Added a test to check in the point to face distance computation to manage the case of degenerated faces. Now correctly resort to distance point to segment.

vcg/simplex/face/distance.h

@@ -62,6 +62,7 @@ created
 
 #include <vcg/math/base.h>
 #include <vcg/space/point3.h>
+#include <vcg/space/segment3.h>
 
 
 namespace vcg {
@@ -310,9 +311,23 @@ namespace vcg {
 				#ifndef NDEBUG
 				static int staticCnt=0; // small piece of code that sometime check that face normals are really normalized
 				if((staticCnt++%100)==0) 
-						assert(f.cN().SquaredNorm() > 0.9999 && f.cN().SquaredNorm()<1.0001); // if you get this assert you have forgot to make a UpdateNormals::PerFaceNormalized(m)
+            assert((f.cN().SquaredNorm() ==0) || (f.cN().SquaredNorm() > 0.9999 && f.cN().SquaredNorm()<1.0001)); // if you get this assert you have forgot to make a UpdateNormals::PerFaceNormalized(m)
-
         #endif
+
+        if(f.cN()==Point3<ScalarType>(0,0,0)) // to correctly manage the case of degenerate triangles we consider them as segments.
+        {
+            Box3<ScalarType> bb;
+            f.GetBBox(bb);
+            Segment3<ScalarType> degenTri(bb.min,bb.max);
+            Point3<ScalarType> closest= ClosestPoint( degenTri, q );
+            ScalarType d = Distance(closest, q);
+            if( d>dist || d<-dist )			// Risultato peggiore: niente di fatto
+                      return false;
+            dist=d;
+            p=closest;
+            return true;
+        }
+
 				Plane3<ScalarType> fPlane;
 				fPlane.Init(f.cP(0),f.cN());
         const ScalarType EPS = ScalarType( 0.000001);