Foundry-VTT-Docker/resources/app/public/scripts/earcut-edges/earcut-edges.js

/* eslint-disable */
/**
 * This is a specialized version of earcut, updated to take into account links between outer edges and holes whenever possible.
 * Modified by Foundry LLC
 *
 * ISC License
 *
 * Copyright (c) 2016, Mapbox
 *
 * Permission to use, copy, modify, and/or distribute this software for any purpose
 * with or without fee is hereby granted, provided that the above copyright notice
 * and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
 * THIS SOFTWARE.
 */
(function() {

function earcutEdges(data, holeIndices) {
  const dim = 3;
  const hasHoles = holeIndices && holeIndices.length
  let outerLen = hasHoles ? holeIndices[0] * dim : data.length;
  let outerNode = linkedList(data, 0, outerLen, dim, true);
  const triangles = [];

  if ( !outerNode || outerNode.next === outerNode.prev ) return triangles;
  let minX, minY, maxX, maxY, x, y, z, invSize;
  if ( hasHoles ) outerNode = eliminateHoles(data, holeIndices, outerNode, dim);

  // if the shape is not too simple, we'll use z-order curve hash later; calculate polygon bbox
  if ( data.length > 240 ) {
    minX = maxX = data[0];
    minY = maxY = data[1];
    for ( let i = dim; i < outerLen; i += dim ) {
      x = data[i];
      y = data[i + 1];
      z = data[i + 2];
      if ( x < minX ) minX = x;
      if ( y < minY ) minY = y;
      if ( x > maxX ) maxX = x;
      if ( y > maxY ) maxY = y;
    }
    // minX, minY and invSize are later used to transform coords into integers for z-order calculation
    invSize = Math.max(maxX - minX, maxY - minY);
    invSize = invSize !== 0 ? 1 / invSize : 0;
  }

  earcutLinked(outerNode, triangles, dim, minX, minY, invSize);
  return triangles;
}

// create a circular doubly linked list from polygon points in the specified winding order
function linkedList(data, start, end, dim, clockwise) {
  let i, last;
  if ( clockwise === (signedArea(data, start, end, dim) > 0) ) {
    for ( i = start; i < end; i += dim ) last = insertNode(i, data[i], data[i + 1], data[i + 2], last);
  }
  else {
    for ( i = end - dim; i >= start; i -= dim ) last = insertNode(i, data[i], data[i + 1], data[i + 2], last);
  }
  if ( last && equals(last, last.next) ) {
    removeNode(last);
    last = last.next;
  }

  return last;
}

// eliminate colinear or duplicate points
function filterPoints(start, end) {
  if ( !start ) return start;
  if ( !end ) end = start;

  let p = start, again;
  do {
    again = false;
    if ( !p.steiner && (equals(p, p.next) || area(p.prev, p, p.next) === 0) ) {
      removeNode(p);
      p = end = p.prev;
      if ( p === p.next ) break;
      again = true;
    }
    else {
      p = p.next;
    }
  } while ( again || p !== end );

  return end;
}

// main ear slicing loop which triangulates a polygon (given as a linked list)
function earcutLinked(ear, triangles, dim, minX, minY, invSize, pass = 0, verifyEdges = true) {
  if ( !ear ) return;

  // interlink polygon nodes in z-order
  if ( !pass && invSize ) indexCurve(ear, minX, minY, invSize);

  let stop = ear, prev, next;

  // iterate through ears, slicing them one by one
  while ( ear.prev !== ear.next ) {
    prev = ear.prev;
    next = ear.next;

    if ( invSize ? isEarHashed(ear, minX, minY, invSize, verifyEdges) : isEar(ear, verifyEdges) ) {

      triangles.push(prev.i / dim);
      triangles.push(ear.i / dim);
      triangles.push(next.i / dim);

      removeNode(ear);

      // skipping the next vertex leads to less sliver triangles
      ear = next.next;
      stop = next.next;
      continue;
    }

    ear = next;

    // if we looped through the whole remaining polygon and can't find any more ears
    if ( ear === stop ) {
      // try filtering points and slicing again
      if ( !pass ) {
        earcutLinked(filterPoints(ear), triangles, dim, minX, minY, invSize, 1, verifyEdges);
      }
      else if ( pass === 1 ) {
        // if this didn't work, try curing all small self-intersections locally
        ear = cureLocalIntersections(filterPoints(ear), triangles, dim);
        earcutLinked(ear, triangles, dim, minX, minY, invSize, 2, false);
      }
      else if ( pass === 2 ) {
        splitEarcut(ear, triangles, dim, minX, minY, invSize);
      }
      break;
    }
  }
}

// check whether a polygon node forms a valid ear with adjacent nodes
function isEar(ear, verifyEdges) {
  let a = ear.prev, b = ear, c = ear.next;

  if ( (a.z === b.z) && (a.z === c.z) && (b.z === c.z) && verifyEdges ) return false;
  if ( area(a, b, c) >= 0 ) return false; // reflex, can't be an ear

  // now make sure we don't have other points inside the potential ear
  let p = ear.next.next;

  while ( p !== ear.prev ) {
    if ( pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) && area(p.prev, p, p.next) >= 0 ) return false;
    p = p.next;
  }
  return true;
}

function isEarHashed(ear, minX, minY, invSize, verifyEdges) {
  let a = ear.prev, b = ear, c = ear.next;

  if ( (a.z === b.z) && (a.z === c.z) && (b.z === c.z) && verifyEdges ) return false; // checking if edges depth are matching
  if ( area(a, b, c) >= 0 ) return false; // reflex, can't be an ear

  // triangle bbox; min & max are calculated like this for speed
  let minTX = a.x < b.x ? (a.x < c.x ? a.x : c.x) : (b.x < c.x ? b.x : c.x),
    minTY = a.y < b.y ? (a.y < c.y ? a.y : c.y) : (b.y < c.y ? b.y : c.y),
    maxTX = a.x > b.x ? (a.x > c.x ? a.x : c.x) : (b.x > c.x ? b.x : c.x),
    maxTY = a.y > b.y ? (a.y > c.y ? a.y : c.y) : (b.y > c.y ? b.y : c.y);

  // z-order range for the current triangle bbox;
  let minZ = zOrder(minTX, minTY, minX, minY, invSize), maxZ = zOrder(maxTX, maxTY, minX, minY, invSize);

  let p = ear.prevZ, n = ear.nextZ;

  // look for points inside the triangle in both directions
  while ( p && p.zc >= minZ && n && n.zc <= maxZ ) {
    if ( p !== ear.prev && p !== ear.next && pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) && area(p.prev, p, p.next) >= 0 ) return false;
    p = p.prevZ;

    if ( n !== ear.prev && n !== ear.next && pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, n.x, n.y) && area(n.prev, n, n.next) >= 0 ) return false;
    n = n.nextZ;
  }

  // look for remaining points in decreasing z-order
  while ( p && p.zc >= minZ ) {
    if ( p !== ear.prev && p !== ear.next && pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) && area(p.prev, p, p.next) >= 0 ) return false;
    p = p.prevZ;
  }

  // look for remaining points in increasing z-order
  while ( n && n.zc <= maxZ ) {
    if ( n !== ear.prev && n !== ear.next && pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, n.x, n.y) && area(n.prev, n, n.next) >= 0 ) return false;
    n = n.nextZ;
  }
  return true;
}

// go through all polygon nodes and cure small local self-intersections
function cureLocalIntersections(start, triangles, dim) {
  let p = start;
  do {
    let a = p.prev, b = p.next.next;
    if ( !equals(a, b) && intersects(a, p, p.next, b) && locallyInside(a, b)
      && locallyInside(b, a) && !((a.z === b.z) && (a.z === p.z) && (b.z === p.z)) ) {

      triangles.push(a.i / dim);
      triangles.push(p.i / dim);
      triangles.push(b.i / dim);

      // remove two nodes involved
      removeNode(p);
      removeNode(p.next);

      p = start = b;
    }
    p = p.next;
  } while ( p !== start );

  return filterPoints(p);
}

// try splitting polygon into two and triangulate them independently
function splitEarcut(start, triangles, dim, minX, minY, invSize) {
  // look for a valid diagonal that divides the polygon into two
  let a = start;
  do {
    let b = a.next.next;
    while ( b !== a.prev ) {
      if ( a.i !== b.i && isValidDiagonal(a, b) ) {
        // split the polygon in two by the diagonal
        let c = splitPolygon(a, b);

        // filter colinear points around the cuts
        a = filterPoints(a, a.next);
        c = filterPoints(c, c.next);

        // run earcut on each half
        earcutLinked(a, triangles, dim, minX, minY, invSize, false);
        earcutLinked(c, triangles, dim, minX, minY, invSize, false);
        return;
      }
      b = b.next;
    }
    a = a.next;
  } while ( a !== start );
}

// link every hole into the outer loop, producing a single-ring polygon without holes
function eliminateHoles(data, holeIndices, outerNode, dim) {
  let queue = [], i, len, start, end, list;
  for ( i = 0, len = holeIndices.length; i < len; i++ ) {
    start = holeIndices[i] * dim;
    end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;
    list = linkedList(data, start, end, dim, false);
    if ( list === list.next ) list.steiner = true;
    queue.push(getLeftmost(list));
  }
  queue.sort(compareX);

  // process holes from left to right
  for ( i = 0; i < queue.length; i++ ) {
    outerNode = eliminateHole(queue[i], outerNode);
    outerNode = filterPoints(outerNode, outerNode.next);
  }
  return outerNode;
}

function compareX(a, b) {
  return a.x - b.x;
}

// find a bridge between vertices that connects hole with an outer ring and and link it
function eliminateHole(hole, outerNode) {
  let bridge = findHoleBridge(hole, outerNode);
  if ( !bridge ) {
    return outerNode;
  }
  let bridgeReverse = splitPolygon(bridge, hole);
  // filter collinear points around the cuts
  let filteredBridge = filterPoints(bridge, bridge.next);
  filterPoints(bridgeReverse, bridgeReverse.next);

  // Check if input node was removed by the filtering
  return outerNode === bridge ? filteredBridge : outerNode;
}

// David Eberly's algorithm for finding a bridge between hole and outer polygon
function findHoleBridge(hole, outerNode) {
  let p = outerNode, hx = hole.x, hy = hole.y, qx = -Infinity, m;

  // find a segment intersected by a ray from the hole's leftmost point to the left;
  // segment's endpoint with lesser x will be potential connection point
  do {
    if ( hy <= p.y && hy >= p.next.y && p.next.y !== p.y ) {
      let x = p.x + (hy - p.y) * (p.next.x - p.x) / (p.next.y - p.y);
      if ( x <= hx && x > qx ) {
        qx = x;
        if ( x === hx ) {
          if ( hy === p.y ) return p;
          if ( hy === p.next.y ) return p.next;
        }
        m = p.x < p.next.x ? p : p.next;
      }
    }
    p = p.next;
  } while ( p !== outerNode );

  if ( !m ) return null;
  if ( hx === qx ) return m; // hole touches outer segment; pick leftmost endpoint

  // look for points inside the triangle of hole point, segment intersection and endpoint;
  // if there are no points found, we have a valid connection;
  // otherwise choose the point of the minimum angle with the ray as connection point
  let stop = m, mx = m.x, my = m.y, tanMin = Infinity, tan;
  p = m;

  do {
    if ( hx >= p.x && p.x >= mx && hx !== p.x && pointInTriangle(hy < my ? hx : qx, hy, mx, my, hy < my ? qx : hx, hy, p.x, p.y) ) {
      tan = Math.abs(hy - p.y) / (hx - p.x); // tangential
      if ( locallyInside(p, hole) && (tan < tanMin || (tan === tanMin && (p.x > m.x || (p.x === m.x && sectorContainsSector(m, p))))) ) {
        m = p;
        tanMin = tan;
      }
    }
    p = p.next;
  } while ( p !== stop );

  return m;
}

// whether sector in vertex m contains sector in vertex p in the same coordinates
function sectorContainsSector(m, p) {
  return area(m.prev, m, p.prev) < 0 && area(p.next, m, m.next) < 0;
}

