OCCT

// Created on: 2011-07-13
// Created by: Sergey ZERCHANINOV
// Copyright (c) 2011-2013 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_PrimitiveArray.hxx>

#include <OpenGl_PointSprite.hxx>
#include <OpenGl_Sampler.hxx>
#include <OpenGl_ShaderManager.hxx>
#include <OpenGl_ShaderProgram.hxx>
#include <OpenGl_VertexBufferCompat.hxx>
#include <OpenGl_View.hxx>
#include <OpenGl_Workspace.hxx>

namespace
{
//! Convert data type to GL info
inline GLenum toGlDataType(const Graphic3d_TypeOfData theType, GLint& theNbComp)
{
  switch (theType)
  {
    case Graphic3d_TOD_USHORT:
      theNbComp = 1;
      return GL_UNSIGNED_SHORT;
    case Graphic3d_TOD_UINT:
      theNbComp = 1;
      return GL_UNSIGNED_INT;
    case Graphic3d_TOD_VEC2:
      theNbComp = 2;
      return GL_FLOAT;
    case Graphic3d_TOD_VEC3:
      theNbComp = 3;
      return GL_FLOAT;
    case Graphic3d_TOD_VEC4:
      theNbComp = 4;
      return GL_FLOAT;
    case Graphic3d_TOD_VEC4UB:
      theNbComp = 4;
      return GL_UNSIGNED_BYTE;
    case Graphic3d_TOD_FLOAT:
      theNbComp = 1;
      return GL_FLOAT;
  }
  theNbComp = 0;
  return GL_NONE;
}

} // namespace

//! Auxiliary template for VBO with interleaved attributes.
template <class TheBaseClass, int NbAttributes>
class OpenGl_VertexBufferT : public TheBaseClass
{
public:
  //! Create uninitialized VBO.
  OpenGl_VertexBufferT(const Graphic3d_Buffer& theAttribs)
      : Stride(theAttribs.IsInterleaved() ? theAttribs.Stride : 0)
  {
    memcpy(Attribs, theAttribs.AttributesArray(), sizeof(Graphic3d_Attribute) * NbAttributes);
  }

  bool HasColorAttribute() const override
  {
    for (int anAttribIter = 0; anAttribIter < NbAttributes; ++anAttribIter)
    {
      const Graphic3d_Attribute& anAttrib = Attribs[anAttribIter];
      if (anAttrib.Id == Graphic3d_TOA_COLOR)
      {
        return true;
      }
    }
    return false;
  }

  bool HasNormalAttribute() const override
  {
    for (int anAttribIter = 0; anAttribIter < NbAttributes; ++anAttribIter)
    {
      const Graphic3d_Attribute& anAttrib = Attribs[anAttribIter];
      if (anAttrib.Id == Graphic3d_TOA_NORM)
      {
        return true;
      }
    }
    return false;
  }

  void BindPositionAttribute(const occ::handle<OpenGl_Context>& theGlCtx) const override
  {
    if (!TheBaseClass::IsValid())
    {
      return;
    }

    TheBaseClass::Bind(theGlCtx);
    GLint          aNbComp;
    const GLubyte* anOffset   = TheBaseClass::myOffset;
    const size_t   aMuliplier = Stride != 0 ? 1 : TheBaseClass::myElemsNb;
    for (int anAttribIter = 0; anAttribIter < NbAttributes; ++anAttribIter)
    {
      const Graphic3d_Attribute& anAttrib  = Attribs[anAttribIter];
      const GLenum               aDataType = toGlDataType(anAttrib.DataType, aNbComp);
      if (anAttrib.Id == Graphic3d_TOA_POS && aDataType != GL_NONE)
      {
        TheBaseClass::bindAttribute(theGlCtx,
                                    Graphic3d_TOA_POS,
                                    aNbComp,
                                    aDataType,
                                    Stride,
                                    anOffset);
        break;
      }

      anOffset += aMuliplier * Graphic3d_Attribute::Stride(anAttrib.DataType);
    }
  }

  void BindAllAttributes(const occ::handle<OpenGl_Context>& theGlCtx) const override
  {
    if (!TheBaseClass::IsValid())
    {
      return;
    }

    TheBaseClass::Bind(theGlCtx);
    GLint          aNbComp;
    const GLubyte* anOffset   = TheBaseClass::myOffset;
    const size_t   aMuliplier = Stride != 0 ? 1 : TheBaseClass::myElemsNb;
    for (int anAttribIter = 0; anAttribIter < NbAttributes; ++anAttribIter)
    {
      const Graphic3d_Attribute& anAttrib  = Attribs[anAttribIter];
      const GLenum               aDataType = toGlDataType(anAttrib.DataType, aNbComp);
      if (aDataType != GL_NONE)
      {
        TheBaseClass::bindAttribute(theGlCtx, anAttrib.Id, aNbComp, aDataType, Stride, anOffset);
      }
      anOffset += aMuliplier * Graphic3d_Attribute::Stride(anAttrib.DataType);
    }
  }

  void UnbindAllAttributes(const occ::handle<OpenGl_Context>& theGlCtx) const override
  {
    if (!TheBaseClass::IsValid())
    {
      return;
    }
    TheBaseClass::Unbind(theGlCtx);

    for (int anAttribIter = 0; anAttribIter < NbAttributes; ++anAttribIter)
    {
      const Graphic3d_Attribute& anAttrib = Attribs[anAttribIter];
      TheBaseClass::unbindAttribute(theGlCtx, anAttrib.Id);
    }
  }

private:
  Graphic3d_Attribute Attribs[NbAttributes];
  int                 Stride;
};

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

void OpenGl_PrimitiveArray::clearMemoryGL(const occ::handle<OpenGl_Context>& theGlCtx) const
{
  if (!myVboIndices.IsNull())
  {
    myVboIndices->Release(theGlCtx.operator->());
    myVboIndices.Nullify();
  }
  if (!myVboAttribs.IsNull())
  {
    myVboAttribs->Release(theGlCtx.operator->());
    myVboAttribs.Nullify();
  }
}

