/**
 * Positioning
 * By Raphael Rouvinov-Kats
 * 
 * what I want to do: make emitter follow mouse, show lagged plot of past locations based on what detectors saw
 * 
 * plot of what I'm talking about
 * https://www.desmos.com/calculator/5g0rb178iu
 * 
 * copy of desmos equations:
 * x1 = 2 // emitter
 * y1 = 2
 * x2 = 0 // detector 1
 * y2 = 0
 * x3 = 3 // detector 2
 * y3 = 0
 * x4 = 3 // detector 3
 * y4 = 2.5
 * (x1, y1) // plot emitter
 * (x2, y2), (x3, y3), (x4, y4) // plot detectors
 * (x-x1)2 + (y-y1)2 = (sqrt((x2-x1)2 + (y2-y1)2))2 // circle centered at emitter with detector 1 on border
 * (x-x1)2 + (y-y1)2 = (sqrt((x3-x1)2 + (y3-y1)2))2 // same with detector 2
 * (x-x1)2 + (y-y1)2 = (sqrt((x4-x1)2 + (y4-y1)2))2 // dsmr with detector 3
 * t1 = sqrt((x2-x1)2 + (y2-y1)2) - sqrt((x3-x1)2 + (y3-y1)2) // difference in time between signal hitting detectors 1 and 2
 *                                                            // dist(emitter, detector1) - dist(emitter, detector2)
 * t2 = sqrt((x3-x1)2 + (y3-y1)2) - sqrt((x4-x1)2 + (y4-y1)2) // same with detecros 2 and 3
 * t3 = sqrt((x4-x1)2 + (y4-y1)2) - sqrt((x2-x1)2 + (y2-y1)2) // same with detecros 3 and 1
 * sqrt((x-x2)2 + (y-y2)2) - sqrt((x-x3)2 + (y-y3)2) = t1 // hyperbola with foci at detectors 1 and 2 and point on emitter
 *                                                        // locus/equation is all points where emitter could be
 *                                                        // that would cause t1 difference in time between
 *                                                        // signal coming to both detectors
 * sqrt((x-x3)2 + (y-y3)2) - sqrt((x-x4)2 + (y-y4)2) = t2 // same detectors 2 and 3
 * sqrt((x-x4)2 + (y-y4)2) - sqrt((x-x2)2 + (y-y2)2) = t3 //same detectors 3 and 4
 * 
 * apparently this is called https://en.wikipedia.org/wiki/Multilateration
 * */

var emitter = {
    x: 100,
    y: 100,
    interval: 100,
    draw : function() {
        pushMatrix();
            stroke(0, 0, 0);
            strokeWeight(5);
            point(emitter.x, emitter.y);
        popMatrix();
    },
    drawEmissions : function() {
        pushMatrix();
            noFill();
            stroke(0, 0, 0);
            strokeWeight(1);
            for(var r = frameCount % emitter.interval; r < width*1.5; r+= emitter.interval) {
                ellipse(emitter.x, emitter.y, r*2, r*2);
            }
        popMatrix();
    }
};

var Detector = function(x, y) {
    this.x = x;
    this.y = y;
    
    this.draw = function() {
        pushMatrix();
            stroke(255, 255, 255);
            strokeWeight(5);
            point(this.x, this.y);
        popMatrix();
    };
};

var detectors = [new Detector(300, 100), new Detector(150, 350)];

var draw = function() {
    background(180, 211, 237);
    
    // draw detectors
    for(var i = 0; i < detectors.length; i++) {
        detectors[i].draw();
    }
     
    // draw emitter/emissions
    emitter.draw();
    emitter.drawEmissions();
};