// Author: Ilya Khramov
// Copyright (c) 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_CubeMap_HeaderFile
#define _Graphic3d_CubeMap_HeaderFile

#include <Graphic3d_CubeMapOrder.hxx>
#include <Graphic3d_TextureMap.hxx>

//! Base class for cubemaps.
//! It is iterator over cubemap sides.
class Graphic3d_CubeMap : public Graphic3d_TextureMap
{
  DEFINE_STANDARD_RTTIEXT(Graphic3d_CubeMap, Graphic3d_TextureMap)
public:

  //! Constructor defining loading cubemap from file.
  Graphic3d_CubeMap (const TCollection_AsciiString& theFileName) :
    Graphic3d_TextureMap (theFileName, Graphic3d_TOT_CUBEMAP),
    myCurrentSide  (Graphic3d_CMS_POS_X),
    myEndIsReached (false),
    myIsTopDown    (true),
    myZIsInverted  (false)
  {}

  //! Constructor defining direct cubemap initialization from PixMap.
  Graphic3d_CubeMap (const Handle(Image_PixMap)& thePixmap = Handle(Image_PixMap)()) :
    Graphic3d_TextureMap (thePixmap, Graphic3d_TOT_CUBEMAP),
    myCurrentSide  (Graphic3d_CMS_POS_X),
    myEndIsReached (false),
    myIsTopDown    (true),
    myZIsInverted  (false)
  {}

  //! Returns whether the iterator has reached the end (true if it hasn't). 
  Standard_Boolean More() const { return !myEndIsReached; }

  //! Returns current cubemap side (iterator state).
  Graphic3d_CubeMapSide CurrentSide() const { return myCurrentSide; }

  //! Moves iterator to the next cubemap side.
  //! Uses OpenGL cubemap sides order +X -> -X -> +Y -> -Y -> +Z -> -Z.
  void Next()
  {
    if (!myEndIsReached && myCurrentSide == Graphic3d_CMS_NEG_Z)
    {
      myEndIsReached = true;
    }
    else
    {
      myCurrentSide = Graphic3d_CubeMapSide (myCurrentSide + 1);
    }
  }

  //! Returns whether row's memory layout is top-down.
  Standard_Boolean IsTopDown() const
  {
    return myIsTopDown;
  }

  //! Sets Z axis inversion (vertical flipping).
  void SetZInversion (Standard_Boolean theZIsInverted)
  {
    myZIsInverted = theZIsInverted;
  }

  //! Returns whether Z axis is inverted.
  Standard_Boolean ZIsInverted() const
  {
    return myZIsInverted;
  }

  //! Returns PixMap containing current side of cubemap.
  //! Returns null handle if current side is invalid.
  virtual Handle(Image_PixMap) Value() = 0;

  //! Sets iterator state to +X cubemap side.
  Graphic3d_CubeMap& Reset()
  { 
    myCurrentSide = Graphic3d_CMS_POS_X;
    myEndIsReached = false;
    return *this;
  }

  //! Empty destructor.
  ~Graphic3d_CubeMap() {}

protected:

  Graphic3d_CubeMapSide myCurrentSide;  //!< Iterator state
  Standard_Boolean      myEndIsReached; //!< Indicates whether end of iteration has been reached or hasn't
  Standard_Boolean      myIsTopDown;    //!< Stores rows's memory layout
  Standard_Boolean      myZIsInverted;  //!< Indicates whether Z axis is inverted that allows to synchronize vertical flip of cubemap

};

DEFINE_STANDARD_HANDLE(Graphic3d_CubeMap, Graphic3d_TextureMap)

#endif // _Graphic3d_CubeMap_HeaderFile