-#include <math.h> /* pow() */
-#include <stddef.h> /* NULL */
-#include <stdint.h> /* ?(u)int(8|16|32)_t, ?(U)INT8_(MIN|MAX) */
-#include <stdlib.h> /* free, malloc */
-#include <string.h> /* memset */
-
-/* Number of degrees a circle is divided into. The greater it is, the greater
- * the angle precision. But make it one whole zero larger and bizarre FOV bugs
- * appear on large maps, probably due to value overflows (TODO: more research!).
- */
-#define CIRCLE 3600000
-
-/* Angle of a shadow. */
-struct shadow_angle
-{
- struct shadow_angle * next;
- uint32_t left_angle;
- uint32_t right_angle;
-};
-
-/* To be used as temporary storage for world map array. */
-static char * worldmap = NULL;
-
-/* Coordinate for maps of max. 256x256 cells. */
-struct yx_uint8
-{
- uint8_t y;
- uint8_t x;
-};
-
-/* Storage for map_length, set by set_maplength(). */
-static uint16_t maplength = 0;
-extern void set_maplength(uint16_t maplength_input)
-{
- maplength = maplength_input;
-}
-
-/* Pseudo-randomness seed for rrand(), set by seed_rrand(). */
-static uint32_t seed = 0;
-
-/* Helper to mv_yx_in_dir_legal(). Move "yx" into hex direction "d". */
-static void mv_yx_in_dir(char d, struct yx_uint8 * yx)
-{
- if (d == 'e')
- {
- yx->x = yx->x + (yx->y % 2);
- yx->y--;
- }
- else if (d == 'd')
- {
- yx->x++;
- }
- else if (d == 'c')
- {
- yx->x = yx->x + (yx->y % 2);
- yx->y++;
- }
- else if (d == 'x')
- {
- yx->x = yx->x - !(yx->y % 2);
- yx->y++;
- }
- else if (d == 's')
- {
- yx->x--;
- }
- else if (d == 'w')
- {
- yx->x = yx->x - !(yx->y % 2);
- yx->y--;
- }
-}
-
-/* Move "yx" into hex direction "dir". Available hex directions are: 'e'
- * (north-east), 'd' (east), 'c' (south-east), 'x' (south-west), 's' (west), 'w'
- * (north-west). Returns 1 if the move was legal, 0 if not, and -1 when internal
- * wrapping limits were exceeded.
- *
- * A move is legal if "yx" ends up within the the map and the original wrap
- * space. The latter is left to a neighbor wrap space if "yx" moves beyond the
- * minimal (0) or maximal (UINT8_MAX) column or row of possible map space – in
- * which case "yx".y or "yx".x will snap to the respective opposite side. The
- * current wrapping state is kept between successive calls until a "yx" of NULL
- * is passed, in which case the function does nothing but zero the wrap state.
- * Successive wrapping may move "yx" several wrap spaces into either direction,
- * or return it into the original wrap space.
- */
-static int8_t mv_yx_in_dir_legal(char dir, struct yx_uint8 * yx)
-{
- static int8_t wrap_west_east = 0;
- static int8_t wrap_north_south = 0;
- if (!yx)
- {
- wrap_west_east = wrap_north_south = 0;
- return 0;
- }
- if ( INT8_MIN == wrap_west_east || INT8_MIN == wrap_north_south
- || INT8_MAX == wrap_west_east || INT8_MAX == wrap_north_south)
- {
- return -1;
- }
- struct yx_uint8 original = *yx;
- mv_yx_in_dir(dir, yx);
- if (('e' == dir || 'd' == dir || 'c' == dir) && yx->x < original.x)
- {
- wrap_west_east++;
- }
- else if (('x' == dir || 's' == dir || 'w' == dir) && yx->x > original.x)
- {
- wrap_west_east--;
- }
- if (('w' == dir || 'e' == dir) && yx->y > original.y)
- {
- wrap_north_south--;
- }
- else if (('x' == dir || 'c' == dir) && yx->y < original.y)
- {
- wrap_north_south++;
- }
- if ( !wrap_west_east && !wrap_north_south
- && yx->x < maplength && yx->y < maplength)
- {
- return 1;
- }
- return 0;
-}
-
-/* Wrapper around mv_yx_in_dir_legal() that stores new coordinate in res_y/x,
- * (return with result_y/x()), and immediately resets the wrapping.
