mirror of
https://github.com/photonstorm/phaser
synced 2024-11-24 13:43:26 +00:00
628 lines
18 KiB
JavaScript
628 lines
18 KiB
JavaScript
/* jshint ignore:start */
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/*
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Copyright (c) 2016, Mapbox
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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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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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/**
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* @class EarCut
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*/
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Phaser.EarCut = {};
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Phaser.EarCut.Triangulate = function (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 = Phaser.EarCut.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 = Phaser.EarCut.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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Phaser.EarCut.earcutLinked(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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Phaser.EarCut.linkedList = function (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 = Phaser.EarCut.insertNode(i, data[i], data[i + 1], last);
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} else {
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for (i = end - dim; i >= start; i -= dim) last = Phaser.EarCut.insertNode(i, data[i], data[i + 1], 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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Phaser.EarCut.filterPoints = function (start, end) {
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if (!start) return start;
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if (!end) end = start;
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var p = start,
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again;
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do {
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again = false;
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if (!p.steiner && (Phaser.EarCut.equals(p, p.next) || Phaser.EarCut.area(p.prev, p, p.next) === 0)) {
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Phaser.EarCut.removeNode(p);
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p = end = p.prev;
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if (p === p.next) return null;
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again = true;
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} else {
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p = p.next;
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}
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} while (again || p !== 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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Phaser.EarCut.earcutLinked = function (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 && size) Phaser.EarCut.indexCurve(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 (size ? Phaser.EarCut.isEarHashed(ear, minX, minY, size) : Phaser.EarCut.isEar(ear)) {
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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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Phaser.EarCut.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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Phaser.EarCut.earcutLinked(Phaser.EarCut.filterPoints(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 = Phaser.EarCut.cureLocalIntersections(ear, triangles, dim);
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Phaser.EarCut.earcutLinked(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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Phaser.EarCut.splitEarcut(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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Phaser.EarCut.isEar = function (ear) {
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var a = ear.prev,
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b = ear,
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c = ear.next;
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if (Phaser.EarCut.area(a, b, c) >= 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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var p = ear.next.next;
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while (p !== ear.prev) {
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if (Phaser.EarCut.pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) &&
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Phaser.EarCut.area(p.prev, p, p.next) >= 0) return false;
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p = p.next;
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}
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return true;
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};
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Phaser.EarCut.isEarHashed = function (ear, minX, minY, size) {
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var a = ear.prev,
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b = ear,
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c = ear.next;
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if (Phaser.EarCut.area(a, b, c) >= 0) return false; // reflex, can't be an ear
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// triangle bbox; min & max are calculated like this for speed
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var minTX = a.x < b.x ? (a.x < c.x ? a.x : c.x) : (b.x < c.x ? b.x : c.x),
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minTY = a.y < b.y ? (a.y < c.y ? a.y : c.y) : (b.y < c.y ? b.y : c.y),
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maxTX = a.x > b.x ? (a.x > c.x ? a.x : c.x) : (b.x > c.x ? b.x : c.x),
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maxTY = a.y > b.y ? (a.y > c.y ? a.y : c.y) : (b.y > c.y ? b.y : c.y);
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// z-order range for the current triangle bbox;
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var minZ = Phaser.EarCut.zOrder(minTX, minTY, minX, minY, size),
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maxZ = Phaser.EarCut.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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var p = ear.nextZ;
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while (p && p.z <= maxZ) {
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if (p !== ear.prev && p !== ear.next &&
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Phaser.EarCut.pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) &&
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Phaser.EarCut.area(p.prev, p, p.next) >= 0) return false;
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p = p.nextZ;
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}
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// then look for points in decreasing z-order
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p = ear.prevZ;
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while (p && p.z >= minZ) {
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if (p !== ear.prev && p !== ear.next &&
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Phaser.EarCut.pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) &&
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Phaser.EarCut.area(p.prev, p, p.next) >= 0) return false;
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p = p.prevZ;
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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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Phaser.EarCut.cureLocalIntersections = function (start, triangles, dim) {
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var p = start;
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do {
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var a = p.prev,
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b = p.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 (Phaser.EarCut.intersects(a, p, p.next, b) && Phaser.EarCut.locallyInside(a, b) && Phaser.EarCut.locallyInside(b, a)) {
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triangles.push(a.i / dim);
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triangles.push(p.i / dim);
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triangles.push(b.i / dim);
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// remove two nodes involved
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Phaser.EarCut.removeNode(p);
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Phaser.EarCut.removeNode(p.next);
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p = start = b;
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}
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p = p.next;
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} while (p !== start);
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return p;
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};
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// try splitting polygon into two and triangulate them independently
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Phaser.EarCut.splitEarcut = function (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 && Phaser.EarCut.isValidDiagonal(a, b)) {
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// split the polygon in two by the diagonal
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var c = Phaser.EarCut.splitPolygon(a, b);
