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// Forked from "Circle packing #2" by reinder
// https://turtletoy.net/turtle/2b822bb094

const shape = 0; // min=0, max=1, step=1 (Box, Circle)
const pattern = 6; // min=0, max=6, step=1 (Uniform, Gradient X, Gradient Y, Radial, Noise, H ripple, V ripple)
const pattern_inverse = 0; // min=0, max=1, step=1 (No, Yes)
const canvas_size = 80; //min = 5, max = 100, step = 1
const max_radius = 10; // min=0.01, max=100, step=0.01
const min_radius = 1.0; // min=0.1, max=20, step=0.1
const noise_seed = 12; // min=0, max=100, step=1
const noise_freq = 0.5; // min=0, max=2, step=0.01
const min_sides = 3; //min = 3, max = 10, step = 1
const radius_decr = .99; 
const max_tries = 5000; 
const noise = new SimplexNoise(noise_seed);

let radius = max_radius;

const circles = [];

const turtle = new Turtle();

function add_circle(t, rt) {
    let coord_found = false;
    let tries = 0;
    
    while (!coord_found && tries < max_tries) {
        tries ++;
        let x = Math.random() * (canvas_size)*2 -canvas_size;
        let y = Math.random() * (canvas_size)*2 -canvas_size;
        
        let factor = 1;
        switch(pattern) {
            case 1: factor = (x+canvas_size) / (2*canvas_size);
                    break;
            case 2: factor = (y+canvas_size) / (2*canvas_size);
                    break;
            case 3: factor = Math.hypot(x,y)/(Math.sqrt(2)*canvas_size);
                    break;
            case 4: factor = noise.noise2D([x * noise_freq / canvas_size, y * noise_freq / canvas_size])*.5 + .5;
                    break;
            case 5: factor = noise.noise2D([Math.floor(x * 12 * noise_freq / canvas_size + 
                                noise.noise2D([x * noise_freq / canvas_size, y * noise_freq / canvas_size])),.5])*.5 + .5;
                    break;
            case 6: factor = noise.noise2D([Math.floor(y * 12 * noise_freq / canvas_size + 
                                noise.noise2D([x * noise_freq / canvas_size, y * noise_freq / canvas_size])),.5])*.5 + .5;
                    break;
        }
        if (pattern_inverse) {
            factor = 1 - factor;
        }
        const r = Math.max(min_radius, factor * rt);
        
        x *= (canvas_size - r) / canvas_size;
        y *= (canvas_size - r) / canvas_size;
        
        let possible = true;
        for (let i=0; i<circles.length; i++) {
            const dx = circles[i][0] - x;
            const dy = circles[i][1] - y;
            const dr = circles[i][2] + r;
            
            if ( dx*dx + dy*dy < dr * dr || 
                 (shape && 
                  x*x+y*y > (canvas_size-r)*(canvas_size-r))) {
                possible = false;
                break;
            }
        }
        if (possible && (!shape || x*x+y*y < (canvas_size-r)*(canvas_size-r))) {
            coord_found = true;
            draw_circle(x,y,t, r);
            circles.push([x,y,r]);
            return true;
        }
    }
    return false;
}

function draw_circle(x,y,t, r) {
    turtle.jump(x,y-r);
    //turtle.circle(r);
    //ellipse(r,aspect);
    poly(r)
}

function walk(i) {
    if (!add_circle(turtle, radius)) {
        radius *= radius_decr;
    }
    return radius >= min_radius;
}

function ellipse(rad, aspect) {
    for (let j = 0; j < 2; j++) {
        turtle.circle(aspect * rad, 90);
        turtle.circle(rad/aspect, 90);
    }
 }

function poly(r) {
    let n = Math.floor(Math.random() * 6 + min_sides);
    let l = 2 * r * Math.PI / n;
    turtle.forward(-l/2);
    for (let j = 0; j < n; j++) {
        turtle.forward(l)
        turtle.right(360 / n)
    }
}

////////////////////////////////////////////////////////////////
// Simplex Noise utility code. Created by Reinder Nijhoff 2020
// https://turtletoy.net/turtle/6e4e06d42e
// Based on: http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
////////////////////////////////////////////////////////////////
function SimplexNoise(seed = 1) {
	const grad = [  [1, 1, 0], [-1, 1, 0], [1, -1, 0], [-1, -1, 0],
	            	[1, 0, 1], [-1, 0, 1], [1, 0, -1], [-1, 0, -1],
            		[0, 1, 1], [0, -1, 1], [0, 1, -1], [0, -1, -1] ];
	const perm = new Uint8Array(512);
            		
	const F2 = (Math.sqrt(3) - 1) / 2, F3 = 1/3;
	const G2 = (3 - Math.sqrt(3)) / 6, G3 = 1/6;

	const dot2 = (a, b) => a[0] * b[0] + a[1] * b[1];
	const sub2 = (a, b) => [a[0] - b[0], a[1] - b[1]];
	const dot3 = (a, b) => a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
	const sub3 = (a, b) => [a[0] - b[0], a[1] - b[1], a[2] - b[2]];

	class SimplexNoise {
		constructor(seed = 1) {
			for (let i = 0; i < 512; i++) {
				perm[i] = i & 255;
			}
			for (let i = 0; i < 255; i++) {
				const r = (seed = this.hash(i+seed)) % (256 - i)  + i;
				const swp = perm[i];
				perm[i + 256] = perm[i] = perm[r];
				perm[r + 256] = perm[r] = swp;
			}
		}
		noise2D(p) {
			const s = dot2(p, [F2, F2]);
			const c = [Math.floor(p[0] + s), Math.floor(p[1] + s)];
			const i = c[0] & 255, j = c[1] & 255;
			const t = dot2(c, [G2, G2]);

			const p0 = sub2(p, sub2(c, [t, t]));
			const o  = p0[0] > p0[1] ? [1, 0] : [0, 1];
			const p1 = sub2(sub2(p0, o), [-G2, -G2]);
			const p2 = sub2(p0, [1-2*G2, 1-2*G2]);
			
			let n =  Math.max(0, 0.5-dot2(p0, p0))**4 * dot2(grad[perm[i+perm[j]] % 12], p0);
			    n += Math.max(0, 0.5-dot2(p1, p1))**4 * dot2(grad[perm[i+o[0]+perm[j+o[1]]] % 12], p1);
		    	n += Math.max(0, 0.5-dot2(p2, p2))**4 * dot2(grad[perm[i+1+perm[j+1]] % 12], p2);
			
			return 70 * n;
		}
		hash(i) {
            i = 1103515245 * ((i >> 1) ^ i);
            const h32 = 1103515245 * (i ^ (i>>3));
            return h32 ^ (h32 >> 16);
		}
	}
	return new SimplexNoise(seed);
}