// Created by: Kirill GAVRILOV
// Copyright (c) 2013-2014 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_VertexBuffer_HeaderFile
#define OpenGl_VertexBuffer_HeaderFile

#include "OpenGl_Buffer.hxx"
#include "Graphic3d_Buffer.hxx"

//! Vertex Buffer Object - is a general storage object for vertex attributes (position, normal,
//! color). Notice that you should use OpenGl_IndexBuffer specialization for array of indices.
class OpenGl_VertexBuffer : public OpenGl_Buffer
{
public:
  //! Create uninitialized VBO.
  Standard_EXPORT OpenGl_VertexBuffer();

  //! Destroy object.
  Standard_EXPORT ~OpenGl_VertexBuffer() override;

  //! Return buffer target GL_ARRAY_BUFFER.
  Standard_EXPORT unsigned int GetTarget() const override;

  //! Bind this VBO to active GLSL program.
  Standard_EXPORT void BindVertexAttrib(const occ::handle<OpenGl_Context>& theGlCtx,
                                        const unsigned int                 theAttribLoc) const;

  //! Unbind any VBO from active GLSL program.
  Standard_EXPORT void UnbindVertexAttrib(const occ::handle<OpenGl_Context>& theGlCtx,
                                          const unsigned int                 theAttribLoc) const;

  //! Bind this VBO and enable specified attribute in OpenGl_Context::ActiveProgram() or FFP.
  //! @param theGlCtx - handle to bound GL context;
  //! @param theMode  - array mode (GL_VERTEX_ARRAY, GL_NORMAL_ARRAY, GL_COLOR_ARRAY,
  //! GL_INDEX_ARRAY, GL_TEXTURE_COORD_ARRAY).
  void BindAttribute(const occ::handle<OpenGl_Context>& theCtx,
                     const Graphic3d_TypeOfAttribute    theMode) const
  {
    if (IsValid())
    {
      Bind(theCtx);
      bindAttribute(theCtx, theMode, static_cast<int>(myComponentsNb), myDataType, 0, myOffset);
    }
  }

  //! Unbind this VBO and disable specified attribute in OpenGl_Context::ActiveProgram() or FFP.
  //! @param theCtx handle to bound GL context
  //! @param theMode  array mode
  void UnbindAttribute(const occ::handle<OpenGl_Context>& theCtx,
                       const Graphic3d_TypeOfAttribute    theMode) const
  {
    if (IsValid())
    {
      Unbind(theCtx);
      unbindAttribute(theCtx, theMode);
    }
  }

public: //! @name advanced methods
  //! Setup array pointer - either for active GLSL program OpenGl_Context::ActiveProgram()
  //! or for FFP using bindFixed() when no program bound.
  Standard_EXPORT static void bindAttribute(const occ::handle<OpenGl_Context>& theGlCtx,
                                            const Graphic3d_TypeOfAttribute    theMode,
                                            const int                          theNbComp,
                                            const unsigned int                 theDataType,
                                            const int                          theStride,
                                            const void*                        theOffset);

  //! Disable GLSL array pointer - either for active GLSL program OpenGl_Context::ActiveProgram()
  //! or for FFP using unbindFixed() when no program bound.
  Standard_EXPORT static void unbindAttribute(const occ::handle<OpenGl_Context>& theGlCtx,
                                              const Graphic3d_TypeOfAttribute    theMode);

private:
  //! Setup FFP array pointer.
  Standard_EXPORT static void bindFixed(const occ::handle<OpenGl_Context>& theGlCtx,
                                        const Graphic3d_TypeOfAttribute    theMode,
                                        const int                          theNbComp,
                                        const unsigned int                 theDataType,
                                        const int                          theStride,
                                        const void*                        theOffset);

  //! Disable FFP array pointer.
  Standard_EXPORT static void unbindFixed(const occ::handle<OpenGl_Context>& theGlCtx,
                                          const Graphic3d_TypeOfAttribute    theMode);

  //! Disable FFP color array pointer.
  Standard_EXPORT static void unbindFixedColor(const occ::handle<OpenGl_Context>& theCtx);

public: //! @name methods for interleaved attributes array
  //! @return true if buffer contains per-vertex color attribute
  Standard_EXPORT virtual bool HasColorAttribute() const;

  //! @return true if buffer contains per-vertex normal attribute
  Standard_EXPORT virtual bool HasNormalAttribute() const;

  //! Bind all vertex attributes to active program OpenGl_Context::ActiveProgram() or for FFP.
  //! Default implementation does nothing.
  Standard_EXPORT virtual void BindAllAttributes(const occ::handle<OpenGl_Context>& theGlCtx) const;

  //! Bind vertex position attribute only. Default implementation does nothing.
  Standard_EXPORT virtual void BindPositionAttribute(
    const occ::handle<OpenGl_Context>& theGlCtx) const;

  //! Unbind all vertex attributes. Default implementation does nothing.
  Standard_EXPORT virtual void UnbindAllAttributes(
    const occ::handle<OpenGl_Context>& theGlCtx) const;

public:
  DEFINE_STANDARD_RTTIEXT(OpenGl_VertexBuffer, OpenGl_Buffer)
};

#endif // _OpenGl_VertexBuffer_H__