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

bool OpenGl_PrimitiveArray::initNormalVbo(const occ::handle<OpenGl_Context>& theCtx) const
{
  switch (myAttribs->NbAttributes)
  {
    case 1:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 1>(*myAttribs);
      break;
    case 2:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 2>(*myAttribs);
      break;
    case 3:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 3>(*myAttribs);
      break;
    case 4:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 4>(*myAttribs);
      break;
    case 5:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 5>(*myAttribs);
      break;
    case 6:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 6>(*myAttribs);
      break;
    case 7:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 7>(*myAttribs);
      break;
    case 8:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 8>(*myAttribs);
      break;
    case 9:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 9>(*myAttribs);
      break;
    case 10:
      myVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBuffer, 10>(*myAttribs);
      break;
  }

  const bool isAttribMutable     = myAttribs->IsMutable();
  const bool isAttribInterleaved = myAttribs->IsInterleaved();
  if (myAttribs->NbElements != myAttribs->NbMaxElements() && myIndices.IsNull()
      && (!isAttribInterleaved || isAttribMutable))
  {
    throw Standard_ProgramError("OpenGl_PrimitiveArray::buildVBO() - vertex attribute data with "
                                "reserved size is not supported");
  }

  // specify data type as Byte and NbComponents as Stride, so that
  // OpenGl_VertexBuffer::EstimatedDataSize() will return correct value
  const int aNbVertexes =
    (isAttribMutable || !isAttribInterleaved) ? myAttribs->NbMaxElements() : myAttribs->NbElements;
  if (!myVboAttribs->init(theCtx,
                          myAttribs->Stride,
                          aNbVertexes,
                          myAttribs->Data(),
                          GL_UNSIGNED_BYTE,
                          myAttribs->Stride))
  {
    TCollection_ExtendedString aMsg =
      TCollection_ExtendedString("VBO creation for Primitive Array has failed for ") + aNbVertexes
      + " vertices. Out of memory?";
    theCtx->PushMessage(GL_DEBUG_SOURCE_APPLICATION,
                        GL_DEBUG_TYPE_PERFORMANCE,
                        0,
                        GL_DEBUG_SEVERITY_LOW,
                        aMsg);

    clearMemoryGL(theCtx);
    return false;
  }
  else if (myIndices.IsNull())
  {
    if (isAttribMutable && isAttribInterleaved)
    {
      // for mutable interlaced array we can change dynamically number of vertexes (they will be
      // just skipped at the end of buffer); this doesn't matter in case if we have indexed array
      myVboAttribs->SetElemsNb(myAttribs->NbElements);
    }
    return true;
  }

  const int aNbIndexes =
    !myIndices->IsMutable() ? myIndices->NbElements : myIndices->NbMaxElements();
  myVboIndices = new OpenGl_IndexBuffer();
  bool isOk    = false;
  switch (myIndices->Stride)
  {
    case 2: {
      isOk = myVboIndices->Init(theCtx,
                                1,
                                aNbIndexes,
                                reinterpret_cast<const GLushort*>(myIndices->Data()));
      myVboIndices->SetElemsNb(myIndices->NbElements);
      myIndices->Validate();
      break;
    }
    case 4: {
      isOk = myVboIndices->Init(theCtx,
                                1,
                                aNbIndexes,
                                reinterpret_cast<const GLuint*>(myIndices->Data()));
      myVboIndices->SetElemsNb(myIndices->NbElements);
      myIndices->Validate();
      break;
    }
    default: {
      clearMemoryGL(theCtx);
      return false;
    }
  }
  if (!isOk)
  {
    TCollection_ExtendedString aMsg =
      TCollection_ExtendedString("VBO creation for Primitive Array has failed for ") + aNbIndexes
      + " indices. Out of memory?";
    theCtx->PushMessage(GL_DEBUG_SOURCE_APPLICATION,
                        GL_DEBUG_TYPE_PERFORMANCE,
                        0,
                        GL_DEBUG_SEVERITY_LOW,
                        aMsg);
    clearMemoryGL(theCtx);
    return false;
  }
  return true;
}

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

bool OpenGl_PrimitiveArray::buildVBO(const occ::handle<OpenGl_Context>& theCtx,
                                     const bool                         theToKeepData) const
{
  bool isNormalMode = theCtx->ToUseVbo();
  clearMemoryGL(theCtx);
  if (myAttribs.IsNull() || myAttribs->IsEmpty() || myAttribs->NbElements < 1
      || myAttribs->NbAttributes < 1 || myAttribs->NbAttributes > 10)
  {
    // vertices should be always defined - others are optional
    return false;
  }

  if (isNormalMode && initNormalVbo(theCtx))
  {
    if (!theCtx->caps->keepArrayData && !theToKeepData && !myAttribs->IsMutable())
    {
      myIndices.Nullify();
      myAttribs.Nullify();
    }
    else
    {
      myAttribs->Validate();
    }
    return true;
  }

  occ::handle<OpenGl_VertexBufferCompat> aVboAttribs;
  switch (myAttribs->NbAttributes)
  {
    case 1:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 1>(*myAttribs);
      break;
    case 2:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 2>(*myAttribs);
      break;
    case 3:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 3>(*myAttribs);
      break;
    case 4:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 4>(*myAttribs);
      break;
    case 5:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 5>(*myAttribs);
      break;
    case 6:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 6>(*myAttribs);
      break;
    case 7:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 7>(*myAttribs);
      break;
    case 8:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 8>(*myAttribs);
      break;
    case 9:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 9>(*myAttribs);
      break;
    case 10:
      aVboAttribs = new OpenGl_VertexBufferT<OpenGl_VertexBufferCompat, 10>(*myAttribs);
      break;
  }
  aVboAttribs->initLink(myAttribs, 0, myAttribs->NbElements, GL_NONE);
  if (!myIndices.IsNull())
  {
    occ::handle<OpenGl_IndexBufferCompat> aVboIndices = new OpenGl_IndexBufferCompat();
    switch (myIndices->Stride)
    {
      case 2: {
        aVboIndices->initLink(myIndices, 1, myIndices->NbElements, GL_UNSIGNED_SHORT);
        break;
      }
      case 4: {
        aVboIndices->initLink(myIndices, 1, myIndices->NbElements, GL_UNSIGNED_INT);
        break;
      }
      default: {
        return false;
      }
    }
    myVboIndices = aVboIndices;
  }
  myVboAttribs = aVboAttribs;
  if (!theCtx->caps->keepArrayData && !theToKeepData)
  {
    // does not make sense for compatibility mode
    // myIndices.Nullify();
    // myAttribs.Nullify();
  }

