added collision conversion
This commit is contained in:
Andreas Wilms
325
scripts/preprocess/convert_lci_to_ply.py
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325
scripts/preprocess/convert_lci_to_ply.py
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#!/usr/bin/env python3
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"""
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XGrids LCI to PLY Converter
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Converts XGrids .lci collision files to standard .ply format
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Usage:
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# Convert with default output name (collision_mesh.ply)
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python convert_lci_to_ply.py path/to/collision.lci
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# Specify custom output file
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python convert_lci_to_ply.py path/to/collision.lci output/mesh.ply
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# Verbose output
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python convert_lci_to_ply.py path/to/collision.lci -v
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"""
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import argparse
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import struct
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import sys
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from pathlib import Path
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# Constants
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LCI_MAGIC = 0x6C6C6F63 # 'coll' in little-endian
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MESH_HEADER_SIZE = 40 # bytes per mesh header
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def read_lci_file(filepath, verbose=False):
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"""
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Parse XGrids .lci collision file according to official LCI specification
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Args:
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filepath: Path to input .lci file
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verbose: Enable verbose output
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Returns:
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Tuple of (vertices, faces) where:
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- vertices: List of (x, y, z) tuples
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- faces: List of (v0, v1, v2) tuples with vertex indices
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"""
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filepath = Path(filepath)
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if not filepath.exists():
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raise FileNotFoundError(f"Input file not found: {filepath}")
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with open(filepath, "rb") as f:
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lci_data = f.read()
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# Validate minimum file size
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if len(lci_data) < 48:
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raise ValueError("File too small to be valid LCI format (minimum 48 bytes required)")
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# Warn about large files that may cause memory issues
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file_size_mb = len(lci_data) / (1024 * 1024)
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if file_size_mb > 100 and verbose:
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print(f"Warning: Large file ({file_size_mb:.1f} MB) loaded into memory")
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# Read main header
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magic = struct.unpack("<I", lci_data[0:4])[0]
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if magic != LCI_MAGIC:
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raise ValueError(
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f"Invalid file format. Expected magic 0x{LCI_MAGIC:08X}, got 0x{magic:08X}"
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)
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version = struct.unpack("<I", lci_data[4:8])[0]
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header_len = struct.unpack("<I", lci_data[8:12])[0]
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min_x, min_y, min_z = struct.unpack("<fff", lci_data[12:24])
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max_x, max_y, max_z = struct.unpack("<fff", lci_data[24:36])
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cell_length_x = struct.unpack("<f", lci_data[36:40])[0]
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cell_length_y = struct.unpack("<f", lci_data[40:44])[0]
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mesh_num = struct.unpack("<I", lci_data[44:48])[0]
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# Validate mesh count
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if mesh_num == 0:
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raise ValueError("LCI file contains no mesh data")
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# Validate header length
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expected_header = 48 + mesh_num * MESH_HEADER_SIZE
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if header_len != expected_header:
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raise ValueError(
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f"Header length mismatch: expected {expected_header}, got {header_len}"
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)
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if verbose:
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print("LCI File Information:")
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print(f" Version: {version}")
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print(f" Header length: {header_len} bytes")
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print(
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f" Bounding box: min({min_x:.2f}, {min_y:.2f}, {min_z:.2f}) "
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f"max({max_x:.2f}, {max_y:.2f}, {max_z:.2f})"
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)
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print(f" Cell length: X={cell_length_x:.2f}, Y={cell_length_y:.2f}")
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print(f" Mesh count: {mesh_num}\n")
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# Read mesh headers (40 bytes each, starting at offset 48)
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meshes = []
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mesh_header_offset = 48
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for i in range(mesh_num):
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offset = mesh_header_offset + i * MESH_HEADER_SIZE
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# Validate buffer bounds for mesh header
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if offset + MESH_HEADER_SIZE > len(lci_data):
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raise ValueError(
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f"Mesh header {i} exceeds file size (offset {offset}, file size {len(lci_data)})"
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)
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index_x = struct.unpack("<I", lci_data[offset : offset + 4])[0]
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index_y = struct.unpack("<I", lci_data[offset + 4 : offset + 8])[0]
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data_offset = struct.unpack("<Q", lci_data[offset + 8 : offset + 16])[0]
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bytes_size = struct.unpack("<Q", lci_data[offset + 16 : offset + 24])[0]
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vertex_num = struct.unpack("<I", lci_data[offset + 24 : offset + 28])[0]
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face_num = struct.unpack("<I", lci_data[offset + 28 : offset + 32])[0]
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bvh_size = struct.unpack("<I", lci_data[offset + 32 : offset + 36])[0]
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meshes.append(
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{
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"index_x": index_x,
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"index_y": index_y,
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"offset": data_offset,
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"bytes_size": bytes_size,
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"vertex_num": vertex_num,
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"face_num": face_num,
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"bvh_size": bvh_size,
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}
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)
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if verbose:
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print(
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f"Mesh {i}: grid({index_x},{index_y}), "
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f"{vertex_num:,} verts, {face_num:,} faces"
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)
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if verbose:
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print()
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# Read all mesh data
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all_vertices = []
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all_faces = []
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global_vertex_offset = 0
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for i, mesh in enumerate(meshes):
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mesh_offset = mesh["offset"]
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vertex_num = mesh["vertex_num"]
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face_num = mesh["face_num"]
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bytes_size = mesh["bytes_size"]
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bvh_size = mesh["bvh_size"]
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# Validate mesh data bounds
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expected_data_size = (vertex_num * 12) + (face_num * 12) + bvh_size
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if expected_data_size != bytes_size:
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raise ValueError(
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f"Mesh {i} data size mismatch: expected {expected_data_size} bytes, "
