supported unsigned distance

Former-commit-id: 83c86755e50b5ab05a85467b2392e32d9395acbb

include/igl/cgal/signed_distance_isosurface.cpp

@@ -65,6 +65,9 @@ IGL_INLINE bool igl::signed_distance_isosurface(
   {
     default:
       assert(false && "Unknown SignedDistanceType");
+    case SIGNED_DISTANCE_TYPE_UNSIGNED:
+      // do nothing
+      break;
     case SIGNED_DISTANCE_TYPE_DEFAULT:
     case SIGNED_DISTANCE_TYPE_WINDING_NUMBER:
       hier.set_mesh(IV,IF);
@@ -96,6 +99,16 @@ IGL_INLINE bool igl::signed_distance_isosurface(
   {
     default:
       assert(false && "Unknown SignedDistanceType");
+    case SIGNED_DISTANCE_TYPE_UNSIGNED:
+      fun = 
+        [&tree,&IV,&IF,&level](const Point_3 & q) -> FT
+        {
+          int i;
+          RowVector3d c;
+          const double sd = tree.squared_distance(
+            IV,IF,RowVector3d(q.x(),q.y(),q.z()),i,c);
+          return sd-level;
+        };
     case SIGNED_DISTANCE_TYPE_DEFAULT:
     case SIGNED_DISTANCE_TYPE_WINDING_NUMBER:
       fun = 

include/igl/cgal/signed_distance_isosurface.h

@@ -18,7 +18,7 @@ namespace igl
   // Inputs:
   //   IV  #IV by 3 list of input mesh vertex positions
   //   IF  #IF by 3 list of input triangle indices
-  //   level  iso-level to contour (e.g. 0)
+  //   level  iso-level to contour in world coords, negative is inside.
   //   angle_bound  lower bound on triangle angles (mesh quality) (e.g. 28)
   //   radius_bound  upper bound on triangle size (mesh density?) (e.g. 0.02)
   //   distance_bound  cgal mysterious parameter (mesh density?) (e.g. 0.01)