  return true;
}

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

void OpenGl_PrimitiveArray::updateVBO(const occ::handle<OpenGl_Context>& theCtx) const
{
  if (!myAttribs.IsNull())
  {
    Graphic3d_BufferRange aRange = myAttribs->InvalidatedRange();
    if (!aRange.IsEmpty() && myVboAttribs->IsValid() && !myVboAttribs->IsVirtual())
    {
      myVboAttribs->Bind(theCtx);
      theCtx->core15fwd->glBufferSubData(myVboAttribs->GetTarget(),
                                         aRange.Start,
                                         aRange.Length,
                                         myAttribs->Data() + aRange.Start);
      myVboAttribs->Unbind(theCtx);
      if (myAttribs->IsInterleaved())
      {
        myVboAttribs->SetElemsNb(myAttribs->NbElements);
      }
    }
    myAttribs->Validate();
  }
  if (!myIndices.IsNull())
  {
    Graphic3d_BufferRange aRange = myIndices->InvalidatedRange();
    if (!aRange.IsEmpty() && myVboIndices->IsValid() && !myVboIndices->IsVirtual())
    {
      myVboIndices->Bind(theCtx);
      theCtx->core15fwd->glBufferSubData(myVboIndices->GetTarget(),
                                         aRange.Start,
                                         aRange.Length,
                                         myIndices->Data() + aRange.Start);
      myVboIndices->Unbind(theCtx);
      myVboIndices->SetElemsNb(myIndices->NbElements);
    }
    myIndices->Validate();
  }
}

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

void OpenGl_PrimitiveArray::drawArray(const occ::handle<OpenGl_Workspace>& theWorkspace,
                                      const NCollection_Vec4<float>*       theFaceColors,
                                      const NCollection_Vec4<float>&       theBackColor,
                                      const bool                           theHasVertColor,
                                      const bool theToUseVertexColorForBackFaces) const
{
  const occ::handle<OpenGl_Context>& aGlContext = theWorkspace->GetGlContext();
  if (myVboAttribs.IsNull())
  {
    if (myDrawMode == GL_POINTS && aGlContext->core11ffp != nullptr)
    {
      // extreme compatibility mode - without sprites but with markers
      drawMarkers(theWorkspace);
    }
    return;
  }

  const bool   toHilight = theWorkspace->ToHighlight();
  const GLenum aDrawMode =
    !aGlContext->ActiveProgram().IsNull() && aGlContext->ActiveProgram()->HasTessellationStage()
      ? GL_PATCHES
      : myDrawMode;
  myVboAttribs->BindAllAttributes(aGlContext);
  if (theHasVertColor && !toHilight && myIsFillType && !theToUseVertexColorForBackFaces
      && aGlContext->ActiveProgram().IsNull() && aGlContext->core11ffp != nullptr)
  {
    // This affects FFP lighting. Unlit FFP uses primary color directly for both sides.
    aGlContext->core11ffp->glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
  }
  if (theHasVertColor && toHilight)
  {
    // disable per-vertex color
    OpenGl_VertexBuffer::unbindAttribute(aGlContext, Graphic3d_TOA_COLOR);
  }
  if (!myVboIndices.IsNull())
  {
    myVboIndices->Bind(aGlContext);
    GLubyte* anOffset = myVboIndices->GetDataOffset();
    if (!myBounds.IsNull())
    {
      // draw primitives by vertex count with the indices
      const size_t aStride = myVboIndices->GetDataType() == GL_UNSIGNED_SHORT
                               ? sizeof(unsigned short)
                               : sizeof(unsigned int);
      for (int aGroupIter = 0; aGroupIter < myBounds->NbBounds; ++aGroupIter)
      {
        const GLint aNbElemsInGroup = myBounds->Bounds[aGroupIter];
        if (theFaceColors != nullptr)
        {
          aGlContext->SetColor4fv(theFaceColors[aGroupIter], theBackColor);
        }
        aGlContext->core11fwd->glDrawElements(aDrawMode,
                                              aNbElemsInGroup,
                                              myVboIndices->GetDataType(),
                                              anOffset);
        anOffset += aStride * aNbElemsInGroup;
      }
    }
    else
    {
      // draw one (or sequential) primitive by the indices
      aGlContext->core11fwd->glDrawElements(aDrawMode,
                                            myVboIndices->GetElemsNb(),
                                            myVboIndices->GetDataType(),
                                            anOffset);
    }
    myVboIndices->Unbind(aGlContext);
  }
  else if (!myBounds.IsNull())
  {
    GLint aFirstElem = 0;
    for (int aGroupIter = 0; aGroupIter < myBounds->NbBounds; ++aGroupIter)
    {
      const GLint aNbElemsInGroup = myBounds->Bounds[aGroupIter];
      if (theFaceColors != nullptr)
      {
        aGlContext->SetColor4fv(theFaceColors[aGroupIter], theBackColor);
      }
      aGlContext->core11fwd->glDrawArrays(aDrawMode, aFirstElem, aNbElemsInGroup);
      aFirstElem += aNbElemsInGroup;
    }
  }
  else
  {
    if (myDrawMode == GL_POINTS)
    {
      drawMarkers(theWorkspace);
    }
    else
    {
      aGlContext->core11fwd->glDrawArrays(aDrawMode, 0, myVboAttribs->GetElemsNb());
    }
  }

