webvr js meetup initial commit
This commit is contained in:
Senad Uka
674
node_modules/three/examples/js/libs/earcut.js
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vendored
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674
node_modules/three/examples/js/libs/earcut.js
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vendored
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/**
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*
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* Earcut https://github.com/mapbox/earcut
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*
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* Copyright (c) 2015, Mapbox
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*
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* Permission to use, copy, modify, and/or distribute this software for any purpose
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* with or without fee is hereby granted, provided that the above copyright notice
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* and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
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* OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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* THIS SOFTWARE.
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*/
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'use strict';
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//module.exports = earcut;
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function earcut(data, holeIndices, dim) {
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dim = dim || 2;
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var hasHoles = holeIndices && holeIndices.length,
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outerLen = hasHoles ? holeIndices[0] * dim : data.length,
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outerNode = filterPoints(data, linkedList(data, 0, outerLen, dim, true)),
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triangles = [];
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if (!outerNode) return triangles;
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var minX, minY, maxX, maxY, x, y, size;
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if (hasHoles) outerNode = eliminateHoles(data, holeIndices, outerNode, dim);
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// if the shape is not too simple, we'll use z-order curve hash later; calculate polygon bbox
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if (data.length > 80 * dim) {
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minX = maxX = data[0];
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minY = maxY = data[1];
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for (var i = dim; i < outerLen; i += dim) {
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x = data[i];
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y = data[i + 1];
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if (x < minX) minX = x;
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if (y < minY) minY = y;
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if (x > maxX) maxX = x;
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if (y > maxY) maxY = y;
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}
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// minX, minY and size are later used to transform coords into integers for z-order calculation
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size = Math.max(maxX - minX, maxY - minY);
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}
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earcutLinked(data, outerNode, triangles, dim, minX, minY, size);
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return triangles;
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}
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// create a circular doubly linked list from polygon points in the specified winding order
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function linkedList(data, start, end, dim, clockwise) {
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var sum = 0,
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i, j, last;
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// calculate original winding order of a polygon ring
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for (i = start, j = end - dim; i < end; i += dim) {
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sum += (data[j] - data[i]) * (data[i + 1] + data[j + 1]);
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j = i;
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}
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// link points into circular doubly-linked list in the specified winding order
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if (clockwise === (sum > 0)) {
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for (i = start; i < end; i += dim) last = insertNode(i, last);
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} else {
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for (i = end - dim; i >= start; i -= dim) last = insertNode(i, last);
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}
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return last;
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}
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// eliminate colinear or duplicate points
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function filterPoints(data, start, end) {
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if (!start) return start;
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if (!end) end = start;
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var node = start,
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again;
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do {
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again = false;
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if (!node.steiner && (equals(data, node.i, node.next.i) || orient(data, node.prev.i, node.i, node.next.i) === 0)) {
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removeNode(node);
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node = end = node.prev;
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if (node === node.next) return null;
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again = true;
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} else {
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node = node.next;
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}
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} while (again || node !== end);
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return end;
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}
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// main ear slicing loop which triangulates a polygon (given as a linked list)
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function earcutLinked(data, ear, triangles, dim, minX, minY, size, pass) {
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if (!ear) return;
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// interlink polygon nodes in z-order
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if (!pass && minX !== undefined) indexCurve(data, ear, minX, minY, size);
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var stop = ear,
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prev, next;
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// iterate through ears, slicing them one by one
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while (ear.prev !== ear.next) {
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prev = ear.prev;
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next = ear.next;
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if (isEar(data, ear, minX, minY, size)) {
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// cut off the triangle
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triangles.push(prev.i / dim);
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triangles.push(ear.i / dim);
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triangles.push(next.i / dim);
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removeNode(ear);
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// skipping the next vertice leads to less sliver triangles
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ear = next.next;
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stop = next.next;
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continue;
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}
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ear = next;
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// if we looped through the whole remaining polygon and can't find any more ears
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if (ear === stop) {
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// try filtering points and slicing again
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if (!pass) {
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earcutLinked(data, filterPoints(data, ear), triangles, dim, minX, minY, size, 1);
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// if this didn't work, try curing all small self-intersections locally
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} else if (pass === 1) {
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ear = cureLocalIntersections(data, ear, triangles, dim);
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earcutLinked(data, ear, triangles, dim, minX, minY, size, 2);
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// as a last resort, try splitting the remaining polygon into two
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} else if (pass === 2) {
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splitEarcut(data, ear, triangles, dim, minX, minY, size);
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}
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break;
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}
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}
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}
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// check whether a polygon node forms a valid ear with adjacent nodes
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function isEar(data, ear, minX, minY, size) {
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var a = ear.prev.i,
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b = ear.i,
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c = ear.next.i,
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ax = data[a], ay = data[a + 1],
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bx = data[b], by = data[b + 1],
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cx = data[c], cy = data[c + 1],
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abd = ax * by - ay * bx,
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acd = ax * cy - ay * cx,
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cbd = cx * by - cy * bx,
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A = abd - acd - cbd;
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if (A <= 0) return false; // reflex, can't be an ear
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// now make sure we don't have other points inside the potential ear;
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// the code below is a bit verbose and repetitive but this is done for performance
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var cay = cy - ay,
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acx = ax - cx,
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aby = ay - by,
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bax = bx - ax,
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i, px, py, s, t, k, node;
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// if we use z-order curve hashing, iterate through the curve
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if (minX !== undefined) {
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// triangle bbox; min & max are calculated like this for speed
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var minTX = ax < bx ? (ax < cx ? ax : cx) : (bx < cx ? bx : cx),
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minTY = ay < by ? (ay < cy ? ay : cy) : (by < cy ? by : cy),
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maxTX = ax > bx ? (ax > cx ? ax : cx) : (bx > cx ? bx : cx),
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maxTY = ay > by ? (ay > cy ? ay : cy) : (by > cy ? by : cy),
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// z-order range for the current triangle bbox;
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minZ = zOrder(minTX, minTY, minX, minY, size),
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maxZ = zOrder(maxTX, maxTY, minX, minY, size);
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// first look for points inside the triangle in increasing z-order
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node = ear.nextZ;
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while (node && node.z <= maxZ) {
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i = node.i;
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node = node.nextZ;
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if (i === a || i === c) continue;
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px = data[i];
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py = data[i + 1];
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s = cay * px + acx * py - acd;
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if (s >= 0) {
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t = aby * px + bax * py + abd;
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if (t >= 0) {
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k = A - s - t;
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if ((k >= 0) && ((s && t) || (s && k) || (t && k))) return false;
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}
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}
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}
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// then look for points in decreasing z-order
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node = ear.prevZ;
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while (node && node.z >= minZ) {
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i = node.i;
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node = node.prevZ;
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if (i === a || i === c) continue;
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px = data[i];
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py = data[i + 1];
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s = cay * px + acx * py - acd;
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if (s >= 0) {
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t = aby * px + bax * py + abd;
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if (t >= 0) {
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k = A - s - t;
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if ((k >= 0) && ((s && t) || (s && k) || (t && k))) return false;
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}
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}
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}
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// if we don't use z-order curve hash, simply iterate through all other points
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} else {
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node = ear.next.next;
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while (node !== ear.prev) {
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i = node.i;
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node = node.next;
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px = data[i];
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py = data[i + 1];
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s = cay * px + acx * py - acd;
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if (s >= 0) {
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t = aby * px + bax * py + abd;
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if (t >= 0) {
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k = A - s - t;
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if ((k >= 0) && ((s && t) || (s && k) || (t && k))) return false;
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}
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}
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}
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}
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return true;
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}
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// go through all polygon nodes and cure small local self-intersections
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function cureLocalIntersections(data, start, triangles, dim) {
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var node = start;
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do {
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var a = node.prev,
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b = node.next.next;
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// a self-intersection where edge (v[i-1],v[i]) intersects (v[i+1],v[i+2])
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if (a.i !== b.i && intersects(data, a.i, node.i, node.next.i, b.i) &&
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locallyInside(data, a, b) && locallyInside(data, b, a) &&
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orient(data, a.i, node.i, b.i) && orient(data, a.i, node.next.i, b.i)) {
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triangles.push(a.i / dim);
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triangles.push(node.i / dim);
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triangles.push(b.i / dim);
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// remove two nodes involved
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removeNode(node);
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removeNode(node.next);
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node = start = b;
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}
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node = node.next;
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} while (node !== start);
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return node;
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}
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// try splitting polygon into two and triangulate them independently
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function splitEarcut(data, start, triangles, dim, minX, minY, size) {
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// look for a valid diagonal that divides the polygon into two
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var a = start;
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do {
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var b = a.next.next;
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while (b !== a.prev) {
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if (a.i !== b.i && isValidDiagonal(data, a, b)) {
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// split the polygon in two by the diagonal
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var c = splitPolygon(a, b);
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// filter colinear points around the cuts
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a = filterPoints(data, a, a.next);
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c = filterPoints(data, c, c.next);
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// run earcut on each half
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earcutLinked(data, a, triangles, dim, minX, minY, size);
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earcutLinked(data, c, triangles, dim, minX, minY, size);
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return;
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}
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b = b.next;
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}
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a = a.next;
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} while (a !== start);
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}
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// link every hole into the outer loop, producing a single-ring polygon without holes
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function eliminateHoles(data, holeIndices, outerNode, dim) {
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var queue = [],
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i, len, start, end, list;
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for (i = 0, len = holeIndices.length; i < len; i++) {
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start = holeIndices[i] * dim;
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end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;
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list = linkedList(data, start, end, dim, false);
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if (list === list.next) list.steiner = true;
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list = filterPoints(data, list);
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if (list) queue.push(getLeftmost(data, list));
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}
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queue.sort(function (a, b) {
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return data[a.i] - data[b.i];
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});
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// process holes from left to right
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for (i = 0; i < queue.length; i++) {
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eliminateHole(data, queue[i], outerNode);
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outerNode = filterPoints(data, outerNode, outerNode.next);
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}
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return outerNode;
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}
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// find a bridge between vertices that connects hole with an outer ring and and link it
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function eliminateHole(data, holeNode, outerNode) {
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outerNode = findHoleBridge(data, holeNode, outerNode);
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if (outerNode) {
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var b = splitPolygon(outerNode, holeNode);
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filterPoints(data, b, b.next);
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}
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}
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// David Eberly's algorithm for finding a bridge between hole and outer polygon
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function findHoleBridge(data, holeNode, outerNode) {
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var node = outerNode,
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i = holeNode.i,
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px = data[i],
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py = data[i + 1],
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qMax = -Infinity,
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mNode, a, b;
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// find a segment intersected by a ray from the hole's leftmost point to the left;
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// segment's endpoint with lesser x will be potential connection point
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do {
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a = node.i;
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b = node.next.i;
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if (py <= data[a + 1] && py >= data[b + 1]) {
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var qx = data[a] + (py - data[a + 1]) * (data[b] - data[a]) / (data[b + 1] - data[a + 1]);
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if (qx <= px && qx > qMax) {
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qMax = qx;
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mNode = data[a] < data[b] ? node : node.next;
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}
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}
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node = node.next;
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} while (node !== outerNode);
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if (!mNode) return null;
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// look for points strictly inside the triangle of hole point, segment intersection and endpoint;
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// if there are no points found, we have a valid connection;
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// otherwise choose the point of the minimum angle with the ray as connection point
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var bx = data[mNode.i],
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by = data[mNode.i + 1],
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pbd = px * by - py * bx,
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pcd = px * py - py * qMax,
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cpy = py - py,
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pcx = px - qMax,
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pby = py - by,
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bpx = bx - px,
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A = pbd - pcd - (qMax * by - py * bx),
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sign = A <= 0 ? -1 : 1,
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stop = mNode,
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tanMin = Infinity,
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mx, my, amx, s, t, tan;
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node = mNode.next;
|
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while (node !== stop) {
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mx = data[node.i];
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my = data[node.i + 1];
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amx = px - mx;
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if (amx >= 0 && mx >= bx) {
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s = (cpy * mx + pcx * my - pcd) * sign;
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if (s >= 0) {
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t = (pby * mx + bpx * my + pbd) * sign;
|
||||
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if (t >= 0 && A * sign - s - t >= 0) {
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tan = Math.abs(py - my) / amx; // tangential
|
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if ((tan < tanMin || (tan === tanMin && mx > bx)) &&
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locallyInside(data, node, holeNode)) {
|
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mNode = node;
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tanMin = tan;
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}
|
||||
}
|
||||
}
|
||||
}
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||||
node = node.next;
|
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}
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||||
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return mNode;
|
||||
}
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||||
|
||||
// interlink polygon nodes in z-order
|
||||
function indexCurve(data, start, minX, minY, size) {
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var node = start;
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||||
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do {
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if (node.z === null) node.z = zOrder(data[node.i], data[node.i + 1], minX, minY, size);
|
||||
node.prevZ = node.prev;
|
||||
node.nextZ = node.next;
|
||||
node = node.next;
|
||||
} while (node !== start);
|
||||
|
||||
node.prevZ.nextZ = null;
|
||||
node.prevZ = null;
|
||||
|
||||
sortLinked(node);
|
||||
}
|
||||
|
||||
// Simon Tatham's linked list merge sort algorithm
|
||||
// http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html
|
||||
function sortLinked(list) {
|
||||
var i, p, q, e, tail, numMerges, pSize, qSize,
|
||||
inSize = 1;
|
||||
|
||||
do {
|
||||
p = list;
|
||||
list = null;
|
||||
tail = null;
|
||||
numMerges = 0;
|
||||
|
||||
while (p) {
|
||||
numMerges++;
|
||||
q = p;
|
||||
pSize = 0;
|
||||
for (i = 0; i < inSize; i++) {
|
||||
pSize++;
|
||||
q = q.nextZ;
|
||||
if (!q) break;
|
||||
}
|
||||
|
||||
qSize = inSize;
|
||||
|
||||
while (pSize > 0 || (qSize > 0 && q)) {
|
||||
|
||||
if (pSize === 0) {
|
||||
e = q;
|
||||
q = q.nextZ;
|
||||
qSize--;
|
||||
} else if (qSize === 0 || !q) {
|
||||
e = p;
|
||||
p = p.nextZ;
|
||||
pSize--;
|
||||
} else if (p.z <= q.z) {
|
||||
e = p;
|
||||
p = p.nextZ;
|
||||
pSize--;
|
||||
} else {
|
||||
e = q;
|
||||
q = q.nextZ;
|
||||
qSize--;
|
||||
}
|
||||
|
||||
if (tail) tail.nextZ = e;
|
||||
else list = e;
|
||||
|
||||
e.prevZ = tail;
|
||||
tail = e;
|
||||
}
|
||||
|
||||
p = q;
|
||||
}
|
||||
|
||||
tail.nextZ = null;
|
||||
inSize *= 2;
|
||||
|
||||
} while (numMerges > 1);
|
||||
|
||||
return list;
|
||||
}
|
||||
|
||||
// z-order of a point given coords and size of the data bounding box
|
||||
function zOrder(x, y, minX, minY, size) {
|
||||
// coords are transformed into non-negative 15-bit integer range
|
||||
x = 32767 * (x - minX) / size;
|
||||
y = 32767 * (y - minY) / size;
|
||||
|
||||
x = (x | (x << 8)) & 0x00FF00FF;
|
||||
x = (x | (x << 4)) & 0x0F0F0F0F;
|
||||
x = (x | (x << 2)) & 0x33333333;
|
||||
x = (x | (x << 1)) & 0x55555555;
|
||||
|
||||
y = (y | (y << 8)) & 0x00FF00FF;
|
||||
y = (y | (y << 4)) & 0x0F0F0F0F;
|
||||
y = (y | (y << 2)) & 0x33333333;
|
||||
y = (y | (y << 1)) & 0x55555555;
|
||||
|
||||
return x | (y << 1);
|
||||
}
|
||||
|
||||
// find the leftmost node of a polygon ring
|
||||
function getLeftmost(data, start) {
|
||||
var node = start,
|
||||
leftmost = start;
|
||||
do {
|
||||
if (data[node.i] < data[leftmost.i]) leftmost = node;
|
||||
node = node.next;
|
||||
} while (node !== start);
|
||||
|
||||
return leftmost;
|
||||
}
|
||||
|
||||
// check if a diagonal between two polygon nodes is valid (lies in polygon interior)
|
||||
function isValidDiagonal(data, a, b) {
|
||||
return a.next.i !== b.i && a.prev.i !== b.i &&
|
||||
!intersectsPolygon(data, a, a.i, b.i) &&
|
||||
locallyInside(data, a, b) && locallyInside(data, b, a) &&
|
||||
middleInside(data, a, a.i, b.i);
|
||||
}
|
||||
|
||||
// winding order of triangle formed by 3 given points
|
||||
function orient(data, p, q, r) {
|
||||
var o = (data[q + 1] - data[p + 1]) * (data[r] - data[q]) - (data[q] - data[p]) * (data[r + 1] - data[q + 1]);
|
||||
return o > 0 ? 1 :
|
||||
o < 0 ? -1 : 0;
|
||||
}
|
||||
|
||||
// check if two points are equal
|
||||
function equals(data, p1, p2) {
|
||||
return data[p1] === data[p2] && data[p1 + 1] === data[p2 + 1];
|
||||
}
|
||||
|
||||
// check if two segments intersect
|
||||
function intersects(data, p1, q1, p2, q2) {
|
||||
return orient(data, p1, q1, p2) !== orient(data, p1, q1, q2) &&
|
||||
orient(data, p2, q2, p1) !== orient(data, p2, q2, q1);
|
||||
}
|
||||
|
||||
// check if a polygon diagonal intersects any polygon segments
|
||||
function intersectsPolygon(data, start, a, b) {
|
||||
var node = start;
|
||||
do {
|
||||
var p1 = node.i,
|
||||
p2 = node.next.i;
|
||||
|
||||
if (p1 !== a && p2 !== a && p1 !== b && p2 !== b && intersects(data, p1, p2, a, b)) return true;
|
||||
|
||||
node = node.next;
|
||||
} while (node !== start);
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
// check if a polygon diagonal is locally inside the polygon
|
||||
function locallyInside(data, a, b) {
|
||||
return orient(data, a.prev.i, a.i, a.next.i) === -1 ?
|
||||
orient(data, a.i, b.i, a.next.i) !== -1 && orient(data, a.i, a.prev.i, b.i) !== -1 :
|
||||
orient(data, a.i, b.i, a.prev.i) === -1 || orient(data, a.i, a.next.i, b.i) === -1;
|
||||
}
|
||||
|
||||
// check if the middle point of a polygon diagonal is inside the polygon
|
||||
function middleInside(data, start, a, b) {
|
||||
var node = start,
|
||||
inside = false,
|
||||
px = (data[a] + data[b]) / 2,
|
||||
py = (data[a + 1] + data[b + 1]) / 2;
|
||||
do {
|
||||
var p1 = node.i,
|
||||
p2 = node.next.i;
|
||||
|
||||
if (((data[p1 + 1] > py) !== (data[p2 + 1] > py)) &&
|
||||
(px < (data[p2] - data[p1]) * (py - data[p1 + 1]) / (data[p2 + 1] - data[p1 + 1]) + data[p1]))
|
||||
inside = !inside;
|
||||
|
||||
node = node.next;
|
||||
} while (node !== start);
|
||||
|
||||
return inside;
|
||||
}
|
||||
|
||||
// link two polygon vertices with a bridge; if the vertices belong to the same ring, it splits polygon into two;
|
||||
// if one belongs to the outer ring and another to a hole, it merges it into a single ring
|
||||
function splitPolygon(a, b) {
|
||||
var a2 = new Node(a.i),
|
||||
b2 = new Node(b.i),
|
||||
an = a.next,
|
||||
bp = b.prev;
|
||||
|
||||
a.next = b;
|
||||
b.prev = a;
|
||||
|
||||
a2.next = an;
|
||||
an.prev = a2;
|
||||
|
||||
b2.next = a2;
|
||||
a2.prev = b2;
|
||||
|
||||
bp.next = b2;
|
||||
b2.prev = bp;
|
||||
|
||||
return b2;
|
||||
}
|
||||
|
||||
// create a node and optionally link it with previous one (in a circular doubly linked list)
|
||||
function insertNode(i, last) {
|
||||
var node = new Node(i);
|
||||
|
||||
if (!last) {
|
||||
node.prev = node;
|
||||
node.next = node;
|
||||
|
||||
} else {
|
||||
node.next = last.next;
|
||||
node.prev = last;
|
||||
last.next.prev = node;
|
||||
last.next = node;
|
||||
}
|
||||
return node;
|
||||
}
|
||||
|
||||
function removeNode(node) {
|
||||
node.next.prev = node.prev;
|
||||
node.prev.next = node.next;
|
||||
|
||||
if (node.prevZ) node.prevZ.nextZ = node.nextZ;
|
||||
if (node.nextZ) node.nextZ.prevZ = node.prevZ;
|
||||
}
|
||||
|
||||
function Node(i) {
|
||||
// vertex coordinates
|
||||
this.i = i;
|
||||
|
||||
// previous and next vertice nodes in a polygon ring
|
||||
this.prev = null;
|
||||
this.next = null;
|
||||
|
||||
// z-order curve value
|
||||
this.z = null;
|
||||
|
||||
// previous and next nodes in z-order
|
||||
this.prevZ = null;
|
||||
this.nextZ = null;
|
||||
|
||||
// indicates whether this is a steiner point
|
||||
this.steiner = false;
|
||||
}
|
||||
Reference in New Issue
Block a user