From d4efa20e8f3d98cc24c824d4367d55e44ecc3a6f Mon Sep 17 00:00:00 2001
From: LinJiarui <jlee686@gmail.com>
Date: Thu, 5 Mar 2015 21:56:45 +0800
Subject: [PATCH] fix csg build

resolve the following issue:
when build 2 or more coplanar polygons, the original method maybe split all the polygons into the front node (or the back node), thus leads to stackoverflow.
---
 csg.js | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/csg.js b/csg.js
index 17b7a2f..0da992a 100644
--- a/csg.js
+++ b/csg.js
@@ -578,10 +578,17 @@ CSG.Node.prototype = {
   // (no heuristic is used to pick a good split).
   build: function(polygons) {
     if (!polygons.length) return;
-    if (!this.plane) this.plane = polygons[0].plane.clone();
+    var myPolygon;
+    if (!this.plane) {
+      myPolygon = polygons[0];
+      this.plane = polygons[0].plane.clone();
+      this.polygons.push(myPolygon);
+    }
     var front = [], back = [];
     for (var i = 0; i < polygons.length; i++) {
-      this.plane.splitPolygon(polygons[i], this.polygons, this.polygons, front, back);
+      if (polygons !== myPolygon){
+        this.plane.splitPolygon(polygons[i], this.polygons, this.polygons, front, back);
+      }
     }
     if (front.length) {
       if (!this.front) this.front = new CSG.Node();