  // bind with 0
  myVboAttribs->UnbindAllAttributes(aGlContext);
}

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

void OpenGl_PrimitiveArray::drawEdges(const occ::handle<OpenGl_Workspace>& theWorkspace) const
{
  const occ::handle<OpenGl_Context>& aGlContext = theWorkspace->GetGlContext();
  if (myVboAttribs.IsNull())
  {
    return;
  }

  const OpenGl_Aspects* anAspect     = theWorkspace->Aspects();
  const int             aPolyModeOld = aGlContext->SetPolygonMode(GL_LINE);

  if (aGlContext->core20fwd != nullptr)
  {
    aGlContext->ShaderManager()->BindLineProgram(occ::handle<OpenGl_TextureSet>(),
                                                 anAspect->Aspect()->EdgeLineType(),
                                                 Graphic3d_TypeOfShadingModel_Unlit,
                                                 Graphic3d_AlphaMode_Opaque,
                                                 false,
                                                 anAspect->ShaderProgramRes(aGlContext));
  }
  aGlContext->SetSampleAlphaToCoverage(
    aGlContext->ShaderManager()->MaterialState().HasAlphaCutoff());
  const GLenum aDrawMode =
    !aGlContext->ActiveProgram().IsNull() && aGlContext->ActiveProgram()->HasTessellationStage()
      ? GL_PATCHES
      : myDrawMode;
  if (aGlContext->ActiveProgram().IsNull() && aGlContext->core11ffp != nullptr)
  {
    aGlContext->core11fwd->glDisable(GL_LIGHTING);
  }

  /// OCC22236 NOTE: draw edges for all situations:
  /// 1) draw elements with GL_LINE style as edges from myPArray->bufferVBO[VBOEdges] indices array
  /// 2) draw elements from vertex array, when bounds defines count of primitive's vertices.
  /// 3) draw primitive's edges by vertexes if no edges and bounds array is specified
  myVboAttribs->BindPositionAttribute(aGlContext);

  aGlContext->SetColor4fv(theWorkspace->EdgeColor().a() >= 0.1f
                            ? theWorkspace->EdgeColor()
                            : theWorkspace->View()->BackgroundColor());
  aGlContext->SetLineStipple((float)anAspect->Aspect()->LineStippleFactor(),
                             anAspect->Aspect()->LinePattern());
  aGlContext->SetLineWidth(anAspect->Aspect()->EdgeWidth());

  if (!myVboIndices.IsNull())
  {
    myVboIndices->Bind(aGlContext);
    GLubyte* anOffset = myVboIndices->GetDataOffset();

    // draw primitives by vertex count with the indices
    if (!myBounds.IsNull())
    {
      const size_t aStride = myVboIndices->GetDataType() == GL_UNSIGNED_SHORT
                               ? sizeof(unsigned short)
                               : sizeof(unsigned int);
      for (int aGroupIter = 0; aGroupIter < myBounds->NbBounds; ++aGroupIter)
      {
        const GLint aNbElemsInGroup = myBounds->Bounds[aGroupIter];
        aGlContext->core11fwd->glDrawElements(aDrawMode,
                                              aNbElemsInGroup,
                                              myVboIndices->GetDataType(),
                                              anOffset);
        anOffset += aStride * aNbElemsInGroup;
      }
    }
    // draw one (or sequential) primitive by the indices
    else
    {
      aGlContext->core11fwd->glDrawElements(aDrawMode,
                                            myVboIndices->GetElemsNb(),
                                            myVboIndices->GetDataType(),
                                            anOffset);
    }
    myVboIndices->Unbind(aGlContext);
  }
  else if (!myBounds.IsNull())
  {
    GLint aFirstElem = 0;
    for (int aGroupIter = 0; aGroupIter < myBounds->NbBounds; ++aGroupIter)
    {
      const GLint aNbElemsInGroup = myBounds->Bounds[aGroupIter];
      aGlContext->core11fwd->glDrawArrays(aDrawMode, aFirstElem, aNbElemsInGroup);
      aFirstElem += aNbElemsInGroup;
    }
  }
  else
  {
    aGlContext->core11fwd->glDrawArrays(aDrawMode,
                                        0,
                                        !myVboAttribs.IsNull() ? myVboAttribs->GetElemsNb()
                                                               : myAttribs->NbElements);
  }

  // unbind buffers
  myVboAttribs->UnbindAttribute(aGlContext, Graphic3d_TOA_POS);

  // restore line context
  aGlContext->SetPolygonMode(aPolyModeOld);
}

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

void OpenGl_PrimitiveArray::drawMarkers(const occ::handle<OpenGl_Workspace>& theWorkspace) const
{
  const OpenGl_Aspects*              anAspectMarker = theWorkspace->Aspects();
  const occ::handle<OpenGl_Context>& aCtx           = theWorkspace->GetGlContext();
  const GLenum                       aDrawMode =
    !aCtx->ActiveProgram().IsNull() && aCtx->ActiveProgram()->HasTessellationStage() ? GL_PATCHES
                                                                                                           : myDrawMode;
  if (anAspectMarker->Aspect()->MarkerType() == Aspect_TOM_POINT)
  {
    aCtx->SetPointSize(anAspectMarker->MarkerSize());
    aCtx->core11fwd->glDrawArrays(aDrawMode,
                                  0,
                                  !myVboAttribs.IsNull() ? myVboAttribs->GetElemsNb()
                                                         : myAttribs->NbElements);
    aCtx->SetPointSize(1.0f);
    return;
  }

  if (aCtx->core11ffp != nullptr)
  {
    aCtx->core11fwd->glEnable(GL_ALPHA_TEST);
    aCtx->core11fwd->glAlphaFunc(GL_GEQUAL, 0.1f);
  }

