/* src/server/ai.c */
#include "ai.h"
-#include <stdint.h> /* uint8_t, uint16_t */
+#include <stddef.h> /* NULL */
+#include <stdint.h> /* uint8_t, uint16_t, uint32_t, UINT16_MAX */
#include <stdlib.h> /* free() */
-#include <string.h> /* strlen(), memset() */
#include "../common/try_malloc.h" /* try_malloc() */
-#include "../common/yx_uint16.h" /* struct yx_uint16 */
#include "map_object_actions.h" /* get_moa_id_by_name() */
#include "map_objects.h" /* struct MapObj */
#include "world.h" /* global world */
-#include "yx_uint16.h" /* yx_uint16_cmp(), mv_yx_in_dir() */
-/* Change cardinal direction string ("NNE" etc.) of any length >1 pointed to by
- * "path_ptr" one step clockwise ("NNE" -> "NEE", "NEE" -> "EEE" etc.).
+#define N_DIRS 6
+
+
+
+/* Write into "neighbors" scores of the N_DIRS immediate neighbors of the
+ * "score_map" cell at "pos_i" (array index), as found in the directions
+ * north-east, east, south-east etc. (clockwise order). Use "max_score" for
+ * illegal neighborhoods (i.e. if direction would lead beyond the map's border).
+ */
+static void get_neighbor_scores(uint16_t * score_map, uint16_t pos_i,
+ uint16_t max_score, uint16_t * neighbors);
+
+/* Iterate over scored cells in "score_map" of world.map's geometry. Compare
+ * each cell's score against the score of its immediate neighbors in N_DIRS
+ * directions. If it's neighbors are low enough that the result would be lower
+ * than the current value, re-set it to 1 point higher than its lowest-scored
+ * neighbor- Repeat this whole process until all cells have settled on their
+ * final score. Ignore cells whose position in "score_map" fits cells of
+ * unreachable terrain in world.map.cells. Expect "max_score" to be the maximum
+ * score for cells, marking them as unreachable.
*/
-static void clockwise_path(char ** path_ptr);
+static void dijkstra_map(uint16_t * score_map, uint16_t max_score);
-/* Return dir char (north = "N" etc.) to enemy nearest to "origin" (beeline). */
-static char nearest_enemy_dir(struct yx_uint16 origin);
+/* Return numpad char of direction ("8", "6", "2", "4" etc.) of enemy with the
+ * shortest path to "mo_origin". If no enemy is around, return 0.
+ */
+static char get_dir_to_nearest_enemy(struct MapObj * mo_origin);
-static void clockwise_path(char ** path_ptr)
+static void get_neighbor_scores(uint16_t * score_map, uint16_t pos_i,
+ uint16_t max_score, uint16_t * neighbors)
{
- char * path = * path_ptr;
- char old_char = path[0];
- char new_char = 'N';
- if ('N' == old_char)
+ uint32_t map_size = world.map.size.y * world.map.size.x;
+ uint8_t i_dir;
+ for (i_dir = 0; i_dir < N_DIRS; neighbors[i_dir] = max_score, i_dir++);
+ uint8_t open_north = pos_i >= world.map.size.x;
+ uint8_t open_east = pos_i + 1 % world.map.size.x;
+ uint8_t open_south = pos_i + world.map.size.x < map_size;
+ uint8_t open_west = pos_i % world.map.size.x;
+ uint8_t is_indented = (pos_i / world.map.size.x) % 2;
+ uint8_t open_diag_west = is_indented || open_west;
+ uint8_t open_diag_east = !is_indented || open_east;
+ if (open_north && open_diag_east)
{
- new_char = 'E';
+ neighbors[0] = score_map[pos_i - world.map.size.x + is_indented];
}
- else if ('E' == old_char)
+ if (open_east)
{
- new_char = 'S';
+ neighbors[1] = score_map[pos_i + 1];
}
- else if ('S' == old_char)
+ if (open_south && open_diag_east)
{
- new_char = 'W';
+ neighbors[2] = score_map[pos_i + world.map.size.x + is_indented];
}
- uint8_t len = strlen(path);
- uint8_t i = 0;
- for (; i < len; i++)
+ if (open_south && open_diag_west)
{
- uint8_t next_i = i + 1;
- if (next_i == len || old_char != path[next_i])
- {
- break;
- }
+ neighbors[3] = score_map[pos_i + world.map.size.x - !is_indented];