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// filter colinear points around the cuts
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a = Phaser.EarCut.filterPoints(a, a.next);
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c = Phaser.EarCut.filterPoints(c, c.next);
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// run earcut on each half
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Phaser.EarCut.earcutLinked(a, triangles, dim, minX, minY, size);
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Phaser.EarCut.earcutLinked(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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Phaser.EarCut.eliminateHoles = function (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 = Phaser.EarCut.linkedList(data, start, end, dim, false);
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if (list === list.next) list.steiner = true;
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queue.push(Phaser.EarCut.getLeftmost(list));
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}
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queue.sort(compareX);
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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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Phaser.EarCut.eliminateHole(queue[i], outerNode);
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outerNode = Phaser.EarCut.filterPoints(outerNode, outerNode.next);
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}
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return outerNode;
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};
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Phaser.EarCut.compareX = function (a, b) {
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return a.x - b.x;
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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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Phaser.EarCut.eliminateHole = function (hole, outerNode) {
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outerNode = Phaser.EarCut.findHoleBridge(hole, outerNode);
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if (outerNode) {
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var b = Phaser.EarCut.splitPolygon(outerNode, hole);
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Phaser.EarCut.filterPoints(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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Phaser.EarCut.findHoleBridge = function (hole, outerNode) {
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var p = outerNode,
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hx = hole.x,
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hy = hole.y,
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qx = -Infinity,
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m;
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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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if (hy <= p.y && hy >= p.next.y) {
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var x = p.x + (hy - p.y) * (p.next.x - p.x) / (p.next.y - p.y);
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if (x <= hx && x > qx) {
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qx = x;
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m = p.x < p.next.x ? p : p.next;
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}
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}
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p = p.next;
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} while (p !== outerNode);
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if (!m) return null;
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if (hole.x === m.x) return m.prev; // hole touches outer segment; pick lower endpoint
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// look for points 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 stop = m,
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tanMin = Infinity,
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tan;
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p = m.next;
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while (p !== stop) {
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if (hx >= p.x && p.x >= m.x &&
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Phaser.EarCut.pointInTriangle(hy < m.y ? hx : qx, hy, m.x, m.y, hy < m.y ? qx : hx, hy, p.x, p.y)) {
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tan = Math.abs(hy - p.y) / (hx - p.x); // tangential
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if ((tan < tanMin || (tan === tanMin && p.x > m.x)) && Phaser.EarCut.locallyInside(p, hole)) {
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m = p;
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tanMin = tan;
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}
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}
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p = p.next;
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}
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return m;
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};
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// interlink polygon nodes in z-order
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Phaser.EarCut.indexCurve = function (start, minX, minY, size) {
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var p = start;
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do {
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if (p.z === null) p.z = Phaser.EarCut.zOrder(p.x, p.y, minX, minY, size);
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p.prevZ = p.prev;
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p.nextZ = p.next;
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p = p.next;
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} while (p !== start);
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p.prevZ.nextZ = null;
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p.prevZ = null;
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Phaser.EarCut.sortLinked(p);
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};
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// Simon Tatham's linked list merge sort algorithm
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// http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html
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Phaser.EarCut.sortLinked = function (list) {
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var i, p, q, e, tail, numMerges, pSize, qSize,
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inSize = 1;
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do {
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p = list;
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list = null;
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tail = null;
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numMerges = 0;
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while (p) {
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numMerges++;
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q = p;
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pSize = 0;
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for (i = 0; i < inSize; i++) {
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pSize++;
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q = q.nextZ;
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if (!q) break;
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}
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qSize = inSize;
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while (pSize > 0 || (qSize > 0 && q)) {
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if (pSize === 0) {
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e = q;
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q = q.nextZ;
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qSize--;
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} else if (qSize === 0 || !q) {
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e = p;
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p = p.nextZ;
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pSize--;
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} else if (p.z <= q.z) {
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e = p;
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p = p.nextZ;
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pSize--;
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} else {
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e = q;
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q = q.nextZ;
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qSize--;
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}
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if (tail) tail.nextZ = e;
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else list = e;
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e.prevZ = tail;
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tail = e;
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}
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p = q;
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}
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tail.nextZ = null;
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inSize *= 2;
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} while (numMerges > 1);
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return list;
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};