  aCtx->core11fwd->glEnable(GL_BLEND);
  aCtx->core11fwd->glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

  if (anAspectMarker->HasPointSprite(aCtx))
  {
    // Textured markers will be drawn with the point sprites
    aCtx->SetPointSize(anAspectMarker->MarkerSize());
    aCtx->SetPointSpriteOrigin();

    aCtx->core11fwd->glDrawArrays(aDrawMode,
                                  0,
                                  !myVboAttribs.IsNull() ? myVboAttribs->GetElemsNb()
                                                         : myAttribs->NbElements);

    aCtx->SetPointSize(1.0f);
  }
  // Textured markers will be drawn with the glBitmap
  else if (const occ::handle<OpenGl_PointSprite>& aSprite =
             anAspectMarker->SpriteRes(aCtx, theWorkspace->ToHighlight()))
  {
    for (int anIter = 0; anIter < myAttribs->NbElements; anIter++)
    {
      aCtx->core11ffp->glRasterPos3fv(myAttribs->Value<NCollection_Vec3<float>>(anIter).GetData());
      aSprite->DrawBitmap(theWorkspace->GetGlContext());
    }
  }

  aCtx->core11fwd->glDisable(GL_BLEND);
  if (aCtx->core11ffp != nullptr)
  {
    if (aCtx->ShaderManager()->MaterialState().AlphaCutoff() >= ShortRealLast())
    {
      aCtx->core11fwd->glDisable(GL_ALPHA_TEST);
    }
    else
    {
      aCtx->core11fwd->glAlphaFunc(GL_GEQUAL, aCtx->ShaderManager()->MaterialState().AlphaCutoff());
    }
  }
}

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

OpenGl_PrimitiveArray::OpenGl_PrimitiveArray(const OpenGl_GraphicDriver* theDriver)

    : myDrawMode(DRAW_MODE_NONE),
      myIsFillType(false),
      myIsVboInit(false)
{
  if (theDriver != nullptr)
  {
    myUID = theDriver->GetNextPrimitiveArrayUID();
  }
}

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

OpenGl_PrimitiveArray::OpenGl_PrimitiveArray(const OpenGl_GraphicDriver*               theDriver,
                                             const Graphic3d_TypeOfPrimitiveArray      theType,
                                             const occ::handle<Graphic3d_IndexBuffer>& theIndices,
                                             const occ::handle<Graphic3d_Buffer>&      theAttribs,
                                             const occ::handle<Graphic3d_BoundBuffer>& theBounds)

    : myIndices(theIndices),
      myAttribs(theAttribs),
      myBounds(theBounds),
      myDrawMode(DRAW_MODE_NONE),
      myIsFillType(false),
      myIsVboInit(false)
{
  if (!myIndices.IsNull() && myIndices->NbElements < 1)
  {
    // dummy index buffer?
    myIndices.Nullify();
  }

  if (theDriver != nullptr)
  {
    myUID                                   = theDriver->GetNextPrimitiveArrayUID();
    const occ::handle<OpenGl_Context>& aCtx = theDriver->GetSharedContext();
    if (!aCtx.IsNull() && aCtx->GraphicsLibrary() == Aspect_GraphicsLibrary_OpenGLES)
    {
      processIndices(aCtx);
    }
  }

  setDrawMode(theType);
}

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

OpenGl_PrimitiveArray::~OpenGl_PrimitiveArray() = default;

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

void OpenGl_PrimitiveArray::Release(OpenGl_Context* theContext)
{
  myIsVboInit = false;
  if (!myVboIndices.IsNull())
  {
    if (theContext)
    {
      theContext->DelayedRelease(myVboIndices);
    }
    myVboIndices.Nullify();
  }
  if (!myVboAttribs.IsNull())
  {
    if (theContext)
    {
      theContext->DelayedRelease(myVboAttribs);
    }
    myVboAttribs.Nullify();
  }
}

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

size_t OpenGl_PrimitiveArray::EstimatedDataSize() const
{
  size_t aSize = 0;
  if (!myVboAttribs.IsNull())
  {
    aSize += myVboAttribs->EstimatedDataSize();
  }
  if (!myVboIndices.IsNull())
  {
    aSize += myVboIndices->EstimatedDataSize();
  }
  return aSize;
}

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

void OpenGl_PrimitiveArray::UpdateDrawStats(Graphic3d_FrameStatsDataTmp& theStats,
                                            bool                         theIsDetailed) const
{
  ++theStats[Graphic3d_FrameStatsCounter_NbElemsNotCulled];
  if (myIsFillType)
  {
    ++theStats[Graphic3d_FrameStatsCounter_NbElemsFillNotCulled];
  }
  else if (myDrawMode == GL_POINTS)
  {
    ++theStats[Graphic3d_FrameStatsCounter_NbElemsPointNotCulled];
  }
  else
  {
    ++theStats[Graphic3d_FrameStatsCounter_NbElemsLineNotCulled];
  }

  if (!theIsDetailed || myVboAttribs.IsNull() || !myVboAttribs->IsValid())
  {
    return;
  }

