function [sys,x0]=pndanim1(t,x,u,flag,ts);
%PNDANIM3 S-function for animating the motion of a pendulum.

%	Ned Gulley, 6-21-93
%	Copyright (c) 1984-94 by The MathWorks, Inc.
global PendAnim1

if flag==2,
    if any(get(0,'Children')==PendAnim1),
      if strcmp(get(PendAnim1,'Name'),'simppend Animation'),
    	set(0,'currentfigure',PendAnim1);
	hndlList=get(gca,'UserData');
    	x=[u(1) u(1)+2*sin(u(2))];
    	y=[0 -2*cos(u(2))];
    	set(hndlList(1),'XData',x,'YData',y);
    	set(hndlList(2),'XData',u(1),'YData',0);
    	drawnow;
      end
    end
    sys=[];

elseif flag == 4 % Return next sample hit
  
  % ns stores the number of samples
  ns = t/ts;

  % This is the time of the next sample hit.
  sys = (1 + floor(ns + 1e-13*(1+ns)))*ts;

elseif flag==0,

    % Initialize the figure for use with this simulation
    animinit('simppend Animation');
	[flag,PendAnim1] = figflag('simppend Animation');
    axis([-3 3 -2 2]);
    hold on;

    x=[0 0];
    y=[0 -2];
    hndlList(1)=plot(x,y,'LineWidth',5,'EraseMode','background');
    hndlList(2)=plot(0,0,'.','MarkerSize',25,'EraseMode','back');
    set(gca,'AspectRatio',[1 1]);
    set(gca,'UserData',hndlList);

    sys=[0 0 0 2 0 0];
    x0=[];

end;

