Invalid object handle error

I have the following code which is a graphic rendering of the movement of a satellite around the Earth.

function ex
global state;
fh = figure('Menu','none','Toolbar','none','Units','characters');
hPanAni = uipanel('parent',fh,'Units','characters','Position',...
    [22.6 10.4 53 23],'title','Controls','FontSize',11,...
    'FontAngle','italic','FontWeight','bold');
hIniAni = uicontrol(hPanAni,'Style','pushbutton','Units','normalized',...
    'Position',[0.14 0.75 0.5 0.12],'String','Spin',...
    'FontSize',10,'Callback',@hIniAniCallback);
hFinAni = uicontrol(hPanAni,'Style','pushbutton','Units','normalized',...
    'Position',[0.14 0.5 0.5 0.12],'String','Stop',...
    'FontSize',10,'Callback',@hFinAniCallback);
hResetAni = uicontrol(hPanAni,'Style','pushbutton','Units','normalized',...
    'Position',[0.14 0.25 0.5 0.12],'String','Reset',...
    'FontSize',10,'Callback',@hResetAniCallback);
hPantSim = uipanel('Parent',fh,'Units','characters',...
    'Position',[107.87 8 157.447 42],'BorderType','none','title',...
    'Screen','FontSize',11,'FontAngle','italic',...
    'FontWeight','bold');
hPantSimInt = uipanel('Parent',hPantSim,'Units','normalized','Position',...
    [0 0 1 1],'BorderType','line','BackgroundColor','black');
ah4 = axes('Parent',hPantSimInt,'Units','normalized','Position',...
    [0 0 1 1],'Color','none','Visible','off','DataAspectRatio',...
    [1 1 1],'NextPlot','add');
rotate3d(ah4);
hgrot = hgtransform('Parent',ah4);
T1 = 0:pi/100:2*pi;
Y = zeros(numel(T1),3);
Y(:,1) = 7000*cos(T1);
Y(:,2) = 7000*sin(T1);
xmin = min(Y(:,1));
ymin = min(Y(:,2));
zmin  = min(Y(:,3));
xmax  = max(Y(:,1));
ymax  = max(Y(:,2));
zmax  = max(Y(:,3));
Resf = 6378;
xmin2 = min(xmin,-Resf);
xmax2  = max(xmax,Resf);
ymin2 = min(ymin,-Resf);
ymax2  = max(ymax,Resf);
zmin2  = min(zmin,-Resf);
zmax2  = max(zmax,Resf);
set(ah4,'XLim',[xmin2 xmax2],'YLim',[ymin2 ymax2],'ZLim',[zmin2 zmax2]);
maptext = imread('tierra.jpg');
[X_im, map] = rgb2ind(maptext,128);
[x_esf,y_esf,z_esf] = sphere(50);
x_esf = Resf*x_esf;
y_esf = Resf*y_esf;
z_esf = Resf*z_esf;
props.FaceColor= 'texture';
props.EdgeColor = 'none';
props.Parent = hgrot;
props.Cdata = flipud(X_im); % it is necesary to do this for getting the 
% appropiate image on the sphere
surface(x_esf,y_esf,z_esf,props);
colormap(map);
axis equal vis3d;
view(3);
az = 0;
Fin = numel(T1);
k = 2;
ind_ini = 0;
state = 0;
handles.tray = zeros(1,Fin);
handles.psat = line('parent',ah4,'XData',Y(1,1), 'YData',Y(1,2),...
    'ZData',Y(1,3),'Marker','o', 'MarkerSize',10,'MarkerFaceColor','b');
       function hIniAniCallback(hObject,evt)
            if (ind_ini == 1)
              return;  
            end
            ind_ini = 1;
            state = 0;
            while (k<Fin)
            az = az + 0.01745329252;
            set(hgrot,'Matrix',makehgtform('zrotate',az));
            handles.tray(k) = line([Y(k-1,1) Y(k,1)],[Y(k-1,2) Y(k,2)],...
                [Y(k-1,3) Y(k,3)],...
        'Color','red','LineWidth',3);
            set(handles.psat,'XData',Y(k,1),'YData',Y(k,2),'ZData',Y(k,3));
            pause(0.02); 
            k = k + 1,

              if (state == 1)
                  state = 0;
                  break;
              end
              end 
         end

      function hFinAniCallback(hObject,evt)
          ind_ini = 0;
          state = 1;
      end
   function hResetAniCallback(hObject,evt)
      set([handles.tray,handles.psat],'Visible','off');
      k = 2;
      ind_ini = 0;
      state = 1;
      az = 0;
      set(hgrot,'Matrix',makehgtform('zrotate',az));
      handles.psat = line('parent',ah4,'XData',Y(1,1), 'YData',Y(1,2),...
      'ZData',Y(1,3),'Marker','o', 'MarkerSize',10,'MarkerFaceColor','b');
  end

end

However, when I copy it to my main program I get the following error message:

??? Error using ==> surface Invalid object handle

    Error in ==> simorbiv8v3>hIniPropCallback at 1911 surface(x_esf,y_esf,z_esf,props);

    ??? Error while evaluating uicontrol Callback

I do not understand what is happening.

[Walter Roberson]

Is this question still active? I note that you just edited it, but I thought fixing the cla problem was the solution ?

Answer 1

[Walter Roberson]

Command

dbstop if error

and then run the code. When it stops at that line, examine props.Parent and in particular check ishandle(props.Parent) . If it says that it is not a handle, chase further up to ah4 and make sure that it is still a handle, then up to hPantSimInt and then to hPantSim and then to fh

[Julián Francisco]

@Walter Roberson: Thank you so much for your answer.

[Julián Francisco]

@Walter Roberson: I have already checked that ishandle(props.Parent) is false and ishandle(ah4) is true. As props.Parent = hgrot, the problem source is this hgtransform variable. It is declared as global one in the main program so there should not be problems then.

[Walter Roberson]

I don't understand about the global part. You do not show any global for hgrot or for props, but you do show hgtransform being called explicitly.

At what point in the sequence of commands does ishandle(hgrot) become false? Is it true immediately before the surface() call?

[Julián Francisco]

@Walter Roberson: The code shown is a part of the code for the main program and it needs to be modified (the hgrot variable should be declared as global one). Now the problem is fixed (as seen in my answer). Thank you for your help.

Answer 2

[Julián Francisco]

Finally, I have found that there was a cla command line, which was the guilty of the error, in the main program before the surface call.