Point Cloud Library (PCL) 1.15.0
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approx_nearest_utils.hpp
1/*
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Point Cloud Library (PCL) - www.pointclouds.org
5 * Copyright (c) 2020-, Open Perception
6 *
7 * All rights reserved
8 */
9
10#pragma once
11
12#include "morton.hpp"
13#include <assert.h>
14
15#include <cstdint>
16#include <limits>
17#include <tuple>
18#include <bitset>
19
20namespace pcl {
21namespace device {
22
23__device__ __host__ __forceinline__ unsigned
24getBitsNum(const unsigned integer)
25{
26 #ifdef __CUDA_ARCH__
27 return __popc(integer);
28 #else
29 return std::bitset<8*sizeof(integer)> (integer).count();
30 #endif
31}
32
33__host__ __device__ __forceinline__ std::pair<uint3, std::uint8_t>
34nearestVoxel(const float3 query,
35 const unsigned& level,
36 const std::uint8_t& mask,
37 const float3& minp,
38 const float3& maxp,
39 const uint3& index)
40{
41 assert(mask != 0);
42 // identify closest voxel
43 float closest_distance = std::numeric_limits<float>::max();
44 unsigned closest_index = 0;
45 uint3 closest = make_uint3(0, 0, 0);
46
47 for (unsigned i = 0; i < 8; ++i) {
48 if ((mask & (1 << i)) == 0) // no child
49 continue;
50
51 const uint3 child = make_uint3((index.x << 1) + (i & 1),
52 (index.y << 1) + ((i >> 1) & 1),
53 (index.z << 1) + ((i >> 2) & 1));
54
55 // find center of child cell
56 const unsigned voxel_width_scale_factor = 1 << (level + 2);
57 const float3 voxel_center =
58 make_float3(minp.x + (maxp.x - minp.x) * (2 * child.x + 1) / voxel_width_scale_factor,
59 minp.y + (maxp.y - minp.y) * (2 * child.y + 1) / voxel_width_scale_factor,
60 minp.z + (maxp.z - minp.z) * (2 * child.z + 1) / voxel_width_scale_factor);
61
62 // compute distance to centroid
63 const float3 dist = make_float3(
64 voxel_center.x - query.x, voxel_center.y - query.y, voxel_center.z - query.z);
65
66 const float distance_to_query = dist.x * dist.x + dist.y * dist.y + dist.z * dist.z;
67
68 // compare distance
69 if (distance_to_query < closest_distance) {
70 closest_distance = distance_to_query;
71 closest_index = i;
72 closest = child;
73 }
74 }
75
76 return {closest, 1 << closest_index};
77}
78
79#pragma hd_warning_disable
80template <typename T>
81__device__ __host__ int
82findNode(const float3 minp, const float3 maxp, const float3 query, const T nodes)
83{
84 size_t node_idx = 0;
85 const auto code = CalcMorton(minp, maxp)(query);
86 unsigned level = 0;
87
88 bool voxel_traversal = false;
89 uint3 index = Morton::decomposeCode(code);
90 std::uint8_t mask_pos;
91
92 while (true) {
93 const auto node = nodes[node_idx];
94 const std::uint8_t mask = node & 0xFF;
95
96 if (!mask) // leaf
97 return node_idx;
98
99 if (voxel_traversal) // empty voxel already encountered, performing nearest-centroid
100 // based traversal
101 {
102 const auto nearest_voxel = nearestVoxel(query, level, mask, minp, maxp, index);
103 index = nearest_voxel.first;
104 mask_pos = nearest_voxel.second;
105 }
106 else {
107 mask_pos = 1 << Morton::extractLevelCode(code, level);
108
109 if (!(mask & mask_pos)) // child doesn't exist
110 {
111 const auto remaining_depth = Morton::levels - level;
112 index.x >>= remaining_depth;
113 index.y >>= remaining_depth;
114 index.z >>= remaining_depth;
115
116 voxel_traversal = true;
117 const auto nearest_voxel = nearestVoxel(query, level, mask, minp, maxp, index);
118 index = nearest_voxel.first;
119 mask_pos = nearest_voxel.second;
120 }
121 }
122 node_idx = (node >> 8) + getBitsNum(mask & (mask_pos - 1));
123 ++level;
124 }
125}
126} // namespace device
127} // namespace pcl
__device__ __host__ int findNode(const float3 minp, const float3 maxp, const float3 query, const T nodes)
__device__ __host__ __forceinline__ unsigned getBitsNum(const unsigned integer)
__host__ __device__ __forceinline__ std::pair< uint3, std::uint8_t > nearestVoxel(const float3 query, const unsigned &level, const std::uint8_t &mask, const float3 &minp, const float3 &maxp, const uint3 &index)
__device__ __host__ static __forceinline__ void decomposeCode(code_t code, int &cell_x, int &cell_y, int &cell_z)
Definition morton.hpp:84
__host__ __device__ static __forceinline__ code_t extractLevelCode(code_t code, int level)
Definition morton.hpp:98
static const int levels
Definition morton.hpp:47