Project 7 – Simin Li

siminl-project7

// Simin Li
// Section C
// siminl@andrew.cmu.edu
// Project 7

//Archimedean Spiral
//r = a * pow( theta, 1 / n)
var nPoints = 100; //number of points in each individual spiral
var radius; // radius of the polar function
function setup() {
    createCanvas(640, 640);
    frameRate(8);
}

function draw() {    
	background(0);
	var X = constrain(mouseX,0,width);
	var Y = constrain(mouseY,0,height);
	//it wont work if cursor is off canvas
    var gap1 = map(X , 0, width, 0, 6);
    var gap2 = map(X, 0 , width, 4,0);
    var ellipseD = map(Y, 0 , height, 0, 4);  
    var R = map(Y, 0 , height, random(0,255), random(0,255));
    var G = map(X, 0 , width, random(0,255), random(0,255));
    var B = map(X + Y, 0 , width + height, random(0,255), random(0,255));
    //RGB values are randomly selected and then influenced by X and Y to make 3 colors
    var angle = map(X,0,width,0,3 * TWO_PI);
    color1 = color(R,G,B);
    color2 = color(G,R,B);
    color3 = color(R,B,G);
    //three colors are used to fill the three spirals in the center
    
    
    spiral(width / 2 ,height / 2,gap1 + 2,ellipseD + 2,color3,angle,1);//largest spiral
    spiral(width / 2 ,height / 2,gap1 + 1.2,ellipseD + 1,color2,angle,1);//larger spiral
    spiral(width / 2 ,height / 2,gap1,ellipseD ,color1,angle,1); //small spiral
    //center spiral group

    spiral(width / 4 ,height * 3 / 4,gap2 + 2,2,255,angle,1);
    spiral(width / 4 ,height * 3 / 4,gap2 + 1,2,255,angle,1);
    spiral(width / 4 ,height * 3 / 4,gap2,2,255,angle,1); 
    //bottom left spiral group

    spiral(width * 3 / 4 ,height * 3 / 4,gap2 + 2,2,255,angle,1);
    spiral(width * 3 / 4 ,height * 3 / 4,gap2 + 1,2,255,angle,1);
    spiral(width * 3 / 4 ,height * 3 / 4,gap2,2,255,angle,1);
    //bottom right spiral group

    spiral(width * 3 / 4 ,height / 4,gap2 + 2,2,255,angle,1);
    spiral(width * 3 / 4  ,height / 4,gap2 + 1,2,255,angle,1);
    spiral(width * 3 / 4  ,height / 4,gap2,2,255,angle,1);
    //top right spiral group

    spiral(width / 4 ,height / 4,gap2 + 2,2,255,angle,1);
    spiral(width / 4 ,height / 4,gap2 + 1,2,255,angle,1);
    spiral(width / 4 ,height / 4,gap2,2,255,angle,1);
    // top left spiral group
 }
 function spiral(spiralX,spiralY,gap,ellipseD,shade,angle,tightness){
 //draw spiral at spiralX,spiralY
 //the gap between each loop is gap
 //the diameter of the small circles or squares that make up the spiral is ellipseD
 //fill with shade
 //rotate by angle
 //tightness controls how wound up the spiral is
 //when tightness = 1 it is the famous Archimedes' spiral
push()
    translate(spiralX, spiralY);
    //coordinates of center of spiral
    rotate(angle);
    for (var i = 0; i < nPoints; i++) {
        var theta = map(i, 0, nPoints,0,  6 * TWO_PI);
        //map theta so there will be nPoints of squares or circles drawn
        radius = gap * pow( theta, 1 / tightness);
        var px = radius * cos(theta);
        var py = radius * sin(theta);
        //coordinates of squares or circles
        noStroke();
        
        fill(shade);
        if(i % 2 == 0){
        rectMode(CENTER);
        rect(px - 5, py - 5, ellipseD, ellipseD);}
        else{
        ellipse(px - 5, py - 5, ellipseD, ellipseD);
        }
        //alternate squares and circles
    }
pop();
}

I searched through the functions provided on math world and selected this   spiral because it had a simplicity to it, yet it could have so many different forms. I created this starry night image because spirals remind me of stars. A problem that I had to deal with was that if you put too many circles in a single spiral each ring would align and look less interesting.