const reality = 0; //min=0 max=1 step=1 (Off, On)
const outlines = 1; //min=0 max=1 step=1 (No, Yes)
const hatchDistance = .8;//min=.2 max=2 step=.01
const depth = 1; //min=0.65 max=1.5 step=.01
const width = 5; //min=1 max=6.5 step=.1
const size = 50; // //min=20 max=70 step=1

// You can find the Turtle API reference here: https://turtletoy.net/syntax
Canvas.setpenopacity(.7);

const perspective = depth / 2;

// Global code will be evaluated once.
turtlelib_init();
const turtle = new Turtle();
const polygons = new Polygons();

// The walk function will be called until it returns false.
function walk(i) {
    if(!reality) {
        switch(i) {
            case 0: polygons.startDeferSession(); break;
            case 6: polygons.stopDeferring(); break;
            case 16: polygons.finalizeDeferSession(turtle); break;
        }
    }
    
    const plane = drawPlaneSections.pop();
    const pts = plane[2].map(pt => project2d(V.add(bigCubeVertices[pt[0]], smallCubeVertices[pt[1]])));

    const p = polygons.create();
    p.addPoints(...pts);
    if(outlines == 1) p.addSegments(...plane[1].flatMap(i => [pts[i], pts[(i+1)%pts.length]]));
    if(hatchDistance < 2) p.addHatching(plane[0]*Math.PI/2+1, hatchDistance*((plane[0]+1)%3 + 1) );
    polygons.draw(turtle, p);

    return drawPlaneSections.length > 0;
}

const cubeVertices = [[-1, -1, 1], [1, -1, 1], [1, 1, 1], [-1, 1, 1],[-1, -1, -1], [1, -1, -1], [1, 1, -1], [-1, 1, -1]];
const [bigCubeVertices, smallCubeVertices] = [size, width].map(s => cubeVertices.map(e => V.scale(e, s)));
const drawPlaneSections = getPlaneSections().reverse();

function project2d(vec3) {
    return V.add(vec3.filter((e, i) => i < 2), V.scale([vec3[2], -vec3[2]], -perspective));
}

function getPlaneSections() {
    //    4 ---- 5
    //   /|     /|
    //  0 +--- 1 |    / 0 is front top left
    //  | 7 ---+ 6    / 6 is back bottom right
    //  |/     |/
    //  3 ---- 2
    
    const cubeEdges = [
        [0, 1], [1, 2], [2, 3], [3, 0],
        [4, 5], [5, 6], [6, 7], [7, 4],
        [0, 4], [1, 5], [2, 6], [3, 7]
    ]
    const HATCHES = {FRONT: 0, TOP: 1, RIGHT: 2};
    
    return [
        [HATCHES.FRONT, [0, 2], [[1, 2], [2, 1], [2, 0], [1, 3]]], //front front right
        [HATCHES.FRONT, [0, 2], [[2, 3], [3, 2], [3, 1], [2, 0]]], //front front bottom
        [HATCHES.FRONT, [0, 2], [[3, 0], [0, 3], [0, 2], [3, 1]]], //front front left
        [HATCHES.FRONT, [0, 2], [[0, 1], [1, 0], [1, 3], [0, 2]]], //front front top ******
    
        [HATCHES.TOP, [0, 2], [[0, 1], [1, 0], [1, 4], [0, 5]]], //top top front ******
        [HATCHES.TOP, [0, 2], [[0, 4], [4, 0], [4, 1], [0, 5]]], //top top left
        [HATCHES.TOP, [0, 2], [[4, 1], [5, 0], [5, 4], [4, 5]]], //top top back
        [HATCHES.TOP, [0, 2], [[1, 4], [5, 0], [5, 1], [1, 5]]], //top top right
    
        [HATCHES.RIGHT, [0, 1, 2, 3], [[0, 5], [4, 1], [4, 2], [0, 6]]], //left right top
        [HATCHES.RIGHT, [0, 1, 2, 3], [[3, 1], [0, 2], [0, 6], [3, 5]]], //left right front
        [HATCHES.RIGHT, [0, 2], [[1, 5], [5, 1], [5, 2], [1, 6]]], //right right top
        [HATCHES.RIGHT, [0, 2], [[2, 1], [1, 2], [1, 6], [2, 5]]], //right right front
    
