Romi Jin – Project-07-Curves

sketch

/*
Romi Jin
Section B
rsjin@andrew.cmu.edu
Project-07
*/

var x;

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

function draw() {
    
    background(174, 198, 207);

    x = constrain(mouseX, 0, width);
    y = constrain(mouseY, 0, height);
    
    //three intersecting hypotrochoids

    push();
    translate(width/2, height/2);
    drawHypotrochoid();
    pop();

    push();
    translate(width/3, height/3);
    drawHypotrochoid();
    pop();

    push();
    translate(width-width/3, height-width/3);
    drawHypotrochoid();
    pop();

}

function drawHypotrochoid() {

    //link: http://mathworld.wolfram.com/Hypotrochoid.html
    //roulette by drawing along two cirles (radius a and b below)

    for (var i = 0; i < TWO_PI; i ++) { 

        a = map(y, 0, height, 100, 200); 
        b = map(x, 0, width, 0, 75); 
        h = 100;

        x = (a - b) * cos(i) + h*cos(((a-b)/b) * i);
        y = (a - b) * sin(i) - h*sin(((a-b)/b) * i);

        noFill();
        stroke(255);
        strokeWeight(1);
        ellipse(0, 0, x, y);

    }

}

For this project, I chose the shape hypotrochoid and drew it three times to create three intersecting hypotrochoids. The parameters are the mouse X and mouse Y position, and the mouse X changes one ellipse’s radius while mouse Y changes the other. It is intriguing to watch the three intersect as they create even more curves together.