- */
-static uint8_t res_y = 0;
-static uint8_t res_x = 0;
-extern uint8_t mv_yx_in_dir_legal_wrap(char dir, uint8_t y, uint8_t x)
-{
- struct yx_uint8 yx;
- yx.y = y;
- yx.x = x;
- uint8_t result = mv_yx_in_dir_legal(dir, &yx);
- mv_yx_in_dir_legal(0, NULL);
- res_y = yx.y;
- res_x = yx.x;
- return result;
-}
-extern uint8_t result_y()
-{
- return res_y;
-}
-extern uint8_t result_x()
-{
- return res_x;
-}
-
-/* With set_seed set, set seed global to seed_input. In any case, return it. */
-extern uint32_t seed_rrand(uint8_t set_seed, uint32_t seed_input)
-{
- if (set_seed)
- {
- seed = seed_input;
- }
- return seed;
-}
-
-/* Return 16-bit number pseudo-randomly generated via Linear Congruential
- * Generator algorithm with some proven constants. Use instead of any rand() to
- * ensure portability of the same pseudo-randomness across systems.
- */
-extern uint16_t rrand()
-{ /* Constants as recommended by POSIX.1-2001 (see man page rand(3)). */
- seed = ((seed * 1103515245) + 12345) % 4294967296;
- return (seed >> 16); /* Ignore less random least significant bits. */
-}
-
-/* Free shadow angles list "angles". */
-static void free_angles(struct shadow_angle * angles)
-{
- if (angles->next)
- {
- free_angles(angles->next);
- }
- free(angles);
-}
-
-/* Recalculate angle < 0 or > CIRCLE to a value between these two limits. */
-static uint32_t correct_angle(int32_t angle)
-{
- while (angle < 0)
- {
- angle = angle + CIRCLE;
- }
- while (angle > CIRCLE)
- {
- angle = angle - CIRCLE;
- }
- return angle;
-}
-
-/* Try merging the angle between "left_angle" and "right_angle" to "shadow" if
- * it meets the shadow from the right or the left. Returns 1 on success, else 0.
- */
-static uint8_t try_merge(struct shadow_angle * shadow,
- uint32_t left_angle, uint32_t right_angle)
-{
- if ( shadow->right_angle <= left_angle + 1
- && shadow->right_angle >= right_angle)
- {
- shadow->right_angle = right_angle;
- }
- else if ( shadow->left_angle + 1 >= right_angle
- && shadow->left_angle <= left_angle)
- {
- shadow->left_angle = left_angle;
- }
- else
- {
- return 0;
- }
- return 1;
-}
-
-/* Try merging the shadow angle between "left_angle" and "right_angle" into an
- * existing shadow angle in "shadows". On success, see if this leads to any
- * additional shadow angle overlaps and merge these accordingly. Return 1 on
- * success, else 0.