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f"header specifies {bytes_size} bytes"
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)
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if mesh_offset + expected_data_size > len(lci_data):
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raise ValueError(
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f"Mesh {i} data exceeds file size (offset {mesh_offset}, "
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f"data size {expected_data_size}, file size {len(lci_data)})"
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)
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# Read vertices
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vertices = []
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pos = mesh_offset
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for j in range(vertex_num):
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x, y, z = struct.unpack("<fff", lci_data[pos : pos + 12])
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vertices.append((x, y, z))
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pos += 12
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# Read faces
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faces = []
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for j in range(face_num):
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v0, v1, v2 = struct.unpack("<III", lci_data[pos : pos + 12])
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# Validate face indices
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if v0 >= vertex_num or v1 >= vertex_num or v2 >= vertex_num:
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raise ValueError(
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f"Invalid face indices in mesh {i}: ({v0}, {v1}, {v2}), "
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f"vertex_num={vertex_num}"
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)
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# Adjust indices to global vertex offset
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faces.append(
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(
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v0 + global_vertex_offset,
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v1 + global_vertex_offset,
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v2 + global_vertex_offset,
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)
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)
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pos += 12
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all_vertices.extend(vertices)
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all_faces.extend(faces)
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global_vertex_offset += len(vertices)
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if verbose:
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print(f"Total: {len(all_vertices):,} vertices, {len(all_faces):,} faces")
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return all_vertices, all_faces
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def write_ply_ascii(filepath, vertices, faces, verbose=False):
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"""
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Write mesh data to ASCII PLY file
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Args:
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filepath: Path to output .ply file
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vertices: List of (x, y, z) vertex tuples
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faces: List of (v0, v1, v2) face tuples
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verbose: Enable verbose output
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"""
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filepath = Path(filepath)
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# Create output directory if needed
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filepath.parent.mkdir(parents=True, exist_ok=True)
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if verbose:
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print(f"\nWriting ASCII PLY to: {filepath}")
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with open(filepath, "w") as f:
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# Write header
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f.write("ply\n")
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f.write("format ascii 1.0\n")
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f.write(f"element vertex {len(vertices)}\n")
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f.write("property float x\n")
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f.write("property float y\n")
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f.write("property float z\n")
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f.write(f"element face {len(faces)}\n")
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f.write("property list uchar int vertex_indices\n")
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f.write("end_header\n")
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# Write vertices with full precision
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for v in vertices:
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f.write(f"{v[0]:.9g} {v[1]:.9g} {v[2]:.9g}\n")
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# Write faces
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for face in faces:
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f.write(f"3 {face[0]} {face[1]} {face[2]}\n")
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if verbose:
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file_size_kb = filepath.stat().st_size / 1024
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print(f" File size: {file_size_kb:.1f} KB")
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def parse_args():
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"""Parse command line arguments"""
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parser = argparse.ArgumentParser(
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description="Convert XGrids .lci collision files to .ply format",
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formatter_class=argparse.RawDescriptionHelpFormatter,
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epilog="""
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Examples:
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# Convert with default output name (collision_mesh.ply in same directory)
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python convert_lci_to_ply.py collision.lci
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# Specify custom output file
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python convert_lci_to_ply.py collision.lci output/mesh.ply
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# Verbose output
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python convert_lci_to_ply.py collision.lci -v
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""",
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)
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parser.add_argument("input", type=Path, help="Input .lci collision file")
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parser.add_argument(
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"output",
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type=Path,
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nargs="?",
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help="Output .ply file (default: collision_mesh.ply in same directory as input)",
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)
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parser.add_argument(
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"-v", "--verbose", action="store_true", help="Enable verbose output"
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)
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return parser.parse_args()
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def main():
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"""Main entry point"""
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args = parse_args()
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# Determine output path
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output_path = (
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args.input.parent / "collision_mesh.ply" if args.output is None else args.output
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)
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if args.verbose:
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print("=" * 60)
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print(f"Converting: {args.input}")
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print(f"Output: {output_path}")
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print("=" * 60 + "\n")
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try:
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# Read LCI file
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vertices, faces = read_lci_file(args.input, verbose=args.verbose)
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if not vertices:
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print("Error: No mesh data extracted from file", file=sys.stderr)
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sys.exit(1)
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# Write PLY file
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write_ply_ascii(output_path, vertices, faces, verbose=args.verbose)
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if args.verbose:
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print("\n" + "=" * 60)
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print("✓ Conversion successful!")
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else:
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print(f"✓ Converted {args.input} -> {output_path}")
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print(f" {len(vertices):,} vertices, {len(faces):,} faces")
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except Exception as e:
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print(f"\n✗ Conversion failed: {e}", file=sys.stderr)
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if args.verbose:
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import traceback
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traceback.print_exc()
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sys.exit(1)
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if __name__ == "__main__":
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main()
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