grid-apps-cmms/src.old/mesh/tool.js

916 lines
32 KiB
JavaScript

/** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
"use strict";
// dep: ext.earcut
// dep: mesh.geom
gapp.register("mesh.tool", [], (root, exports) => {
const { mesh } = root;
const { geom } = mesh;
const { Vector3 } = THREE;
const empty = 0xffffffff;
/**
* tool for identiying defects and healing them
* copied from base/mesh which is used by KM. the
* two need to be merged. earcut needs to be migrated
* to base.util.triagulate
*/
mesh.tool = class MeshTool {
constructor(params = {}) {
this.precision = Math.pow(10, params.precision || 6);
}
checkVertices(vertices, mod) {
if (!vertices) {
throw "missing vertices";
}
if (mod && vertices.length % mod !== 0) {
throw "invalid vertices";
}
return vertices;
}
getIndex() {
if (!this.indexed) {
throw "missing index";
}
return this.indexed;
}
listZ() {
let verts = this.checkVertices(this.uvert).group(3);
let zs = new Set();
for (let vert of verts) {
zs.add(vert[2]);
}
return Array.from(zs).sort((a,b) => a - b);
}
flattenZ(faceIdxs) {
let { uvert, faces } = this;
let zsum = 0;
let zunq = [];
for (let faceIdx of faceIdxs) {
let fv1 = faces[faceIdx * 3 + 0];
let fv2 = faces[faceIdx * 3 + 1];
let fv3 = faces[faceIdx * 3 + 2];
let z1 = uvert[fv1 + 2];
let z2 = uvert[fv2 + 2];
let z3 = uvert[fv3 + 2];
zunq.push(z1,z2,z3);
zsum = zsum + z1 + z2 + z3;
}
let zavg = ((( zsum / (faceIdxs.length * 3) ) * 10000 ) | 0) / 10000;
for (let faceIdx of faceIdxs) {
let fv1 = faces[faceIdx * 3 + 0];
let fv2 = faces[faceIdx * 3 + 1];
let fv3 = faces[faceIdx * 3 + 2];
uvert[fv1 + 2] = zavg;
uvert[fv2 + 2] = zavg;
uvert[fv3 + 2] = zavg;
}
return { unique: zunq.sort().uniq(), average: zavg };
}
/**
* @param {number[]} vertices non-indexed
*/
generateFaces(vertices, opt = {}) {
this.checkVertices(vertices, 3);
let doClean = opt.clean !== false;
let doDedup = opt.dedup !== false;
let round = Math.pow(10, opt.round || 0);
let faces = [];
let fcac = {}; // seen face hash
let fnew = []; // accumulate vertex triplets
let nuvt = []; // new vertex list
let hash = {}; // find vertex matches
let prec = this.precision;
let dups = 0;
let cull = 0;
if (round > 1) {
for (let i=0, l=vertices.length; i<l; i++) {
vertices[i] = ((vertices[i] * round) | 0) / round;
}
}
for (let i=0, l=vertices.length; i<l; i += 3) {
let x = vertices[i];
let y = vertices[i+1];
let z = vertices[i+2];
let key = [
(x * prec) | 0,
(y * prec) | 0,
(z * prec) | 0
].join('');
let vpos = hash[key];
if (vpos === undefined) {
// add new vertex x,y,z and hash entry with index
hash[key] = vpos = nuvt.length;
nuvt.push(x);
nuvt.push(y);
nuvt.push(z);
}
if (doClean) {
// add vertex position to face accumulator
fnew.push(vpos);
if (fnew.length === 3) {
// check and emit face if it's unique
// cull invalid faces (has 2 or more shared vertices)
if (fnew[0] === fnew[1] || fnew[0] === fnew[2] || fnew[1] === fnew[2]) {
fnew = [];
cull++;
continue;
}
if (doDedup) {
let key = fnew.slice().sort().join('-');
// drop duplicate faces (sort handles reverse order)
if (!fcac[key]) {
faces.appendAll(fnew);
fcac[key] = key;
} else {
dups++;
}
} else {
faces.appendAll(fnew);
}
fnew = [];
}
} else {
faces.push(vpos);
}
}
