最近天気予報で見る風の可視化がかっこよかったので，真似して研究で使うベクトル場の可視化をやってみたところ，細部がわかりやすくていい感じでした．
汚いですがコードはMATLABのコードは以下のような感じです．
動画のベクトル場を生成するコードはすごく長いので，単純な円を描く流れにしてあります．コードの最初の部分でお好みのベクトル場を指定してみてください．
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| % vector field | |
| dxdt = @(x) [x(2);-x(1)]; | |
| % mesh | |
| [GX,GY] = meshgrid(linspace(-2*pi,2*pi,100),linspace(-10,10,100)); | |
| % stream | |
| DX = arrayfun(@(x,y) [1,0]*dxdt([x;y]),GX,GY); | |
| DY = arrayfun(@(x,y) [0,1]*dxdt([x;y]),GX,GY); | |
| [verts,averts] = streamslice(GX,GY,DX,DY,400); | |
| iverts = interpstreamspeed(GX,GY,DX,DY,verts,1/60/3); | |
| % visualize | |
| v = VideoWriter('stream.m4v','MPEG-4'); | |
| v.FrameRate=60; | |
| open(v) | |
| nframe = 60*10-1; | |
| seglen = 60; | |
| offset =randi(seglen,numel(iverts),1)-1; | |
| frames = cell(seglen,1); | |
| for frame=1:seglen | |
| fig = figure(6); | |
| clf | |
| fig.Position = [fig.Position(1:2),1024,768]; | |
| axes('Units', 'normalized', 'Position', [0 0 1 1]) | |
| set(fig,'Color',[0,0,0.2]) | |
| colormap([linspace(0,0,100);linspace(0,1,100);linspace(0.2,1,100)]') | |
| hold on | |
| for k=1:length(iverts) | |
| xy = iverts{k}; | |
| C = mod((0:(size(xy,1)-1))-frame+offset(k),seglen)/(seglen-1); | |
| C = exp(-(1-C)*1); | |
| xy(end+1,:)=[0,NaN]; | |
| patch(xy(:,1)',xy(:,2)',[C,0],'EdgeColor','interp','LineWidth',0.5) | |
| end | |
| xlim([min(GX(:)),max(GX(:))]) | |
| ylim([min(GY(:)),max(GY(:))]) | |
| set(gca,'Color',[0,0,0.2]) | |
| drawnow | |
| frames{frame}=getframe(gcf); | |
| end | |
| for frame=1:nframe | |
| writeVideo(v,frames{mod(frame,seglen)+1}) | |
| end | |
| close(v) |
