fix steiner points, better tests

mapbox · May 11, 2015 · 68da53f · 68da53f
1 parent a169519
commit 68da53f
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Showing 3 changed files with 38 additions and 24 deletions.
diff --git a/src/earcut.js b/src/earcut.js
@@ -65,14 +65,12 @@ function linkedList(data, start, end, dim, clockwise) {
 function filterPoints(data, start, end) {
     if (!end) end = start;
 
-    if (start.next === start) return start;
-
     var node = start,
         again;
     do {
         again = false;
 
-        if (equals(data, node.i, node.next.i) || orient(data, node.prev.i, node.i, node.next.i) === 0) {
+        if (!node.steiner && (equals(data, node.i, node.next.i) || orient(data, node.prev.i, node.i, node.next.i) === 0)) {
 
             // remove node
             node.prev.next = node.next;
@@ -326,7 +324,9 @@ function eliminateHoles(data, holeIndices, outerNode, dim) {
     for (i = 0, len = holeIndices.length; i < len; i++) {
         start = holeIndices[i] * dim;
         end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;
-        list = filterPoints(data, linkedList(data, start, end, dim, false));
+        list = linkedList(data, start, end, dim, false);
+        if (list === list.next) list.steiner = true;
+        list = filterPoints(data, list);
         if (list) queue.push(getLeftmost(data, list));
     }
 
@@ -336,19 +336,19 @@ function eliminateHoles(data, holeIndices, outerNode, dim) {
 
     // process holes from left to right
     for (i = 0; i < queue.length; i++) {
-        eliminateHole(data, queue[i], outerNode, queue[i] === queue[i].next);
+        eliminateHole(data, queue[i], outerNode);
         outerNode = filterPoints(data, outerNode, outerNode.next);
     }
 
     return outerNode;
 }
 
 // find a bridge between vertices that connects hole with an outer ring and and link it
-function eliminateHole(data, holeNode, outerNode, isSteinerPoint) {
+function eliminateHole(data, holeNode, outerNode) {
     outerNode = findHoleBridge(data, holeNode, outerNode);
     if (outerNode) {
         var b = splitPolygon(outerNode, holeNode);
-        if (!isSteinerPoint) filterPoints(data, b, b.next);
+        filterPoints(data, b, b.next);
     }
 }
 
@@ -656,4 +656,7 @@ function Node(i) {
     // previous and next nodes in z-order
     this.prevZ = null;
     this.nextZ = null;
+
+    // indicates whether this is a steiner point
+    this.steiner = false;
 }
diff --git a/test/fixtures/steiner.json b/test/fixtures/steiner.json
@@ -0,0 +1,7 @@
+[
+[[0,0],[100,0],[100,100],[0,100]],
+[[50,50]],
+[[30,40]],
+[[70,60]],
+[[20,70]]
+]
diff --git a/test/test.js b/test/test.js
@@ -5,20 +5,21 @@ var test = require('tape'),
     fs = require('fs'),
     path = require('path');
 
-areaTest('building');
-areaTest('dude');
-areaTest('water', 0.0019);
-areaTest('water2');
-areaTest('water3');
-areaTest('water3b');
-areaTest('water4');
-areaTest('water-huge', 0.0015);
-areaTest('water-huge2', 0.0020);
-areaTest('degenerate');
-areaTest('bad-hole', 0.0420);
-areaTest('empty-square');
-areaTest('issue16');
-areaTest('issue17');
+areaTest('building', 12);
+areaTest('dude', 106);
+areaTest('water', 2482, 0.0019);
+areaTest('water2', 1211);
+areaTest('water3', 197);
+areaTest('water3b', 25);
+areaTest('water4', 705);
+areaTest('water-huge', 5162, 0.0015);
+areaTest('water-huge2', 4456, 0.0020);
+areaTest('degenerate', 0);
+areaTest('bad-hole', 34, 0.0420);
+areaTest('empty-square', 0);
+areaTest('issue16', 12);
+areaTest('issue17', 11);
+areaTest('steiner', 9);
 
 test('indices-2d', function (t) {
     var indices = earcut([10, 0, 0, 50, 60, 60, 70, 10]);
@@ -32,13 +33,11 @@ test('indices-3d', function (t) {
     t.end();
 });
 
-function areaTest(filename, expectedDeviation) {
+function areaTest(filename, expectedTriangles, expectedDeviation) {
     expectedDeviation = expectedDeviation || 1e-14;
 
     test(filename, function (t) {
 
-        console.log(filename);
-
         var data = JSON.parse(fs.readFileSync(path.join(__dirname, '/fixtures/' + filename + '.json'))),
             data2 = flattenData(data),
             vertices = data2.vertices,
@@ -60,6 +59,11 @@ function areaTest(filename, expectedDeviation) {
         t.ok(deviation < expectedDeviation,
             'deviation ' + formatPercent(deviation) + ' is less than ' + formatPercent(expectedDeviation));
 
+        if (expectedTriangles) {
+            t.ok(indices.length / 3 === expectedTriangles, (indices.length / 3) + ' triangles when expected ' +
+                expectedTriangles);
+        }
+
         t.end();
     });
 }