this.stats = {cull, dups, faces: faces.length/3};
// unique vertex array
this.uvert = nuvt;
// unique face array. elements are offset into vertices
this.faces = faces;
return this;
}
// todo: supercede generatedFaces() for patch()
// face record: vi1, vi2, vi3, nx, ny, nz
// vi = vertex index
// n = normal
// af = adjacent face index
index(vertices) {
this.vertices = this.checkVertices(vertices, 3);
const prec = this.precision;
const vcount = vertices.length / 3;
const fcount = vcount / 3;
const vround = vertices.map(v => (v * prec) | 0);
// side records [ vi0, vi1, fn1, fn2 ]
const sides = new Uint32Array(fcount * 4 * 3).fill(empty);
// map of side index to face count
const srecs = {};
// side extended records when face count exceeds 2 (bad mesh)
const sideExt = {};
// face record array [ nx, ny, nz, sn0, sn1, sn2 ]
const faces = new Float32Array(fcount * 6);
// vertex key to vertex index
const vimap = {};
// normal key to normal index
const nimap = {};
// side key to side index
const simap = {};
// tmp face vertex indices
const vinds = [ 0, 0, 0 ];
// tmp face raw vertex offset
const viraw = [ 0, 0, 0 ];
// tmp vector array
const vects = [ new Vector3(), new Vector3(), new Vector3() ];
// i=vround index, fi=faces record index
// vi=vinds index % 3, x,y,z = tmp vars
// fn=next face index, vn=next vertex index, sn=next side index
for (let i=0, l=vround.length, fn=0, vn=0, sn=0, fi=0, vi=0, x, y, z; i<l; ) {
const vroot = i;
// create unique vertex map
vects[vi].set(x = vround[i++], y = vround[i++], z = vround[i++]);
let key = x + ',' + y + ',' + z;
// vertex index
let vid = vimap[key];
if (vid === undefined) {
vid = vimap[key] = vn++;
}
viraw[vi] = vroot;
vinds[vi++] = vid;
// completed record for a face
if (vi === 3) {
// create indexed unique normal map
const cfn = THREE.computeFaceNormal(...vects);
const [ v0, v1, v2 ] = vinds;
// create consistent side order for index key
const s0 = (v0 < v1 ? v0 + "," + v1 : v1 + "," +v0);
const s1 = (v1 < v2 ? v1 + "," + v2 : v2 + "," +v1);
const s2 = (v2 < v0 ? v2 + "," + v0 : v0 + "," +v2);
// for storing raw vertex offset in side record
const [ vr0, vr1, vr2 ] = viraw;
// store face indexes into sdrec array for each side
const smap = [ s0, s1, s2 ].map((key,ki) => {
let sid = simap[key], sdoff, sdcnt;
if (sid === undefined) {
sid = simap[key] = sn++;
sdcnt = srecs[sid] = 1;
sdoff = sid * 4;
sides[sdoff] = viraw[ki];
sides[sdoff + 1] = viraw[(ki + 1) % 3];
} else {
sdoff = sid * 4;
sdcnt = ++srecs[sid];
}
if (sdcnt > 2) {
(sideExt[sid] = sideExt[sid] ||
[ sides[sdoff], sides[sdoff + 1], sides[sdoff + 2], sides[sdoff + 3] ]
).push(fn);
} else {
sides[sdoff + sdcnt + 1] = fn;
}
return sid;
});
faces[fi++] = cfn.x;
faces[fi++] = cfn.y;
faces[fi++] = cfn.z;
faces[fi++] = smap[0];
faces[fi++] = smap[1];
faces[fi++] = smap[2];
vi = 0;
fn++;
}
}
this.indexed = {
faces, sides, sideExt
};
}
getAdjacentFaces(face) {
const { faces, sides } = this.getIndex();
const foff = face * 6;
const s0 = faces[foff + 3];
const s1 = faces[foff + 4];
const s2 = faces[foff + 5];
const farr = [
sides[s0 * 4 + 2],
sides[s0 * 4 + 3],
sides[s1 * 4 + 2],
sides[s1 * 4 + 3],
sides[s2 * 4 + 2],
sides[s2 * 4 + 3]
].filter(f => f !== empty && f !== face);
if (!farr.length) {
