12. Animation

12.1     Animating by whiting out successive images

12.2     Watching comets

12.3     Animating by drawing now

12.4     Making movies

12.5     Saving movies

12.6     Reading and running previously saved movies

12.7     Practicing animation

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12.1 Animating by whiting out successive images

Code 12.1.1

close all

clear all

Sx = 0;

Sy = 0;

moves = 6;

Sa = linspace(.15*pi,.45*pi,moves);

Ea = linspace(.75*pi,.55*pi,moves);

position = [];

figure(1)

hold on; grid on; box on;

xlim([-2.5 2.5]);

ylim([-2.5 2.5]);

for i = 1:moves

Ex(i) = Sx + cos(Sa(i));

Ey(i) = Sy + sin(Sa(i));

Hx(i) = Ex(i) + cos(Ea(i));

Hy(i) = Ey(i) + sin(Ea(i));

    position = [position; [Sx Ex(i) Hx(i)] [Sy Ey(i) Hy(i)]];

    plot(position(i,1:3),position(i,4:6),'ko-');

    if i == 1

        pause;

    end

    want_animation = 0;

    if want_animation

        pause(.1)

        if i < moves

            plot(position(i,1:3),position(i,4:6),'wo-');

        end

    end

end

Output 12.1.1

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12.3 Animating by drawing now

Code 12.3.1

figure(2)

pause

hold off

for i = 1:moves

    plot(position(i,1:3),position(i,4:6),'ko-');

    grid on

    xlim([-2.5 2.5]);

    ylim([-2.5 2.5]);

    drawnow

end

pause

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12.4 Making movies

Code 12.4.1

figure(3)

grid on

box on

xlim([-2.5 2.5]);

ylim([-2.5 2.5]);

hold on

F = moviein(moves);  % reserve n frames for the movie

for i = 1:moves

    plot(position(i,1:3),position(i,4:6),…

'ko-','erasemode','normal');

    F(i) = getframe;

end

pause

movie(F,1)  % movie(F,0) is often preferable

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12.5 Saving movies

Code 12.5.1

movie2avi(F,'myfirstmovie.avi')

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12.6 Reading and running previously saved movies

Code 12.6.1

figure(4)

pause

mov = aviread('myfirstmovie.avi');

axis off

movie(mov,0)

Code 12.6.2

figure(5)

mov = aviread('track.avi');

axis off

movie(mov,0)

im = mov(4).cdata;

image(im);

axis image;

Output 12.6.2