more convenience

src/polymesh/algorithms/properties.hh

@@ -114,6 +114,11 @@ Scalar angle_sum(vertex_handle v, vertex_attribute<Vec3> const& position);
 template <class Vec3, class Scalar = typename field_3d<Vec3>::Scalar>
 Scalar angle_defect(vertex_handle v, vertex_attribute<Vec3> const& position);
 
+/// efficiently computes the voronoi areas of all vertices
+/// assumes triangle meshes for now
+template <class Vec3, class Scalar = typename field_3d<Vec3>::Scalar>
+vertex_attribute<Scalar> vertex_voronoi_areas(Mesh const& m, vertex_attribute<Vec3> const& position);
+
 /// ======== IMPLEMENTATION ========
 
 inline bool is_boundary(vertex_handle v) { return v.is_boundary(); }
@@ -340,4 +345,20 @@ Vec3 bary_interpolate(face_handle f, Vec3 bary, vertex_attribute<Vec3> const& po
     auto v2 = h.next().next().vertex_to()[position];
     return v0 * bary[0] + v1 * bary[1] + v2 * bary[2];
 }
+
+template <class Vec3, class Scalar>
+vertex_attribute<Scalar> vertex_voronoi_areas(Mesh const& m, vertex_attribute<Vec3> const& position)
+{
+    vertex_attribute<Scalar> areas = m.vertices().make_attribute_with_default(Scalar(0));
+
+    for (auto f : m.faces())
+    {
+        Scalar a = face_area(f, position);
+        int v_cnt = f.vertices().size();
+        for (auto v : f.vertices())
+            areas[v] += a / v_cnt;
+    }
+
+    return areas;
+}
 }

src/polymesh/attributes.hh

@@ -63,6 +63,9 @@ public:
     /// applies to given function to each attribute entry (calls f(e))
     template <class FuncT>
     void apply(FuncT&& f);
+    /// sets each attribute to f(primitive)
+    template <class FuncT>
+    void compute(FuncT&& f);
 
     /// copies as much data as possible from the given vector
     void copy_from(std::vector<AttrT> const& data);
@@ -74,6 +77,10 @@ public:
     /// Saves ALL data into a vector (includes possibly removed ones)
     std::vector<AttrT> to_vector() const;
 
+    // public ctor
+public:
+    primitive_attribute(Mesh const& mesh, AttrT const& def_value = AttrT());
+
     // data
 protected:
     attribute_data<AttrT> mData;

src/polymesh/impl/impl_attributes.hh

@@ -283,6 +283,11 @@ void primitive_attribute_base<tag>::deregister_attr()
     }
 }
 
+template <class tag, class AttrT>
+primitive_attribute<tag, AttrT>::primitive_attribute(Mesh const &mesh, const AttrT &def_value) : primitive_attribute(&mesh, def_value)
+{
+}
+
 template <class tag, class AttrT>
 primitive_attribute<tag, AttrT>::primitive_attribute(const Mesh *mesh, const AttrT &def_value)
   : primitive_attribute_base<tag>(mesh), mDefaultValue(def_value)
@@ -330,4 +335,14 @@ void primitive_attribute<tag, AttrT>::apply(FuncT &&f)
     for (auto i = 0; i < s; ++i)
         f(d[i]);
 }
+
+template <class tag, class AttrT>
+template <class FuncT>
+void primitive_attribute<tag, AttrT>::compute(FuncT &&f)
+{
+    auto s = size();
+    auto d = data();
+    for (auto h : primitive<tag>::valid_collection_of(*this->mMesh))
+        d[(int)h] = f(h);
+}
 }