function flickerPairs_PTB_3_46_4_small

Screen('Preference','DebugMakeTexture', 1);

filename = 'cb_file_test_long.txt';
% filename = 'cb_6_18_07_PTB3_format.txt';

[timeout img1 img1_secs img2 img2_secs img3 img3_secs img4 img4_secs]=textread(filename,'%f %s %f %s %f %s %f %s %f', 'delimiter', ',');

[w,rect]=Screen('OpenWindow',0,[128 128 128]);

% % establish screen center
% x0 = rect(3)/2; % x = width (512)
% y0 = rect(4)/2; % y = height (384)

num_trials = length(timeout);

escPressed = false;

for index = 1:num_trials
    pic1=imread(char(img1(index)));
    pic2=imread(char(img3(index)));
    div=imread(char(img2(index)));
    
    trialStartSecs = GetSecs();
    Priority(1);
    while (~escPressed && (GetSecs() < trialStartSecs + timeout(index)))
        
        imgStart = GetSecs();
        t=Screen('MakeTexture',w,pic1);
        Screen('DrawTexture',w,t,[]);
        Screen('Flip', w);

        while (~escPressed && (GetSecs() < imgStart + img1_secs(index)))
            [keyIsDown, secs, keyCode] = KbCheck();
                if keyCode(27)
                    escPressed = 1;
                end
                WaitSecs(0.01);
        end

        imgStart = GetSecs();
        t=Screen('MakeTexture',w,div);
        Screen('DrawTexture',w,t,[]);
        Screen('Flip',w);
    
        while (~escPressed && (GetSecs() < imgStart + img2_secs(index)))
            [keyIsDown, secs, keyCode] = KbCheck();
                if keyCode(27)
                    escPressed = 1;
                end
                WaitSecs(0.01);
        end

        imgStart = GetSecs();
        t=Screen('MakeTexture',w,pic2);
        Screen('DrawTexture',w,t,[]);
        Screen('Flip', w);
        while (~escPressed && (GetSecs() < imgStart + img3_secs(index)))
            [keyIsDown, secs, keyCode] = KbCheck();
                if keyCode(27)
                    escPressed = 1;
                end
                WaitSecs(0.01);
        end

        imgStart = GetSecs();
        t=Screen('MakeTexture',w,div);
        Screen('DrawTexture',w,t,[]);
        Screen('Flip',w);

        while (~escPressed && (GetSecs() < imgStart + img2_secs(index)))
            [keyIsDown, secs, keyCode] = KbCheck();
                if keyCode(27)
                    escPressed = 1;
                end
                WaitSecs(0.01);
        end

%         buttons = 0;
%          while ~any(buttons) % wait for press
%             [x,y,buttons] = GetMouse;
%             % Wait 10 ms before checking the mouse again to prevent
%             % overload of the machine at elevated Priority()
%             WaitSecs(0.01);
%         end
        
    end
    

end

Priority(0);
fclose('all');
Screen('CloseAll');

end