        [HATCHES.FRONT, [0, 1, 2, 3], [[4, 1], [5, 0], [5, 3], [4, 2]]], //back front top
        [HATCHES.FRONT, [0, 1, 2, 3], [[5, 2], [6, 1], [6, 0], [5, 3]]], //back front right
        [HATCHES.FRONT, [0, 1, 2, 3], [[7, 0], [4, 3], [4, 2], [7, 1]]], //back front left  ******
    
        [HATCHES.RIGHT, [0, 1, 2, 3], [[4, 2], [7, 1], [7, 5], [4, 6]]], //left right back ******
    
        [HATCHES.TOP, [0, 1, 2, 3], [[3, 4], [7, 0], [7, 1], [3, 5]]], //bottom top left
        [HATCHES.TOP, [0, 1, 2, 3], [[6, 0], [7, 1], [7, 5], [6, 4]]], //bottom top back
        [HATCHES.TOP, [0, 1, 2, 3], [[2, 4], [6, 0], [6, 1], [2, 5]]], //bottom top right
        [HATCHES.TOP, [0, 1, 2, 3], [[2, 0], [3, 1], [3, 5], [2, 4]]], //bottom top front
    
        [HATCHES.RIGHT, [0, 2], [[5, 2], [6, 1], [6, 5], [5, 6]]], //right right back
        [HATCHES.RIGHT, [0, 2], [[2, 5], [6, 1], [6, 2], [2, 6]]], //right right bottom
        [HATCHES.RIGHT, [0, 1, 2, 3], [[3, 5], [7,1], [7, 2], [3, 6]]], //left right bottom
    
        [HATCHES.FRONT, [0, 1, 2, 3], [[6, 0], [7, 1], [7, 2], [6, 3]]], //back front bottom
    
        //little cubes on vertices
        ...Array.from({length: 8}).flatMap((e, i, a) => [
            [HATCHES.FRONT, [0, 1, 2, 3]],
            [HATCHES.TOP, [0, 4, 5, 1]],
            [HATCHES.RIGHT, [1, 5, 6, 2]]
        ].map((ee, ii) => [
            ee[0],
            ((vIdx = ee[1].indexOf(i)) == -1)? []: [vIdx, (vIdx - 1 + ee[1].length) % ee[1].length],
            ee[1].map(eee => [i, eee])
        ]))
    ];
}

// Below is automatically maintained by Turtlelib 1.0
// Changes below this comment might interfere with its correct functioning.
function turtlelib_init() {
	turtlelib_ns_c6665b0e9b_Jurgen_Vector_Math();
	turtlelib_ns_80dcba45dd_Jurgen_Polygons();
}
// Turtlelib Jurgen Vector Math v 4 - start - {"id":"c6665b0e9b","package":"Jurgen","name":"Vector Math","version":"4"}
function turtlelib_ns_c6665b0e9b_Jurgen_Vector_Math() {
/////////////////////////////////////////////////////////
// Vector functions - Created by Jurgen Westerhof 2024 //
/////////////////////////////////////////////////////////
class Vector {
    static add  (a,b) { return a.map((v,i)=>v+b[i]); }
    static sub  (a,b) { return a.map((v,i)=>v-b[i]); }
    static mul  (a,b) { return a.map((v,i)=>v*b[i]); }
    static div  (a,b) { return a.map((v,i)=>v/b[i]); }
    static scale(a,s) { return a.map(v=>v*s); }

    static det(m)                { return m.length == 1? m[0][0]: m.length == 2 ? m[0][0]*m[1][1]-m[0][1]*m[1][0]: m[0].reduce((r,e,i) => r+(-1)**(i+2)*e*this.det(m.slice(1).map(c => c.filter((_,j) => i != j))),0); }
    static angle(a)              { return Math.PI - Math.atan2(a[1], -a[0]); } //compatible with turtletoy heading
    static rot2d(angle)          { return [[Math.cos(angle), -Math.sin(angle)], [Math.sin(angle), Math.cos(angle)]]; }
    static rot3d(yaw,pitch,roll) { return [[Math.cos(yaw)*Math.cos(pitch), Math.cos(yaw)*Math.sin(pitch)*Math.sin(roll)-Math.sin(yaw)*Math.cos(roll), Math.cos(yaw)*Math.sin(pitch)*Math.cos(roll)+Math.sin(yaw)*Math.sin(roll)],[Math.sin(yaw)*Math.cos(pitch), Math.sin(yaw)*Math.sin(pitch)*Math.sin(roll)+Math.cos(yaw)*Math.cos(roll), Math.sin(yaw)*Math.sin(pitch)*Math.cos(roll)-Math.cos(yaw)*Math.sin(roll)],[-Math.sin(pitch), Math.cos(pitch)*Math.sin(roll), Math.cos(pitch)*Math.cos(roll)]]; }
    static trans(matrix,a)       { return a.map((v,i) => a.reduce((acc, cur, ci) => acc + cur * matrix[ci][i], 0)); }
    //Mirror vector a in a ray through [0,0] with direction mirror
    static mirror2d(a,mirror)    { return [Math.atan2(...mirror)].map(angle => this.trans(this.rot2d(angle), this.mul([-1,1], this.trans(this.rot2d(-angle), a)))).pop(); }

