fix #17 (another edge case)

README.md

@@ -90,6 +90,10 @@ npm test
 
 #### Changelog
 
+##### 1.4.2 (Mar 18, 2015)
+
+- Fixed another rare edge case with a tiny hole in a huge polygon.
+
 ##### 1.4.1 (Mar 17, 2015)
 
 - Fixed a rare edge case that led to incomplete triangulation.

src/earcut.js

@@ -327,7 +327,7 @@ function splitEarcut(start, triangles, minX, minY, size) {
     do {
         var b = a.next.next;
         while (b !== a.prev) {
-            if (isValidDiagonal(a, b)) {
+            if (a.p !== b.p && isValidDiagonal(a, b)) {
                 // split the polygon in two by the diagonal
                 var c = splitPolygon(a, b);
 

test/fixtures/issue17.json

@@ -0,0 +1,13 @@
+[
+ [[-20037508.34,19971868.877628453,0],
+  [-20037508.34,-19971868.877628453,0],
+  [20037508.34,-19971868.877628453,0],
+  [20037508.34,19971868.877628453,0]],
+ [[537637.6007702783,5907542.234420554,0],
+  [539500.1483225027,5905165.501947839,0],
+  [538610.3146341922,5905217.430281373,0],
+  [538040.6306361248,5906132.0755739985,0],
+  [538068.958329954,5906571.138846622,0],
+  [537711.0379352621,5906645.06648362,0],
+  [537629.886026485,5907533.69114742,0]]
+]

test/test.js

@@ -19,6 +19,7 @@ areaTest('degenerate');
 areaTest('bad-hole', 0.0420);
 areaTest('empty-square');
 areaTest('issue16');
+areaTest('issue17');
 
 indicesCreationTest('indices-2d');
 indicesCreationTest('indices-3d');