message: Use index offset provided by ImGui when rendering UI
diff: @@ -205,7 +205,6 @@ void ImGuiHelper::processImGuiCommands(ImDrawData* commands, const ImGuiIO& io)
  int primIndex = 0;
  for (int cmdListIndex = 0; cmdListIndex < commands->CmdListsCount; cmdListIndex++) {
  const ImDrawList* cmds = commands->CmdLists[cmdListIndex];
  - size_t indexOffset = 0;
  populateVertexData(bufferIndex,
  cmds->VtxBuffer.Size * sizeof(ImDrawVert), cmds->VtxBuffer.Data,
  cmds->IdxBuffer.Size * sizeof(ImDrawIdx), cmds->IdxBuffer.Data);
  @@ -226,12 +225,11 @@ void ImGuiHelper::processImGuiCommands(ImDrawData* commands, const ImGuiIO& io)
  rbuilder
  .geometry(primIndex, RenderableManager::PrimitiveType::TRIANGLES,
  mVertexBuffers[bufferIndex], mIndexBuffers[bufferIndex],
  - indexOffset, pcmd.ElemCount)
  + pcmd.IdxOffset, pcmd.ElemCount)
  .blendOrder(primIndex, primIndex)
  .material(primIndex, materialInstance);
  primIndex++;
  }
  - indexOffset += pcmd.ElemCount;
  }
  bufferIndex++;
  }
  