From 0aec75be3949617033a5e3c44dc07dad371942ce Mon Sep 17 00:00:00 2001
From: malomo <luigi.malomo@isti.cnr.it>
Date: Wed, 23 Mar 2016 17:08:22 +0000
Subject: [PATCH] added option for computing biharmonic field

---
 vcg/complex/algorithms/harmonic.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/vcg/complex/algorithms/harmonic.h b/vcg/complex/algorithms/harmonic.h
index e7f9b040..73fe5da7 100644
--- a/vcg/complex/algorithms/harmonic.h
+++ b/vcg/complex/algorithms/harmonic.h
@@ -55,7 +55,7 @@ public:
      * @note the algorithm has unexpected behavior if the mesh contains unreferenced vertices.
      */
     template <typename ACCESSOR>
-    static bool ComputeScalarField(MeshType & m, const ConstraintVec & constraints, ACCESSOR field)
+    static bool ComputeScalarField(MeshType & m, const ConstraintVec & constraints, ACCESSOR field, bool biharmonic = false)
     {
         typedef Eigen::SparseMatrix<CoeffScalar> SpMat;  // sparse matrix type
         typedef Eigen::Triplet<CoeffScalar>      Triple; // triplet type to fill the matrix
@@ -115,6 +115,13 @@ public:
         }
         laplaceMat.setFromTriplets(coeffs.begin(), coeffs.end());
 
+        if (biharmonic)
+        {
+            SpMat lap_t = laplaceMat;
+            lap_t.transpose();
+            laplaceMat = lap_t * laplaceMat;
+        }
+
 
         // Setting the constraints
         const CoeffScalar alpha = pow(10.0, 8.0); // penalty factor alpha