- */
-static uint8_t try_merging_angles(uint32_t left_angle, uint32_t right_angle,
- struct shadow_angle ** shadows)
-{
- uint8_t angle_merge = 0;
- struct shadow_angle * shadow;
- for (shadow = *shadows; shadow; shadow = shadow->next)
- {
- if (try_merge(shadow, left_angle, right_angle))
- {
- angle_merge = 1;
- }
- }
- if (angle_merge)
- {
- struct shadow_angle * shadow1;
- for (shadow1 = *shadows; shadow1; shadow1 = shadow1->next)
- {
- struct shadow_angle * last_shadow = NULL;
- struct shadow_angle * shadow2;
- for (shadow2 = *shadows; shadow2; shadow2 = shadow2->next)
- {
- if ( shadow1 != shadow2
- && try_merge(shadow1, shadow2->left_angle,
- shadow2->right_angle))
- {
- struct shadow_angle * to_free = shadow2;
- if (last_shadow)
- {
- last_shadow->next = shadow2->next;
- shadow2 = last_shadow;
- }
- else
- {
- *shadows = shadow2->next;
- shadow2 = *shadows;
- }
- free(to_free);
- }
- last_shadow = shadow2;
- }
- }
- }
- return angle_merge;
-}
-
-/* To "shadows", add shadow defined by "left_angle" and "right_angle", either as
- * new entry or as part of an existing shadow (swallowed whole or extending it).
- * Return 1 on malloc error, else 0.
- */
-static uint8_t set_shadow(uint32_t left_angle, uint32_t right_angle,
- struct shadow_angle ** shadows)
-{
- struct shadow_angle * shadow_i;
- if (!try_merging_angles(left_angle, right_angle, shadows))
- {
- struct shadow_angle * shadow;
- shadow = malloc(sizeof(struct shadow_angle));
- if (!shadow)
- {
- return 1;
- }
- shadow->left_angle = left_angle;
- shadow->right_angle = right_angle;
- shadow->next = NULL;
- if (*shadows)
- {
- for (shadow_i = *shadows; shadow_i; shadow_i = shadow_i->next)
- {
- if (!shadow_i->next)
- {
- shadow_i->next = shadow;
- return 0;
- }
- }
- }
- *shadows = shadow;
- }
- return 0;
-}
-
-/* Test whether angle between "left_angle" and "right_angle", or at least
- * "middle_angle", is captured inside one of the shadow angles in "shadows". If
- * so, set hex in "fov_map" indexed by "pos_in_map" to 'H'. If the whole angle
- * and not just "middle_angle" is captured, return 1. Any other case: 0.
- */
-static uint8_t shade_hex(uint32_t left_angle, uint32_t right_angle,
- uint32_t middle_angle, struct shadow_angle ** shadows,
- uint16_t pos_in_map, char * fov_map)
-{
- struct shadow_angle * shadow_i;
- if (fov_map[pos_in_map] == 'v')
- {
- for (shadow_i = *shadows; shadow_i; shadow_i = shadow_i->next)
- {
- if ( left_angle <= shadow_i->left_angle
- && right_angle >= shadow_i->right_angle)
- {
- fov_map[pos_in_map] = 'H';
- return 1;
- }
- if ( middle_angle < shadow_i->left_angle
- && middle_angle > shadow_i->right_angle)
- {
- fov_map[pos_in_map] = 'H';
- }
- }
- }
- return 0;
-}
-
-/* Evaluate map position "test_pos" in distance "dist" to the view origin, and
- * on the circle of that distance to the origin on hex "hex_i" (as counted from
- * the circle's rightmost point), for setting shaded hexes in "fov_map" and
- * potentially adding a new shadow to linked shadow angle list "shadows".
- * Return 1 on malloc error, else 0.