+ }
+ if (open_west)
+ {
+ neighbors[4] = score_map[pos_i - 1];
+ }
+ if (open_north && open_diag_west)
+ {
+ neighbors[5] = score_map[pos_i - world.map.size.x - !is_indented];
}
- path[i] = new_char;
}
-static char nearest_enemy_dir(struct yx_uint16 origin)
+static void dijkstra_map(uint16_t * score_map, uint16_t max_score)
{
- char * f_name = "nearest_enemy_dir()";
- struct MapObj * mo;
- char sel = 0;
- uint16_t dist_max = world.map.size.y;
- if (world.map.size.x > world.map.size.y)
+ uint32_t map_size = world.map.size.y * world.map.size.x;
+ uint16_t pos, i_scans, neighbors[N_DIRS], min_neighbor;
+ uint8_t scores_still_changing = 1;
+ uint8_t i_dirs;
+ for (i_scans = 0; scores_still_changing; i_scans++)
{
- dist_max = world.map.size.x;
- }
- uint8_t escape = 0;
- uint8_t dist, j;
- uint16_t i;
- for (dist = 1; !escape && dist <= dist_max; dist++)
- {
- char * path = try_malloc(dist + 1, f_name);
- memset(path, 'N', dist);
- path[dist] = '\0';
- for (i = 0; !escape && i < (dist * 4); i++)
+ scores_still_changing = 0;
+ for (pos = 0; pos < map_size; pos++)
{
- clockwise_path(&path);
- struct yx_uint16 testpos = origin;
- for (j = 0; j < dist; j++)
+ if ('.' == world.map.cells[pos])
{
- testpos = mv_yx_in_dir(path[j], testpos);
- }
- if (yx_uint16_cmp(&testpos, &origin) ||
- testpos.y > world.map.size.y || testpos.x > world.map.size.x)
- {
- continue;
- }
- for (mo = world.map_objs; mo != 0; mo = mo->next)
- {
- if (mo->lifepoints && 1 == yx_uint16_cmp(&testpos, &mo->pos))
+ get_neighbor_scores(score_map, pos, max_score, neighbors);
+ min_neighbor = max_score;
+ for (i_dirs = 0; i_dirs < N_DIRS; i_dirs++)
{
- sel = path[0];
- escape = 1;
- break;
+ if (min_neighbor > neighbors[i_dirs])
+ {
+ min_neighbor = neighbors[i_dirs];
+ }
+ }
+ if (score_map[pos] > min_neighbor + 1)
+ {
+ score_map[pos] = min_neighbor + 1;
+ scores_still_changing = 1;
}
}
}
- free(path);
}
- return sel;
}
-extern void pretty_dumb_ai(struct MapObj * mo)
+static char get_dir_to_nearest_enemy(struct MapObj * mo_origin)
+{
+ char * f_name = "get_dir_to_nearest_enemy()";
+
+ /* Calculate for each cell the distance to the nearest map actor that is
+ * not "mo_origin", with movement only possible in the directions of "dir".
+ * (Actors' own cells start with a distance of 0 towards themselves.)
+ */
+ uint32_t map_size = world.map.size.y * world.map.size.x;
+ uint16_t max_score = UINT16_MAX;
+ uint16_t * score_map = try_malloc(map_size * sizeof(uint16_t), f_name);
+ uint32_t i;
+ for (i = 0; i < map_size; i++)
+ {
+ score_map[i] = max_score;
+ }
+ struct MapObj * mo = world.map_objs;
+ for (; mo != NULL; mo = mo->next)
+ {
+ if (!mo->lifepoints || mo == mo_origin)
+ {
+ continue;
+ }
+ score_map[(mo->pos.y * world.map.size.x) + mo->pos.x] = 0;
+ }
+ dijkstra_map(score_map, max_score);
+
+ /* Return direction of "mo_origin"'s lowest-scored neighbor cell. */
+ uint16_t neighbors[N_DIRS];
+ uint16_t pos_i = (mo_origin->pos.y * world.map.size.x) + mo_origin->pos.x;
+ get_neighbor_scores(score_map, pos_i, max_score, neighbors);
+ free(score_map);
+ char dir_to_nearest_enemy = 0;
+ uint16_t min_neighbor = max_score;
+ char * dirs = "edcxsw"; /* get_neighbor_scores()'s clockwise dir order.*/
+ for (i = 0; i < N_DIRS; i++)
+ {
+ if (min_neighbor > neighbors[i])
+ {
+ min_neighbor = neighbors[i];
+ dir_to_nearest_enemy = dirs[i];
+ }
+ }
+ return dir_to_nearest_enemy;
+}
+
+
+
+extern void ai(struct MapObj * mo)
{
mo->command = get_moa_id_by_name("wait");
- char sel = nearest_enemy_dir(mo->pos);
+ char sel = get_dir_to_nearest_enemy(mo);
if (0 != sel)
{
mo->command = get_moa_id_by_name("move");
projects / plomrogue / blobdiff