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Diffstat (limited to 'scripts/obj_trimmer.py')
-rw-r--r-- | scripts/obj_trimmer.py | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/scripts/obj_trimmer.py b/scripts/obj_trimmer.py new file mode 100644 index 0000000000..703c648dd5 --- /dev/null +++ b/scripts/obj_trimmer.py @@ -0,0 +1,132 @@ +# Copyright (c) 2022 Ultimaker B.V. +# Cura is released under the terms of the LGPLv3 or higher. +import argparse +import os +from typing import Optional, List, TextIO + +""" + Used to reduce the size of obj files used for printer platform models. + + Trims trailing 0 from coordinates + Removes duplicate vertex texture coordinates + Removes any rows that are not a face, vertex or vertex texture +""" + + +def process_obj(input_file: str, output_file: str) -> None: + with open(input_file, "r") as in_obj, open("temp", "w") as temp: + trim_lines(in_obj, temp) + + with open("temp", "r") as temp, open(output_file, "w") as out_obj: + merge_duplicate_vt(temp, out_obj) + + os.remove("temp") + + +def trim_lines(in_obj: TextIO, out_obj: TextIO) -> None: + for line in in_obj: + line = trim_line(line) + if line: + out_obj.write(line + "\n") + + +def trim_line(line: str) -> Optional[str]: + # Discards all rows that are not a vertex ("v"), face ("f") or vertex texture ("vt") + values = line.split() + + if values[0] == "vt": + return trim_vertex_texture(values) + elif values[0] == "f": + return trim_face(values) + elif values[0] == "v": + return trim_vertex(values) + + return + + +def trim_face(values: List[str]) -> str: + # Removes face normals (vn) + # f 15/15/17 15/15/17 14/14/17 -> f 15/15 15/15 14/14 + for i, coordinates in enumerate(values[1:]): + v, vt = coordinates.split("/")[:2] + values[i + 1] = v + "/" + vt + + return " ".join(values) + + +def trim_vertex(values: List[str]) -> str: + # Removes trailing zeros from vertex coordinates + # v 0.044000 0.137000 0.123000 -> v 0.044 0.137 0.123 + for i, coordinate in enumerate(values[1:]): + values[i + 1] = str(float(coordinate)) + return " ".join(values) + + +def trim_vertex_texture(values: List[str]) -> str: + # Removes trailing zeros from vertex texture coordinates + # vt 0.137000 0.123000 -> v 0.137 0.123 + for i, coordinate in enumerate(values[1:]): + values[i + 1] = str(float(coordinate)) + return " ".join(values) + + +def merge_duplicate_vt(in_obj, out_obj): + # Removes duplicate vertex texture ("vt") + # Points references to all deleted copies in face ("f") to a single vertex texture + + # Maps index of all copies of a vt line to the same index + vt_index_mapping = {} + # Maps vt line to index ("vt 0.043 0.137" -> 23) + vt_to_index = {} + + # .obj file indexes start at 1 + vt_index = 1 + skipped_count = 0 + + # First write everything except faces + for line in in_obj.readlines(): + if line[0] == "f": + continue + + if line[:2] == "vt": + if line in vt_to_index.keys(): + # vt with same value has already been written + # this points the current vt index to the one that has been written + vt_index_mapping[vt_index] = vt_to_index[line] + skipped_count += 1 + else: + # vt has not been seen, point vt line to index + vt_to_index[line] = vt_index - skipped_count + vt_index_mapping[vt_index] = vt_index - skipped_count + out_obj.write(line) + + vt_index += 1 + else: + out_obj.write(line) + + # Second pass remaps face vt index + in_obj.seek(0) + for line in in_obj.readlines(): + if line[0] != "f": + continue + + values = line.split() + + for i, coordinates in enumerate(values[1:]): + v, vt = coordinates.split("/")[:2] + vt = int(vt) + + if vt in vt_index_mapping.keys(): + vt = vt_index_mapping[vt] + + values[i + 1] = v + "/" + str(vt) + + out_obj.write(" ".join(values) + "\n") + + +if __name__ == "__main__": + parser = argparse.ArgumentParser(description = "Reduce the size of a .obj file") + parser.add_argument("input_file", type = str, help = "Input .obj file name") + parser.add_argument("--output_file", default = "output.obj", type = str, help = "Output .obj file name") + args = parser.parse_args() + process_obj(args.input_file, args.output_file) |