Question

count = 1;                              
R_Ball = 2;
initpos.x = 0;
initpos.y = 2.4;
initvel.x = 2;
initvel.y = 4;
gravity.x = 0;
gravity.y = 9.81;
restitution = 0.7;
GroundBall_friction = 0.2;
dt = 0.001;
pos.x = initpos.x; % initial position
pos.y = initpos.y; % initial position
vel.x = initvel.x; % initial velocity-x
vel.y = initvel.y; % initial velocity-y
t_arc = linspace(0,(2*vel.y)/gravity.y,2000);
for k =  1:2000

%Updating the ball's position
vel.x = vel.x;
vel.y = vel.y - gravity.y*t_arc(k);
pos.x = pos.x + vel.x*t_arc(k);
pos.y = pos.y + vel.y*t_arc(k) - (1/2)*gravity.y*(t_arc(k).^2);
if  vel.y < 0 && pos.y < 0
vel.y = (-1)*(restitution)*vel.y;
vel.x = vel.x + GroundBall_friction*(restitution - 1)*vel.x;
end
pos.y = max(0, pos.y);
clf;
subplot(2,1,1)
hold on
line([0 30],[0 0]);
rectangle('position', [pos.x pos.y R_Ball R_Ball],'Curvature',[1 1],'FaceColor','r');
posyy(count) = pos.y;
plot(posxx + 1/2*R_Ball, posyy + 1/2*R_Ball,'b');
axis([0 30 0 10]);
hold off
subplot(2,1,2)
hold on
velyy(count) = vel.y;
velxx(count) = vel.x;
plot(posxx,velxx,'r','LineWidth',2);
plot(posxx,velyy,'b','LineWidth',2);
count = count+1;
legend('Velocity.X','Velocity.Y');
hold off
axis([0 30 -10 10]);
%Refresh rate
pause(dt)
end
% save video as .mp4;
myVideo = VideoWriter('Boucing_Ball','mpeg-4');
myVideo.FrameRate = 60; % frames per second
open(myVideo);
writeVideo(myVideo,);
close(myVideo);

我有点不知道如何解决这个问题。我想导出这个动画并使用MP4格式的VideoWriter函数保存它。但我是新手写动画，所以任何帮助都会受到赞赏。

Answer 1

代码原样给出以下错误：

Undefined function or variable 'posxx'

您应该添加以下代码（第18行之前）：posxx=0;

在此帖子Approaches to create a video in matlab中，您可以使用writeVideo获取有关如何制作视频的信息。您应该获取当前帧并存储它，然后调用该函数。

将动画导出并保存为视频文件

1 个答案: