Skip to content

Commit

Permalink
Fix bug mapbox#74
Browse files Browse the repository at this point in the history 
Only `water-huge2` failed .
the log says : 
```
not ok 18 4464 triangles when expected 4461
```

I think maybe  something is wrong in the test-case.
  • Loading branch information
@finscn
finscn authored Dec 9, 2017
1 parent 41ab1e1 commit 8605515
Showing 1 changed file with 71 additions and 28 deletions.
99 changes: 71 additions & 28 deletions src/earcut.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ function earcut(data, holeIndices, dim) {

var hasHoles = holeIndices && holeIndices.length,
outerLen = hasHoles ? holeIndices[0] * dim : data.length,
outerNode = linkedList(data, 0, outerLen, dim, true),
outerNode = linkedList(data, 0, outerLen, dim, true, null),
triangles = [];

if (!outerNode) return triangles;
Expand Down Expand Up @@ -42,19 +42,27 @@ function earcut(data, holeIndices, dim) {
return triangles;
}

// create a circular doubly linked list from polygon points in the specified winding order
function linkedList(data, start, end, dim, clockwise) {
// Create a circular doubly linked list from polygon points in the specified winding order.
// holeId is used to identify which polygons（holes）the points belong to.
function linkedList(data, start, end, dim, clockwise, holeId) {
var 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], last);
for (i = start; i < end; i += dim) {
last = insertNode(i, data[i], data[i + 1], last);
last.holeId = holeId;
}
} else {
for (i = end - dim; i >= start; i -= dim) last = insertNode(i, data[i], data[i + 1], last);
for (i = end - dim; i >= start; i -= dim) {
last = insertNode(i, data[i], data[i + 1], last);
last.holeId = holeId;
}
}

if (last && equals(last, last.next)) {
removeNode(last);
last = last.next;
last.holeId = holeId;
}

return last;
Expand All @@ -70,12 +78,32 @@ function filterPoints(start, end) {
do {
again = false;

if (!p.steiner && (equals(p, p.next) || area(p.prev, p, p.next) === 0)) {
var prevHole = p.prev.holeId;
var currentHole = p.holeId;
var nextHole = p.next.holeId;

// Don't remove p , if `p.prev, p & p.next` don't belong to the same polygon(hole).

var toRemove = false;

if (!p.steiner) {
if (equals(p, p.next) || equals(p.prev, p)) {
toRemove = true;
} else if (area(p.prev, p, p.next) === 0) {
toRemove = true;
if (prevHole && nextHole && prevHole !== nextHole && prevHole === currentHole) {
toRemove = false;
}
}
}

if (toRemove) {
removeNode(p);
p = end = p.prev;
if (p === p.next) break;
if (p === p.next) {
break;
}
again = true;

} else {
p = p.next;
}
Expand All @@ -98,8 +126,9 @@ function earcutLinked(ear, triangles, dim, minX, minY, invSize, pass) {
while (ear.prev !== ear.next) {
prev = ear.prev;
next = ear.next;
var _isEar = isEar(ear);

if (invSize ? isEarHashed(ear, minX, minY, invSize) : isEar(ear)) {
if (invSize ? isEarHashed(ear, minX, minY, invSize) : _isEar) {
// cut off the triangle
triangles.push(prev.i / dim);
triangles.push(ear.i / dim);
Expand All @@ -122,12 +151,12 @@ function earcutLinked(ear, triangles, dim, minX, minY, invSize, pass) {
if (!pass) {
earcutLinked(filterPoints(ear), triangles, dim, minX, minY, invSize, 1);

// if this didn't work, try curing all small self-intersections locally
// if this didn't work, try curing all small self-intersections locally
} else if (pass === 1) {
ear = cureLocalIntersections(ear, triangles, dim);
earcutLinked(ear, triangles, dim, minX, minY, invSize, 2);

// as a last resort, try splitting the remaining polygon into two
// as a last resort, try splitting the remaining polygon into two
} else if (pass === 2) {
splitEarcut(ear, triangles, dim, minX, minY, invSize);
}
Expand All @@ -143,14 +172,18 @@ function isEar(ear) {
b = ear,
c = ear.next;

if (area(a, b, c) >= 0) return false; // reflex, can't be an ear
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
var 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;
area(p.prev, p, p.next) >= 0) {
return false;
}
p = p.next;
}

Expand Down Expand Up @@ -251,12 +284,14 @@ function splitEarcut(start, triangles, dim, minX, minY, invSize) {
// link every hole into the outer loop, producing a single-ring polygon without holes
function eliminateHoles(data, holeIndices, outerNode, dim) {
var queue = [],
i, len, start, end, list;
i, len, start, end, list, holeId;

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);

holeId = i + 1; // ensure holeId != 0 ;
list = linkedList(data, start, end, dim, false, holeId);
if (list === list.next) list.steiner = true;
queue.push(getLeftmost(list));
}
Expand Down Expand Up @@ -328,7 +363,7 @@ function findHoleBridge(hole, outerNode) {

while (p !== stop) {
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)) {
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

Expand Down Expand Up @@ -447,14 +482,15 @@ function getLeftmost(start) {
// 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;
(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) &&
locallyInside(a, b) && locallyInside(b, a) && middleInside(a, b);
var rs = a.next.i !== b.i && a.prev.i !== b.i && !intersectsPolygon(a, b) &&
locallyInside(a, b) && locallyInside(b, a) && middleInside(a, b);
return rs;
}

// signed area of a triangle
Expand All @@ -472,15 +508,15 @@ function intersects(p1, q1, p2, q2) {
if ((equals(p1, q1) && equals(p2, q2)) ||
(equals(p1, q2) && equals(p2, q1))) return true;
return area(p1, q1, p2) > 0 !== area(p1, q1, q2) > 0 &&
area(p2, q2, p1) > 0 !== area(p2, q2, q1) > 0;
area(p2, q2, p1) > 0 !== area(p2, q2, q1) > 0;
}

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

Expand All @@ -502,7 +538,7 @@ function middleInside(a, b) {
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))
(px < (p.next.x - p.x) * (py - p.y) / (p.next.y - p.y) + p.x))
inside = !inside;
p = p.next;
} while (p !== a);
Expand All @@ -518,6 +554,9 @@ function splitPolygon(a, b) {
an = a.next,
bp = b.prev;

a2.holeId = a.holeId;
b2.holeId = b.holeId;

a.next = b;
b.prev = a;

Expand Down Expand Up @@ -583,7 +622,7 @@ function Node(i, x, y) {

// return a percentage difference between the polygon area and its triangulation area;
// used to verify correctness of triangulation
earcut.deviation = function (data, holeIndices, dim, triangles) {
earcut.deviation = function(data, holeIndices, dim, triangles) {
var hasHoles = holeIndices && holeIndices.length;
var outerLen = hasHoles ? holeIndices[0] * dim : data.length;

Expand Down Expand Up @@ -620,10 +659,14 @@ function signedArea(data, start, end, dim) {
}

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

for (var i = 0; i < data.length; i++) {
for (var j = 0; j < data[i].length; j++) {
Expand Down

0 comments on commit 8605515

Please sign in to comment.