Fractional Fourier Transformation Animation

writerObj = VideoWriter('test.avi');
open(writerObj);

func=@(t) rectpuls(t);
HalfDur=20;
t=-HalfDur:0.1:HalfDur;
x=func(t);



%animation setup
plot(t,real(x))
hold on
plot(t,imag(x),'r')
title('0.000')
axis([-5 5 -0.5 1.5])
set(gca,'nextplot','replacechildren');
set(gcf,'Renderer','zbuffer');


frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);

N=60;
% x_a=zeros(N,length(t));

tic;
for n = 1:N

    a=n/60;
    x=sqrt(1-1i*cot(a*pi/2)) *integral(@(u) ...
            rectpuls(u).*exp(1i*pi* (  cot(a*pi/2)*t.^2   -2*csc(a*pi/2)*u.*t   +cot(a*pi/2)*u.^2  )) ,-HalfDur,HalfDur ,'AbsTol',1e-2,'ArrayValued',true);


        hold off
        plot(t,real(x))
        hold on
        plot(t,imag(x),'r')
        title(sprintf('%0.3f',a))
        axis([-5 5 -0.5 1.5])
        frame = getframe( gcf );
        writeVideo(writerObj,frame);
        frame = getframe( gcf );
        writeVideo(writerObj,frame);

end
toc;
frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);
frame = getframe( gcf );
writeVideo(writerObj,frame);
close(writerObj);