diff options
Diffstat (limited to 'io_mesh_stl/stl_utils.py')
| -rw-r--r-- | io_mesh_stl/stl_utils.py | 52 |
1 files changed, 28 insertions, 24 deletions
diff --git a/io_mesh_stl/stl_utils.py b/io_mesh_stl/stl_utils.py index 0ab24e3f..6294184d 100644 --- a/io_mesh_stl/stl_utils.py +++ b/io_mesh_stl/stl_utils.py @@ -62,6 +62,15 @@ class ListDict(dict): return value + +# an stl binary file is +# - 80 bytes of description +# - 4 bytes of size (unsigned int) +# - size triangles : +# +# - 12 bytes of normal +# - 9 * 4 bytes of coordinate (3*3 floats) +# - 2 bytes of garbage (usually 0) BINARY_HEADER = 80 BINARY_STRIDE = 12 * 4 + 2 @@ -96,19 +105,6 @@ def _is_ascii_file(data): def _binary_read(data): - # an stl binary file is - # - 80 bytes of description - # - 4 bytes of size (unsigned int) - # - size triangles : - # - # - 12 bytes of normal - # - 9 * 4 bytes of coordinate (3*3 floats) - # - 2 bytes of garbage (usually 0) - - # OFFSET is to skip normal bytes - # STRIDE between each triangle (first normal + coordinates + garbage) - OFFSET = 12 - # Skip header... data.seek(BINARY_HEADER) size = struct.unpack('<I', data.read(4))[0] @@ -129,15 +125,15 @@ def _binary_read(data): chunks = [CHUNK_LEN] * (size // CHUNK_LEN) chunks.append(size % CHUNK_LEN) - unpack = struct.Struct('<9f').unpack_from + unpack = struct.Struct('<12f').unpack_from for chunk_len in chunks: if chunk_len == 0: continue buf = data.read(BINARY_STRIDE * chunk_len) for i in range(chunk_len): - # read the points coordinates of each triangle - pt = unpack(buf, OFFSET + BINARY_STRIDE * i) - yield pt[:3], pt[3:6], pt[6:] + # read the normal and points coordinates of each triangle + pt = unpack(buf, BINARY_STRIDE * i) + yield pt[:3], (pt[3:6], pt[6:9], pt[9:]) def _ascii_read(data): @@ -156,11 +152,15 @@ def _ascii_read(data): # strip header data.readline() + curr_nor = None + for l in data: - # if we encounter a vertex, read next 2 l = l.lstrip() + if l.startswith(b'facet'): + curr_nor = tuple(map(float, l_item.split()[2:])) + # if we encounter a vertex, read next 2 if l.startswith(b'vertex'): - yield [tuple(map(float, l_item.split()[1:])) for l_item in (l, data.readline(), data.readline())] + yield curr_nor, [tuple(map(float, l_item.split()[1:])) for l_item in (l, data.readline(), data.readline())] def _binary_write(filepath, faces): @@ -232,19 +232,22 @@ def read_stl(filepath): Please note that this process can take lot of time if the file is huge (~1m30 for a 1 Go stl file on an quad core i7). - - returns a tuple(triangles, points). + - returns a tuple(triangles, triangles' normals, points). triangles A list of triangles, each triangle as a tuple of 3 index of point in *points*. + triangles' normals + A list of vectors3 (tuples, xyz). + points An indexed list of points, each point is a tuple of 3 float (xyz). Example of use: - >>> tris, pts = read_stl(filepath, lambda x:) + >>> tris, tri_nors, pts = read_stl(filepath) >>> pts = list(pts) >>> >>> # print the coordinate of the triangle n @@ -253,22 +256,23 @@ def read_stl(filepath): import time start_time = time.process_time() - tris, pts = [], ListDict() + tris, tri_nors, pts = [], [], ListDict() with open(filepath, 'rb') as data: # check for ascii or binary gen = _ascii_read if _is_ascii_file(data) else _binary_read - for pt in gen(data): + for nor, pt in gen(data): # Add the triangle and the point. # If the point is allready in the list of points, the # index returned by pts.add() will be the one from the # first equal point inserted. tris.append([pts.add(p) for p in pt]) + tri_nors.append(nor) print('Import finished in %.4f sec.' % (time.process_time() - start_time)) - return tris, pts.list + return tris, tri_nors, pts.list if __name__ == '__main__': |