    static equals(a,b)   { return !a.some((e, i) => e != b[i]); }
    static approx(a,b,p) { return this.len(this.sub(a,b)) < (p === undefined? .001: p); }
    static norm  (a)     { return this.scale(a,1/this.len(a)); }
    static len   (a)     { return Math.hypot(...a); }
    static lenSq (a)     { return a.reduce((a,c)=>a+c**2,0); }
    static lerp  (a,b,t) { return a.map((v, i) => v*(1-t) + b[i]*t); }
    static dist  (a,b)   { return Math.hypot(...this.sub(a,b)); }
    
    static dot  (a,b)   { return a.reduce((a,c,i) => a+c*b[i], 0); }
    static cross(...ab) { return ab[0].map((e, i) => ab.map(v => v.filter((ee, ii) => ii != i))).map((m,i) => (i%2==0?-1:1)*this.det(m)); }
    
    static clamp(a,min,max) { return a.map((e,i) => Math.min(Math.max(e, min[i]), max[i])) };
    static rotateClamp(a,min,max) { return a.map((e,i) => {const d = max[i]-min[i];if(d == 0) return min[i];while(e < min[i]) { e+=d; }while(e > max[i]) { e-=d; }return e;});
    }
}
this.V = Vector;
}
// Turtlelib Jurgen Vector Math v 4 - end
// Turtlelib Jurgen Polygons v 1 - start - {"id":"80dcba45dd","package":"Jurgen","name":"Polygons","version":"1"}
function turtlelib_ns_80dcba45dd_Jurgen_Polygons() {
////////////////////////////////////////////////////////////////
// Polygon Clipping utility code - Created by Reinder Nijhoff 2019
// (Polygon binning by Lionel Lemarie 2021) https://turtletoy.net/turtle/95f33bd383
// (Delegated Hatching by Jurgen Westerhof 2024) https://turtletoy.net/turtle/d068ad6040
// (Deferred Polygon Drawing by Jurgen Westerhof 2024) https://turtletoy.net/turtle/6f3d2bc0b5
// https://turtletoy.net/turtle/a5befa1f8d
//
// const polygons = new Polygons();
// const p = polygons.create();
// polygons.draw(turtle, p);
// polygons.list();
// polygons.startDeferSession();
// polygons.stopDeferring();
// polygons.finalizeDeferSession(turtle);
//
// p.addPoints(...[[x,y],]);
// p.addSegments(...[[x,y],]);
// p.addOutline();
// p.addHatching(angle, distance); OR p.addHatching(HatchObject); where HatchObject has a method 'hatch(PolygonClass, thisPolygonInstance)'
// p.inside([x,y]);
// p.boolean(polygon, diff = true);
// p.segment_intersect([x,y], [x,y], [x,y], [x,y]);
////////////////////////////////////////////////////////////////
function Polygons(){const t=[],s=25,e=Array.from({length:s**2},t=>[]),n=class{constructor(){this.cp=[],this.dp=[],this.aabb=[]}addPoints(...t){let s=1e5,e=-1e5,n=1e5,h=-1e5;(this.cp=[...this.cp,...t]).forEach(t=>{s=Math.min(s,t[0]),e=Math.max(e,t[0]),n=Math.min(n,t[1]),h=Math.max(h,t[1])}),this.aabb=[s,n,e,h]}addSegments(...t){t.forEach(t=>this.dp.push(t))}addOutline(){for(let t=0,s=this.cp.length;t<s;t++)this.dp.push(this.cp[t],this.cp[(t+1)%s])}draw(t){for(let s=0,e=this.dp.length;s<e;s+=2)t.jump(this.dp[s]),t.goto(this.dp[s+1])}addHatching(t, s) {if(typeof t == 