- */
-static uint8_t eval_position(uint16_t dist, uint16_t hex_i, char * fov_map,
- struct yx_uint8 * test_pos,
- struct shadow_angle ** shadows)
-{
- int32_t left_angle_uncorrected = ((CIRCLE / 12) / dist)
- - (hex_i * (CIRCLE / 6) / dist);
- int32_t right_angle_uncorrected = left_angle_uncorrected
- - (CIRCLE / (6 * dist));
- uint32_t left_angle = correct_angle(left_angle_uncorrected);
- uint32_t right_angle = correct_angle(right_angle_uncorrected);
- uint32_t right_angle_1st = right_angle > left_angle ? 0 : right_angle;
- uint32_t middle_angle = 0;
- if (right_angle_1st)
- {
- middle_angle = right_angle + ((left_angle - right_angle) / 2);
- }
- uint16_t pos_in_map = test_pos->y * maplength + test_pos->x;
- uint8_t all_shaded = shade_hex(left_angle, right_angle_1st, middle_angle,
- shadows, pos_in_map, fov_map);
- if (!all_shaded && 'X' == worldmap[pos_in_map])
- {
- if (set_shadow(left_angle, right_angle_1st, shadows))
- {
- return 1;
- }
- if (right_angle_1st != right_angle)
- {
- left_angle = CIRCLE;
- if (set_shadow(left_angle, right_angle, shadows))
- {
- return 1;
- }
- }
- }
- return 0;
-}
-
-/* Update field of view in "fovmap" of "worldmap_input" as seen from "y"/"x".
- * Return 1 on malloc error, else 0.
- */
-extern uint8_t build_fov_map(uint8_t y, uint8_t x,
- char * fovmap, char * worldmap_input)
-{
- worldmap = worldmap_input;
- struct shadow_angle * shadows = NULL;
- struct yx_uint8 test_pos;
- test_pos.y = y;
- test_pos.x = x;
- char * circledirs_string = "xswedc";
- uint16_t circle_i;
- uint8_t circle_is_on_map;
- for (circle_i = 1, circle_is_on_map = 1; circle_is_on_map; circle_i++)
- {
- circle_is_on_map = 0;
- if (1 < circle_i) /* All circles but the 1st are */
- { /* moved into starting from a */
- mv_yx_in_dir_legal('c', &test_pos);/* previous circle's last hex, */
- } /* i.e. from the upper left. */
- char dir_char = 'd'; /* Circle's 1st hex is entered by rightward move.*/
- uint8_t dir_char_pos_in_circledirs_string = UINT8_MAX;
- uint16_t dist_i, hex_i;
- for (hex_i=0, dist_i=circle_i; hex_i < 6 * circle_i; dist_i++, hex_i++)
- {
- if (circle_i < dist_i)
- {
- dist_i = 1;
- dir_char=circledirs_string[++dir_char_pos_in_circledirs_string];
- }
- if (mv_yx_in_dir_legal(dir_char, &test_pos))
- {
- if (eval_position(circle_i, hex_i, fovmap, &test_pos, &shadows))
- {
- return 1;
- }
- circle_is_on_map = 1;
- }
- }
- }
- mv_yx_in_dir_legal(0, NULL);
- free_angles(shadows);
- return 0;
-}
-
-static uint16_t * score_map = NULL;
-static uint16_t neighbor_scores[6];
-
-/* Init AI score map. Return 1 on failure, else 0. */
-extern uint8_t init_score_map()
-{
- uint32_t map_size = maplength * maplength;
- score_map = malloc(map_size * sizeof(uint16_t));
- if (!score_map)
- {
- return 1;
- }
- uint32_t i = 0;
- for (; i < map_size; i++)
- {
- score_map[i] = UINT16_MAX;
- }
- return 0;
-}
-
-/* Set score_map[pos] to score. Return 1 on failure, else 0. */
-extern uint8_t set_map_score(uint16_t pos, uint16_t score)
-{
- if (!score_map)
- {
- return 1;
- }
- score_map[pos] = score;
- return 0;
-}
-
-/* Get score_map[pos]. Return uint16_t value on success, -1 on failure. */
-extern int32_t get_map_score(uint16_t pos)
-{
- if (!score_map)
- {
- return -1;
- }
- return score_map[pos];
-}
-
-/* Free score_map. */
-extern void free_score_map()
-{
- free(score_map);
- score_map = NULL;
-}
-
-/* Write into "neighbors" scores of the 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 kill_score for illegal neighborhoods
- * (i.e. if direction would lead beyond the map's border).