console.log(`no adjacent faces to ${face}`);
return [];
}
return farr;
}
// depends on index() being run first
findConnectedSurface(faces, radians, filterZ, found = {}) {
const norms = this.getIndex().faces;
if (filterZ !== undefined) {
// optional filter to z normal >= value
faces = faces.filter(f => norms[f * 6 + 2] >= filterZ);
}
const checked = {};
const check = faces.slice();
for (let face of faces) {
found[face] = 1;
}
while (check.length) {
const face = check.shift();
const froot = face * 6;
if (filterZ !== undefined && norms[froot + 2] < filterZ) {
continue;
}
const fadj = this.getAdjacentFaces(face);
for (let f of fadj) {
if (found[f] || checked[f]) {
continue;
}
const aroot = f * 6;
let sum = 0;
for (let i=0; i<3; i++) {
sum += Math.pow(norms[froot + i] - norms[aroot + i], 2);
}
const fn = Math.sqrt(sum);
if (fn <= radians) {
faces.push(f);
check.push(f)
checked[f] = 1;
found[f] = 1;
}
}
}
return faces;
}
// given a list of faces (indices), return an array of closed
// polylines that represent the outlines of each discrete island
generateOutlines(list) {
const { faces, sides } = this.getIndex();
const prec = this.precision;
const verts = this.vertices;
const lines = {};
const point = {};
const pindx = {};
let pnext = 0;
function vert2point(v) {
const x = verts[v];
const y = verts[v + 1];
const z = verts[v + 2];
const key = ((x * prec) | 0) + ',' + ((y * prec) | 0) + ',' + ((z * prec) | 0);
const rec = point[key];
if (rec === undefined) {
pindx[pnext] = { x, y, z, to: [] };
return point[key] = pnext++;
} else {
return rec;
}
}
function addLine(s) {
if (s === empty) return;
const v0 = vert2point(sides[s * 4]);
const v1 = vert2point(sides[s * 4 + 1]);
const key = v0 < v1 ? v0 + ',' + v1 : v1 +',' + v0;
const rec = lines[key];
if (rec) {
rec.del = true;
} else {
lines[key] = { v0, v1 };
}
}
for (let face of list) {
const foff = face * 6;
addLine(faces[foff + 3]);
addLine(faces[foff + 4]);
addLine(faces[foff + 5]);
}
const pairs = Object.values(lines).filter(l => !l.del);
for (let line of pairs) {
const { v0, v1 } = line;
const p0 = pindx[v0];
const p1 = pindx[v1];
p0.to.push(v1);
p1.to.push(v0);
}
let curr;
let outs = [ ];
for (let prec of Object.values(pindx)) {
if (prec.used || prec.to.length === 0) continue;
outs.push(curr = []);
while (prec) {
let { to, x, y, z } = prec;
if (to.length < 2) {
throw `invalid to ${to.length} @ ${x},${y},${z}`;
}
prec.used = true;
curr.push({ x, y, z });
const t0 = pindx[to[0]];
const t1 = pindx[to[1]];
if (!t0.used) {
prec = t0;
} else if (!t1.used) {
prec = t1;
} else {
prec = undefined;
}
}
}
// console.log({lines, pairs, pindx, outs});
return outs;
}
// depends on index() being run first
isolateBodies() {
const verts = this.checkVertices(this.vertices);
const bodies = [];
const used = {};
for (let i=0, l=verts.length / 9; i<l; i++) {
if (used[i]) {
continue;
}
const body = this.findConnectedSurface([i], Infinity, undefined, used);
if (body.length) {
// todo: pre-allocate known length
// then copy array regions from verts to bverts
const bverts = [];
for (let f of body) {
bverts.push(...verts.slice(f*9, f*9+9));
}
bodies.push(bverts);
}
}
return bodies;
}
/**
* finds edge lines which are line segments on a single face.
