1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
/*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* The Original Code is Copyright (C) 2014 Blender Foundation.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): Bastien Montagne.
*
* ***** END GPL LICENSE BLOCK *****
*/
#ifndef __BLI_ASTAR_H__
#define __BLI_ASTAR_H__
/** \file BLI_astar.h
* \ingroup bli
* \brief An implementation of the A* (AStar) algorithm to solve shortest path problem.
*/
#include "BLI_utildefines.h"
#include "BLI_bitmap.h"
/* -------------------------------------------------------------------- */
typedef struct BLI_AStarGNLink {
int nodes[2];
float cost;
void *custom_data;
} BLI_AStarGNLink;
typedef struct BLI_AStarGNode {
struct ListBase neighbor_links;
void *custom_data;
} BLI_AStarGNode;
typedef struct BLI_AStarSolution {
/* Final 'most useful' data. */
int steps; /* Number of steps (i.e. walked links) in path (nodes num, including start and end, is steps + 1). */
int *prev_nodes; /* Store the path, in reversed order (from destination to source node), as indices. */
BLI_AStarGNLink **prev_links; /* Indices are nodes' ones, as prev_nodes, but they map to relevant link. */
void *custom_data;
/* Mostly runtime data. */
BLI_bitmap *done_nodes;
float *g_costs;
int *g_steps;
struct MemArena *mem; /* Memory arena. */
} BLI_AStarSolution;
typedef struct BLI_AStarGraph {
int node_num;
BLI_AStarGNode *nodes;
void *custom_data;
struct MemArena *mem; /* Memory arena. */
} BLI_AStarGraph;
void BLI_astar_node_init(BLI_AStarGraph *as_graph, const int node_index, void *custom_data);
void BLI_astar_node_link_add(
BLI_AStarGraph *as_graph, const int node1_index, const int node2_index, const float cost, void *custom_data);
int BLI_astar_node_link_other_node(BLI_AStarGNLink *lnk, const int idx);
void BLI_astar_solution_init(BLI_AStarGraph *as_graph, BLI_AStarSolution *as_solution, void *custom_data);
void BLI_astar_solution_clear(BLI_AStarSolution *as_solution);
void BLI_astar_solution_free(BLI_AStarSolution *as_solution);
/**
* Callback computing the current cost (distance) to next node, and the estimated overall cost to destination node
* (A* expects this estimation to always be less or equal than actual shortest path from next node to destination one).
*
* \param link the graph link between current node and next one.
* \param node_idx_curr current node index.
* \param node_idx_next next node index.
* \param node_idx_dst destination node index.
*/
typedef float (*astar_f_cost)(BLI_AStarGraph *as_graph, BLI_AStarSolution *as_solution, BLI_AStarGNLink *link,
const int node_idx_curr, const int node_idx_next, const int node_idx_dst);
void BLI_astar_graph_init(BLI_AStarGraph *as_graph, const int node_num, void *custom_data);
void BLI_astar_graph_free(BLI_AStarGraph *as_graph);
bool BLI_astar_graph_solve(
BLI_AStarGraph *as_graph, const int node_index_src, const int node_index_dst, astar_f_cost f_cost_cb,
BLI_AStarSolution *r_solution, const int max_steps);
#endif /* __BLI_ASTAR_H__ */
|
