Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/normal_derivative.h

@@ -0,0 +1,44 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+// 
+// Copyright (C) 2015 Alec Jacobson <alecjacobson@gmail.com>
+// 
+// This Source Code Form is subject to the terms of the Mozilla Public License 
+// v. 2.0. If a copy of the MPL was not distributed with this file, You can 
+// obtain one at http://mozilla.org/MPL/2.0/.
+#ifndef IGL_NORMAL_DERIVATIVE_H
+#define IGL_NORMAL_DERIVATIVE_H
+#include "igl_inline.h"
+
+#include <Eigen/Core>
+#include <Eigen/Sparse>
+namespace igl 
+{
+  // NORMAL_DERIVATIVE Computes the directional derivative **normal** to
+  // **all** (half-)edges of a triangle mesh (not just boundary edges). These
+  // are integrated along the edge: they're the per-face constant gradient dot
+  // the rotated edge vector (unit rotated edge vector for direction then
+  // magnitude for integration).
+  //
+  // Inputs:
+  //   V  #V by dim list of mesh vertex positions
+  //   F  #F by 3|4 list of triangle|tetrahedron indices into V
+  // Outputs:
+  //   DD  #F*3|4 by #V sparse matrix representing operator to compute
+  //     directional derivative with respect to each facet of each element.
+  //
+  template <
+    typename DerivedV, 
+    typename DerivedEle, 
+    typename Scalar>
+  IGL_INLINE void normal_derivative(
+    const Eigen::PlainObjectBase<DerivedV> & V,
+    const Eigen::PlainObjectBase<DerivedEle> & Ele,
+    Eigen::SparseMatrix<Scalar>& DD);
+}
+
+#ifndef IGL_STATIC_LIBRARY
+#  include "normal_derivative.cpp"
+#endif
+
+#endif
+