// interlink polygon nodes in z-order
function indexCurve(start, minX, minY, invSize) {
  let p = start;
  do {
    if ( p.zc === null ) p.zc = zOrder(p.x, p.y, minX, minY, invSize);
    p.prevZ = p.prev;
    p.nextZ = p.next;
    p = p.next;
  } while ( p !== start );

  p.prevZ.nextZ = null;
  p.prevZ = null;

  sortLinked(p);
}

// Simon Tatham's linked list merge sort algorithm
// http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html
function sortLinked(list) {
  let 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 && (qSize === 0 || !q || p.zc <= q.zc) ) {
          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 inverse of the longer side of data bbox
function zOrder(x, y, minX, minY, invSize) {
  // coords are transformed into non-negative 15-bit integer range
  x = 32767 * (x - minX) * invSize;
  y = 32767 * (y - minY) * invSize;

  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(start) {
  let p = start, leftmost = start;
  do {
    if ( p.x < leftmost.x || (p.x === leftmost.x && p.y < leftmost.y) ) leftmost = p;
    p = p.next;
  } while ( p !== start );
  return leftmost;
}

// check if a point lies within a convex triangle
function pointInTriangle(ax, ay, bx, by, cx, cy, px, py) {
  return (cx - px) * (ay - py) - (ax - px) * (cy - py) >= 0 && (ax - px) * (by - py) - (bx - px) * (ay - py) >= 0 && (bx - px) * (cy - py) - (cx - px) * (by - py) >= 0;
}

// check if a diagonal between two polygon nodes is valid (lies in polygon interior)
function isValidDiagonal(a, b) {
  return a.next.i !== b.i && a.prev.i !== b.i && !intersectsPolygon(a, b) && // dones't intersect other edges
    (locallyInside(a, b) && locallyInside(b, a) && middleInside(a, b) && // locally visible
      (area(a.prev, a, b.prev) || area(a, b.prev, b)) || // does not create opposite-facing sectors
      equals(a, b) && area(a.prev, a, a.next) > 0 && area(b.prev, b, b.next) > 0); // special zero-length case
}

// signed area of a triangle
function area(p, q, r) {
  return (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y);
}

// check if two points are equal
function equals(p1, p2) {
  return p1.x === p2.x && p1.y === p2.y;
}

// check if two segments intersect
function intersects(p1, q1, p2, q2) {
  let o1 = sign(area(p1, q1, p2));
  let o2 = sign(area(p1, q1, q2));
  let o3 = sign(area(p2, q2, p1));
  let o4 = sign(area(p2, q2, q1));

  if ( o1 !== o2 && o3 !== o4 ) return true; // general case

  if ( o1 === 0 && onSegment(p1, p2, q1) ) return true; // p1, q1 and p2 are collinear and p2 lies on p1q1
  if ( o2 === 0 && onSegment(p1, q2, q1) ) return true; // p1, q1 and q2 are collinear and q2 lies on p1q1
  if ( o3 === 0 && onSegment(p2, p1, q2) ) return true; // p2, q2 and p1 are collinear and p1 lies on p2q2
  if ( o4 === 0 && onSegment(p2, q1, q2) ) return true; // p2, q2 and q1 are collinear and q1 lies on p2q2

  return false;
}

// for collinear points p, q, r, check if point q lies on segment pr
function onSegment(p, q, r) {
  return q.x <= Math.max(p.x, r.x) && q.x >= Math.min(p.x, r.x) && q.y <= Math.max(p.y, r.y) && q.y >= Math.min(p.y, r.y);
}

function sign(num) {
  return num > 0 ? 1 : num < 0 ? -1 : 0;
}

// check if a polygon diagonal intersects any polygon segments
function intersectsPolygon(a, b) {
  let p = a;
  do {
    if ( p.i !== a.i && p.next.i !== a.i && p.i !== b.i && p.next.i !== b.i && intersects(p, p.next, a, b) ) return true;
    p = p.next;
  } while ( p !== a );
  return false;
}