  const int aNbIndices =
    !myVboIndices.IsNull() ? myVboIndices->GetElemsNb() : myVboAttribs->GetElemsNb();
  const int aNbBounds = !myBounds.IsNull() ? myBounds->NbBounds : 1;
  switch (myDrawMode)
  {
    case GL_POINTS: {
      theStats[Graphic3d_FrameStatsCounter_NbPointsNotCulled] += aNbIndices;
      break;
    }
    case GL_LINES: {
      theStats[Graphic3d_FrameStatsCounter_NbLinesNotCulled] += aNbIndices / 2;
      break;
    }
    case GL_LINE_STRIP: {
      theStats[Graphic3d_FrameStatsCounter_NbLinesNotCulled] += aNbIndices - aNbBounds;
      break;
    }
    case GL_LINES_ADJACENCY: {
      theStats[Graphic3d_FrameStatsCounter_NbLinesNotCulled] += aNbIndices / 4;
      break;
    }
    case GL_LINE_STRIP_ADJACENCY: {
      theStats[Graphic3d_FrameStatsCounter_NbLinesNotCulled] += aNbIndices - 4 * aNbBounds;
      break;
    }
    case GL_TRIANGLES: {
      theStats[Graphic3d_FrameStatsCounter_NbTrianglesNotCulled] += aNbIndices / 3;
      break;
    }
    case GL_TRIANGLE_STRIP:
    case GL_TRIANGLE_FAN: {
      theStats[Graphic3d_FrameStatsCounter_NbTrianglesNotCulled] += aNbIndices - 2 * aNbBounds;
      break;
    }
    case GL_TRIANGLES_ADJACENCY: {
      theStats[Graphic3d_FrameStatsCounter_NbTrianglesNotCulled] += aNbIndices / 6;
      break;
    }
    case GL_TRIANGLE_STRIP_ADJACENCY: {
      theStats[Graphic3d_FrameStatsCounter_NbTrianglesNotCulled] += aNbIndices - 4 * aNbBounds;
      break;
    }
    case GL_QUADS: {
      theStats[Graphic3d_FrameStatsCounter_NbTrianglesNotCulled] += aNbIndices / 2;
      break;
    }
    case GL_QUAD_STRIP: {
      theStats[Graphic3d_FrameStatsCounter_NbTrianglesNotCulled] +=
        (aNbIndices / 2 - aNbBounds) * 2;
      break;
    }
  }
}

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

void OpenGl_PrimitiveArray::Render(const occ::handle<OpenGl_Workspace>& theWorkspace) const
{
  if (myDrawMode == DRAW_MODE_NONE)
  {
    return;
  }

  const OpenGl_Aspects*              anAspectFace = theWorkspace->Aspects();
  const occ::handle<OpenGl_Context>& aCtx         = theWorkspace->GetGlContext();

  bool toDrawArray = true, toSetLinePolygMode = false;
  int  toDrawInteriorEdges = 0; // 0 - no edges, 1 - glsl edges, 2 - polygonMode
  if (myIsFillType)
  {
    toDrawArray = anAspectFace->Aspect()->InteriorStyle() != Aspect_IS_EMPTY;
    if (anAspectFace->Aspect()->ToDrawEdges())
    {
      toDrawInteriorEdges = 1;
      toDrawArray         = true;
      if (aCtx->GraphicsLibrary() != Aspect_GraphicsLibrary_OpenGLES
          && (anAspectFace->Aspect()->EdgeLineType() != Aspect_TOL_SOLID
              || aCtx->hasGeometryStage == OpenGl_FeatureNotAvailable
              || aCtx->caps->usePolygonMode))
      {
        toDrawInteriorEdges = 2;
        if (anAspectFace->Aspect()->InteriorStyle() == Aspect_IS_EMPTY)
        {
          if (anAspectFace->Aspect()->EdgeLineType() != Aspect_TOL_SOLID)
          {
            toDrawArray = false;
          }
          else
          {
            toSetLinePolygMode = true;
          }
        }
      }
    }
  }
  else
  {
    if (myDrawMode == GL_POINTS)
    {
      if (anAspectFace->Aspect()->MarkerType() == Aspect_TOM_EMPTY)
      {
        return;
      }
    }
    else
    {
      if (anAspectFace->Aspect()->LineType() == Aspect_TOL_EMPTY)
      {
        return;
      }
    }
  }

  // create VBOs on first render call
  if (!myIsVboInit)
  {
    // compatibility - keep data to draw markers using display lists
    bool toKeepData = myDrawMode == GL_POINTS && anAspectFace->IsDisplayListSprite(aCtx);
    if (aCtx->GraphicsLibrary() == Aspect_GraphicsLibrary_OpenGLES)
    {
      processIndices(aCtx);
    }
    buildVBO(aCtx, toKeepData);
    myIsVboInit = true;
  }
  else if ((!myAttribs.IsNull() && myAttribs->IsMutable())
           || (!myIndices.IsNull() && myIndices->IsMutable()))
  {
    updateVBO(aCtx);
  }

  Graphic3d_TypeOfShadingModel aShadingModel = Graphic3d_TypeOfShadingModel_Unlit;
  // clang-format off
  anAspectFace = theWorkspace->ApplyAspects (false); // do not bind textures before binding the program
  // clang-format on
  const occ::handle<OpenGl_TextureSet>& aTextureSet = theWorkspace->TextureSet();
  const bool                            toEnableEnvMap =
    !aTextureSet.IsNull() && aTextureSet == theWorkspace->EnvironmentTexture();
  if (toDrawArray)
  {
    const bool hasColorAttrib = !myVboAttribs.IsNull() && myVboAttribs->HasColorAttribute();
    const bool toHilight      = theWorkspace->ToHighlight();
    const bool hasVertColor   = hasColorAttrib && !toHilight;
    const bool hasVertNorm    = !myVboAttribs.IsNull() && myVboAttribs->HasNormalAttribute();
    switch (myDrawMode)
    {
      case GL_POINTS: {
        aShadingModel =
          aCtx->ShaderManager()->ChooseMarkerShadingModel(anAspectFace->ShadingModel(),
                                                          hasVertNorm);
        aCtx->ShaderManager()->BindMarkerProgram(aTextureSet,
                                                 aShadingModel,
                                                 Graphic3d_AlphaMode_Opaque,
                                                 hasVertColor,
                                                 anAspectFace->ShaderProgramRes(aCtx));
        break;
      }
      case GL_LINES:
      case GL_LINE_STRIP: {
        aShadingModel =
          aCtx->ShaderManager()->ChooseLineShadingModel(anAspectFace->ShadingModel(), hasVertNorm);
        aCtx->ShaderManager()->BindLineProgram(occ::handle<OpenGl_TextureSet>(),
                                               anAspectFace->Aspect()->LineType(),
                                               aShadingModel,
                                               Graphic3d_AlphaMode_Opaque,
                                               hasVertColor,
                                               anAspectFace->ShaderProgramRes(aCtx));
        break;
      }
      default: {
        aShadingModel =
          aCtx->ShaderManager()->ChooseFaceShadingModel(anAspectFace->ShadingModel(), hasVertNorm);
        aCtx->ShaderManager()->BindFaceProgram(
          aTextureSet,
          aShadingModel,
          aCtx->ShaderManager()->MaterialState().HasAlphaCutoff() ? Graphic3d_AlphaMode_Mask
                                                                  : Graphic3d_AlphaMode_Opaque,
          toDrawInteriorEdges == 1 ? anAspectFace->Aspect()->InteriorStyle() : Aspect_IS_SOLID,
          hasVertColor,
          anAspectFace->Aspect()->ToUseVertexColorForBackFaces(),
          toEnableEnvMap,
          toDrawInteriorEdges == 1,
          anAspectFace->ShaderProgramRes(aCtx));
        if (toDrawInteriorEdges == 1)
        {
          aCtx->ShaderManager()->PushInteriorState(aCtx->ActiveProgram(), anAspectFace->Aspect());
        }
        else if (toSetLinePolygMode)
        {
          aCtx->SetPolygonMode(GL_LINE);
        }
        break;
      }
    }

