126 lines
4.0 KiB
C
126 lines
4.0 KiB
C
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* The Original Code is Copyright (C) 2014 Blender Foundation.
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* All rights reserved.
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*/
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#ifndef __BLI_ASTAR_H__
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#define __BLI_ASTAR_H__
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/** \file
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* \ingroup bli
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* \brief An implementation of the A* (AStar) algorithm to solve shortest path problem.
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*/
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#include "BLI_utildefines.h"
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#include "BLI_bitmap.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* -------------------------------------------------------------------- */
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typedef struct BLI_AStarGNLink {
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int nodes[2];
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float cost;
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void *custom_data;
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} BLI_AStarGNLink;
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typedef struct BLI_AStarGNode {
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struct ListBase neighbor_links;
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void *custom_data;
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} BLI_AStarGNode;
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typedef struct BLI_AStarSolution {
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/* Final 'most useful' data. */
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/** Number of steps (i.e. walked links) in path
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* (nodes num, including start and end, is steps + 1). */
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int steps;
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/** Store the path, in reversed order (from destination to source node), as indices. */
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int *prev_nodes;
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/** Indices are nodes' ones, as prev_nodes, but they map to relevant link. */
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BLI_AStarGNLink **prev_links;
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void *custom_data;
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/* Mostly runtime data. */
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BLI_bitmap *done_nodes;
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float *g_costs;
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int *g_steps;
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struct MemArena *mem; /* Memory arena. */
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} BLI_AStarSolution;
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typedef struct BLI_AStarGraph {
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int node_num;
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BLI_AStarGNode *nodes;
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void *custom_data;
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struct MemArena *mem; /* Memory arena. */
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} BLI_AStarGraph;
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void BLI_astar_node_init(BLI_AStarGraph *as_graph, const int node_index, void *custom_data);
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void BLI_astar_node_link_add(BLI_AStarGraph *as_graph,
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const int node1_index,
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const int node2_index,
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const float cost,
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void *custom_data);
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int BLI_astar_node_link_other_node(BLI_AStarGNLink *lnk, const int idx);
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void BLI_astar_solution_init(BLI_AStarGraph *as_graph,
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BLI_AStarSolution *as_solution,
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void *custom_data);
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void BLI_astar_solution_clear(BLI_AStarSolution *as_solution);
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void BLI_astar_solution_free(BLI_AStarSolution *as_solution);
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/**
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* Callback computing the current cost (distance) to next node,
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* and the estimated overall cost to destination node
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* (A* expects this estimation to always be less or equal than actual shortest path
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* from next node to destination one).
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*
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* \param link: the graph link between current node and next one.
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* \param node_idx_curr: current node index.
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* \param node_idx_next: next node index.
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* \param node_idx_dst: destination node index.
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*/
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typedef float (*astar_f_cost)(BLI_AStarGraph *as_graph,
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BLI_AStarSolution *as_solution,
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BLI_AStarGNLink *link,
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const int node_idx_curr,
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const int node_idx_next,
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const int node_idx_dst);
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void BLI_astar_graph_init(BLI_AStarGraph *as_graph, const int node_num, void *custom_data);
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void BLI_astar_graph_free(BLI_AStarGraph *as_graph);
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bool BLI_astar_graph_solve(BLI_AStarGraph *as_graph,
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const int node_index_src,
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const int node_index_dst,
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astar_f_cost f_cost_cb,
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BLI_AStarSolution *r_solution,
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const int max_steps);
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#ifdef __cplusplus
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}
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#endif
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#endif /* __BLI_ASTAR_H__ */
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