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// z-order of a point given coords and size of the data bounding box
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Phaser.EarCut.zOrder = function (x, y, minX, minY, size) {
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// coords are transformed into non-negative 15-bit integer range
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x = 32767 * (x - minX) / size;
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y = 32767 * (y - minY) / size;
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x = (x | (x << 8)) & 0x00FF00FF;
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x = (x | (x << 4)) & 0x0F0F0F0F;
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x = (x | (x << 2)) & 0x33333333;
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x = (x | (x << 1)) & 0x55555555;
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y = (y | (y << 8)) & 0x00FF00FF;
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y = (y | (y << 4)) & 0x0F0F0F0F;
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y = (y | (y << 2)) & 0x33333333;
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y = (y | (y << 1)) & 0x55555555;
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return x | (y << 1);
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};
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// find the leftmost node of a polygon ring
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Phaser.EarCut.getLeftmost = function (start) {
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var p = start,
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leftmost = start;
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do {
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if (p.x < leftmost.x) leftmost = p;
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p = p.next;
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} while (p !== start);
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return leftmost;
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};
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// check if a point lies within a convex triangle
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Phaser.EarCut.pointInTriangle = function (ax, ay, bx, by, cx, cy, px, py) {
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return (cx - px) * (ay - py) - (ax - px) * (cy - py) >= 0 &&
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(ax - px) * (by - py) - (bx - px) * (ay - py) >= 0 &&
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(bx - px) * (cy - py) - (cx - px) * (by - py) >= 0;
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};
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// check if a diagonal between two polygon nodes is valid (lies in polygon interior)
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Phaser.EarCut.isValidDiagonal = function (a, b) {
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return Phaser.EarCut.equals(a, b) || a.next.i !== b.i && a.prev.i !== b.i && !Phaser.EarCut.intersectsPolygon(a, b) &&
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Phaser.EarCut.locallyInside(a, b) && Phaser.EarCut.locallyInside(b, a) && Phaser.EarCut.middleInside(a, b);
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};
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// signed area of a triangle
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Phaser.EarCut.area = function (p, q, r) {
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return (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y);
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};
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// check if two points are equal
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Phaser.EarCut.equals = function (p1, p2) {
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return p1.x === p2.x && p1.y === p2.y;
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};
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// check if two segments intersect
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Phaser.EarCut.intersects = function (p1, q1, p2, q2) {
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return Phaser.EarCut.area(p1, q1, p2) > 0 !== Phaser.EarCut.area(p1, q1, q2) > 0 &&
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Phaser.EarCut.area(p2, q2, p1) > 0 !== Phaser.EarCut.area(p2, q2, q1) > 0;
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};
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// check if a polygon diagonal intersects any polygon segments
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Phaser.EarCut.intersectsPolygon = function (a, b) {
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var p = a;
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do {
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if (p.i !== a.i && p.next.i !== a.i && p.i !== b.i && p.next.i !== b.i &&
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Phaser.EarCut.intersects(p, p.next, a, b)) return true;
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p = p.next;
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} while (p !== a);
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return false;
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};
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// check if a polygon diagonal is locally inside the polygon
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Phaser.EarCut.locallyInside = function (a, b) {
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return Phaser.EarCut.area(a.prev, a, a.next) < 0 ?
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Phaser.EarCut.area(a, b, a.next) >= 0 && Phaser.EarCut.area(a, a.prev, b) >= 0 :
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Phaser.EarCut.area(a, b, a.prev) < 0 || Phaser.EarCut.area(a, a.next, b) < 0;
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};
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// check if the middle point of a polygon diagonal is inside the polygon
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Phaser.EarCut.middleInside = function (a, b) {
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var p = a,
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inside = false,
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px = (a.x + b.x) / 2,
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py = (a.y + b.y) / 2;
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do {
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if (((p.y > py) !== (p.next.y > py)) && (px < (p.next.x - p.x) * (py - p.y) / (p.next.y - p.y) + p.x))
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inside = !inside;
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p = p.next;
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} while (p !== a);
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return inside;
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};
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// link two polygon vertices with a bridge; if the vertices belong to the same ring, it splits polygon into two;
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// if one belongs to the outer ring and another to a hole, it merges it into a single ring
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Phaser.EarCut.splitPolygon = function (a, b) {
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var a2 = new Phaser.EarCut.Node(a.i, a.x, a.y),
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b2 = new Phaser.EarCut.Node(b.i, b.x, b.y),
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an = a.next,
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bp = b.prev;
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a.next = b;
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b.prev = a;
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a2.next = an;
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an.prev = a2;
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|
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b2.next = a2;
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a2.prev = b2;
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|
|
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bp.next = b2;
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b2.prev = bp;
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|
|
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return b2;
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};
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|
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// create a node and optionally link it with previous one (in a circular doubly linked list)
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|
|
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Phaser.EarCut.insertNode = function (i, x, y, last) {
|
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var p = new Phaser.EarCut.Node(i, x, y);
|
|
|
|
if (!last) {
|
|
p.prev = p;
|
|
p.next = p;
|
|
|
|
} else {
|
|
p.next = last.next;
|
|
p.prev = last;
|
|
last.next.prev = p;
|
|
last.next = p;
|
|
}
|
|
return p;
|
|
};
|
|
|
|
Phaser.EarCut.removeNode = function (p) {
|
|
p.next.prev = p.prev;
|
|
p.prev.next = p.next;
|
|
|
|
if (p.prevZ) p.prevZ.nextZ = p.nextZ;
|
|
if (p.nextZ) p.nextZ.prevZ = p.prevZ;
|
|
};
|
|
|
|
Phaser.EarCut.Node = function (i, x, y) {
|
|
// vertice index in coordinates array
|
|
this.i = i;
|
|
|
|
// vertex coordinates
|
|
this.x = x;
|
|
this.y = y;
|
|
|
|
// 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;
|
|
};
|
|
|
|
/* jshint ignore:end */
|