% Clear the workspace close all; clear; sca; % Here we call some default settings for setting up Psychtoolbox PsychDefaultSetup(2); % Get the screen numbers screens = Screen('Screens'); % Draw to the external screen if avaliable screenNumber = max(screens); % Define black and white white = WhiteIndex(screenNumber); black = BlackIndex(screenNumber); grey = white / 2; inc = white - grey; % Open an on screen window [window, windowRect] = PsychImaging('OpenWindow', screenNumber, grey); % Get the size of the on screen window [screenXpixels, screenYpixels] = Screen('WindowSize', window); % Query the frame duration ifi = Screen('GetFlipInterval', window); % Get the centre coordinate of the window [xCenter, yCenter] = RectCenter(windowRect); % Set up alpha-blending for smooth (anti-aliased) lines Screen('BlendFunction', window, 'GL_SRC_ALPHA', 'GL_ONE_MINUS_SRC_ALPHA'); % Dimension of our texure (it will be this value +1 pixel) dim = 250; % Make a second dimension value which is increased by a factor of the % squareroot of 2. We need to do this because in this demo we will be using % internal texture rotation. We round this to the nearest pixel. dim2 = ceil(dim * sqrt(2)); % Contrast for our contrast modulation mask: 0 = mask has no effect, 1 = mask % will at its strongest part be completely opaque i.e. 0 and 100% contrast % respectively contrast = 1; % Define a simple spiral texture by defining X and Y coordinates with the % meshgrid command, converting these to polar coordinates and finally % defining the spiral. This time we create a two layer texture fill % the first layer with the background color and then place the spiral % texure in the second 'alpha' layer. Note that we make the mask texture % larger for internal texture rotation. [x, y] = meshgrid(-dim2:1:dim2, -dim2:1:dim2); [th, r] = cart2pol(x, y); spiral = (white .* (1 - cos(r / 5 + th * 5))) ./ 2; [s1, s2] = size(x); mask = ones(s1, s2, 2) .* grey; mask(:, :, 2)= spiral .* contrast; % Make our sprial into a screen texture for drawing maskTexture = Screen('MakeTexture', window, mask); % Make ablack and white noise texture, we make this 1/3 the size of the % destination rectangle we are putting it in so that it is scaled up, % giving us a more chunky noise pattern. This will be viewed through the % spiral mask noiseDim = round(s1 / 3); noise = round(rand(noiseDim, noiseDim)); noiseTexture = Screen('MakeTexture', window, noise); % We are going to draw three textures to show how a black and white texture % can be color modulated upon drawing. yPos = yCenter; xPos = linspace(screenXpixels * 0.2, screenXpixels * 0.8, 3); % Define the destination rectangles for our spiral textures. For this demo % these will be the same size as out actualy texture, but this doesn't have % to be the case. ndim = dim * 2 + 1; baseRect = [0 0 ndim ndim]; dstRects = nan(4, 3); for i = 1:3 dstRects(:, i) = CenterRectOnPointd(baseRect, xPos(i), yPos); end % Now we create a window through which we will view our texture. This is % the same size as our destination rectangles. But we shift it in X and Y % by a value of dim2 - dim. This makes sure our window is centered on the % middle of the enlarged texture we made for internal texture rotation. srcRect = baseRect + (dim2 - dim); % Color Modulation colorMod = [1 0 0; 0 1 0; 0 0 1]'; % Set the initial angle to zero and the angular increment per farme to 2 % degrees angle = 0; angleInc = 2; % Sync us to the vertical retrace waitframes = 1; vbl = Screen('Flip', window); while ~KbCheck % Batch Draw all of the texures to screen Screen('DrawTextures', window, noiseTexture, [], dstRects, [], [], [], colorMod); Screen('DrawTextures', window, maskTexture, srcRect, dstRects, angle,... [], [], [],[], kPsychUseTextureMatrixForRotation); % Flip to the screen vbl = Screen('Flip', window, vbl + (waitframes - 0.5) * ifi); % Increment the angle angle = angle + angleInc; end % Clear the screen sca;