% Evaluate the displacement of an mass-spring system
%clc;
clear;
global k m C

k = 3;  % stiffness [kg /s^2]
m = 2; % inertia  [m/s^2]
C = 0;

x0 = 1; % initial displacement  [m]
v0 = 0; % initial velocity  [m/s]

t0 = -5; tf = 25; %start and end time [s]

%Integrate Mass-Spring System
[t,x] = ode45('undamped', [t0,tf], [x0,v0]);


xx=x(:,1);
vv=x(:,2);

w=0.3;
h=0.3;
d=0.2;


for an=1:1:(length(xx))
   
   if mod(an,3)==0
subplot(3,3,[1 4]);
plot(xx(1:an),t(1:an),'b-','linewidth', 2);  axis([-1 1 -5 25])
hold on
plot(xx(an),t(an),'ko','linewidth',6,'markersize',5);
hold off
ylabel('Displacement, x', 'fontsize', 13 );xlabel('Time (sec)','fontsize', 13 );grid;
subplot(3,3,[8 9]);
plot(t(1:an),vv(1:an),'r-','linewidth', 2);  axis([-5 25 -2 2])
hold on
plot(t(an),vv(an),'bo','linewidth',6,'markersize',5);
hold off
ylabel('Velocity, v','fontsize', 13 );xlabel('Time (sec)','fontsize', 13 );grid;
subplot(3,3,7);
plot(xx(1:an),vv(1:an),'g-', 'linewidth', 2);  axis([-1 1 -2 2])
hold on
plot(xx(an),vv(an),'bo','linewidth',6,'markersize',5);
hold off
ylabel('Velocity','fontsize', 13);xlabel('Displacement','fontsize', 13 );grid;
%pause(0.1);
pause(0.01)   %change the speed of plotting time
subplot(3,3,[2 3 5 6])
plot([-1.4 -1.4 1.4],[1.4 0.1 0.1],'k','linewidth',3), axis([-1.5, 1.5,0,1.5]), hold on
   plot([xx(an)-w/2,xx(an)+w/2],[0.15,0.15],'ko','linewidth',5,'markersize',10)
   patch([xx(an)-w xx(an)-w  xx(an)+w  xx(an)+w],[d d+h d+h d],[0 0 0 0],'y') 
   hold off
   else
   hi=1;
end

pause(0.01)   %change the speed of plotting time

end





%patch([1.5 1.5 1.6 1.6],[1.25 1.35 1.35 1.25],[0 0 0 0],'r')