Compass generator 🧭

Different on every Compile & Run

Inspired by watabou.itch.io/compass-rose-generator

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// You can find the Turtle API reference here: https://turtletoy.net/syntax
Canvas.setpenopacity(1);

function walk() {
    // new Compass(x, y, scale)
    new Compass(0, 0, 1.0);
}

class Compass {
    constructor(x = 0, y = 0, scale = 1.0) {
        this.turtle = new Tortoise();
        this.text = new Text();
        this.polygons = new Polygons();
        this.layers = [
            new Layer(this.polygons),
            new Layer(this.polygons),
            new Layer(this.polygons),
        ];
        
        this.turtle.addTransform(Rotate(Random.range(-0.1,0.2)));
        this.turtle.addTransform(Scale(scale));
        this.turtle.addTransform(Translate(x,y));

        const hatching = 1.0 / scale;
        if (Random.bool()) {
            this.layers[0].circle(Random.range(10,20), true, hatching);
        }
        this.layers[0].star({
            inner: Random.range(30,5),
            outer: 70,
            angle: Math.PI / 4,
            corners: 4,
            hatching: hatching,
        });
        if (Random.bool()) {
            this.layers[0].circle(Random.range(10,30), true, hatching);
        }
        
        if (Random.bool(.75)) {
            this.layers[1].star({
                inner: Random.range(30,5),
                outer: Random.range(40,70),
                angle: Math.PI / 2,
                corners: 4,
                hatching: hatching,
            });
            
        }
    
        this.layers[2].circles(Random.range(50,70), Random.range(40,70), Random.bool(), hatching);
        
        if (Random.bool(.75)) {
            const start = Random.range(40,60);
            this.layers[2].simpleStar({
                inner: Random.range(start,5),
                outer: Random.range(start+1,70),
                angle: Math.PI*2 * 2/8,
                corners: Random.or(8, Random.or(360/2,360/4)),
                hatching: hatching,
            });
        }
       
        for(let layer of this.layers) {
            layer.draw(this.turtle);
        }
        
        const fontSize = Random.range(0.3, 0.5);
        this.turtle.jump(-4, -80);
        this.text.print(this.turtle, "N", fontSize);
        this.turtle.jump(80-4, 0);
        this.text.print(this.turtle, "E", fontSize);
        this.turtle.jump(-4, 80);
        this.text.print(this.turtle, "S", fontSize);
        this.turtle.jump(-80-4, 0);
        this.text.print(this.turtle, "W", fontSize);
    }
}

class Random {
    static range(from, to) {
        return from + Random.next() * (to-from);
    }
    static bool(change = 0.5) {
        return Random.next() < change;
    }
    static or(a, b, change = 0.5) {
        return Random.bool(change) ? a : b;
    }
    static next() {
        return Math.random();
    }
}

class Layer {
    constructor(polygons) {
        this.hatchingAngle = -Math.PI/4;
        this.polygons = polygons;
        this.shapes = [];
    }
    
    draw(turtle) {
        for(let shape of this.shapes) {
            this.polygons.draw(turtle, shape, true);
        }
    }
    
    create() {
        const shape = this.polygons.create();
        this.shapes.push(shape);
        return shape;
    }
    
    star(config) {
        const odd = Random.bool();
        const superOdd = Random.bool();
        
        const a = this.create();
        PolygonsUtil.starParts(a, true, 0, 0, config.outer, config.inner, config.corners, config.angle);
        if (odd && Random.bool(.75)) a.addHatching(this.hatchingAngle, config.hatching);
        else if(superOdd && Random.bool(.75)) a.addHatching(this.hatchingAngle*-1, config.hatching);
        a.addOutline();
        
        const b = this.create();
        PolygonsUtil.starParts(b, false, 0, 0, config.outer, config.inner, config.corners, config.angle);
        if (!odd && Random.bool(.75)) b.addHatching(this.hatchingAngle, config.hatching);
        b.addOutline();
    }
    
    simpleStar(config) {
       
        const c = this.create();
        PolygonsUtil.circle(c, 0, 0, Random.range(5, 50))
        c.addOutline();
        
        const s = this.create();
        PolygonsUtil.star(s, 0, 0, config.outer, config.inner, config.corners, config.angle);
        
        if (Random.bool()) if (config.corners < 100) s.addHatching(this.hatchingAngle, config.hatching);
        s.addOutline();
        
        
        
