376 lines
14 KiB
JavaScript
376 lines
14 KiB
JavaScript
/** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
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"use strict";
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(function() {
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const BASE = self.base = self.base || {};
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if (BASE.Mesh) {
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return;
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}
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BASE.Mesh = class Mesh {
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constructor(params = {}) {
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this.precision = params.precision || 6;
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if (params.vertices) {
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this.setData(params.vertices, params.faces);
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}
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}
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/**
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* set vertices and faces of the mesh. if only vertices are provided
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* then the data is assumed to be un-indexed and will be indexed into
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* faces. if faces are provided, they are assumed to be index references
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* into the vertex data. removes invalid faces.
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*
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* the end result is face data mapped to an indexed set of unique vertices.
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*
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* @param {number[]} vertices
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* @param {number[]} faces
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*/
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setData(vertices, faces) {
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if (!vertices) {
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throw "missing vertices";
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}
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if (vertices.length % 3 !== 0) {
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throw "invalid vertices";
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}
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// when face/index data is missing, vertices need to be normalized
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if (!faces) {
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faces = [];
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let fcac = {}; // seen face hash
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let fnew = []; // accumulate vertex triplets
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let nuvt = []; // new vertex list
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let hash = {}; // find vertex matches
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let prec = this.precision;
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for (let i=0, l=vertices.length; i<l; i += 3) {
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let x = vertices[i];
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let y = vertices[i+1];
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let z = vertices[i+2];
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let key = [
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x.toFixed(prec),
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y.toFixed(prec),
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z.toFixed(prec)
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].join(',');
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let vpos = hash[key];
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if (vpos === undefined) {
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hash[key] = vpos = nuvt.length;
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nuvt.push(x);
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nuvt.push(y);
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nuvt.push(z);
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}
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fnew.push(vpos);
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if (fnew.length === 3) {
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// cull invalid faces (shares 2 or more points)
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if (fnew[0] === fnew[1] || fnew[0] === fnew[2] || fnew[1] === fnew[2]) {
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fnew = [];
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continue;
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}
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let key = fnew.slice().sort().join('-');
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// drop duplicate faces (even when reversed - thus the sort)
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if (!fcac[key]) {
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faces.appendAll(fnew);
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}
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fcac[key] = key;
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fnew = [];
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}
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}
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vertices = nuvt;
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}
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this.vertices = vertices;
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this.faces = faces;
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return this;
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}
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// return non-indexed vertex list (for compatibility)
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unrolled() {
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let out = [];
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let vertices = this.vertices;
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for (let face of this.faces) {
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out.push(vertices[face]);
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out.push(vertices[face+1]);
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out.push(vertices[face+2]);
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}
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return out;
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}
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/**
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* finds edge lines which are line segments on a single face.
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* construct ordered line maps with array of connected edges.
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* connect lines into polys. earcut polys into new faces.
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*/
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heal() {
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let vertices = this.vertices;
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let faces = this.faces;
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let hash = {}; // key to line map
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let vmap = {}; // vertext to line map
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let lines = [];
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class Line {
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constructor(v1, v2) {
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this.v1 = v1;
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this.v2 = v2;
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this.faces = [];
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}
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addFace(face) {
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if (this.faces.indexOf(face) < 0) {
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this.faces.push(face);
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} else {
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console.log('adding face to line twice', this, face);
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}
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return this;
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}
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adjacentUnused() {
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return vmap[this.v1]
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.concat(vmap[this.v2])
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.filter(l => l !== this && !l.used && l.faces.length === 1);
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}
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adjacentUsed() {
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return vmap[this.v1]
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.concat(vmap[this.v2])
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.filter(l => l !== this && l.used && l.faces.length === 1);
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}
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touches(line) {
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return this.v1 === line.v1 ||
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this.v1 === line.v2 ||
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this.v2 === line.v1 ||
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this.v2 === line.v2;
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}
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unitVector() {
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if (this.unit !== undefined) {
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return this.unit;
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}
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let v1 = this.v1;
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let v2 = this.v2;
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let d = [
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vertices[v1] - vertices[v2],
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vertices[v1 + 1] - vertices[v2 + 1],
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vertices[v1 + 2] - vertices[v2 + 2],
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];
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let max = Math.max(...d.map(v => Math.abs(v)));
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// console.log({d, max});
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return this.unit = d.map(v => v / max);
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}
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}
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function diffUnitVector(uv1, uv2) {
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let diff = 0;
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for (let i=0; i<3; i++) {
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diff += Math.abs(uv1[i] - uv2[i]);
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}
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return diff;
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}
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function getLine(v1, v2) {
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let s1 = vertices[v1] + vertices[v1+1]*1000 + vertices[v1+2]*100000;
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let s2 = vertices[v2] + vertices[v2+1]*1000 + vertices[v2+2]*100000;
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let key = s1 <= s2 ? [v1,v2].join('-') : [v2,v1].join('-');
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let line = hash[key];
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if (!line) {
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// point order will be swapped for reconstructed faces
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// to preserve chirality (assuming face normals are correct)
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line = hash[key] = new Line(v1, v2);
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line.key = key;
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lines.push(line);
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let lm1 = vmap[v1] = vmap[v1] || [];
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let lm2 = vmap[v2] = vmap[v2] || [];
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lm1.push(line);
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lm2.push(line);
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}
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return line;
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}
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function getXYZ(v) {
