Merge pull request #271 from ybhvf/offset-surface-bindings

Add binding for offset_surface()

Author: alecjacobson

src/offset_surface.cpp

@@ -0,0 +1,51 @@
+#include "default_types.h"
+#include <igl/offset_surface.h>
+#include <nanobind/nanobind.h>
+#include <nanobind/ndarray.h>
+#include <nanobind/eigen/dense.h>
+#include <nanobind/stl/tuple.h>
+#include <nanobind/stl/vector.h>
+
+namespace nb = nanobind;
+using namespace nb::literals;
+
+namespace pyigl {
+auto offset_surface(const nb::DRef<const Eigen::MatrixXN> &V,
+                    const nb::DRef<const Eigen::MatrixXI> &F,
+                    const Numeric isolevel, const Integer s,
+                    const igl::SignedDistanceType signed_distance_type) {
+
+  Eigen::MatrixXN SV;
+  Eigen::MatrixXI SF;
+  Eigen::MatrixXN GV;
+
+  Eigen::VectorXI side;
+  Eigen::MatrixXN so;
+
+  igl::offset_surface(V, F, isolevel, s, signed_distance_type, SV, SF, GV, side,
+                      so);
+
+  return std::make_tuple(SV, SF, GV, side, so);
+}
+} // namespace pyigl
+
+// Bind the wrapper to the Python module
+void bind_offset_surface(nb::module_ &m) {
+  m.def(
+      "offset_surface", &pyigl::offset_surface, "V"_a, "F"_a, "isolevel"_a,
+      "s"_a, "signed_distance_type"_a,
+      R"(Compute a triangulated offset surface using matching cubes on a grid of signed distance values from the input triangle mesh.
+
+@param[in] V  #V by 3 list of mesh vertex positions
+@param[in] F  #F by 3 list of mesh triangle indices into V
+@param[in] isolevel  iso level to extract (signed distance: negative inside)
+@param[in] s  number of grid cells along longest side (controls resolution)
+@param[in] signed_distance_type  type of signing to use one of SIGNED_DISTANCE_TYPE_PSEUDONORMAL, SIGNED_DISTANCE_TYPE_WINDING_NUMBER, SIGNED_DISTANCE_TYPE_DEFAULT, SIGNED_DISTANCE_TYPE_UNSIGNED, SIGNED_DISTANCE_TYPE_FAST_WINDING_NUMBER
+
+@return Tuple containing:
+   - SV: #SV by 3 list of output surface mesh vertex positions
+   - SF: #SF by 3 list of output mesh triangle indices into SV
+   - GV: #GV=side(0)*side(1)*side(2) by 3 list of grid cell centers
+   - side: list of number of grid cells in x, y, and z directions
+   - so: #GV by 3 list of signed distance values _near_ `isolevel` ('far' from `isolevel` these values are incorrect))");
+}

tests/test_all.py

@@ -261,6 +261,10 @@ def test_volume():
     F = np.array([[2,1,3]],dtype=np.int64)
     NV,NF,I,J = igl.remove_unreferenced(V,F)
 
+def test_offset_surface():
+    V,F = triangulated_square()
+    v, f, _, _, _ = igl.offset_surface(V, F, -0.1, 1, igl.SIGNED_DISTANCE_TYPE_DEFAULT)
+
 def test_oriented_facets():
     V,F,T = single_tet()
     E = igl.oriented_facets(F)