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const turtle = new Turtle();
const seed = 50; //// min=1, max=100, step=1
const rows = 24; // min=4, max=50, step=1
const size = 90; // min=10, max=100, step=1
let itemMinSize = 5; // min=1, max=50, step=1
let itemMaxSize = 20; // min=1, max=50, step=1
const space = 2; // min=1, max=20, step=1
const hatch = 0; // min=0, max=4, step=0.1
const hatchDirection = 2; // min=0, max=4, step=1 (Random, Horizontal/Vertical, Diagonal, Radial, Gradient)
const hatchFill = 0; // min=0, max=3, step=1 (Solid, Random, Gradient, Radial)
const border = 0; // min=0, max=5, step=0.25
const distortion = 0; // min=0, max=1, step=0.01
if (itemMinSize > itemMaxSize) {
[itemMinSize, itemMaxSize] = [itemMaxSize, itemMinSize];
}
function walk(i) {
let height = size / (rows * 0.5) - space;
let mod = i % 2;
let x = -size + space * 0.5;
let y = space * 0.5 + -size + i * (height + space);
while (x < size - space - itemMaxSize) {
let width = itemMinSize + Math.random() * (itemMaxSize - itemMinSize);
drawBrick([x, y, width, height], mod++);
x += width + space;
}
drawBrick([x, y, size - space *0.5 - x, height], mod++); // closing brick
return i < rows - 1;
}
function drawBrick(rect, idx = 0) {
let [x,y,w,h] = rect;
const rectPoints = [[x,y],[x+w,y],[x+w,y+h],[x,y+h]];
const randomizedPoints = randomizePoints(rectPoints, distortion);
if (border) {
const borderPoints = [[x-border,y-border],[x+w+border,y-border],[x+w+border,y+h+border],[x-border,y+h+border]];
drawPoints(randomizePoints(borderPoints, distortion), turtle);
}
drawPoints(randomizedPoints, turtle);
if (hatch > 0) {
let util = new Polygons();
let p = util.create();
randomizedPoints.forEach(pt => p.addPoints(pt));
let angle;
if (hatchDirection === 0) angle = Math.random() * Math.PI*2;
else if (hatchDirection === 1) angle = (idx % 2)/2 * Math.PI + Math.PI/2;
else if (hatchDirection === 2) angle = (idx % 2)/2 * Math.PI+ Math.PI/4;
else if (hatchDirection === 3) angle = -Math.atan2(y+h*0.5, x+w*0.5);
else if (hatchDirection === 4) angle = Math.abs((x+w/2)/size)*Math.PI/2 + Math.PI/2;
let fill;
if (hatchFill === 0) fill = hatch + 0.5;
else if (hatchFill === 1) fill = 0.5 + Math.random()*hatch;
else if (hatchFill === 2) fill = 0.5 + hatch *Math.abs((x+w/2)/size)/2;
else if (hatchFill === 3) fill = 0.5 + hatch * Math.pow(Math.abs(Math.atan2(y+h*0.5, x+w*0.5)/3),2);
p.addHatching(angle, fill);
util.draw(turtle,p);
}
}
function drawPoints(points, turtle) {
if (points.length > 0) turtle.jump(points[points.length-1]);
points.forEach(point => turtle.goto(point));
}
function scl2(a,b) { return [a[0]*b, a[1]*b]; }
function add2(a,b) { return [a[0]+b[0], a[1]+b[1]]; }
function sub2(a,b) { return [a[0]-b[0], a[1]-b[1]]; }
function dot2(a,b) { return a[0]*b[0] + a[1]*b[1]; }
function randomizePoints(points, scale = 1) {
return points.map( point => add2(point, scl2( add2( [hash(dot2(point, [11, 13])), hash(dot2(point, [17, 19]))], [-.5,-.5]), scale)));
}
// pseudo random methods
function hash(p) {
p += seed;
p = 1103515245 * (((p) >> 1) ^ (p));
p = 1103515245 * (p ^ (p>>3));
p = p ^ (p >> 16);
return p / 1103515245 % 1;
}
let rseed = seed;
function rand() {
let r = 1103515245 * (((rseed) >> 1) ^ (rseed++));
r = 1103515245 * (r ^ (r>>3));
r = r ^ (r >> 16);
return r / 1103515245 % 1;
}
////////////////////////////////////////////////////////////////
// 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);
}
};
}