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return {x: vertices[v], y: vertices[v+1], z: vertices[v+2]};
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}
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for (let i=0, l=this.faces.length; i<l; i += 3) {
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let v1 = faces[i];
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let v2 = faces[i+1];
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let v3 = faces[i+2];
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let l1 = getLine(v1, v2).addFace(i);
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let l2 = getLine(v2, v3).addFace(i);
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let l3 = getLine(v3, v1).addFace(i);
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}
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this.lines = lines;
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// lines belonging to only one face are on the edge of a hole
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let edges = this.edges = lines.filter(l => l.faces.length === 1);
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let loops = this.loops = [];
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// console.log({edges});
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// connect edge lines into closed loops
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for (let i=0, l=edges.length; i<l; i++) {
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let line = edges[i];
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if (line.used) {
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continue;
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}
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// cannot start on split
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if (line.adjacentUnused().length > 2) {
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// console.log('cannot start on a split');
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continue;
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}
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// line.used = true;
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let loop = [ ];
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// build line through adjacent lines
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while (true) {
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let adjacent = line.adjacentUnused();
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if (adjacent.length === 0) {
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let first = loop[0];
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let last = loop.last();
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loop.open = loop.length < 3
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|| (first.v1 !== last.v1
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&& first.v2 !== last.v2
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&& first.v1 !== last.v2
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&& first.v2 !== last.v1);
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// console.log({term: line, adj: line.adjacentUsed(), open, loop});
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break;
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} else if (adjacent.length === 1) {
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if (line.v2 !== adjacent[0].v1) {
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let tmp = adjacent[0].v1;
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adjacent[0].v1 = adjacent[0].v2;
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adjacent[0].v2 = tmp;
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// console.log('chirality mismatch fixed');
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}
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line = adjacent[0];
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} else if (adjacent.length === 2) {
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// follow edges according to chirality
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line = adjacent[0].v1 === line.v2 ?
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adjacent[0] :
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adjacent[1]
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} else {
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// console.log('error adjacent', line, adjacent, loops.length, loop.length);
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line.split = adjacent;
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line = adjacent[0];
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}
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loop.push(line);
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line.used = true;
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}
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if (loop.length) {
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loops.push(loop);
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}
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}
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// attempt to connect open loops
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if (loops.length > 1) {
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outer: for (let i=0; i<loops.length-1; i++) {
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let l1 = loops[i];
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if (!(l1 && l1.open)) {
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continue;
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}
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for (let j=i+1; j<loops.length; j++) {
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let l2 = loops[j];
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if (!(l2 && l2.open)) {
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continue;
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}
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let nuloop;
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if (l1[0].touches(l2[0])) {
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nuloop = [...l2.reverse(), ...l1];
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} else if (l1[0].touches(l2.last())) {
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nuloop = [...l2, ...l1];
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} else if (l1.last().touches(l2[0])) {
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nuloop = [...l1, ...l2];
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} else if (l1.last().touches(l2.last())) {
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nuloop = [...l1, ...l2.reverse()];
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}
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if (nuloop) {
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nuloop.open = true;
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loops.push(nuloop);
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loops[i] = loops[j] = undefined;
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continue outer;
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}
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}
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}
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}
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// console.log({loops})
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// store invalid loops for display / culling
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this.shorts = loops.filter(l => l && l.length <= 2);
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// filter out null and short loops
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this.loops = loops = loops.filter(l => l && l.length > 2);
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// console.log({loops})
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// rotate/flatten to Z plane and use earcut to generate faces
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// because earcut emits point indexes, no need to un-rotate
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function emitLoop(loop) {
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let lastPoint;
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let pindex = [];
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let points = [];
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let dx = 0, dy = 0, dz = 0;
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// gather points, find axis with least deviaton to swap with Z
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let loop1 = loop.slice();
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loop1.push(loop[0]);
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for (let i=0; i<loop1.length; i++) {
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let line = loop1[i];
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let nextPoint;
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if (line.v1 === lastPoint) {
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nextPoint = line.v2;
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} else {
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nextPoint = line.v1;
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}
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if (i < loop1.length - 1) {
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pindex.push(nextPoint);
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points.push([
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vertices[nextPoint],
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vertices[nextPoint+1],
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vertices[nextPoint+2]
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]);
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}
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if (lastPoint >= 0) {
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dx = Math.max(dx, Math.abs(vertices[lastPoint] - vertices[nextPoint]));
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dy = Math.max(dy, Math.abs(vertices[lastPoint+1] - vertices[nextPoint+1]));
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dz = Math.max(dz, Math.abs(vertices[lastPoint+2] - vertices[nextPoint+2]));
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}
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lastPoint = nextPoint;
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}
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// swap Z axis with least delta axis
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let swap = 2;
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if (dy < dx && dy < dz) {
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// swap y,z
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swap = 1;
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} else if (dx < dy && dx < dz) {
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// swap x,z
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swap = 0;
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}
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if (swap < 2) {
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// console.log({swap_axis: swap});
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for (let point of points) {
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let tmpz = point[2];
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point[2] = point[swap];
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point[swap] = tmpz;
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}
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}
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let fpoints = points.flat();
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let ec = earcut(fpoints, undefined, 3);
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// console.log({points, fpoints, ec, dx, dy, dz});
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for (let point of ec) {
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faces.push(pindex[point]);
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}
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}
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// emit loops
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let faceCount = this.faces.length;
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for (let loop of loops) {
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emitLoop(loop);
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}
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this.newFaces = this.faces.length - faceCount;
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// console.log({newFaces: this.newFaces});
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return this;
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}
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};
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})();
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