154 lines
4.7 KiB
C
154 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
|
|
* Copyright 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;
|
|
|
|
/**
|
|
* Initialize a node in A* graph.
|
|
*
|
|
* \param custom_data: an opaque pointer attached to this link,
|
|
* available e.g. to cost callback function.
|
|
*/
|
|
void BLI_astar_node_init(BLI_AStarGraph *as_graph, int node_index, void *custom_data);
|
|
/**
|
|
* Add a link between two nodes of our A* graph.
|
|
*
|
|
* \param cost: The 'length' of the link
|
|
* (actual distance between two vertices or face centers e.g.).
|
|
* \param custom_data: An opaque pointer attached to this link,
|
|
* available e.g. to cost callback function.
|
|
*/
|
|
void BLI_astar_node_link_add(
|
|
BLI_AStarGraph *as_graph, int node1_index, int node2_index, float cost, void *custom_data);
|
|
/**
|
|
* \return The index of the other node of given link.
|
|
*/
|
|
int BLI_astar_node_link_other_node(BLI_AStarGNLink *lnk, int idx);
|
|
|
|
/**
|
|
* Initialize a solution data for given A* graph. Does not compute anything!
|
|
*
|
|
* \param custom_data: an opaque pointer attached to this link, available e.g
|
|
* . to cost callback function.
|
|
*
|
|
* \note BLI_AStarSolution stores nearly all data needed during solution compute.
|
|
*/
|
|
void BLI_astar_solution_init(BLI_AStarGraph *as_graph,
|
|
BLI_AStarSolution *as_solution,
|
|
void *custom_data);
|
|
/**
|
|
* Clear given solution's data, but does not release its memory.
|
|
* Avoids having to recreate/allocate a memarena in loops, e.g.
|
|
*
|
|
* \note This *has to be called* between each path solving.
|
|
*/
|
|
void BLI_astar_solution_clear(BLI_AStarSolution *as_solution);
|
|
/**
|
|
* Release the memory allocated for this 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,
|
|
int node_idx_curr,
|
|
int node_idx_next,
|
|
int node_idx_dst);
|
|
|
|
/**
|
|
* Initialize an A* graph. Total number of nodes must be known.
|
|
*
|
|
* Nodes might be e.g. vertices, faces, ... etc.
|
|
*
|
|
* \param custom_data: an opaque pointer attached to this link,
|
|
* available e.g. to cost callback function.
|
|
*/
|
|
void BLI_astar_graph_init(BLI_AStarGraph *as_graph, int node_num, void *custom_data);
|
|
void BLI_astar_graph_free(BLI_AStarGraph *as_graph);
|
|
/**
|
|
* Solve a path in given graph, using given 'cost' callback function.
|
|
*
|
|
* \param max_steps: maximum number of nodes the found path may have.
|
|
* Useful in performance-critical usages.
|
|
* If no path is found within given steps, returns false too.
|
|
* \return true if a path was found, false otherwise.
|
|
*/
|
|
bool BLI_astar_graph_solve(BLI_AStarGraph *as_graph,
|
|
int node_index_src,
|
|
int node_index_dst,
|
|
astar_f_cost f_cost_cb,
|
|
BLI_AStarSolution *r_solution,
|
|
int max_steps);
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|