    // bind textures after GLSL program to set mock textures to slots used by program
    aCtx->BindTextures(aTextureSet, aCtx->ActiveProgram());
    if (!aTextureSet.IsNull() && !aTextureSet->IsEmpty()
        && myDrawMode != GL_POINTS) // transformation is not supported within point sprites
    {
      if (const occ::handle<OpenGl_Texture>& aFirstTexture = aTextureSet->First())
      {
        aCtx->SetTextureMatrix(aFirstTexture->Sampler()->Parameters(), aFirstTexture->IsTopDown());
      }
    }
    aCtx->SetSampleAlphaToCoverage(aCtx->ShaderManager()->MaterialState().HasAlphaCutoff());

    const bool isForcedBlend = anAspectFace->Aspect()->AlphaMode() == Graphic3d_AlphaMode_MaskBlend;
    if (isForcedBlend)
    {
      aCtx->core11fwd->glEnable(GL_BLEND);
      aCtx->core11fwd->glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    }

    const NCollection_Vec4<float>* aFaceColors =
      !myBounds.IsNull() && !toHilight
          && anAspectFace->Aspect()->InteriorStyle() != Aspect_IS_HIDDENLINE
        ? myBounds->Colors
        : nullptr;
    const NCollection_Vec4<float>& anInteriorColor    = theWorkspace->InteriorColor();
    const NCollection_Vec4<float>& aBackInteriorColor = theWorkspace->BackInteriorColor();
    aCtx->SetColor4fv(anInteriorColor, aBackInteriorColor);
    if (!myIsFillType)
    {
      if (myDrawMode == GL_LINES || myDrawMode == GL_LINE_STRIP)
      {
        aCtx->SetLineStipple((float)anAspectFace->Aspect()->LineStippleFactor(),
                             anAspectFace->Aspect()->LinePattern());
        aCtx->SetLineWidth(anAspectFace->Aspect()->LineWidth());
      }

      drawArray(theWorkspace,
                aFaceColors,
                aBackInteriorColor,
                hasColorAttrib,
                anAspectFace->Aspect()->ToUseVertexColorForBackFaces());
      if (isForcedBlend)
      {
        aCtx->core11fwd->glDisable(GL_BLEND);
      }
      return;
    }

    drawArray(theWorkspace,
              aFaceColors,
              aBackInteriorColor,
              hasColorAttrib,
              anAspectFace->Aspect()->ToUseVertexColorForBackFaces());

    // draw outline - only closed triangulation with defined vertex normals can be drawn in this way
    if (anAspectFace->Aspect()->ToDrawSilhouette() && aCtx->ToCullBackFaces()
        && aCtx->ShaderManager()->BindOutlineProgram())
    {
      const NCollection_Vec2<int> aViewSize(aCtx->Viewport()[2], aCtx->Viewport()[3]);
      const int                   aMin = aViewSize.minComp();
      const GLfloat               anEdgeWidth =
        (GLfloat)anAspectFace->Aspect()->EdgeWidth() * aCtx->LineWidthScale() / (GLfloat)aMin;
      const GLfloat anOrthoScale =
        aCtx->Camera()->IsOrthographic() ? (GLfloat)aCtx->Camera()->Scale() : -1.0f;

      const occ::handle<OpenGl_ShaderProgram>& anOutlineProgram = aCtx->ActiveProgram();
      anOutlineProgram->SetUniform(
        aCtx,
        anOutlineProgram->GetStateLocation(OpenGl_OCCT_SILHOUETTE_THICKNESS),
        anEdgeWidth);
      anOutlineProgram->SetUniform(aCtx,
                                   anOutlineProgram->GetStateLocation(OpenGl_OCCT_ORTHO_SCALE),
                                   anOrthoScale);
      aCtx->SetColor4fv(anAspectFace->Aspect()->EdgeColorRGBA());

      aCtx->SetFaceCulling(Graphic3d_TypeOfBackfacingModel_FrontCulled);
      drawArray(theWorkspace, nullptr, aBackInteriorColor, false, true);
      aCtx->SetFaceCulling(Graphic3d_TypeOfBackfacingModel_BackCulled);
    }

    if (isForcedBlend)
    {
      aCtx->core11fwd->glDisable(GL_BLEND);
    }
  }

  // draw triangulation edges using Polygon Mode
  if (toDrawInteriorEdges == 2)
  {
    if (anAspectFace->Aspect()->InteriorStyle() == Aspect_IS_HOLLOW
        && anAspectFace->Aspect()->EdgeLineType() == Aspect_TOL_SOLID)
    {
      aCtx->SetPolygonMode(GL_FILL);
    }
    else
    {
      drawEdges(theWorkspace);
    }
  }
}

