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fairland: Replace distance_to_land(), distance_to_sea()

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distance_to_land() searches for closest land sector, and
distance_to_sea() for the closest sea sector.  We already have a more
efficient alternative: the breadth-first search recently added for
spheres of influence can precompute these distances.  Put it to use,
and retire distance_to_land() and distance_to_sea().

distance_to_what() could now be simplified.  Don't bother, because
it'll soon be deleted entirely.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
This commit is contained in:
Markus Armbruster 2020-08-16 14:01:32 +02:00
parent 7f1bbcad94
commit fb2bd2408e
1 changed files with 27 additions and 8 deletions
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35
src/util/fairland.c
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@ -240,7 +240,8 @@ static unsigned cur_seen;
/*
* Closest continent and "distance"
* closest[XYOFFSET(x, y)] is the closest continent's number.
* distance[] is complicated; see init_spheres_of_influence().
* distance[] is complicated; see init_spheres_of_influence() and
* init_distance_to_coast().
*/
static natid *closest;
static unsigned short *distance;
@ -962,6 +963,24 @@ init_spheres_of_influence(void)
bfs_run_queue();
}
/*
* Precompute distance to coast
* Set distance[XYOFFSET(x, y)] to the distance to the closest coastal
* land sector.
* Set closest[XYOFFSET(x, y)] to the closest continent's number,
* -1 if no single continent is closest.
*/
static void
init_distance_to_coast(void)
{
int c;
bfs_init();
for (c = 0; c < nc + ni; c++)
bfs_enqueue_island(c);
bfs_run_queue();
}
/*
* Is @x,@y in the same sphere of influence as island @c?
* Always true when @c is a continent.
@ -1266,6 +1285,7 @@ create_elevations(void)
for (j = 0; j < WORLD_Y; j++)
elev[i][j] = -INFINITE_ELEVATION;
}
init_distance_to_coast();
elevate_land();
elevate_sea();
}
@ -1301,7 +1321,6 @@ distance_to_what(int x, int y, int flag)
return d;
}
#define distance_to_sea() (sectc[c][i]?1:distance_to_what(sectx[c][i], secty[c][i], 0))
#define distance_to_mountain() distance_to_what(sectx[c][i], secty[c][i], 2)
/* Decide where the mountains go
@ -1309,7 +1328,7 @@ distance_to_what(int x, int y, int flag)
static void
elevate_land(void)
{
int i, mountain_search, k, c, total, ns, nm, r, x, y;
int i, off, mountain_search, k, c, total, ns, nm, r, x, y;
int highest, where, h, newk, dk;
for (c = 0; c < nc + ni; ++c) {
@ -1320,7 +1339,8 @@ elevate_land(void)
/* Place the mountains */
for (i = 0; i < ns; ++i) {
dsea[i] = distance_to_sea();
off = XYOFFSET(sectx[c][i], secty[c][i]);
dsea[i] = MIN(5, distance[off] + 1);
weight[i] = (total += (dsea[i] * dsea[i]));
}
@ -1400,17 +1420,16 @@ elevate_land(void)
}
}
#define distance_to_land() distance_to_what(x, y, 1)
static void
elevate_sea(void)
{
int x, y;
int x, y, off;
for (y = 0; y < WORLD_Y; ++y) {
for (x = y % 2; x < WORLD_X; x += 2) {
off = XYOFFSET(x, y);
if (elev[x][y] == -INFINITE_ELEVATION)
elev[x][y] = -roll(distance_to_land() * 20 + 27);
elev[x][y] = -roll(MIN(5, distance[off]) * 20 + 27);
}
}
}