jsPsych/plugins/jspsych-visual-search-circle.js

/**
 * jspsych-visual-search-circle
 * Josh de Leeuw
 * 
 * display a set of objects, with or without a target, equidistant from fixation
 * subject responds to whether or not the target is present
 * 
 * based on code written for psychtoolbox by Ben Motz
 * 
 * todo: 
 * 
 * allow for use of display_element
 * 
 **/

(function($) {
    jsPsych["visual-search-circle"] = (function() {

        var plugin = {};

        plugin.create = function(params) {

            var trials = new Array(params.target_present.length);

            for (var i = 0; i < trials.length; i++) {
                trials[i] = {};
                trials[i].type = "visual-search-circle";
                trials[i].target_present = params.target_present[i];
                trials[i].set_size = params.set_size[i];
                trials[i].target = params.target;
                trials[i].foil = params.foil;
                trials[i].fixation_image = params.fixation_image;
                trials[i].target_size = params.target_size || [50, 50];
                trials[i].fixation_size = params.fixation_size || [16, 16];
                trials[i].circle_diameter = params.circle_diameter || 250;
                trials[i].target_present_key = params.target_present_key || 74;
                trials[i].target_absent_key = params.target_absent_key || 70;
                trials[i].timing_max_search = (typeof params.timing_max_search === 'undefined') ? -1 : params.timing_max_search;
                trials[i].timing_fixation = (typeof params.timing_fixation === 'undefined') ? 1000 : params.timing_fixation;
                trials[i].timing_post_trial = (typeof params.timing_post_trial === 'undefined') ? 1000 : params.timing_post_trial;
                trials[i].data = (typeof params.data === 'undefined') ? {} : params.data[i];
            }

            return trials;
        };

        plugin.trial = function(display_element, block, trial, part) {

            trial = jsPsych.pluginAPI.normalizeTrialVariables(trial);

            // screen information
            var screenw = $(window).width();
            var screenh = $(window).height();
            var centerx = screenw / 2;
            var centery = screenh / 2;

            // circle params
            var diam = trial.circle_diameter; // pixels
            var radi = diam / 2;
            var paper_size = diam + trial.target_size[0];

            // stimuli width, height
            var stimh = trial.target_size[0];
            var stimw = trial.target_size[1];
            var hstimh = stimh / 2;
            var hstimw = stimw / 2;
            
            // fixation location
            var fix_loc = [Math.floor(paper_size / 2 - trial.fixation_size[0]), Math.floor(paper_size / 2 - trial.fixation_size[1])];

            // possible stimulus locations on the circle
            var display_locs = [];
            var possible_display_locs = trial.set_size;
            var random_offset = Math.floor(Math.random()*360);
            for(var i = 0; i < possible_display_locs; i++){
                display_locs.push([
                    Math.floor(paper_size / 2 + (cosd(random_offset + (i * (360/possible_display_locs))) * radi) - hstimw),
                    Math.floor(paper_size / 2 - (sind(random_offset + (i * (360/possible_display_locs))) * radi) - hstimh)
                ]);
            }
                
            // get target to draw on
            var paper = Raphael(centerx - diam / 2, centery - diam / 2, paper_size, paper_size);

            show_fixation();

            function show_fixation() {
                // show fixation
                var fixation = paper.image(trial.fixation_image, fix_loc[0], fix_loc[1], trial.fixation_size[0], trial.fixation_size[1]);

                // wait 
                setTimeout(function() {
                    // after wait is over
                    fixation.remove();
                    show_search_array();
                }, trial.timing_fixation);
            }

            function show_search_array() {

                var search_array_images = [];

                for (var i = 0; i < display_locs.length; i++) {
                    
                    var which_image = (i == 0 && trial.target_present) ? trial.target : trial.foil;

                    var img = paper.image(which_image, display_locs[i][0], display_locs[i][1], trial.target_size[0], trial.target_size[1]);

                    search_array_images.push(img);
                    
                }

                var trial_over = false;
                
                var after_response = function(info){
                    
                    trial_over = true;
                    
                    var correct = 0;
                    
                    if (info.key == trial.target_present_key && trial.target_present || 
                        info.key == trial.target_absent_key && !trial.target_present) {
                        correct = 1;
                    }
                    
                    clear_display();
                    
                    end_trial(info.rt, correct, info.key);
                        
                }
                
                var valid_keys = [trial.target_present_key, trial.target_absent_key];
                
                key_listener = jsPsych.pluginAPI.getKeyboardResponse(after_response, valid_keys, 'date',false);

                if (trial.timing_max_search > 0) {
                    setTimeout(function() {

                        if (!trial_over) {
                            
                            jsPsych.pluginAPI.cancelKeyboardResponse(key_listener);
                            
                            trial_over = true;
                            
                            var rt = -1;
                            var correct = 0;
                            var key_press = -1;

                            clear_display();

                            end_trial(rt, correct, key_press);
                        }
                    }, trial.timing_max_search);
                }

                function clear_display() {
                    paper.remove();
                }
            }


            function end_trial(rt, correct, key_press) {
                
                // data saving
                var trial_data = {
                    trial_type: trial.type,
                    trial_index: block.trial_idx,
                    correct: correct,
                    rt: rt,
                    key_press: key_press,
                    locations: JSON.stringify(display_locs),
                    target_present: trial.target_present,
                    set_size: trial.set_size
                };

                // this line merges together the trial_data object and the generic
                // data object (trial.data), and then stores them.
                block.writeData($.extend({}, trial_data, trial.data));

                // go to next trial
                if(trial.timing_post_trial > 0){
                    setTimeout(function() {
                        block.next();
                    }, trial.timing_post_trial);
                } else {
                    block.next();
                }
            }
        };

        // helper function for determining stimulus locations

        function cosd(num) {
            return Math.cos(num / 180 * Math.PI);
        }

        function sind(num) {
            return Math.sin(num / 180 * Math.PI);
        }

        return plugin;
    })();
})(jQuery);