% DarkScreen.m
%
% opens a window using Psychtoolbox, 
% makes the window black, then white, and then closes 
% the window again
%
% written for Psychtoolbox 3 on the PC by IF 3/2007 ASR Verified that it
% runs on MAC OSX 07/2007

screenNum=0;
res=[1280 1024];
clrdepth=32;
[wPtr,rect]=Screen('OpenWindow',screenNum,0,...
[0 0 res(1) res(2)], clrdepth);
black=BlackIndex(wPtr);
white=WhiteIndex(wPtr);
Screen('FillRect',wPtr,black); 
Screen(wPtr, 'Flip');
 
HideCursor;
tic
while toc<3
    ;
end
 
Screen('FillRect',wPtr,white); 
Screen(wPtr, 'Flip');
HideCursor;
tic
while toc<3
    ;
end
 
 
Screen('CloseAll');
ShowCursor