C++ (Cpp) DataReader::size示例

int RunVertices(int vtx_attr_group, int primitive, int count, DataReader src, bool skip_drawing,
                bool is_preprocess)
{
  if (!count)
    return 0;

  VertexLoaderBase* loader = RefreshLoader(vtx_attr_group, is_preprocess);

  int size = count * loader->m_VertexSize;
  if ((int)src.size() < size)
    return -1;

  if (skip_drawing || is_preprocess)
    return size;

  // If the native vertex format changed, force a flush.
  if (loader->m_native_vertex_format != s_current_vtx_fmt ||
      loader->m_native_components != g_current_components)
  {
    VertexManagerBase::Flush();
  }
  s_current_vtx_fmt = loader->m_native_vertex_format;
  g_current_components = loader->m_native_components;

  // if cull mode is CULL_ALL, tell VertexManager to skip triangles and quads.
  // They still need to go through vertex loading, because we need to calculate a zfreeze refrence
  // slope.
  bool cullall = (bpmem.genMode.cullmode == GenMode::CULL_ALL && primitive < 5);

  DataReader dst = VertexManagerBase::PrepareForAdditionalData(
      primitive, count, loader->m_native_vtx_decl.stride, cullall);

  count = loader->RunVertices(src, dst, count);

  IndexGenerator::AddIndices(primitive, count);

  VertexManagerBase::FlushData(count, loader->m_native_vtx_decl.stride);

  ADDSTAT(stats.thisFrame.numPrims, count);
  INCSTAT(stats.thisFrame.numPrimitiveJoins);
  return size;
}