* construct ordered line maps with array of connected edges.
* connect lines into polys. earcut polys into new faces.
* requires generateFaces() be run first
*/
patch(opt = { merge: true }) {
let vertices = this.checkVertices(this.uvert);
let faces = this.faces;
let hash = {}; // key to line map
let vmap = {}; // vertext to line map
let lines = [];
class Line {
constructor(v1, v2) {
this.v1 = v1;
this.v2 = v2;
this.faces = [];
}
addFace(face) {
if (this.faces.indexOf(face) < 0) {
this.faces.push(face);
} else if (false) {
console.log('adding face to line twice', this, face);
}
return this;
}
adjacentUnused() {
return vmap[this.v1]
.concat(vmap[this.v2])
.filter(l => l !== this && !l.used && l.faces.length === 1);
}
adjacentUsed() {
return vmap[this.v1]
.concat(vmap[this.v2])
.filter(l => l !== this && l.used && l.faces.length === 1);
}
touches(line) {
return this.v1 === line.v1 ||
this.v1 === line.v2 ||
this.v2 === line.v1 ||
this.v2 === line.v2;
}
unitVector() {
if (this.unit !== undefined) {
return this.unit;
}
let v1 = this.v1;
let v2 = this.v2;
let d = [
vertices[v1] - vertices[v2],
vertices[v1 + 1] - vertices[v2 + 1],
vertices[v1 + 2] - vertices[v2 + 2],
];
let max = Math.max(...d.map(v => Math.abs(v)));
// console.log({d, max});
return this.unit = d.map(v => v / max);
}
}
function diffUnitVector(uv1, uv2) {
let diff = 0;
for (let i=0; i<3; i++) {
diff += Math.abs(uv1[i] - uv2[i]);
}
return diff;
}
function getLine(v1, v2) {
let s1 = vertices[v1] + vertices[v1+1]*1000 + vertices[v1+2]*100000;
let s2 = vertices[v2] + vertices[v2+1]*1000 + vertices[v2+2]*100000;
let key = s1 <= s2 ? [v1,v2].join('-') : [v2,v1].join('-');
let line = hash[key];
if (!line) {
// point order will be swapped for reconstructed faces
// to preserve chirality (assuming face normals are correct)
line = hash[key] = new Line(v1, v2);
line.key = key;
lines.push(line);
let lm1 = vmap[v1] = vmap[v1] || [];
let lm2 = vmap[v2] = vmap[v2] || [];
lm1.push(line);
lm2.push(line);
}
return line;
}
function getXYZ(v) {
return {x: vertices[v], y: vertices[v+1], z: vertices[v+2]};
}
for (let i=0, l=this.faces.length; i<l; i += 3) {
let v1 = faces[i];
let v2 = faces[i+1];
let v3 = faces[i+2];
let l1 = getLine(v1, v2).addFace(i);
let l2 = getLine(v2, v3).addFace(i);
let l3 = getLine(v3, v1).addFace(i);
}
// array of unique line segment records with vertices
// and a list of faces. one = edge, two = inside
// all lines should be inside or object is not manifold
// but does not preclude self-intersecting geometries
this.lines = lines;
// lines belonging to only one face are on the edge of a hole
let edges = this.edges = lines.filter(l => l.faces.length === 1);
// arrays of connected edges that form a closed loop
let loops = this.loops = [];
// connect edge lines into closed loops
for (let i=0, l=edges.length; i<l; i++) {
let line = edges[i];
if (line.used) {
continue;
}
// cannot start on split
if (line.adjacentUnused().length > 2) {
// console.log('cannot start on a split');
continue;
}
// line.used = true;
let loop = [ ];
// build line through adjacent lines
while (true) {
let adjacent = line.adjacentUnused();
if (adjacent.length === 0) {
let first = loop[0];
let last = loop.last();
loop.open = loop.length < 3
|| (first.v1 !== last.v1
&& first.v2 !== last.v2
&& first.v1 !== last.v2
&& first.v2 !== last.v1);
// console.log({term: line, adj: line.adjacentUsed(), open, loop});
break;
} else if (adjacent.length === 1) {
if (line.v2 !== adjacent[0].v1) {
let tmp = adjacent[0].v1;
adjacent[0].v1 = adjacent[0].v2;
adjacent[0].v2 = tmp;
// console.log('chirality mismatch fixed');
}
line = adjacent[0];
} else if (adjacent.length === 2) {
// follow edges according to chirality
line = adjacent[0].v1 === line.v2 ?
