Y(),
                                            theAnchor->Z());
      }
      else
      {
        Graphic3d_TransformUtils::Translate(aWorldView,
                                            myParams.Params3d.PntX,
                                            myParams.Params3d.PntY,
                                            myParams.Params3d.PntZ);
      }

      if ((myMode & Graphic3d_TMF_RotatePers) != 0)
      {
        NCollection_Mat3<double> aRotMat =
          persistentRotationMatrix(theCamera, theViewportWidth, theViewportHeight);

        aWorldView.SetValue(0, 0, aRotMat.GetColumn(0).x());
        aWorldView.SetValue(1, 0, aRotMat.GetColumn(0).y());
        aWorldView.SetValue(2, 0, aRotMat.GetColumn(0).z());

        aWorldView.SetValue(0, 1, aRotMat.GetColumn(1).x());
        aWorldView.SetValue(1, 1, aRotMat.GetColumn(1).y());
        aWorldView.SetValue(2, 1, aRotMat.GetColumn(1).z());

        aWorldView.SetValue(0, 2, aRotMat.GetColumn(2).x());
        aWorldView.SetValue(1, 2, aRotMat.GetColumn(2).y());
        aWorldView.SetValue(2, 2, aRotMat.GetColumn(2).z());
      }
      if (IsAxial())
      {
        Graphic3d_TransformUtils::Scale(aWorldView,
                                        1.0 / theCamera->AxialScale().X(),
                                        1.0 / theCamera->AxialScale().Y(),
                                        1.0 / theCamera->AxialScale().Z());
      }
      if ((myMode & Graphic3d_TMF_ZoomPers) != 0)
      {
        // lock zooming
        double aScale = persistentScale(aProxyCamera, theViewportWidth, theViewportHeight);
        Graphic3d_TransformUtils::Scale(aWorldView, aScale, aScale, aScale);
      }
    }
    theCamera = aProxyCamera;
    return aWorldView;
  }

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

private:
  //! 3D anchor point for zoom/rotate transformation persistence.
  struct PersParams3d
  {
    double PntX;
    double PntY;
    double PntZ;

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

  //! 2d/trihedron transformation persistence parameters.
  struct PersParams2d
  {
    int                           OffsetX;
    int                           OffsetY;
    Aspect_TypeOfTriedronPosition Corner;

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

private:
  Graphic3d_TransModeFlags myMode; //!< Transformation persistence mode flags

  union {
    PersParams3d Params3d;
    PersParams2d Params2d;
  } myParams;
};

// =======================================================================
// function : Apply
// purpose  : Apply transformation to world view and projection matrices.
// =======================================================================
template <class T>
void Graphic3d_TransformPers::Apply(const occ::handle<Graphic3d_Camera>& theCamera,
                                    const NCollection_Mat4<T>&           theProjection,
                                    NCollection_Mat4<T>&                 theWorldView,
                                    const int                            theViewportWidth,
                                    const int                            theViewportHeight,
                                    const gp_Pnt*                        theAnchor,
                                    const bool                           theToApplyProjPers) const
{
  (void)theViewportWidth;
  if (myMode == Graphic3d_TMF_None || theViewportHeight == 0)
  {
    return;
  }

  occ::handle<Graphic3d_Camera> aCamera = new Graphic3d_Camera(*theCamera);
  NCollection_Mat4<double>      aWorldView =
    ComputeApply(aCamera, theViewportWidth, theViewportHeight, theAnchor);

  if (!theCamera->IsOrthographic() && IsOrthoPers() && theToApplyProjPers)
  {
    NCollection_Mat4<double> aProjInv;
    aProjInv.ConvertFrom(theProjection.Inverted());
    aWorldView = (aProjInv * aCamera->ProjectionMatrix()) * aWorldView;
  }

  theWorldView.ConvertFrom(aWorldView);
}

// =======================================================================
// function : Apply
// purpose  : Apply transformation to bounding box of presentation.
// =======================================================================
template <class T>
void Graphic3d_TransformPers::Apply(const occ::handle<Graphic3d_Camera>& theCamera,
                                    const NCollection_Mat4<T>&           theProjection,
                                    const NCollection_Mat4<T>&           theWorldView,
                                    const int                            theViewportWidth,
                                    const int                            theViewportHeight,
                                    Bnd_Box&                             theBoundingBox) const
{
  if (theBoundingBox.IsVoid())
  {
    return;
  }

