Lan Wei-Project -07-Curves

my-sketch.js

//Lan Wei
//Section D
//lanw@andrew.cmu.edu
//Project-07

function setup() {
    createCanvas(450, 450);
    strokeWeight(2);
    noFill();
}

//http://mathworld.wolfram.com/LogarithmicSpiral.html
var nPoints = 1000;
function draw() {
    background(0);
    push();
    var red = map(mouseX, 0, width, 255, 0);
    var green = map(mouseX, 0, width, 20, 150);
    var blue = map(mouseX, 0, width, 0, 150)
    var col = color(red, green, blue); //change the color
    stroke(col);
    translate(mouseX, mouseY); //draw  with the mouse
    logarithmicSpiral();
    pop();
    push();//another logarithmicSpiral
    var red = map(mouseX, 0, width, 0, 200);
    var green = map(mouseX, 0, width, 100, 50);
    var blue = map(mouseY, 0, width, 0, 150)
    var col = color(red, green, blue); //change the color
    stroke(col);
    translate(width - mouseX, height - mouseY); //draw  with the mouse
    logarithmicSpiral();
    pop();
    stroke(255);
}

function logarithmicSpiral(){
    var a = 0.1;
    var b = 0.1;
    beginShape();
    for (var i = 0; i < nPoints; i++) {
        var t = map(i, 0, nPoints, - 16 * PI, 8 * PI);
        var x = 1000 * a * cos(t) * pow(Math.E, b * t);
        var y = 1000 * a * sin(t) * pow(Math.E, b * t);
        vertex(x, y);
        rotate(atan(mouseY/mouseX)); //rotate with the tangent of the mouse
    }
    endShape();
}

In the project I try to create rotating spirals that change angles and color with mouse movement. I struggled with it at first, having problems figuring out the relationships between the parameters. But finally it works.