adjacent[0] :
adjacent[1]
} else {
// console.log('error adjacent', line, adjacent, loops.length, loop.length);
line.split = adjacent;
line = adjacent[0];
}
loop.push(line);
line.used = true;
}
if (loop.length) {
loops.push(loop);
}
}
// attempt to connect open loops
if (loops.length > 1) {
outer: for (let i=0; i<loops.length-1; i++) {
let l1 = loops[i];
if (!(l1 && l1.open)) {
continue;
}
for (let j=i+1; j<loops.length; j++) {
let l2 = loops[j];
if (!(l2 && l2.open)) {
continue;
}
let nuloop;
if (l1[0].touches(l2[0])) {
nuloop = [...l2.reverse(), ...l1];
} else if (l1[0].touches(l2.last())) {
nuloop = [...l2, ...l1];
} else if (l1.last().touches(l2[0])) {
nuloop = [...l1, ...l2];
} else if (l1.last().touches(l2.last())) {
nuloop = [...l1, ...l2.reverse()];
}
if (nuloop) {
nuloop.open = true;
loops.push(nuloop);
loops[i] = loops[j] = undefined;
continue outer;
}
}
}
}
// store invalid loops for display / culling
this.shorts = loops.filter(l => l && l.length <= 2);
// console.log({edges, loops, shorts: this.shorts});
// filter out null and short loops
this.loops = loops = loops.filter(l => l && l.length > 2);
// console.log({loops_filtered: loops});
// rotate/flatten to Z plane and use earcut to generate faces
// because earcut emits point indexes, no need to un-rotate
function emitLoop(loop) {
let lastPoint;
let pindex = [];
let points = [];
let dx = 0, dy = 0, dz = 0;
// gather points, find axis with least deviaton to swap with Z
let loop1 = loop.slice();
loop1.push(loop[0]);
for (let i=0; i<loop1.length; i++) {
let line = loop1[i];
let nextPoint;
if (line.v1 === lastPoint) {
nextPoint = line.v2;
} else {
nextPoint = line.v1;
}
if (i < loop1.length - 1) {
pindex.push(nextPoint);
points.push([
vertices[nextPoint],
vertices[nextPoint+1],
vertices[nextPoint+2]
]);
}
if (lastPoint >= 0) {
dx = Math.max(dx, Math.abs(vertices[lastPoint] - vertices[nextPoint]));
dy = Math.max(dy, Math.abs(vertices[lastPoint+1] - vertices[nextPoint+1]));
dz = Math.max(dz, Math.abs(vertices[lastPoint+2] - vertices[nextPoint+2]));
}
lastPoint = nextPoint;
}
// swap Z axis with least delta axis
let swap = 2;
if (dy < dx && dy < dz) {
// swap y,z
swap = 1;
} else if (dx < dy && dx < dz) {
// swap x,z
swap = 0;
}
if (swap < 2) {
// swap x or y for z axes
for (let point of points) {
let tmpz = point[2];
point[2] = point[swap];
point[swap] = tmpz;
}
}
return { index: pindex, points: points.flat(), swap };
}
// given a loop with holes, emit faces
function emitFaces(loop) {
let { index, points } = loop;
let ec = earcut(points, undefined, 3);
// map earcut point indexes back to vertex indexes
return ec.map(p => index[p]);
}
function emitTop(rec) {
let points = rec.loop.points.slice();
let index = rec.loop.index.slice();
let holes = [];
for (let inner of rec.inner) {
holes.push(points.length / 3);
points.appendAll(inner.loop.points);
index.appendAll(inner.loop.index);
}
let ec = earcut(points, holes, 3);
return ec.map(p => index[p]);
}
// new patch areas
let areas = this.areas = [];
if (opt.compound) {