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

void OpenGl_PrimitiveArray::setDrawMode(const Graphic3d_TypeOfPrimitiveArray theType)
{
  if (myAttribs.IsNull())
  {
    myDrawMode   = DRAW_MODE_NONE;
    myIsFillType = false;
    return;
  }

  switch (theType)
  {
    case Graphic3d_TOPA_POINTS:
      myDrawMode   = GL_POINTS;
      myIsFillType = false;
      break;
    case Graphic3d_TOPA_SEGMENTS:
      myDrawMode   = GL_LINES;
      myIsFillType = false;
      break;
    case Graphic3d_TOPA_POLYLINES:
      myDrawMode   = GL_LINE_STRIP;
      myIsFillType = false;
      break;
    case Graphic3d_TOPA_TRIANGLES:
      myDrawMode   = GL_TRIANGLES;
      myIsFillType = true;
      break;
    case Graphic3d_TOPA_TRIANGLESTRIPS:
      myDrawMode   = GL_TRIANGLE_STRIP;
      myIsFillType = true;
      break;
    case Graphic3d_TOPA_TRIANGLEFANS:
      myDrawMode   = GL_TRIANGLE_FAN;
      myIsFillType = true;
      break;
    //
    case Graphic3d_TOPA_LINES_ADJACENCY:
      myDrawMode   = GL_LINES_ADJACENCY;
      myIsFillType = false;
      break;
    case Graphic3d_TOPA_LINE_STRIP_ADJACENCY:
      myDrawMode   = GL_LINE_STRIP_ADJACENCY;
      myIsFillType = false;
      break;
    case Graphic3d_TOPA_TRIANGLES_ADJACENCY:
      myDrawMode   = GL_TRIANGLES_ADJACENCY;
      myIsFillType = true;
      break;
    case Graphic3d_TOPA_TRIANGLE_STRIP_ADJACENCY:
      myDrawMode   = GL_TRIANGLE_STRIP_ADJACENCY;
      myIsFillType = true;
      break;
    //
    case Graphic3d_TOPA_QUADRANGLES:
      myDrawMode   = GL_QUADS;
      myIsFillType = true;
      break;
    case Graphic3d_TOPA_QUADRANGLESTRIPS:
      myDrawMode   = GL_QUAD_STRIP;
      myIsFillType = true;
      break;
    case Graphic3d_TOPA_POLYGONS:
      myDrawMode   = GL_POLYGON;
      myIsFillType = true;
      break;
    case Graphic3d_TOPA_UNDEFINED:
      myDrawMode   = DRAW_MODE_NONE;
      myIsFillType = false;
      break;
  }
}

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

bool OpenGl_PrimitiveArray::processIndices(const occ::handle<OpenGl_Context>& theContext) const
{
  if (myIndices.IsNull() || myAttribs.IsNull() || theContext->hasUintIndex)
  {
    return true;
  }

  if (myAttribs->NbElements > std::numeric_limits<GLushort>::max())
  {
    occ::handle<Graphic3d_Buffer> anAttribs =
      new Graphic3d_Buffer(Graphic3d_Buffer::DefaultAllocator());
    if (!anAttribs->Init(myIndices->NbElements,
                         myAttribs->AttributesArray(),
                         myAttribs->NbAttributes))
    {
      return false; // failed to initialize attribute array
    }

    for (int anIdxIdx = 0; anIdxIdx < myIndices->NbElements; ++anIdxIdx)
    {
      const int anIndex = myIndices->Index(anIdxIdx);
      memcpy(anAttribs->ChangeData() + myAttribs->Stride * anIdxIdx,
             myAttribs->Data() + myAttribs->Stride * anIndex,
             myAttribs->Stride);
    }

    myIndices.Nullify();
    myAttribs = anAttribs;
  }

  return true;
}

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

void OpenGl_PrimitiveArray::InitBuffers(const occ::handle<OpenGl_Context>&        theContext,
                                        const Graphic3d_TypeOfPrimitiveArray      theType,
                                        const occ::handle<Graphic3d_IndexBuffer>& theIndices,
                                        const occ::handle<Graphic3d_Buffer>&      theAttribs,
                                        const occ::handle<Graphic3d_BoundBuffer>& theBounds)
{
  // Release old graphic resources
  Release(theContext.get());

  myIndices = theIndices;
  myAttribs = theAttribs;
  myBounds  = theBounds;
  if (!theContext.IsNull() && theContext->GraphicsLibrary() == Aspect_GraphicsLibrary_OpenGLES)
  {
    processIndices(theContext);
  }

  setDrawMode(theType);
}

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

void OpenGl_PrimitiveArray::DumpJson(Standard_OStream& theOStream, int theDepth) const
{
  OCCT_DUMP_CLASS_BEGIN(theOStream, OpenGl_PrimitiveArray)

  OCCT_DUMP_BASE_CLASS(theOStream, theDepth, OpenGl_Element)

  OCCT_DUMP_FIELD_VALUES_DUMPED(theOStream, theDepth, myVboIndices.get())
  OCCT_DUMP_FIELD_VALUES_DUMPED(theOStream, theDepth, myVboAttribs.get())

  OCCT_DUMP_FIELD_VALUES_DUMPED(theOStream, theDepth, myIndices.get())
  OCCT_DUMP_FIELD_VALUES_DUMPED(theOStream, theDepth, myAttribs.get())
  OCCT_DUMP_FIELD_VALUES_DUMPED(theOStream, theDepth, myBounds.get())

  OCCT_DUMP_FIELD_VALUE_NUMERICAL(theOStream, myDrawMode)
  OCCT_DUMP_FIELD_VALUE_NUMERICAL(theOStream, myIsFillType)
  OCCT_DUMP_FIELD_VALUE_NUMERICAL(theOStream, myIsVboInit)
  OCCT_DUMP_FIELD_VALUE_NUMERICAL(theOStream, myUID)
}