You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: Intensity3DProcessGUI.m
    path of file: ./repos/u-shape3D/software
    
    the code of the file until where you have to start completion: function varargout = Intensity3DProcessGUI(varargin)
% intensity3dprocessgui M-file for intensity3dprocessgui.fig
%      intensity3dprocessgui, by itself, creates a new intensity3dprocessgui or raises the existing
%      singleton*.
%
%      H = intensity3dprocessgui returns the handle to a new intensity3dprocessgui or the handle to
%      the existing singleton*.
%
%      intensity3dprocessgui('CALLBACK',hObject,eventData,handles,...)
    
function popupmenu_meshMode_Callback(hObject, eventdata, handles)
% hObject    handle to popupmenu_meshMode (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns popupmenu_meshMode contents as cell array
%        contents{get(hObject,'Value')} returns selected item from popupmenu_meshMode


% --- Executes on selection change in popupmenu_intensityMode.
function popupmenu_intensityMode_Callback(hObject, eventdata, handles)
% hObject    handle to popupmenu_intensityMode (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns popupmenu_intensityMode contents as cell array
%        contents{get(hObject,'Value')} returns selected item from popupmenu_intensityMode


% --- Executes during object creation, after setting all properties.
function popupmenu_intensityMode_CreateFcn(hObject, eventdata, handles)
% hObject    handle to popupmenu_intensityMode (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: popupmenu controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end