Slow performance on python wrapper #275
Description
Let's start by considering this snippet:
import time
from pathlib import Path
import tinyobjloader
def load_obj(filename):
path = Path(filename).resolve()
start = time.time()
reader = tinyobjloader.ObjReader()
if not reader.ParseFromFile(str(path)):
raise Exception(f"Problem loading '{path}'")
attrib = reader.GetAttrib()
start = time.time()
num_vertices = 0
num_normals = 0
num_texcoords = 0
for shape in reader.GetShapes():
num_vertices += len(attrib.vertices)
num_normals += len(attrib.normals)
num_texcoords += len(attrib.texcoords)
for f in shape.mesh.indices:
attrib.vertices[f.vertex_index * 3 + 0]
attrib.vertices[f.vertex_index * 3 + 1]
attrib.vertices[f.vertex_index * 3 + 2]
attrib.normals[f.normal_index * 3 + 0]
attrib.normals[f.normal_index * 3 + 1]
attrib.normals[f.normal_index * 3 + 2]
attrib.texcoords[f.texcoord_index * 2 + 0]
attrib.texcoords[f.texcoord_index * 2 + 1]
print(
f"num_vertices={num_vertices} num_normals={num_normals} num_texcoords={num_texcoords}"
)
print(time.time() - start)
if __name__ == "__main__":
load_obj(r"mcve.obj")
And here's the link to both mcve.obj and mcve.mtl, this object is a very small & trivial scene, that looks like this:
Problem being... if you run that snippet you'll get this output:
num_vertices=36150 num_normals=38400 num_texcoords=27950
13.565775871276855
That's really slow & unusable for such a trivial scene. I wanted to san miguel's scene from https://casual-effects.com/data/ but after seeing these poor results on such a trivial scene I'm not even considering it till I figure out how to proceed here.
So yeah, the main question would be, how could we use the tinyobjloader effectively on python so we can test real-world scenes?
Thanks in advance.
Ps. I've got allocated a huge chunk of memory for interleaved data (vertices+normals+texcoords) so I'm not sure how difficult would be providing a wrapper to make a fast memcpy or similar... Main problem seems to be the whole overhead of wrapping c++ to python