From c4cae2a29a7df82f4f1b43543e6b22b642a275b0 Mon Sep 17 00:00:00 2001
From: Marius Kintel <marius@kintel.net>
Date: Thu, 2 May 2013 22:11:23 -0400
Subject: Fixes crash if hull's children are empty objects. Fixes #345


diff --git a/src/CGALEvaluator.cc b/src/CGALEvaluator.cc
index 6ad9e4d..d0140fa 100644
--- a/src/CGALEvaluator.cc
+++ b/src/CGALEvaluator.cc
@@ -141,6 +141,9 @@ CGAL_Nef_polyhedron CGALEvaluator::applyHull(const CgaladvNode &node)
 			PRINT("WARNING: hull() does not support mixing 2D and 3D objects.");
 			continue;
 		}
+		if (chN.isNull()) { // If one of the children evaluated to a null object
+			continue;
+		}		
 		if (dim == 2) {
 			CGAL_Nef_polyhedron2::Explorer explorer = chN.p2->explorer();
 			BOOST_FOREACH(const CGAL_Nef_polyhedron2::Explorer::Vertex &vh, 
diff --git a/testdata/scad/features/hull2-tests.scad b/testdata/scad/features/hull2-tests.scad
index e656e6a..82b56e4 100644
--- a/testdata/scad/features/hull2-tests.scad
+++ b/testdata/scad/features/hull2-tests.scad
@@ -31,7 +31,15 @@ module hull2dForLoop() {
   }
 }
 
+module hull2null() {
+  hull() {
+    square(0);
+    circle(0);
+  }
+}
+
 convex2dHole();
 translate([40,0,0]) convex2dSimple();
 translate([0,-20,0]) concave2dSimple();
 translate([30,-25,0]) hull2dForLoop();
+hull2null();
\ No newline at end of file
diff --git a/testdata/scad/features/hull3-tests.scad b/testdata/scad/features/hull3-tests.scad
index e3fc8e7..0f48b8f 100644
--- a/testdata/scad/features/hull3-tests.scad
+++ b/testdata/scad/features/hull3-tests.scad
@@ -26,3 +26,12 @@ translate([-5,-5,-5]) {
     }
   }
 }
+
+module hull3null() {
+  hull() {
+    cube(0);
+    sphere(0);
+  }
+}
+hull3null();
+
diff --git a/tests/regression/dumptest/hull2-tests-expected.txt b/tests/regression/dumptest/hull2-tests-expected.txt
index e4c5a5b..c14282f 100644
--- a/tests/regression/dumptest/hull2-tests-expected.txt
+++ b/tests/regression/dumptest/hull2-tests-expected.txt
@@ -56,4 +56,10 @@
 			}
 		}
 	}
+	group() {
+		hull() {
+			square(size = [0, 0], center = false);
+			circle($fn = 0, $fa = 12, $fs = 2, r = 0);
+		}
+	}
 
diff --git a/tests/regression/dumptest/hull3-tests-expected.txt b/tests/regression/dumptest/hull3-tests-expected.txt
index 4c05e2c..f8def3b 100644
--- a/tests/regression/dumptest/hull3-tests-expected.txt
+++ b/tests/regression/dumptest/hull3-tests-expected.txt
@@ -27,4 +27,10 @@
 			}
 		}
 	}
+	group() {
+		hull() {
+			cube(size = [0, 0, 0], center = false);
+			sphere($fn = 0, $fa = 12, $fs = 2, r = 0);
+		}
+	}
 
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