Can I know how many times the cylinder rotates?

Hello.

I am a beginner in matlab.

I got the code in psychtoolbox that can make rotating cylinder.

I want to create a cylinder that rotates only once in 1.43 seconds at 60fps.

So I put number 60 in nframes and 86 in while fr (like under).

nFrames = 60; % 3 line on number 2 file

while fr <= 86 % 15 line on number 2 file

But I do not know how can I make a cylinder only once rotating in that time. I think I should put adequate number in NumFrames (8 line on number 1 file). If it is right, what number should I put it?

Because when I put 86(the same number with while fr), the resulting cylinder appears to rotate for one and a half round.

Could anyone help me, please..?

Below is rotating cylinder code file.

#number 1 file

clear;
makeCyl = 1;

%% parameters

W = 153; %width
ndot = 900;
NumFrames = 86;
stepD = 400;  % ie the half perimeter of the cylinder
cylR = stepD/pi;       %guarantee the cylinder aprroaches with the same distance per 180 degree as the figure walks a step

%% cylinder
if makeCyl
    
    backCol=0.9;
    dotx = sin((rand(1,ndot)-0.5)*pi)* W/2; %dots are more concentrated on the two boundaries after ttransformed to sin, more natural than sqrt
    dotc = ones(1, ndot);
    angs = 2*pi* rand(1,ndot);
    angpf = 2*pi/NumFrames;  %angle per frame
    
    Cylin = NaN(NumFrames*3,ndot);  %keep it the same format as the mov file
    dotC = cell(NumFrames,1);
    for zz = 1:NumFrames
        
        Cylin(zz*3-2,:) = dotx;
        Cylin(zz*3-1,:) = cylR*cos(angs);
        Cylin(zz*3,:) = cylR*sin(angs);  % all dots are in the same depth so that it won'd contain perspective cue when drawn by moglDrawDots3D
        angs = angs-angpf;
        dotc = ones(1, ndot);
        dotc(:, mod(angs,2*pi)<=pi) = backCol;
        dotC{zz}= [1;1;1]*dotc;
    end
    
    save('Cylin_aaa','Cylin' ,'ndot');
end

#number 2 file

InitializeMatlabOpenGL;
load('Cylin_aaa.mat')
nFrames = 60;
fr = 1;
InitializeMatlabOpenGL; % open GL reset, moglDrawDots3D Required for function execution
%Screen('Preference', 'SkipSyncTests', 1);
Screen('Preference', 'SkipSyncTests', 1) % Skip sync test for testing
whichScreen = max(Screen('Screens'));
[w, screenRect] = Screen('OpenWindow', whichScreen,[0 0 0],[]); % small screen output
ScreenCenter = [screenRect(3)/2 screenRect(4)/2];
commandwindow;



while fr <= 86
    
    thefr = fr;
    while thefr > nFrames; thefr =thefr-nFrames; end

    disp(thefr); % Check frame progress
    this_xyz =  Cylin(thefr*3-2:thefr*3,:);
     Screen('DrawDots',w, this_xyz(1:2,:),[],[255 255 255],ScreenCenter, 0);
%     moglDrawDots3D(w, this_xyz, 1, [1 1 1]); %
    
    Screen('Flip',w);
    %WaitSecs(0.05); % To see the dot move slowly
    
    fr = fr +1;
end
sca;

Thank you.

Answer 1

[Angelo Yeo]

Check the script below and see that the Cylinder rotates only once during the 86 frames. I intentionally added a red marker to visually check how the cylinder rotates.

InitializeMatlabOpenGL;
load('Cylin_aaa.mat')
nFrames = 60;
fr = 1;
InitializeMatlabOpenGL; % open GL reset, moglDrawDots3D Required for function execution
Screen('Preference', 'SkipSyncTests', 1) % Skip sync test for testing
whichScreen = max(Screen('Screens'));
[w, screenRect] = Screen('OpenWindow', whichScreen,[0 0 0],[]); % small screen output
ScreenCenter = [screenRect(3)/2 screenRect(4)/2];
Screen('NominalFrameRate', w, 0, nFrames); % setting frame rate to 60 Hz
commandwindow;

while fr <= 86

    Screen('DrawDots',w, Cylin(3*fr -2:3*fr-1,:),[],[255 255 255],ScreenCenter, 0);
    Screen('DrawDots',w, Cylin(3*fr -2:3*fr-1,1), 10, [255,0,0] , ScreenCenter, 0); % For reference
    %     moglDrawDots3D(w, this_xyz, 1, [1 1 1]); %

    Screen('Flip',w);
    %WaitSecs(0.05); % To see the dot move slowly

    fr = fr +1;
end
sca;

[희영]

I am really sorry for the delay in accepting the answer.

I ran the code you provided, and I could check the red dot spinning! I really appreciate your help.

I hope you have a good to this week!!