'object') return t.hatch(n, this);const e=new n;e.cp.push([-1e5,-1e5],[1e5,-1e5],[1e5,1e5],[-1e5,1e5]);const h=Math.sin(t)*s,o=Math.cos(t)*s,a=200*Math.sin(t),i=200*Math.cos(t);for(let t=.5;t<150/s;t++) {e.dp.push([h*t+i,o*t-a],[h*t-i,o*t+a]);e.dp.push([-h*t+i,-o*t-a],[-h*t-i,-o*t+a]);}e.boolean(this,!1);this.dp=[...this.dp,...e.dp]}inside(t){let s=0;for(let e=0,n=this.cp.length;e<n;e++)this.segment_intersect(t,[.1,-1e3],this.cp[e],this.cp[(e+1)%n])&&s++;return 1&s}boolean(t,s=!0){const e=[];for(let n=0,h=this.dp.length;n<h;n+=2){const h=this.dp[n],o=this.dp[n+1],a=[];for(let s=0,e=t.cp.length;s<e;s++){const n=this.segment_intersect(h,o,t.cp[s],t.cp[(s+1)%e]);!1!==n&&a.push(n)}if(0===a.length)s===!t.inside(h)&&e.push(h,o);else{a.push(h,o);const n=o[0]-h[0],i=o[1]-h[1];a.sort((t,s)=>(t[0]-h[0])*n+(t[1]-h[1])*i-(s[0]-h[0])*n-(s[1]-h[1])*i);for(let n=0;n<a.length-1;n++)(a[n][0]-a[n+1][0])**2+(a[n][1]-a[n+1][1])**2>=.001&&s===!t.inside([(a[n][0]+a[n+1][0])/2,(a[n][1]+a[n+1][1])/2])&&e.push(a[n],a[n+1])}}return(this.dp=e).length>0}segment_intersect(t,s,e,n){const h=(n[1]-e[1])*(s[0]-t[0])-(n[0]-e[0])*(s[1]-t[1]);if(0===h)return!1;const o=((n[0]-e[0])*(t[1]-e[1])-(n[1]-e[1])*(t[0]-e[0]))/h,a=((s[0]-t[0])*(t[1]-e[1])-(s[1]-t[1])*(t[0]-e[0]))/h;return o>=0&&o<=1&&a>=0&&a<=1&&[t[0]+o*(s[0]-t[0]),t[1]+o*(s[1]-t[1])]}};const y=function(n,j=[]){const h={},o=200/s;for(var a=0;a<s;a++){const c=a*o-100,r=[0,c,200,c+o];if(!(n[3]<r[1]||n[1]>r[3]))for(var i=0;i<s;i++){const c=i*o-100;r[0]=c,r[2]=c+o,n[0]>r[2]||n[2]<r[0]||e[i+a*s].forEach(s=>{const e=t[s];n[3]<e.aabb[1]||n[1]>e.aabb[3]||n[0]>e.aabb[2]||n[2]<e.aabb[0]||j.includes(s)||(h[s]=1)})}}return Array.from(Object.keys(h),s=>t[s])};return{list:()=>t,create:()=>new n,draw:(n,h,o=!0)=>{rpl=y(h.aabb, this.dei === undefined? []: Array.from({length: t.length - this.dei}).map((e, i) => this.dsi + i));for(let t=0;t<rpl.length&&h.boolean(rpl[t]);t++);const td=n.isdown();if(this.dsi!==undefined&&this.dei===undefined)n.pu();h.draw(n),o&&function(n){t.push(n);const h=t.length-1,o=200/s;e.forEach((t,e)=>{const a=e%s*o-100,i=(e/s|0)*o-100,c=[a,i,a+o,i+o];c[3]<n.aabb[1]||c[1]>n.aabb[3]||c[0]>n.aabb[2]||c[2]<n.aabb[0]||t.push(h)})}(h);if(td)n.pd();},startDeferSession:()=>{if(this.dei!==undefined)throw new Error('Finalize deferring before starting new session');this.dsi=t.length;},stopDeferring:()=>{if(this.dsi === undefined)throw new Error('Start deferring before stopping');this.dei=t.length;},finalizeDeferSession:(n)=>{if(this.dei===undefined)throw new Error('Stop deferring before finalizing');for(let i=this.dsi;i<this.dei;i++) {rpl = y(t[i].aabb,Array.from({length:this.dei-this.dsi+1}).map((e,j)=>i+j));for(let j=0;j<rpl.length&&t[i].boolean(rpl[j]);j++);t[i].draw(n);}this.dsi=undefined;this.dei=undefined;}}}
this.Polygons = Polygons;
}
// Turtlelib Jurgen Polygons v 1 - end