fix Eberly-3 hole algorithm case, ref #56

src/earcut.js

@@ -299,6 +299,10 @@ function findHoleBridge(hole, outerNode) {
             var 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;
             }
         }
@@ -307,7 +311,7 @@ function findHoleBridge(hole, outerNode) {
 
     if (!m) return null;
 
-    if (hole.x === m.x) return m.prev; // hole touches outer segment; pick lower endpoint
+    if (hx === qx) return m.prev; // hole touches outer segment; pick lower 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;

test/fixtures/eberly-3.json

@@ -0,0 +1 @@
+[[[2328,2408],[2328,2472],[2344,2472],[2344,2432],[2384,2448],[2384,2536],[2408,2552],[2448,2544],[2456,2560],[2496,2544],[2480,2624],[2456,2664],[2424,2680],[2400,2768],[2376,2768],[2368,2704],[2336,2704],[2264,2784],[2216,2784],[2200,2760],[2168,2760],[2152,2744],[2128,2744],[2128,2784],[2072,2768],[2032,2720],[2000,2720],[2000,2688],[1936,2696],[1920,2736],[1888,2728],[1896,2696],[1928,2688],[1928,2664],[1896,2664],[1896,2640],[1912,2632],[1872,2608],[1888,2576],[2056,2576],[2088,2600],[2184,2608],[2216,2632],[2256,2624],[2248,2600],[2216,2592],[2192,2560],[2120,2576],[2072,2544],[2096,2544],[2080,2520],[2080,2488],[2096,2480],[2080,2448],[2096,2432],[2176,2496],[2200,2488],[2224,2528],[2248,2528],[2240,2488],[2256,2472],[2280,2480],[2264,2416],[2272,2392],[2328,2408]],[[2320,2608],[2304,2640],[2312,2664],[2360,2632],[2352,2608],[2320,2608]],[[1912,2632],[1936,2632],[1936,2616],[1912,2608],[1912,2632]]]

test/test.js

@@ -30,6 +30,7 @@ areaTest('touching-holes', 57);
 areaTest('hole-touching-outer', 77);
 areaTest('hilbert', 1024);
 areaTest('issue45', 10);
+areaTest('eberly-3', 73);
 areaTest('eberly-6', 1429);
 areaTest('issue52', 109);