Merge pull request AcademySoftwareFoundation#1893 from apradhana/fix_…

…vec3h_regression

Bug fix: the half type doesn't satisfy std::is_arithmetic so the operator doesn't get instantiated

openvdb/openvdb/math/Vec3.h

@@ -594,6 +594,20 @@ Abs(const Vec3<T>& v)
     return Vec3<T>(Abs(v[0]), Abs(v[1]), Abs(v[2]));
 }
 
+template<>
+inline auto cwiseAdd(const Vec3<math::internal::half>& v, const float s)
+{
+    Vec3<math::internal::half> out;
+    const math::internal::half* ip = v.asPointer();
+    math::internal::half* op = out.asPointer();
+    for (unsigned i = 0; i < 3; ++i, ++op, ++ip) {
+        OPENVDB_NO_TYPE_CONVERSION_WARNING_BEGIN
+        *op = *ip + s;
+        OPENVDB_NO_TYPE_CONVERSION_WARNING_END
+    }
+    return out;
+}
+
 /// Orthonormalize vectors v1, v2 and v3 and store back the resulting
 /// basis e.g.   Vec3d::orthonormalize(v1,v2,v3);
 template <typename T>