    }
    circles(radius1, radius2, outline, hatching) {
        const c = this.create();
        if (Random.bool()) PolygonsUtil.circle(c, 0, 0, radius1/1.5);
        if (Random.bool()) PolygonsUtil.circle(c, 0, 0, radius1/2);
        PolygonsUtil.circle(c, 0, 0, radius2);
        PolygonsUtil.circle(c, 0, 0, radius1);
        
        if (outline) c.addOutline();
        if (Random.bool() || !outline) c.addHatching(this.hatchingAngle, Random.or(1,2) * hatching); 
    }
    
    circle(radius, outline, hatching) {
        const c = this.create();
        PolygonsUtil.circle(c, 0, 0, radius);
        if (outline) c.addOutline();
        c.addHatching(this.hatchingAngle, Random.or(1,2) * hatching); 
    }
}

////////////////////////////////////////////////////////////////
// Polygon helper utility code - Created by Mark Knol 2019
// https://turtletoy.net/turtle/5ef089d251
////////////////////////////////////////////////////////////////

class PolygonsUtil {
    static circle(polygon, x, y, radius = 10, segments = 45) {
        for (let ii = 0; ii <= segments; ii++) {
            const a = ii/ segments * Math.PI * 2;
            polygon.addPoints([x + Math.cos(a) * radius, y + Math.sin(a) * radius]);
        }
    }
    static rect(polygon, x, y, width, height) {
        polygon.addPoints([x, y], [x + width, y], [x + width, y + height], [x, y + height]);
    }
    static star(polygon, x, y, radiusInner = 30, radiusOuter = radiusInner * 0.3, corners = 4, rotation = 0.0) {
        const segments = corners *2;
        for (let ii = 0; ii <= segments; ii++) {
            const a = ii / segments * Math.PI * 2;
            const radius = ii & 1 ? radiusInner : radiusOuter;
            polygon.addPoints([x + Math.cos(rotation + a) * radius, y + Math.sin(rotation +a) * radius]);
        }
    }
    static starParts(polygon, odd, x, y, radiusInner = 30, radiusOuter = radiusInner * 0.3, corners = 4, rotation = 0.0) {
        const segments = corners * 2;
        const start = 0;
        for (let ii = 0; ii <= segments; ii++) {
            const a = ii / segments * Math.PI * 2;
            
            let radius = ii % 2 == 1 ? radiusInner : radiusOuter;
            if (radius == radiusInner && !odd) polygon.addPoints([x, y]);
            polygon.addPoints([x + Math.cos(rotation + a) * radius, y + Math.sin(rotation +a) * radius]);
            if (radius == radiusInner && odd) polygon.addPoints([x, y]);
            
        }
    }
}


////////////////////////////////////////////////////////////////
// Polygon Clipping utility code - Created by Reinder Nijhoff 2019
// https://turtletoy.net/turtle/a5befa1f8d
////////////////////////////////////////////////////////////////

function Polygons() {
	const polygonList = [];
	const Polygon = class {
		constructor() {
			this.cp = [];       // clip path: array of [x,y] pairs
			this.dp = [];       // 2d lines [x0,y0],[x1,y1] to draw
			this.aabb = [];     // AABB bounding box
		}
		addPoints(...points) {
		    // add point to clip path and update bounding box
		    let xmin = 1e5, xmax = -1e5, ymin = 1e5, ymax = -1e5;
			(this.cp = [...this.cp, ...points]).forEach( p => {
				xmin = Math.min(xmin, p[0]), xmax = Math.max(xmax, p[0]);
				ymin = Math.min(ymin, p[1]), ymax = Math.max(ymax, p[1]);
			});
		    this.aabb = [(xmin+xmax)/2, (ymin+ymax)/2, (xmax-xmin)/2, (ymax-ymin)/2];
		}
		addSegments(...points) {
		    // add segments (each a pair of points)
		    points.forEach(p => this.dp.push(p));
		}
		addOutline() {
			for (let i = 0, l = this.cp.length; i < l; i++) {
				this.dp.push(this.cp[i], this.cp[(i + 1) % l]);
			}
		}
		draw(t) {
			for (let i = 0, l = this.dp.length; i < l; i+=2) {
				t.jump(this.dp[i]), t.goto(this.dp[i + 1]);
			}
		}
		addHatching(a, d) {
			const tp = new Polygon();
			tp.cp.push([-1e5,-1e5],[1e5,-1e5],[1e5,1e5],[-1e5,1e5]);
			const dx = Math.sin(a) * d,   dy = Math.cos(a) * d;
			const cx = Math.sin(a) * 200, cy = Math.cos(a) * 200;
			for (let i = 0.5; i < 150 / d; i++) {
				tp.dp.push([dx * i + cy,   dy * i - cx], [dx * i - cy,   dy * i + cx]);
				tp.dp.push([-dx * i + cy, -dy * i - cx], [-dx * i - cy, -dy * i + cx]);
			}
			tp.boolean(this, false);
			this.dp = [...this.dp, ...tp.dp];
		}
		inside(p) {
			let int = 0; // find number of i ntersection points from p to far away
			for (let i = 0, l = this.cp.length; i < l; i++) {
				if (this.segment_intersect(p, [0.1, -1000], this.cp[i], this.cp[(i + 1) % l])) {
					int++;
				}
			}
			return int & 1; // if even your outside
		}
		boolean(p, diff = true) {
		    // bouding box optimization by ge1doot.
		    if (Math.abs(this.aabb[0] - p.aabb[0]) - (p.aabb[2] + this.aabb[2]) >= 0 &&
				Math.abs(this.aabb[1] - p.aabb[1]) - (p.aabb[3] + this.aabb[3]) >= 0) return this.dp.length > 0;
				