- */
-static void get_neighbor_scores(uint16_t pos_i, uint16_t kill_score,
- uint16_t * neighbors)
-{
- uint32_t map_size = maplength * maplength;
- uint8_t open_north = pos_i >= maplength;
- uint8_t open_east = pos_i + 1 % maplength;
- uint8_t open_south = pos_i + maplength < map_size;
- uint8_t open_west = pos_i % maplength;
- uint8_t is_indented = (pos_i / maplength) % 2;
- uint8_t open_diag_west = is_indented || open_west;
- uint8_t open_diag_east = !is_indented || open_east;
- neighbors[0] = !(open_north && open_diag_east) ? kill_score :
- score_map[pos_i - maplength + is_indented];
- neighbors[1] = !(open_east) ? kill_score : score_map[pos_i + 1];
- neighbors[2] = !(open_south && open_diag_east) ? kill_score :
- score_map[pos_i + maplength + is_indented];
- neighbors[3] = !(open_south && open_diag_west) ? kill_score :
- score_map[pos_i + maplength - !is_indented];
- neighbors[4] = !(open_west) ? kill_score : score_map[pos_i - 1];
- neighbors[5] = !(open_north && open_diag_west) ? kill_score :
- score_map[pos_i - maplength - !is_indented];
-}
-
-/* Call get_neighbor_scores() on neighbor_scores buffer. Return 1 on error. */
-extern uint8_t ready_neighbor_scores(uint16_t pos)
-{
- if (!score_map)
- {
- return 1;
- }
- get_neighbor_scores(pos, UINT16_MAX, neighbor_scores);
- return 0;
-}
-
-/* Return i-th position from neighbor_scores buffer.*/
-extern uint16_t get_neighbor_score(uint8_t i)
-{
- return neighbor_scores[i];
-}
-
-/* Iterate over scored cells in score_map geometry. Compare each cell's score
- * against the score of its immediate neighbors in 6 directions. If any
- * neighbor's score is at least two points lower than the current cell's score,
- * 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 score is greater than UINT16_MAX - 1 (treat those as unreachable).
- * Return 1 on error, else 0.
- */
-extern uint8_t dijkstra_map()
-{
- if (!score_map)
- {
- return 1;
- }
- uint16_t max_score = UINT16_MAX - 1;
- uint32_t map_size = maplength * maplength;
- uint32_t pos;
- uint16_t i_scans, neighbors[6], min_neighbor;
- uint8_t scores_still_changing = 1;
- uint8_t i_dirs;
- for (i_scans = 0; scores_still_changing; i_scans++)
- {
- scores_still_changing = 0;
- for (pos = 0; pos < map_size; pos++)
- {
- if (score_map[pos] <= max_score)
- {
- get_neighbor_scores(pos, max_score, neighbors);
- min_neighbor = max_score;
- for (i_dirs = 0; i_dirs < 6; i_dirs++)
- {
- 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;
- }
- }
- }
- }
- return 0;
-}
-
-extern uint8_t zero_score_map_where_char_on_memdepthmap(char c,
- char * memdepthmap)
-{
- if (!score_map)
- {
- return 1;
- }
- uint32_t map_size = maplength * maplength;
- uint16_t pos;
- for (pos = 0; pos < map_size; pos++)
- {
- if (c == memdepthmap[pos])
- {
- score_map[pos] = 0;
- }
- }
- return 0;
-}
-
-extern void age_some_memdepthmap_on_nonfov_cells(char * memdepthmap,
- char * fovmap)
-{
- uint32_t map_size = maplength * maplength;
- uint16_t pos;
- for (pos = 0; pos < map_size; pos++)
- {
- if ('v' != fovmap[pos])
- {
- char c = memdepthmap[pos];
- if( '0' <= c && '9' > c && !(rrand() % (uint16_t) pow(2, c - 48)))
- {
- memdepthmap[pos]++;
- }
- }
- }
-}
projects / plomrogue / commitdiff