BLI: add 'A*' (AStar) shortest path solver algorithm.

Needed for transfer data.

1 files changed, 98 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_astar.h b/source/blender/blenlib/BLI_astar.h
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+++ b/source/blender/blenlib/BLI_astar.h
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+/*
+ * ***** 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);
+
+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__ */