			// polygon diff algorithm (narrow phase)
			const ndp = [];
			for (let i = 0, l = this.dp.length; i < l; i+=2) {
				const ls0 = this.dp[i];
				const ls1 = this.dp[i + 1];
				// find all intersections with clip path
				const int = [];
				for (let j = 0, cl = p.cp.length; j < cl; j++) {
					const pint = this.segment_intersect(ls0, ls1, p.cp[j], p.cp[(j + 1) % cl]);
					if (pint !== false) {
						int.push(pint);
					}
				}
				if (int.length === 0) {
					// 0 intersections, inside or outside?
					if (diff === !p.inside(ls0)) {
						ndp.push(ls0, ls1);
					}
				} else {
					int.push(ls0, ls1);
					// order intersection points on line ls.p1 to ls.p2
					const cmpx = ls1[0] - ls0[0];
					const cmpy = ls1[1] - ls0[1];
					int.sort( (a,b) =>  (a[0] - ls0[0]) * cmpx + (a[1] - ls0[1]) * cmpy - 
					                    (b[0] - ls0[0]) * cmpx - (b[1] - ls0[1]) * cmpy);
					 
					for (let j = 0; j < int.length - 1; j++) {
						if ((int[j][0] - int[j+1][0])**2 + (int[j][1] - int[j+1][1])**2 >= 0.001) {
							if (diff === !p.inside([(int[j][0]+int[j+1][0])/2,(int[j][1]+int[j+1][1])/2])) {
								ndp.push(int[j], int[j+1]);
							}
						}
					}
				}
			}
			return (this.dp = ndp).length > 0;
		}
		//port of http://paulbourke.net/geometry/pointlineplane/Helpers.cs
		segment_intersect(l1p1, l1p2, l2p1, l2p2) {
			const d   = (l2p2[1] - l2p1[1]) * (l1p2[0] - l1p1[0]) - (l2p2[0] - l2p1[0]) * (l1p2[1] - l1p1[1]);
			if (d === 0) return false;
			const n_a = (l2p2[0] - l2p1[0]) * (l1p1[1] - l2p1[1]) - (l2p2[1] - l2p1[1]) * (l1p1[0] - l2p1[0]);
			const n_b = (l1p2[0] - l1p1[0]) * (l1p1[1] - l2p1[1]) - (l1p2[1] - l1p1[1]) * (l1p1[0] - l2p1[0]);
			const ua = n_a / d;
			const ub = n_b / d;
			if (ua >= 0 && ua <= 1 && ub >= 0 && ub <= 1) {
				return [l1p1[0] + ua * (l1p2[0] - l1p1[0]), l1p1[1] + ua * (l1p2[1] - l1p1[1])];
			}
			return false;
		}
	};
	return {
		list: () => polygonList,
		create: () => new Polygon(),
		draw: (turtle, p, addToVisList=true) => {
			for (let j = 0; j < polygonList.length && p.boolean(polygonList[j]); j++);
			p.draw(turtle);
			if (addToVisList) polygonList.push(p);
		}
	};
}




