% Clear the workspace sca; clear; close all; %-------------------------------------------------------------------------- % Set up the screen %-------------------------------------------------------------------------- % Set the stereomode 6 for red-green anaglyph presentation. You will need % to view the image with the red filter over the left eye and the green % filter over the right eye. stereoMode = 6; % Here we call some default settings for setting up Psychtoolbox PsychDefaultSetup(2); % Setup Psychtoolbox for OpenGL 3D rendering support and initialize the % mogl OpenGL for Matlab wrapper InitializeMatlabOpenGL; % Get the screen number screenid = max(Screen('Screens')); % Open the main window [window, windowRect] = PsychImaging('OpenWindow', screenid, 0, [], 32, 2, stereoMode); % Query the frame duration ifi = Screen('GetFlipInterval', window); % Screen size pixels [screenXpix, screenYpix] = Screen('WindowSize', window); % Set up alpha-blending for smooth (anti-aliased) edges to our dots Screen('BlendFunction', window, 'GL_SRC_ALPHA', 'GL_ONE_MINUS_SRC_ALPHA'); % Maximum priority level topPriorityLevel = MaxPriority(window); Priority(topPriorityLevel); %-------------------------------------------------------------------------- % Set up the screen %-------------------------------------------------------------------------- % Set the size of the square to be a fraction of the screen size. This will % give us similar results on any demo system hopefully squareDimPix = screenYpix * 0.75; % For ease will will position dots +/- half of this size i.e. centered % around zero. When we draw to the screen we center the dots automatically. squareHalfDimPix = squareDimPix / 2; % Number of dots numDots = 1500; % Dot base position in pixels for the left and right eye. As you will see % the vertical do positions will be the same in both cases. dotPosXleft = (rand(1, numDots) .* 2 - 1) .* squareHalfDimPix; dotPosYleft = (rand(1, numDots) .* 2 - 1) .* squareHalfDimPix; dotPosXright = dotPosXleft; dotPosYright = dotPosYleft; % Dot diameter in pixels dotDiaPix = 6; % Our square will oscilate in depth with a sine wave function. To do this % we will modulate the lateral posotion of the dots defining the square % with a sine wave. % These are the parameters for the sine wave % See: http://en.wikipedia.org/wiki/Sine_wave amplitude = 15; frequency = 0.2; angFreq = 2 * pi * frequency; startPhase = 0; time = 0; %------------------------ % Drawing to the screen %------------------------ % We will update the screen on every frame waitframes = 1; % Sync us and get a time stamp vbl = Screen('Flip', window); % Loop the animation until a key is pressed while ~KbCheck % Here we grab the value for the sine wave left-right shift of the % dots. Note that we do this once and then multiply by -1 in the other % eye. This is because we want equal and opposite shifts in each eyes % image leftEyeShift = amplitude * sin(angFreq * time + startPhase); rightEyeShift = leftEyeShift * (-1); % Select left-eye image buffer for drawing (buffer = 0) Screen('SelectStereoDrawBuffer', window, 0); % Now draw our left eyes dots Screen('DrawDots', window, [dotPosXleft + leftEyeShift; dotPosYleft], dotDiaPix,... [], [screenXpix / 2 screenYpix / 2], 2); % Select right-eye image buffer for drawing (buffer = 1) Screen('SelectStereoDrawBuffer', window, 1); % Now draw our right eyes dots Screen('DrawDots', window, [dotPosXright + rightEyeShift; dotPosYright], dotDiaPix,... [], [screenXpix / 2 screenYpix / 2], 2); % Flip to the screen vbl = Screen('Flip', window, vbl + (waitframes - 0.5) * ifi); % Increment the time time = time + ifi; end % Wait for a button press to exit the demo KbStrokeWait; sca;