// group loops by normal (using swap as crude proxy for now)
// then attempt to nest them (find holes)
let polys = loops.map(loop => {
return emitLoop(loop);
});
// return nested mapping
let nested = geom.nest(polys.map(p => p.points));
// recover and map loops from point arrays
for (let rec of nested) {
rec.loop = polys.filter(loop => loop.points === rec.points)[0];
}
// extract tops which have nesting depth mod 2 === 0
let tops = nested.filter(rec => rec.depth % 2 === 0);
for (let top of tops) {
areas.push(emitTop(top));
}
} else {
// create area faces covering loops
for (let loop of loops) {
let l2 = emitLoop(loop);
let fs = emitFaces(l2);
areas.push(fs);
}
}
// auto-merge newly found enclosed areas
if (opt.merge) {
this.merge();
}
// de-reference loops and edges
if (opt.mapped) {
this.mapped = {
edges: this.expandLoop(this.edges),
areas: this.areas.map(a => this.expandArray(a))
};
}
return this;
}
// add vertex data from given index into array
appendVertex(index, array = []) {
let vertx = this.uvert;
array.push(vertx[index++]);
array.push(vertx[index++]);
array.push(vertx[index]);
return array;
}
// add vertices from a vertex index list to an array
expandArray(indices, array = []) {
for (let i of indices) {
this.appendVertex(i, array);
}
return array;
}
// turn loop into XYZ vertex array
expandLoop(loop, array = []) {
for (let line of loop) {
this.appendVertex(line.v1, array);
this.appendVertex(line.v2, array);
}
return array;
}
// merge generated poly areas into faces
merge() {
for (let area of this.areas || []) {
this.faces.appendAll(area);
}
}
// return non-indexed vertex list (for compatibility)
unrolled() {
let out = [];
for (let face of this.faces) {
this.appendVertex(face, out);
}
return out;
}
// returns points array for a polygon
// extrusion and twist is handled in work.js
generateGear(numTeeth, module, pressureAngle, offset) {
// Adapted from: Public Domain Parametric Involute Spur Gear by Leemon Baird, 2011, Leemon@Leemon.com http://www.thingiverse.com/thing:5505
// see also http://grabcad.com/questions/tutorial-how-to-model-involute-gears-in-solidworks-and-show-design-intent
// const pitch_radius = (numTeeth * module) / 2;
const pi = Math.PI;
// degrees to radians
function degrees_to_radians(theta) { return theta / 180 * pi; }
// polar to cartesian
function polar(r, theta) { return [r * Math.sin(theta), r * Math.cos(theta)]; }
// point on involute curve
function q6(b, s, t, d) { return polar(d, s * (iang(b, d) + t)); }
// unwind this many degrees to go from r1 to r2
function iang(r1, r2) { return Math.sqrt((r2 / r1) * (r2 / r1) - 1) - Math.acos(r1 / r2); }
// radius a fraction f up the curved side of the tooth
function q7(f, r, b, r2, t, s) { return q6(b, s, t, (1 - f) * Math.max(b, r) + f * r2); }
// lerp q7 0..1 with a given # steps
function qf(steps, r, b, r2, t, s) {
let res = [];
let step = 1/steps;
for (let f=0; f <= 1; f += step) {
res.push(q7(f, r, b, r2, t, s));
}
return res;
}
// rotate an array of 2d points
function rotate(points_array, angle) {
let answer = [];
