Example
This is a complete Matlab program (in just 36 lines plus comments) to synthesize and show a movie. If you haven't already, you'll probably want to read our tutorial on using the Psychtoolbox with Matlab.
function MovieDemo
- % MovieDemo uses Screen.mex to make and show a movie.
- fprintf('MovieDemo.m is only 36 lines, plus comments.\n');
- fprintf('Read it to see how easy it is to show movies.\n\n');
-
- % Open a window in center of screen
- screenNumber=0;
- rect=CenterRect([0 0 200 200],Screen(screenNumber,'Rect'));
- window=Screen(screenNumber,'OpenWindow',[],rect);
-
- % Make a movie by drawing ovals into 101 offscreen windows.
- fprintf('Computing the movie... ');
- black=BlackIndex(window);
- w=zeros(101,1);
- for i=1:101
- w(i)=Screen(window,'OpenOffscreenWindow');
- r=[0 0 2 2]*(i-1);
- Screen(w(i),'FillOval',black,r);
- end
- fprintf('Done.\nRoll ''em!\n');
-
- % Show the movie, first forwards, then backwards.
- HideCursor;
- rect=Screen(w(1),'Rect');
- for i=[1:101 101:-1:1]
- Screen(window,'WaitBlanking');
- Screen('CopyWindow',w(i),window,rect,rect);
- end
-
- % Show the movie again, now using Rush to minimize interruptions.
- loop={
- 'for i=[1:101 101:-1:1];'
'Screen(window,''WaitBlanking'');'
'Screen(''CopyWindow'',w(i),window,rect,rect);'
'end;'
- };
- priorityLevel=MaxPriority(screenNumber,'WaitBlanking');
- Rush(loop,priorityLevel);
- ShowCursor;
-
- % Close the on- and off-screen windows
- Screen('CloseAll');
-
- fprintf('The movie was shown twice. The first showing may have been jerky, due to\n');
- fprintf('interruptions. The second showing used Rush to minimize interruptions, to\n');
- fprintf('make the movie run smoothly. See MovieTearDemo and Rush.\n');
visitors since 20 March 2000.
David Brainard, Denis Pelli & Allen Ingling.
psychtoolbox@yahoogroups.com
- 19 September 2000
