| """Crop several XY boxes from one huge ASCII PLY in a single streaming pass. |
| Usage: python crop.py boxes.json (boxes.json: list of {name, src, xmin, xmax, ymin, ymax, out})""" |
| import sys, os, json, time |
| import polars as pl, numpy as np |
|
|
| def header_len(path): |
| n = 0 |
| with open(path, 'rb') as f: |
| for line in f: |
| n += 1 |
| if line.strip() == b'end_header': return n |
|
|
| def write_ply(path, df, comments): |
| pts = df.select(['x', 'y', 'z']).to_numpy() |
| rgb = df.select(['r', 'g', 'b']).to_numpy() |
| with open(path, 'w', newline='\n') as f: |
| f.write('ply\nformat ascii 1.0\n') |
| for c in comments: f.write(f'comment {c}\n') |
| f.write(f'element vertex {len(pts)}\nproperty float x\nproperty float y\nproperty float z\n' |
| 'property uchar red\nproperty uchar green\nproperty uchar blue\nend_header\n') |
| np.savetxt(f, np.c_[pts, rgb], fmt='%.6f %.6f %.6f %d %d %d') |
|
|
| def run(boxes): |
| by_src = {} |
| for b in boxes: by_src.setdefault(b['src'], []).append(b) |
| for src, bl in by_src.items(): |
| t0 = time.time(); hl = header_len(src) |
| lf = pl.scan_csv(src, separator=' ', has_header=False, skip_rows=hl, new_columns=['x','y','z','r','g','b'], |
| schema_overrides={'x': pl.Float64, 'y': pl.Float64, 'z': pl.Float64, 'r': pl.UInt8, 'g': pl.UInt8, 'b': pl.UInt8}, |
| low_memory=True) |
| preds = [(pl.col('x') >= b['xmin']) & (pl.col('x') < b['xmax']) & (pl.col('y') >= b['ymin']) & (pl.col('y') < b['ymax']) for b in bl] |
| anyp = preds[0] |
| for p in preds[1:]: anyp = anyp | p |
| tag = pl.lit(None, dtype=pl.Int32) |
| for i, p in reversed(list(enumerate(preds))): |
| tag = pl.when(p).then(pl.lit(i, dtype=pl.Int32)).otherwise(tag) |
| df = lf.filter(anyp).with_columns(tag.alias('box')).collect(engine='streaming') |
| for i, b in enumerate(bl): |
| sub = df.filter(pl.col('box') == i) |
| os.makedirs(os.path.dirname(b['out']), exist_ok=True) |
| write_ply(b['out'], sub, [f"Subiaco change-detection raw crop {b['name']} (source-map coordinates, uncorrected)", |
| f"source {os.path.basename(src)}", |
| f"crop box x[{b['xmin']},{b['xmax']}) y[{b['ymin']},{b['ymax']}) all z", |
| 'Generated 2026-09-27 by crop.py']) |
| print(f"{b['name']}: {os.path.basename(src)} -> {len(sub):,} pts -> {b['out']}", flush=True) |
| print(f" pass over {os.path.basename(src)}: {time.time()-t0:.1f}s", flush=True) |
|
|
| if __name__ == '__main__': |
| run(json.load(open(sys.argv[1]))) |
|
|
