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/*
* 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.
*/
#pragma once
/** \file
* \ingroup bli
* \brief An implementation of the A* (AStar) algorithm to solve shortest path problem.
*/
#include "BLI_utildefines.h"
#include "BLI_bitmap.h"
#ifdef __cplusplus
extern "C" {
#endif
/* -------------------------------------------------------------------- */
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. */
/** Number of steps (i.e. walked links) in path
* (nodes num, including start and end, is steps + 1). */
int steps;
/** Store the path, in reversed order (from destination to source node), as indices. */
int *prev_nodes;
/** Indices are nodes' ones, as prev_nodes, but they map to relevant link. */
BLI_AStarGNLink **prev_links;
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);
#ifdef __cplusplus
}
#endif
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