diff options
| -rw-r--r-- | chroma/geometry.py | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/chroma/geometry.py b/chroma/geometry.py index 601dcf7..be3e7eb 100644 --- a/chroma/geometry.py +++ b/chroma/geometry.py @@ -1,5 +1,6 @@ import sys import os +from itertools import chain from hashlib import md5 import cPickle as pickle import gzip @@ -54,6 +55,16 @@ class Mesh(object): # remap the triangles to the unique vertices self.triangles = inverse[self.triangles] + def remove_null_triangles(self): + '''Remove any zero-area triangles from a mesh. + + Returns the mask of retained triangles, which may be applied to the + material, surface, etc., arrays of an associated ``Solid``. + ''' + mask = np.array([(len(set(x)) == 3) for x in self.triangles]) + self.triangles = self.triangles[mask] + return mask + def assemble(self, key=slice(None), group=True): """ Return an assembled triangle mesh; i.e. return the vertex positions @@ -127,6 +138,49 @@ class Solid(object): def __add__(self, other): return Solid(self.mesh + other.mesh, np.concatenate((self.material1, other.material1)), np.concatenate((self.material2, other.material2)), np.concatenate((self.surface, other.surface)), np.concatenate((self.color, other.color))) + def weld(self, other, shared_triangle_surface=None, shared_triangle_color=None): + '''Merge this solid with another at any identical triangles. + + Triangles that are common to both solids will be reduced to one, with the + surface and color properties of this one unless otherwise specified with + ``shared_triangle_surface`` and/or ``shared_triangle_color``. + + Note that this is NOT a boolean union! + ''' + # create arrays of sets of (three-tuple) points + # use sets to take care of point order permutations, numpy element-wise-ness + points_self = np.array([set(map(tuple, [self.mesh.vertices[x] for x in y])) for y in self.mesh.triangles], dtype=set) + points_other = np.array([set(map(tuple, [other.mesh.vertices[x] for x in y])) for y in other.mesh.triangles], dtype=set) + + # find any triangles in other that also exist in self + match = [np.where(points_other == x)[0] for x in points_self] + mask = np.array(map(lambda x: len(x)>0, match)) + if mask.sum() == 0: + raise Exception('cannot weld solids with no shared triangles') + + # get triangle ids of the duplicates + duplicates = sorted(list(chain(*[np.where(points_other == x)[0] for x in points_self]))) + + # create temporary second solid -- solid2 with duplicate triangles removed + mesh = Mesh(other.mesh.vertices, np.delete(other.mesh.triangles, duplicates, 0)) + material1 = np.delete(other.material1, duplicates, 0) + material2 = np.delete(other.material2, duplicates, 0) + surface = np.delete(other.surface, duplicates, 0) + color = np.delete(other.color, duplicates, 0) + + self.mesh = self.mesh + mesh + self.material1 = np.concatenate((self.material1, material1)) + self.material2 = np.concatenate((self.material2, material2)) + self.surface = np.concatenate((self.surface, surface)) + self.color = np.concatenate((self.color, color)) + + # set properties at interface + self.material2[mask] = other.material1[0] + if shared_triangle_surface is not None: + self.surface[mask] = shared_triangle_surface + if shared_triangle_color is not None: + self.color[mask] = shared_triangle_color + @memoize_method_with_dictionary_arg def material1_indices(self, material_lookup): return np.fromiter(imap(material_lookup.get, self.material1), dtype=np.int32, count=len(self.material1)) @@ -295,3 +349,4 @@ class Geometry(object): self.surface_index[self.surface_index == surface_lookup[None]] = -1 except KeyError: pass + |