  T aXmin, aYmin, aZmin, aXmax, aYmax, aZmax;

  theBoundingBox.Get(aXmin, aYmin, aZmin, aXmax, aYmax, aZmax);

  typename BVH_Box<T, 3>::BVH_VecNt aMin(aXmin, aYmin, aZmin);
  typename BVH_Box<T, 3>::BVH_VecNt aMax(aXmax, aYmax, aZmax);
  BVH_Box<T, 3>                     aBBox(aMin, aMax);

  Apply(theCamera, theProjection, theWorldView, theViewportWidth, theViewportHeight, aBBox);

  theBoundingBox = Bnd_Box();
  theBoundingBox.Update(aBBox.CornerMin().x(),
                        aBBox.CornerMin().y(),
                        aBBox.CornerMin().z(),
                        aBBox.CornerMax().x(),
                        aBBox.CornerMax().y(),
                        aBBox.CornerMax().z());
}

// =======================================================================
// function : Apply
// purpose  : Apply transformation to bounding box of presentation.
// =======================================================================
template <class T>
void Graphic3d_TransformPers::Apply(const occ::handle<Graphic3d_Camera>& theCamera,
                                    const NCollection_Mat4<T>&           theProjection,
                                    const NCollection_Mat4<T>&           theWorldView,
                                    const int                            theViewportWidth,
                                    const int                            theViewportHeight,
                                    BVH_Box<T, 3>&                       theBoundingBox) const
{
  NCollection_Mat4<T> aTPers =
    Compute(theCamera, theProjection, theWorldView, theViewportWidth, theViewportHeight, false);
  if (aTPers.IsIdentity() || !theBoundingBox.IsValid())
  {
    return;
  }

  const typename BVH_Box<T, 3>::BVH_VecNt& aMin = theBoundingBox.CornerMin();
  const typename BVH_Box<T, 3>::BVH_VecNt& aMax = theBoundingBox.CornerMax();

  typename BVH_Box<T, 4>::BVH_VecNt anArrayOfCorners[8];
  anArrayOfCorners[0] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMin.x(), aMin.y(), aMin.z(), static_cast<T>(1.0));
  anArrayOfCorners[1] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMin.x(), aMin.y(), aMax.z(), static_cast<T>(1.0));
  anArrayOfCorners[2] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMin.x(), aMax.y(), aMin.z(), static_cast<T>(1.0));
  anArrayOfCorners[3] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMin.x(), aMax.y(), aMax.z(), static_cast<T>(1.0));
  anArrayOfCorners[4] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMax.x(), aMin.y(), aMin.z(), static_cast<T>(1.0));
  anArrayOfCorners[5] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMax.x(), aMin.y(), aMax.z(), static_cast<T>(1.0));
  anArrayOfCorners[6] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMax.x(), aMax.y(), aMin.z(), static_cast<T>(1.0));
  anArrayOfCorners[7] =
    typename BVH_Box<T, 4>::BVH_VecNt(aMax.x(), aMax.y(), aMax.z(), static_cast<T>(1.0));

  theBoundingBox.Clear();
  for (int anIt = 0; anIt < 8; ++anIt)
  {
    typename BVH_Box<T, 4>::BVH_VecNt& aCorner = anArrayOfCorners[anIt];
    aCorner                                    = aTPers * aCorner;
    aCorner                                    = aCorner / aCorner.w();
    theBoundingBox.Add(typename BVH_Box<T, 3>::BVH_VecNt(aCorner.x(), aCorner.y(), aCorner.z()));
  }
}

//=================================================================================================

template <class T>
NCollection_Mat4<T> Graphic3d_TransformPers::Compute(const occ::handle<Graphic3d_Camera>& theCamera,
                                                     const NCollection_Mat4<T>& theProjection,
                                                     const NCollection_Mat4<T>& theWorldView,
                                                     const int                  theViewportWidth,
                                                     const int                  theViewportHeight,
                                                     const bool theToApplyProjPers) const
{
  if (myMode == Graphic3d_TMF_None)
  {
    return NCollection_Mat4<T>();
  }

  NCollection_Mat4<T> aWorldView(theWorldView);
  NCollection_Mat4<T> anUnviewMat;
  if (!theWorldView.Inverted(anUnviewMat))
  {
    return NCollection_Mat4<T>();
  }

  // compute only world-view matrix difference to avoid floating point instability
  // caused by projection matrix modifications outside of this algorithm (e.g. by Z-fit)
  Apply(theCamera,
        theProjection,
        aWorldView,
        theViewportWidth,
        theViewportHeight,
        nullptr,
        theToApplyProjPers);
  return anUnviewMat * aWorldView;
}

#endif // _Graphic3d_TransformPers_HeaderFile