machina.py 文件源码

def init_framefield(self):
        """Initialize the frame field based on surface curvature and normals."""
        boundary_frames = []
        boundary_ids = {}
        # The frame field is initialized at the boundary,
        # based on the curvature cross-field and normals.
        for fi, face in enumerate(self.surf_mesh.faces):
            # Retrieve the tet this face belongs to.
            ti = self.tet_mesh.adjacent_elements[self.surf_mesh.face_map.inv[fi]][0]
            tet = self.tet_mesh.elements[ti]
            # Ignore faces which have 0 curvature.
            if np.isclose(self.surf_mesh.k1[face[0]], 0) and np.isclose(self.surf_mesh.k2[face[0]], 0):
                continue
            # @TODO(aidan) Find actual face values, not vertex values.
            uvw = np.hstack((np.vstack(self.surf_mesh.pdir1[face[0]]),
                             np.vstack(self.surf_mesh.pdir2[face[0]]),
                             np.vstack(self.surf_mesh.vertex_normals[face[0]])))
            boundary_frames.append(Frame(uvw, tet_centroid(self.tet_mesh, ti)))
            boundary_ids[ti] = len(boundary_frames) - 1

        # Prepare a KDTree of boundary frame coords for quick spatial queries.
        tree = spatial.KDTree(np.vstack([frame.location for frame in boundary_frames]))

        # Now propagate the boundary frames throughout the tet mesh.
        # Each tet frame takes the value of its nearest boundary tet.
        for ti, tet in enumerate(self.tet_mesh.elements):
            location = tet_centroid(self.tet_mesh, ti)
            if ti in boundary_ids:
                self.frames.append(Frame(boundary_frames[boundary_ids[ti]].uvw, location, True))
            else:
                nearest_ti = tree.query(location)[1] # Find closest boundary frame
                self.frames.append(Frame(boundary_frames[nearest_ti].uvw, location, False))