// check if a polygon diagonal is locally inside the polygon
function locallyInside(a, b) {
  return area(a.prev, a, a.next) < 0 ? area(a, b, a.next) >= 0 && area(a, a.prev, b) >= 0 : area(a, b, a.prev) < 0 || area(a, a.next, b) < 0;
}

// check if the middle point of a polygon diagonal is inside the polygon
function middleInside(a, b) {
  let p = a, inside = false, px = (a.x + b.x) / 2, py = (a.y + b.y) / 2;
  do {
    if ( ((p.y > py) !== (p.next.y > py)) && p.next.y !== p.y && (px < (p.next.x - p.x) * (py - p.y) / (p.next.y - p.y) + p.x) ) inside = !inside;
    p = p.next;
  } while ( p !== a );
  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) {
  let a2 = new Node(a.i, a.x, a.y, a.z), b2 = new Node(b.i, b.x, b.y, b.z), 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, x, y, z, last) {
  let p = new Node(i, x, y, z);

  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;
}

function removeNode(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;
}

function Node(i, x, y, z) {
  // vertex index in coordinates array
  this.i = i;

  // vertex coordinates
  this.x = x;
  this.y = y;
  this.z = z; // depth

  // previous and next vertex nodes in a polygon ring
  this.prev = null;
  this.next = null;

  // z-order curve value
  this.zc = null;

  // previous and next nodes in z-order
  this.prevZ = null;
  this.nextZ = null;

  // indicates whether this is a steiner point
  this.steiner = false;
}

// return a percentage difference between the polygon area and its triangulation area;
// used to verify correctness of triangulation
earcutEdges.deviation = function(data, holeIndices, dim, triangles) {
  let hasHoles = holeIndices && holeIndices.length;
  let outerLen = hasHoles ? holeIndices[0] * dim : data.length;
  let polygonArea = Math.abs(signedArea(data, 0, outerLen, dim));
  if ( hasHoles ) {
    for ( let i = 0, len = holeIndices.length; i < len; i++ ) {
      let start = holeIndices[i] * dim;
      let end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;
      polygonArea -= Math.abs(signedArea(data, start, end, dim));
    }
  }
  let trianglesArea = 0;
  for ( let i = 0; i < triangles.length; i += 3 ) {
    let a = triangles[i] * dim;
    let b = triangles[i + 1] * dim;
    let c = triangles[i + 2] * dim;
    trianglesArea += Math.abs((data[a] - data[c]) * (data[b + 1] - data[a + 1]) - (data[a] - data[b]) * (data[c + 1] - data[a + 1]));
  }
  return polygonArea === 0 && trianglesArea === 0 ? 0 : Math.abs((trianglesArea - polygonArea) / polygonArea);
};

function signedArea(data, start, end, dim) {
  let sum = 0;
  for ( let i = start, j = end - dim; i < end; i += dim ) {
    sum += (data[j] - data[i]) * (data[i + 1] + data[j + 1]);
    j = i;
  }
  return sum;
}

// turn a polygon in a multi-dimensional array form (e.g. as in GeoJSON) into a form Earcut accepts
earcutEdges.flatten = function(data) {
  let dim = data[0][0].length, result = {vertices: [], holes: [], dimensions: dim}, holeIndex = 0;

  for ( let i = 0; i < data.length; i++ ) {
    for ( let j = 0; j < data[i].length; j++ ) {
      for ( let d = 0; d < dim; d++ ) result.vertices.push(data[i][j][d]);
    }
    if ( i > 0 ) {
      holeIndex += data[i - 1].length;
      result.holes.push(holeIndex);
    }
  }
  return result;
};

globalThis.earcut = {earcutEdges};
})();