for (let i = 0; i < points_array.length; i++) {
let x = points_array[i][0];
let y = points_array[i][1];
let xr = x * Math.cos(angle) - y * Math.sin(angle);
let yr = y * Math.cos(angle) + x * Math.sin(angle);
answer.push([xr, yr]);
}
return answer;
}
// gear parameter setup
let mm_per_tooth = module * pi; // mm size of one gear tooth
let clearance = offset/2 || 0; // freedom between two gear centers
let backlash = offset || 0; // freedom between two gear contact points
let pressure_angle = degrees_to_radians(pressureAngle);
let gear = [];
let pitch;
// involute gear maker
{
let p = mm_per_tooth * numTeeth / pi / 2; // radius of pitch circle
let c = p + mm_per_tooth / pi - clearance; // radius of outer circle
let b = p * Math.cos(pressure_angle); // radius of base circle
let r = p - (c - p) - clearance; // radius of root circle
let t = mm_per_tooth / 2 - backlash / 2; // tooth thickness at pitch circle
let k = -iang(b, p) - t / 2 / p; // angle where involute meets base circle on side of tooth
let f = 10 + ((p/5) | 0); // increase number of tooth curve points on larger gears
let points = [ // [x,y] points for a single gear tooth
polar(r, -pi / numTeeth),
polar(r, r < b ? k : -pi / numTeeth),
...qf(f, r, b, c, k, 1),
...qf(f, r, b, c, k, -1).reverse(),
polar(r, r < b ? -k : pi / numTeeth),
// polar(r, 3.142 / numTeeth) // omit b/c overlaps start when rotated
];
// create all gear teeth by rotating the first tooth
for (var i = 0; i < numTeeth; i++) {
gear.appendAll(rotate(points, -i * 2 * pi / numTeeth));
}
pitch = p.round(3);
mesh.log(`gear pitch radius: ${pitch}`);
}
return { gear, pitch };
}
generateThreads(height, radius, turns, depth, steps, taper) {
let verts = [];
let zstep = height / turns;
let rstep = (Math.PI * 2) / steps;
let z2step = zstep / steps;
let points = []
let iter = 0;
let iter_max = turns * steps + steps;
let mute_min = Math.round(steps * 2.5);
let mute_max = iter_max - mute_min;
for (let turn=0; turn<turns; turn++) {
for (let step=0; step<steps; step++) {
iter++;
let itern = iter + steps;
let rm = radius - depth;
let rx = true &&
taper && iter < mute_min ? rm + (iter / mute_min) * depth :
taper && iter > mute_max ? rm + ((iter_max - iter) / mute_min) * depth :
radius;
let rxt = true &&
taper && itern < mute_min ? rm + (itern / mute_min) * depth :
taper && itern > mute_max ? rm + ((iter_max - itern) / mute_min) * depth :
radius;
let angle0 = rstep * step - Math.PI/2;
let z0 = (zstep * turn) + (z2step * step);
let x0 = Math.cos(angle0) * (rm);
let y0 = Math.sin(angle0) * (rm);
let x1 = Math.cos(angle0) * (rx);
let y1 = Math.sin(angle0) * (rx);
let x1t = Math.cos(angle0) * (rxt);
let y1t = Math.sin(angle0) * (rxt);
let p0 = [ x1t, y1t, z0 + zstep/2 ];
let p1 = [ x0, y0, z0 ];
let p2 = [ x1, y1, z0 - zstep/2 ];
let [ pp0, pp1, pp2 ] = points;
if (pp0 && pp1 && pp2) {
verts.push(...pp0, ...pp1, ...p0);
verts.push(...p0, ...pp1, ...p1);
verts.push(...pp1, ...pp2, ...p1);
verts.push(...p1, ...pp2, ...p2);
}
points = [ p0, p1, p2 ];
}
}
return verts;
}
};
});