Project 07 – srauch – curves

//Sam Rauch, section B, srauch@andrew.cmu.edu, project 07
//This code produces a "laser ballerinas" using epicycloid curves. Ten epicycloid curves of decreasing
//size and random colors are drawn on top of each other to produce "nested curves", and six nested curves
//are drawn in a hexagon pattern around the center of the canvas, which spins. MouseX controls the size of
//the curves and the rotation of the hexagon pattern, while mouseY controls the number of "lobes" produced
//in each epicycloid curve. Click to change the colors of the ballerinas!

var coloroptions;

function setup() {
    createCanvas(400, 400);
    background(220);
    text("p5.js vers 0.9.0 test.", 10, 15);

    coloroptions = [];
    for (var i = 0; i < 9; i++) {
        coloroptions[i] = color(random(255), random(255), random(255));
    }

}

function draw() {
    background(0);
    translate(width/2, height/2);
    
    //create spin the hexagon of curves around the center of the canvas according to mouseX
    push();
    var spinamt = map(mouseX, 0, width, 0, 2*PI)
    rotate(spinamt);


    //draws six nested curves in a hexagon pattern
    for (var i = 0; i < 6; i++){
        push();
        translate(100, 0);
        nestedCurve();
        pop();
        rotate(radians(60));
    }

    pop();

}

//generates epicycloid curve (https://mathworld.wolfram.com/Epicycloid.html) with center at 0,0
function drawCurve(color){ 
    
    noFill();
    stroke(color);
    strokeCap(ROUND);
    strokeJoin(ROUND);
    strokeWeight(3);

    var points = 80;
    var xValues = [];
    var yValues = [];
    var a = mouseX/4; //radius of larger inner circle 
    var b = constrain(mouseY/10, 0, a) ; //40; //radius of smaller outer circle
    var theta = 0;

    //generating x and y values based on epicycloid curve forumla, and increasing the center angle
    //by a small amount
    for (var i = 0; i < points; i++) {
        theta += radians(5);
        xValues[i] = (a+b)*cos(theta) - b*cos(((a+b)/b)*theta);
        yValues[i] = (a+b)*sin(theta) - b*sin(((a+b)/b)*theta);
    }
    
    //plotting x and y values
    beginShape();
    for (var i = 0; i <points; i++) {
        vertex(xValues[i], yValues[i]);
    }
    endShape();
}

//draws ten epicycloid curves of random colors nested inside each other
function nestedCurve() {
    push();

    var size = 1;
    var sizeIncrement = 0.1;

    //draws ten epicycloid curves, but for each one, decreases scale and change color
    for (var i = 0; i < 9; i++) {
        scale(size);

        var col = coloroptions[i];
        drawCurve(col);
        size -= sizeIncrement;
    }

    pop();
}

function mousePressed(){
    for (var i = 0; i < 9; i++) {
        coloroptions[i] = color(random(255), random(255), random(255));
    }
}