Method ApplyMutation

libs/drape/vertex_array_buffer.cpp:342–387

}

void VertexArrayBuffer::ApplyMutation(ref_ptr<GraphicsContext> context, ref_ptr<IndexBufferMutator> indexMutator,
                                      ref_ptr<AttributeBufferMutator> attrMutator)
{
  // We need to bind current VAO before calling glBindBuffer if OES_vertex_array_object is
  // supported. Otherwise we risk affecting a previously bound VAO.
  Bind();

  if (indexMutator != nullptr)
  {
    ASSERT(m_indexBuffer != nullptr, ());
    if (indexMutator->GetCapacity() > m_indexBuffer->GetBuffer()->GetCapacity())
    {
      m_indexBuffer = make_unique_dp<IndexBuffer>(indexMutator->GetCapacity());
      m_indexBuffer->MoveToGPU(context, GPUBuffer::IndexBuffer, m_batcherHash);
    }
    m_indexBuffer->UpdateData(context, indexMutator->GetIndexes(), indexMutator->GetIndexCount());
  }

  if (attrMutator == nullptr)
  {
    Unbind();
    return;
  }

  auto const & data = attrMutator->GetMutateData();
  for (auto it = data.begin(); it != data.end(); ++it)
  {
    auto const & nodes = it->second;
    if (nodes.empty())
      continue;

    auto const offsets = CalculateMappingPart(nodes);

    ref_ptr<DataBuffer> buffer = GetDynamicBuffer(it->first);
    ASSERT(buffer != nullptr, ());
    DataBufferMapper mapper(context, buffer, offsets.first, offsets.second);
    for (size_t i = 0; i < nodes.size(); ++i)
    {
      MutateNode const & node = nodes[i];
      ASSERT_GREATER(node.m_region.m_count, 0, ());
      mapper.UpdateData(node.m_data.get(), node.m_region.m_offset - offsets.first, node.m_region.m_count);
    }
  }

  Unbind();
}

bool VertexArrayBuffer::Bind() const
{