// Created on: 2011-08-05
// Created by: Sergey ZERCHANINOV
// Copyright (c) 2011-2014 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 OpenGl_Element_HeaderFile
#define OpenGl_Element_HeaderFile

#include <Standard_Type.hxx>
#include <Standard_Handle.hxx>

class Graphic3d_FrameStatsDataTmp;
class OpenGl_Workspace;
class OpenGl_Context;

//! Base interface for drawable elements.
class OpenGl_Element
{
public:

  Standard_EXPORT OpenGl_Element();

  virtual void Render (const Handle(OpenGl_Workspace)& theWorkspace) const = 0;

  //! Release GPU resources.
  //! Pointer to the context is used because this method might be called
  //! when the context is already being destroyed and usage of a handle
  //! would be unsafe
  virtual void Release (OpenGl_Context* theContext) = 0;

  //! Pointer to the context is used because this method might be called
  //! when the context is already being destroyed and usage of a handle
  //! would be unsafe
  template <typename theResource_t>
  static void Destroy (OpenGl_Context* theContext,
                       theResource_t*& theElement)
  {
    if (theElement == NULL)
    {
      return;
    }

    theElement->Release (theContext);
    OpenGl_Element* anElement = theElement;
    delete anElement;
    theElement = NULL;
  }

public:

  //! Return TRUE if primitive type generates shaded triangulation (to be used in filters).
  virtual Standard_Boolean IsFillDrawMode() const { return false; }

  //! Returns estimated GPU memory usage for holding data without considering overheads and allocation alignment rules.
  virtual Standard_Size EstimatedDataSize() const { return 0; }

  //! Increment memory usage statistics.
  //! Default implementation puts EstimatedDataSize() into Graphic3d_FrameStatsCounter_EstimatedBytesGeom.
  Standard_EXPORT virtual void UpdateMemStats (Graphic3d_FrameStatsDataTmp& theStats) const;

  //! Increment draw calls statistics.
  //! @param theStats [in] [out] frame counters to increment
  //! @param theIsDetailed  [in] indicate detailed dump (more counters - number of triangles, points, etc.)
  Standard_EXPORT virtual void UpdateDrawStats (Graphic3d_FrameStatsDataTmp& theStats,
                                                 bool theIsDetailed) const;

  //! Update parameters of the drawable elements.
  virtual void SynchronizeAspects() {}

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

protected:

  Standard_EXPORT virtual ~OpenGl_Element();

public:

  DEFINE_STANDARD_ALLOC

};

#endif // OpenGl_Element_Header