Project 7: Curves

//global variables
var nPoints = 1000;
var angle = 0;

function setup() {
    createCanvas(480, 480);
}

function draw() {
    background(mouseY, 100, mouseX); //change background color
    //draw 2 sets of 36 hypotrochoids 
    for (var x = 80; x <= 400; x += 64) {
        for (var y = 80; y <= 400; y += 64) {
            push();
            translate(x, y);
            drawHypotrochoid1();
            drawHypotrochoid2();
            pop();
        }
    }
}

function drawHypotrochoid1() {
    var a = map(mouseX, 0, 480, 0, 80); //radius of outside circle
    var b = map(mouseX, 0, 480, 0, 20); //radius of inside circle
    var h = map(mouseY, 0, 480, 0, 40); //point distance from center of inner circle

    strokeWeight(.5);
    stroke(mouseX, mouseY, 100); //change stroke color
    noFill();
    beginShape(); //create hypotrochoid
    for (var i=0; i<nPoints; i++) {
        var angle = map(i, 0, 100, 0, TWO_PI);
        x = (a-b) * cos(angle) + h * cos(((a-b)/b) * angle);
        y = (a-b) * sin(angle) - h * sin(((a-b)/b) * angle);
        vertex(x, y);
    }
    endShape();
}

function drawHypotrochoid2() {
    var a = map(mouseX, 0, 480, 2, 80); //radius of outside circle
    var b = map(mouseX, 0, 480, 2, 20); //radius of inside circle
    var h = map(mouseY, 0, 480, 2, 40); //point distance from center of inner circle

    strokeWeight(.35);
    stroke(mouseX, mouseX, mouseY); //change stroke color
    noFill();
    beginShape(); //create hypotrochoid
    for (var i=0; i<nPoints; i++) {
        var angle = map(i, 0, 100, 0, TWO_PI);
        x = (a-b) * cos(angle) + h * cos(((a-b)/b) * angle);
        y = (a-b) * sin(angle) - h * sin(((a-b)/b) * angle);
        vertex(x, y);
    }
    endShape();
}