Check for NANs when computing distances to avoid infinite loops

with bad input geometry.

Rename the computeDistance to updateDistance to better reflect
its behaviour.

Signed-off-by: jlait <[email protected]>

Author: jmlait

openvdb/tools/MeshToVolume.h

@@ -2137,7 +2137,10 @@ class VoxelizePolygons
         ijk = Coord::floor(prim.a);
         coordList.push_back(ijk);
 
-        computeDistance(ijk, prim, data);
+        // The first point may not be quite in bounds, and rely
+        // on one of the neighbours to have the first valid seed,
+        // so we cannot early-exit here.
+        updateDistance(ijk, prim, data);
 
         unsigned char primId = data.getNewPrimId();
         data.primIdAcc.setValueOnly(ijk, primId);
@@ -2150,13 +2153,13 @@ class VoxelizePolygons
                 nijk = ijk + util::COORD_OFFSETS[i];
                 if (primId != data.primIdAcc.getValue(nijk)) {
                     data.primIdAcc.setValueOnly(nijk, primId);
-                    if(computeDistance(nijk, prim, data)) coordList.push_back(nijk);
+                    if(updateDistance(nijk, prim, data)) coordList.push_back(nijk);
                 }
             }
         }
     }
 
-    static bool computeDistance(const Coord& ijk, const Triangle& prim, VoxelizationDataType& data)
+    static bool updateDistance(const Coord& ijk, const Triangle& prim, VoxelizationDataType& data)
     {
         Vec3d uvw, voxelCenter(ijk[0], ijk[1], ijk[2]);
 
@@ -2165,6 +2168,11 @@ class VoxelizePolygons
         const ValueType dist = ValueType((voxelCenter -
             closestPointOnTriangleToPoint(prim.a, prim.c, prim.b, voxelCenter, uvw)).lengthSqr());
 
+        // Either the points may be NAN, or they could be far enough from
+        // the origin that computing distance fails.
+        if (std::isnan(dist))
+            return false;
+
         const ValueType oldDist = data.distAcc.getValue(ijk);
 
         if (dist < oldDist) {