////////////////////////////////////////////////////////////////
// Text utility code
////////////////////////////////////////////////////////////////
// Created by Reinder Nijhoff 2019 
// @reindernijhoff 
// source: https://turtletoy.net/turtle/1713ddbe99
function Text() {
    class Text {
        print (t, str, scale) {
            t.radians();
            let pos = [t.x(), t.y()], h = t.h(), o = pos;
            str.split('').map(c => {
                const i = c.charCodeAt(0) - 32;
                if (i < 0 ) {
                    pos = o = this.rotAdd([0, 48*scale], o, h);
                } else if (i > 96 ) {
                    pos = this.rotAdd([16*scale, 0], o, h);
                } else {
                    const d = dat[i], lt = d[0]*scale, rt = d[1]*scale, paths = d[2];
                    paths.map( p => {
                        t.up();
                    	p.map( s=> {
                        	t.goto(this.rotAdd([s[0]*scale - lt, s[1]*scale], pos, h));
                        	t.down();
                        });
                    });
                    pos = this.rotAdd([rt - lt, 0], pos, h);
                }
            });
        }
        rotAdd (a, b, h) {
            return [Math.cos(h)*a[0] - Math.sin(h)*a[1] + b[0], 
                    Math.cos(h)*a[1] + Math.sin(h)*a[0] + b[1]];
        }
    }
    
const dat = ('br>eoj^jl<jqirjskrjq>brf^fe<n^ne>`ukZdz<qZjz<dgrg<cmqm>`thZhw<lZlw<qao_l^h^e_caccdeefg'+
'gmiojpkqmqporlshsercp>^vs^as<f^h`hbgdeeceacaab_d^f^h_k`n`q_s^<olmmlolqnspsrrspsnqlol>]wtgtfsereqfph'+
'nmlpjrhsdsbraq`o`makbjifjekckaj_h^f_eaecffhimporqssstrtq>eoj`i_j^k_kajcid>cqnZl\\j_hcghglhqjulxnz>c'+
'qfZh\\j_lcmhmllqjuhxfz>brjdjp<egom<ogem>]wjajs<ajsj>fnkojpiojnkokqis>]wajsj>fnjniojpkojn>_usZaz>`ti'+
'^f_dbcgcjdofrisksnrpoqjqgpbn_k^i^>`tfbhak^ks>`tdcdbe`f_h^l^n_o`pbpdofmicsqs>`te^p^jfmfogphqkqmppnrk'+
'shserdqco>`tm^clrl<m^ms>`to^e^dgefhekenfphqkqmppnrkshserdqco>`tpao_l^j^g_ebdgdlepgrjsksnrppqmqlping'+
'kfjfggeidl>`tq^gs<c^q^>`th^e_dadceegfkgnhpjqlqopqorlshserdqcocldjfhigmfoepcpao_l^h^>`tpeohmjjkikfjd'+
'hcecddaf_i^j^m_oapepjoomrjshserdp>fnjgihjikhjg<jniojpkojn>fnjgihjikhjg<kojpiojnkokqis>^vrabjrs>]wag'+
'sg<amsm>^vbarjbs>asdcdbe`f_h^l^n_o`pbpdofngjijl<jqirjskrjq>]xofndlcicgdfeehekfmhnknmmnk<icgefhfkgmh'+
'n<ocnknmpnrntluiugtdsbq`o_l^i^f_d`bbad`g`jambodqfrislsorqqrp<pcokompn>asj^bs<j^rs<elol>_tc^cs<c^l^o'+
'_p`qbqdpfoglh<chlhoipjqlqopqorlscs>`urcqao_m^i^g_eadccfckdnepgrismsorqprn>_tc^cs<c^j^m_oapcqfqkpnop'+
'mrjscs>`sd^ds<d^q^<dhlh<dsqs>`rd^ds<d^q^<dhlh>`urcqao_m^i^g_eadccfckdnepgrismsorqprnrk<mkrk>_uc^cs<'+
'q^qs<chqh>fnj^js>brn^nnmqlrjshsfreqdndl>_tc^cs<q^cl<hgqs>`qd^ds<dsps>^vb^bs<b^js<r^js<r^rs>_uc^cs<c'+
'^qs<q^qs>_uh^f_daccbfbkcndpfrhslsnrppqnrkrfqcpan_l^h^>_tc^cs<c^l^o_p`qbqepgohlici>_uh^f_daccbfbkcnd'+
'pfrhslsnrppqnrkrfqcpan_l^h^<koqu>_tc^cs<c^l^o_p`qbqdpfoglhch<jhqs>`tqao_l^h^e_caccdeefggmiojpkqmqpo'+
'rlshsercp>brj^js<c^q^>_uc^cmdpfrisksnrppqmq^>asb^js<r^js>^v`^es<j^es<j^os<t^os>`tc^qs<q^cs>asb^jhjs'+
'<r^jh>`tq^cs<c^q^<csqs>cqgZgz<hZhz<gZnZ<gznz>cqc^qv>cqlZlz<mZmz<fZmZ<fzmz>brj\\bj<j\\rj>asazsz>fnkc'+
'ieigjhkgjfig>atpeps<phnfleiegfehdkdmepgrislsnrpp>`sd^ds<dhffhekemfohpkpmopmrkshsfrdp>asphnfleiegfeh'+
'dkdmepgrislsnrpp>atp^ps<phnfleiegfehdkdmepgrislsnrpp>asdkpkpiognfleiegfehdkdmepgrislsnrpp>eqo^m^k_j'+
'bjs<gene>atpepuoxnylzizgy<phnfleiegfehdkdmepgrislsnrpp>ate^es<eihfjemeofpips>fni^j_k^j]i^<jejs>eoj^'+
'k_l^k]j^<kekvjyhzfz>are^es<oeeo<ikps>fnj^js>[y_e_s<_ibfdegeifjijs<jimfoeretfuius>ateees<eihfjemeofp'+
'ips>atiegfehdkdmepgrislsnrppqmqkphnfleie>`sdedz<dhffhekemfohpkpmopmrkshsfrdp>atpepz<phnfleiegfehdkd'+
'mepgrislsnrpp>cpgegs<gkhhjfleoe>bsphofleieffehfjhkmlompopporlsisfrep>eqj^jokrmsos<gene>ateeeofrhsks'+
'mrpo<peps>brdejs<pejs>_ubefs<jefs<jens<rens>bseeps<pees>brdejs<pejshwfydzcz>bspees<eepe<esps>cqlZj['+
'i\\h^h`ibjckekgii<j[i]i_jakbldlfkhgjkllnlpkrjsiuiwjy<ikkmkojqirhthvixjylz>fnjZjz>cqhZj[k\\l^l`kbjci'+
'eigki<j[k]k_jaibhdhfihmjilhnhpirjskukwjy<kkimiojqkrltlvkxjyhz>^vamakbhdgfghhlknlplrksi<akbidhfhhill'+
'nmpmrlsisg>brb^bscsc^d^dsese^f^fsgsg^h^hsisi^j^jsksk^l^lsmsm^n^nsoso^p^psqsq^r^rs').split('>').map(
    r=> { return [r.charCodeAt(0)-106,r.charCodeAt(1)-106, r.substr(2).split('<').map(a => {const ret 
    = []; for (let i=0; i<a.length; i+=2) {ret.push(a.substr(i, 2).split('').map(b => b.charCodeAt(0)
    -106));} return ret; })]; });

