rust_3d/io/las/
load.rs

1/*
2Copyright 2020 Martin Buck
3
4Permission is hereby granted, free of charge, to any person obtaining a copy
5of this software and associated documentation files (the "Software"),
6to deal in the Software without restriction, including without limitation the
7rights to use, copy, modify, merge, publish, distribute, sublicense,
8and/or sell copies of the Software, and to permit persons to whom the Software
9is furnished to do so, subject to the following conditions:
10
11The above copyright notice and this permission notice shall
12be included all copies or substantial portions of the Software.
13
14THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
17IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
18DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
19TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
20OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21*/
22
23//! Module for load functions of the .las file format
24
25use crate::*;
26
27use super::types::*;
28
29use std::{
30    convert::{TryFrom, TryInto},
31    io::{BufRead, Read, Seek, SeekFrom},
32};
33
34use super::super::from_bytes::*;
35
36//------------------------------------------------------------------------------
37
38/// Loads points from .las file into IsPushable<IsBuildable3D>
39pub fn load_las<IP, P, R>(read: &mut R, ip: &mut IP) -> LasResult<()>
40where
41    IP: IsPushable<P>,
42    P: IsBuildable3D,
43    R: BufRead + Seek,
44{
45    let header_raw = load_header(read)?;
46    let header = Header::try_from(header_raw)?;
47
48    ip.reserve(header.n_point_records as usize);
49
50    read.seek(SeekFrom::Start(header.offset_point_data as u64))?;
51
52    let mut buffer = vec![0u8; header.point_record_length as usize];
53
54    for _ in 0..header.n_point_records {
55        read.read_exact(&mut buffer)?;
56
57        let pd = PointData::from_bytes(buffer[0..12].try_into()?);
58
59        let x = header.offset_x + (pd.x as f64 * header.scale_factor_x);
60        let y = header.offset_y + (pd.y as f64 * header.scale_factor_y);
61        let z = header.offset_z + (pd.z as f64 * header.scale_factor_z);
62
63        ip.push(P::new(x, y, z))
64    }
65
66    Ok(())
67}
68
69//------------------------------------------------------------------------------
70
71fn load_header<R>(read: &mut R) -> LasResult<HeaderRaw>
72where
73    R: Read,
74{
75    let mut buffer = [0u8; 375];
76    read.read_exact(&mut buffer)?;
77
78    Ok(HeaderRaw {
79        file_signature: array_from_bytes_le!(u8, 4, &buffer[0..4])?, //4 4
80        file_source_id: u16::from_le_bytes(buffer[4..6].try_into()?), //2 6
81        global_encoding: u16::from_le_bytes(buffer[6..8].try_into()?), //2 8
82        guid1: u32::from_le_bytes(buffer[8..12].try_into()?),        //4 12
83        guid2: u16::from_le_bytes(buffer[12..14].try_into()?),       //2 14
84        guid3: u16::from_le_bytes(buffer[14..16].try_into()?),       //2 16
85        guid4: buffer[16..24].try_into()?,                           //8 24
86        version_major: u8::from_le_bytes(buffer[24..25].try_into()?), //1 25
87        version_minor: u8::from_le_bytes(buffer[25..26].try_into()?), //1 26
88        system_identifier: array_from_bytes_le!(u8, 32, &buffer[26..58])?, //32 58
89        generating_software: array_from_bytes_le!(u8, 32, &buffer[58..90])?, //32 90
90        file_creation_day: u16::from_le_bytes(buffer[90..92].try_into()?), //2 92
91        file_creation_year: u16::from_le_bytes(buffer[92..94].try_into()?), //2 94
92        header_size: u16::from_le_bytes(buffer[94..96].try_into()?), //2 96
93        offset_point_data: u32::from_le_bytes(buffer[96..100].try_into()?), //4 100
94        n_variable_length_records: u32::from_le_bytes(buffer[100..104].try_into()?), //4 104
95        point_record_format: u8::from_le_bytes(buffer[104..105].try_into()?), //1 105
96        point_record_length: u16::from_le_bytes(buffer[105..107].try_into()?), //2 107
97        legacy_n_point_records: u32::from_le_bytes(buffer[107..111].try_into()?), //4 111
98        legacy_n_point_return: array_from_bytes_le!(u32, 5, &buffer[111..131])?, //20 131
99        scale_factor_x: f64::from_le_bytes(buffer[131..139].try_into()?), //8 139
100        scale_factor_y: f64::from_le_bytes(buffer[139..147].try_into()?), //8 147
101        scale_factor_z: f64::from_le_bytes(buffer[147..155].try_into()?), //8 155
102        offset_x: f64::from_le_bytes(buffer[155..163].try_into()?),  //8 163
103        offset_y: f64::from_le_bytes(buffer[163..171].try_into()?),  //8 171
104        offset_z: f64::from_le_bytes(buffer[171..179].try_into()?),  //8 179
105        max_x: f64::from_le_bytes(buffer[179..187].try_into()?),     //8 187
106        min_x: f64::from_le_bytes(buffer[187..195].try_into()?),     //8 195
107        max_y: f64::from_le_bytes(buffer[195..203].try_into()?),     //8 203
108        min_y: f64::from_le_bytes(buffer[203..211].try_into()?),     //8 211
109        max_z: f64::from_le_bytes(buffer[211..219].try_into()?),     //8 219
110        min_z: f64::from_le_bytes(buffer[219..227].try_into()?),     //8 227
111        start_wavefront_data: u64::from_le_bytes(buffer[227..235].try_into()?), //8 235
112        start_extended_variable_length: u64::from_le_bytes(buffer[235..243].try_into()?), //8 243
113        n_extended_variable_length: u32::from_le_bytes(buffer[243..247].try_into()?), //4 247
114        n_point_records: u64::from_le_bytes(buffer[247..255].try_into()?), //8 255
115        n_points_return: array_from_bytes_le!(u64, 15, &buffer[255..375])?, //120 375
116    })
117}
rust_3d/io/las/load.rs

rust_3d/io/las/
load.rs
