% This script makes 3 videos.
%   The first one shows a wave propagating from left to right
%   The second one shows a wave propagating from right to left  
%   The third one shows the solution for the problem 3 form the chapter 5.
%
%
% Created by M. Caldarola on 27 april 2013. (caldarola@df.uba.ar)
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%
clear 
%% parameters
f = 1;        % Frequency in Hz
w = 2*pi*f;   % Angular frequency [Hz]
c = 1;        % phase velocity [m/s]
k=w/c;        % wave vector [1/m]
%% Functions
A=1;        % wave amplitude (the units depend on th physical meaning of psi
L=1;        % distance mentioned in the problem.
psi1 = @(x,t) A*cos(w.*t-k.*x);             % incident wave function
psi2 = @(x,t) -A*cos(w.*t+k.*(x-2*L));      % reflected wave function


%% vectors for evaluation
x = linspace(-3*L,L,10^3);  % space vector, from -3L to L
t = linspace(0,4/f,10^2);   % time vector, from 0 to 4 times the temporal period

%% Single plots to check
% figure
% plot(x,psi1(x,0),'r','Linewidth',2)
% hold on
% plot(x,psi2(x,0),'k','Linewidth',2)
% plot(x,psi1(x,0)+psi2(x,0),'--k','Linewidth',2)
% xlabel('x/L','Fontsize',16)
% ylabel('\psi(x)','Fontsize',16)
% grid on
% hold off
%% for to generate the movie for one propagating wave (positive phase speed)

aviobj = avifile('propagante_der.avi','compression','None');

fig = figure;
for i = 1:size(t,2)
    plot(x,psi1(x,t(i)),'r','Linewidth',2)
    hold on
    plot(c*t(i)-3*L,psi1(c*t(i),t(i)),'s','MarkerEdgeColor','k',...
                'MarkerFaceColor','g',...
                'MarkerSize',10)
    hold off
    ylim([-1.2,1.2])
    xlabel('x','Fontsize',16)
    ylabel('\psi_{derecha}(x)','Fontsize',16)
    grid on
    
    F1 = getframe(fig);
    aviobj = addframe(aviobj,F1);
end
close(fig);
aviobj = close(aviobj);
%% for to generate the movie for one propagating wave (negative phase speed)

aviobj = avifile('propagante_izq2.avi','quality',50,'fps',10);

fig = figure;
for i = 1:size(t,2)
    plot(x,psi2(x,t(i)),'k','Linewidth',2)
    hold on
    plot(-c*t(i)+L,psi2(-c*t(i)+L,t(i)),'s','MarkerEdgeColor','k',...
                'MarkerFaceColor','g',...
                'MarkerSize',10)
    hold off
    ylim([-1.2,1.2])
    xlabel('x','Fontsize',16)
    ylabel('\psi_{Izquierda}(x)','Fontsize',16)
    grid on

    F2 = getframe(fig);
    aviobj = addframe(aviobj,F2);
end
close(fig);
aviobj = close(aviobj);

%% Guia 5 Ej2: Reflexión en un punto fijo. Genero un avifile

aviobj = avifile('G5_ej2.avi','compression','None');

fig=figure;
for i = 1:size(t,2)
    plot(x,psi1(x,t(i)),'r','Linewidth',2)
    hold on
    plot(x,psi2(x,t(i)),'k','Linewidth',2)
    plot(x,psi1(x,t(i))+psi2(x,t(i)),'--k','Linewidth',2)
    xlabel('x','Fontsize',16)
    ylabel('\psi(x)','Fontsize',16)
    grid on
    ylim([-2,2])
    plot(c*t(i)-3*L,psi1(c*t(i),t(i)),'s','MarkerEdgeColor','k',...
        'MarkerFaceColor','g',...
        'MarkerSize',10)
    plot(-c*t(i)+L,psi2(-c*t(i)+L,t(i)),'s','MarkerEdgeColor','k',...
        'MarkerFaceColor','g',...
        'MarkerSize',10)
    plot(L,psi1(L,t(i))+psi2(L,t(i)),'s','MarkerEdgeColor','k',...
        'MarkerFaceColor','g',...
        'MarkerSize',10)
    hold off
    
    F3 = getframe(fig);
    aviobj = addframe(aviobj,F3);
end
close(fig);
aviobj = close(aviobj);