    return new Text();
}


function Translate(x,y) { return p => [p[0]+x, p[1]+y]; }
function Rotate(a) { return p => [p[0]*Math.cos(a)+p[1]*Math.sin(a), p[1]*Math.cos(a)-p[0]*Math.sin(a)]; }
function Scale(s) { return p => [p[0]*s, p[1]*s]; }


////////////////////////////////////////////////////////////////
// Tortoise utility code (Minimal Turtle and Transforms)
// https://turtletoy.net/turtle/102cbd7c4d
////////////////////////////////////////////////////////////////

function Tortoise(x, y) {
    class Tortoise extends Turtle {
        constructor(x, y) {
            super(x, y);
            this.ps = Array.isArray(x) ? [...x] : [x || 0, y || 0];
            this.transforms = [];
        }
        addTransform(t) {
            this.transforms.push(t);
            this.jump(this.ps);
            return this;
        }
        applyTransforms(p) {
            if (!this.transforms) return p;
            let pt = [...p];
            this.transforms.map(t => { pt = t(pt); });
            return pt;
        }
        goto(x, y) {
            const p = Array.isArray(x) ? [...x] : [x, y];
            const pt = this.applyTransforms(p);
            if (this.isdown() && (this.pt[0]-pt[0])**2 + (this.pt[1]-pt[1])**2 > 4) {
               this.goto((this.ps[0]+p[0])/2, (this.ps[1]+p[1])/2);
               this.goto(p);
            } else {
                super.goto(pt);
                this.ps = p;
                this.pt = pt;
            }
        }
        position() { return this.ps; }
    }
    return new Tortoise(x,y);
}