// 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.

#include <OpenGl_VertexBuffer.hxx>

#include <OpenGl_Context.hxx>
#include <OpenGl_ShaderManager.hxx>
#include <Standard_Assert.hxx>

IMPLEMENT_STANDARD_RTTIEXT(OpenGl_VertexBuffer, OpenGl_Buffer)

// =======================================================================
// function : OpenGl_VertexBuffer
// purpose  :
// =======================================================================
OpenGl_VertexBuffer::OpenGl_VertexBuffer()
{
  //
}

// =======================================================================
// function : ~OpenGl_VertexBuffer
// purpose  :
// =======================================================================
OpenGl_VertexBuffer::~OpenGl_VertexBuffer()
{
  //
}

// =======================================================================
// function : GetTarget
// purpose  :
// =======================================================================
unsigned int OpenGl_VertexBuffer::GetTarget() const
{
  return GL_ARRAY_BUFFER;
}

// =======================================================================
// function : BindVertexAttrib
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::BindVertexAttrib (const Handle(OpenGl_Context)& theGlCtx,
                                            const unsigned int            theAttribLoc) const
{
  if (!IsValid() || theAttribLoc == GLuint (-1))
  {
    return;
  }
  Bind (theGlCtx);
  theGlCtx->core20fwd->glEnableVertexAttribArray (theAttribLoc);
  theGlCtx->core20fwd->glVertexAttribPointer (theAttribLoc, GLint (myComponentsNb), myDataType, GL_FALSE, 0, myOffset);
}

// =======================================================================
// function : UnbindVertexAttrib
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::UnbindVertexAttrib (const Handle(OpenGl_Context)& theGlCtx,
                                              const unsigned int            theAttribLoc) const
{
  if (!IsValid() || theAttribLoc == GLuint (-1))
  {
    return;
  }
  theGlCtx->core20fwd->glDisableVertexAttribArray (theAttribLoc);
  Unbind (theGlCtx);
}

// =======================================================================
// function : BindAllAttributes
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::BindAllAttributes (const Handle(OpenGl_Context)& ) const
{
  //
}

// =======================================================================
// function : BindPositionAttribute
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::BindPositionAttribute (const Handle(OpenGl_Context)& ) const
{
  //
}

// =======================================================================
// function : UnbindAllAttributes
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::UnbindAllAttributes (const Handle(OpenGl_Context)& ) const
{
  //
}

// =======================================================================
// function : HasColorAttribute
// purpose  :
// =======================================================================
bool OpenGl_VertexBuffer::HasColorAttribute() const
{
  return false;
}

// =======================================================================
// function : HasNormalAttribute
// purpose  :
// =======================================================================
bool OpenGl_VertexBuffer::HasNormalAttribute() const
{
  return false;
}

// =======================================================================
// function : bindAttribute
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::bindAttribute (const Handle(OpenGl_Context)&   theCtx,
                                         const Graphic3d_TypeOfAttribute theAttribute,
                                         const Standard_Integer          theNbComp,
                                         const unsigned int              theDataType,
                                         const Standard_Integer          theStride,
                                         const void*                     theOffset)
{
  if (theCtx->ActiveProgram().IsNull())
  {
    if (theCtx->core11ffp != NULL)
    {
      bindFixed (theCtx, theAttribute, theNbComp, theDataType, theStride, theOffset);
    }
    else
    {
      // OpenGL handles vertex attribute setup independently from active GLSL program,
      // but OCCT historically requires program to be bound beforehand (this check could be removed in future).
      Message::SendFail ("Error: OpenGl_VertexBuffer::bindAttribute() does nothing without active GLSL program");
    }
    return;
  }

  theCtx->core20fwd->glEnableVertexAttribArray (theAttribute);
  theCtx->core20fwd->glVertexAttribPointer (theAttribute, theNbComp, theDataType, theDataType != GL_FLOAT, theStride, theOffset);
}

// =======================================================================
// function : unbindAttribute
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::unbindAttribute (const Handle(OpenGl_Context)&   theCtx,
                                           const Graphic3d_TypeOfAttribute theAttribute)
{
  if (theCtx->ActiveProgram().IsNull())
  {
    if (theCtx->core11ffp != NULL)
    {
      unbindFixed (theCtx, theAttribute);
    }
    return;
  }

  theCtx->core20fwd->glDisableVertexAttribArray (theAttribute);
}

// =======================================================================
// function : bindFixed
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::bindFixed (const Handle(OpenGl_Context)&   theCtx,
                                     const Graphic3d_TypeOfAttribute theMode,
                                     const Standard_Integer          theNbComp,
                                     const unsigned int              theDataType,
                                     const Standard_Integer          theStride,
                                     const void*                     theOffset)
{
  switch (theMode)
  {
    case Graphic3d_TOA_POS:
    {
      theCtx->core11ffp->glEnableClientState (GL_VERTEX_ARRAY);
      theCtx->core11ffp->glVertexPointer (theNbComp, theDataType, theStride, theOffset);
      return;
    }
    case Graphic3d_TOA_NORM:
    {
      theCtx->core11ffp->glEnableClientState (GL_NORMAL_ARRAY);
      theCtx->core11ffp->glNormalPointer (theDataType, theStride, theOffset);
      return;
    }
    case Graphic3d_TOA_UV:
    {
      theCtx->core11ffp->glEnableClientState (GL_TEXTURE_COORD_ARRAY);
      theCtx->core11ffp->glTexCoordPointer (theNbComp, theDataType, theStride, theOffset);
      return;
    }
    case Graphic3d_TOA_COLOR:
    {
      theCtx->core11ffp->glEnableClientState (GL_COLOR_ARRAY);
      theCtx->core11ffp->glColorPointer (theNbComp, theDataType, theStride, theOffset);
      theCtx->core11ffp->glColorMaterial (GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);
      theCtx->core11fwd->glEnable (GL_COLOR_MATERIAL);
      return;
    }
    case Graphic3d_TOA_CUSTOM:
    {
      return;
    }
  }
}

// =======================================================================
// function : unbindFixed
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::unbindFixed (const Handle(OpenGl_Context)&   theCtx,
                                       const Graphic3d_TypeOfAttribute theMode)
{
  switch (theMode)
  {
    case Graphic3d_TOA_POS:   theCtx->core11ffp->glDisableClientState (GL_VERTEX_ARRAY);        return;
    case Graphic3d_TOA_NORM:  theCtx->core11ffp->glDisableClientState (GL_NORMAL_ARRAY);        return;
    case Graphic3d_TOA_UV:    theCtx->core11ffp->glDisableClientState (GL_TEXTURE_COORD_ARRAY); return;
    case Graphic3d_TOA_COLOR: unbindFixedColor (theCtx); return;
    case Graphic3d_TOA_CUSTOM:
    {
      return;
    }
  }
}

// =======================================================================
// function : unbindFixedColor
// purpose  :
// =======================================================================
void OpenGl_VertexBuffer::unbindFixedColor (const Handle(OpenGl_Context)& theCtx)
{
  theCtx->core11ffp->glDisableClientState (GL_COLOR_ARRAY);
  theCtx->core11fwd->glDisable (GL_COLOR_MATERIAL);

  // invalidate FFP material state after GL_COLOR_MATERIAL has modified it (took values from the vertex color)
  theCtx->ShaderManager()->UpdateMaterialState();
}