#include "path.hpp"
// path.cpp - Pathfinding system.
//
// Copyright © ????-2004 Athena Dev Teams
// Copyright © 2004-2011 The Mana World Development Team
// Copyright © 2011-2014 Ben Longbons <b.r.longbons@gmail.com>
// Copyright © 2013 Stefan Dombrowski
//
// This file is part of The Mana World (Athena server)
//
// 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 3 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, see <http://www.gnu.org/licenses/>.
#include <cassert>
#include <cstddef>
#include <cstdlib>
#include "../compat/nullpo.hpp"
#include "../strings/literal.hpp"
#include "../io/cxxstdio.hpp"
#include "magic-interpreter.t.hpp"
#include "map.hpp"
#include "../poison.hpp"
constexpr int MAX_HEAP = 150;
struct tmp_path
{
short x, y, dist, before, cost;
DIR dir;
char flag;
};
static
int calc_index(int x, int y)
{
return (x + y * MAX_WALKPATH) % (MAX_WALKPATH * MAX_WALKPATH);
}
/*==========================================
* 経路探索補助heap push
*------------------------------------------
*/
static
void push_heap_path(int *heap, struct tmp_path *tp, int index)
{
int i, h;
if (heap == NULL || tp == NULL)
{
PRINTF("push_heap_path nullpo\n"_fmt);
return;
}
heap[0]++;
for (h = heap[0] - 1, i = (h - 1) / 2;
h > 0 && tp[index].cost < tp[heap[i + 1]].cost; i = (h - 1) / 2)
heap[h + 1] = heap[i + 1], h = i;
heap[h + 1] = index;
}
/*==========================================
* 経路探索補助heap update
* costが減ったので根の方へ移動
*------------------------------------------
*/
static
void update_heap_path(int *heap, struct tmp_path *tp, int index)
{
int i, h;
nullpo_retv(heap);
nullpo_retv(tp);
for (h = 0; h < heap[0]; h++)
if (heap[h + 1] == index)
break;
if (h == heap[0])
{
FPRINTF(stderr, "update_heap_path bug\n"_fmt);
exit(1);
}
for (i = (h - 1) / 2;
h > 0 && tp[index].cost < tp[heap[i + 1]].cost; i = (h - 1) / 2)
heap[h + 1] = heap[i + 1], h = i;
heap[h + 1] = index;
}
/*==========================================
* 経路探索補助heap pop
*------------------------------------------
*/
static
int pop_heap_path(int *heap, struct tmp_path *tp)
{
int i, h, k;
int ret, last;
nullpo_retr(-1, heap);
nullpo_retr(-1, tp);
if (heap[0] <= 0)
return -1;
ret = heap[1];
last = heap[heap[0]];
heap[0]--;
for (h = 0, k = 2; k < heap[0]; k = k * 2 + 2)
{
if (tp[heap[k + 1]].cost > tp[heap[k]].cost)
k--;
heap[h + 1] = heap[k + 1], h = k;
}
if (k == heap[0])
heap[h + 1] = heap[k], h = k - 1;
for (i = (h - 1) / 2;
h > 0 && tp[heap[i + 1]].cost > tp[last].cost; i = (h - 1) / 2)
heap[h + 1] = heap[i + 1], h = i;
heap[h + 1] = last;
return ret;
}
/*==========================================
* 現在の点のcost計算
*------------------------------------------
*/
static
int calc_cost(struct tmp_path *p, int x1, int y1)
{
int xd, yd;
nullpo_ret(p);
xd = x1 - p->x;
if (xd < 0)
xd = -xd;
yd = y1 - p->y;
if (yd < 0)
yd = -yd;
return (xd + yd) * 10 + p->dist;
}
/*==========================================
* 必要ならpathを追加/修正する
*------------------------------------------
*/
static
int add_path(int *heap, struct tmp_path *tp, int x, int y, int dist,
DIR dir, int before, int x1, int y1)
{
int i;
nullpo_ret(heap);
nullpo_ret(tp);
i = calc_index(x, y);
if (tp[i].x == x && tp[i].y == y)
{
if (tp[i].dist > dist)
{
tp[i].dist = dist;
tp[i].dir = dir;
tp[i].before = before;
tp[i].cost = calc_cost(&tp[i], x1, y1);
if (tp[i].flag)
push_heap_path(heap, tp, i);
else
update_heap_path(heap, tp, i);
tp[i].flag = 0;
}
return 0;
}
if (tp[i].x || tp[i].y)
return 1;
tp[i].x = x;
tp[i].y = y;
tp[i].dist = dist;
tp[i].dir = dir;
tp[i].before = before;
tp[i].cost = calc_cost(&tp[i], x1, y1);
tp[i].flag = 0;
push_heap_path(heap, tp, i);
return 0;
}
/*==========================================
* (x,y)が移動不可能地帯かどうか
* flag 0x10000 遠距離攻撃判定
*------------------------------------------
*/
static
bool can_place(struct map_local *m, int x, int y)
{
nullpo_ret(m);
return !bool(read_gatp(m, x, y) & MapCell::UNWALKABLE);
}
/*==========================================
* (x0,y0)から(x1,y1)へ1歩で移動可能か計算
*------------------------------------------
*/
static
int can_move(struct map_local *m, int x0, int y0, int x1, int y1)
{
nullpo_ret(m);
if (x0 - x1 < -1 || x0 - x1 > 1 || y0 - y1 < -1 || y0 - y1 > 1)
return 0;
if (x1 < 0 || y1 < 0 || x1 >= m->xs || y1 >= m->ys)
return 0;
if (!can_place(m, x0, y0))
return 0;
if (!can_place(m, x1, y1))
return 0;
if (x0 == x1 || y0 == y1)
return 1;
if (!can_place(m, x0, y1) || !can_place(m, x1, y0))
return 0;
return 1;
}
/*==========================================
* path探索 (x0,y0)->(x1,y1)
*------------------------------------------
*/
int path_search(struct walkpath_data *wpd, map_local *m, int x0, int y0, int x1, int y1, int flag)
{
int heap[MAX_HEAP + 1];
int i, rp, x, y;
int dx, dy;
nullpo_ret(wpd);
assert (m->gat);
map_local *md = m;
if (x1 < 0 || x1 >= md->xs || y1 < 0 || y1 >= md->ys
|| bool(read_gatp(md, x1, y1) & MapCell::UNWALKABLE))
return -1;
// easy
dx = (x1 - x0 < 0) ? -1 : 1;
dy = (y1 - y0 < 0) ? -1 : 1;
for (x = x0, y = y0, i = 0; x != x1 || y != y1;)
{
if (i >= sizeof(wpd->path))
return -1;
if (x != x1 && y != y1)
{
if (!can_move(md, x, y, x + dx, y + dy))
break;
x += dx;
y += dy;
wpd->path[i++] = (dx < 0)
? ((dy > 0) ? DIR::SW : DIR::NW)
: ((dy < 0) ? DIR::NE : DIR::SE);
}
else if (x != x1)
{
if (!can_move(md, x, y, x + dx, y))
break;
x += dx;
wpd->path[i++] = (dx < 0) ? DIR::W : DIR::E;
}
else
{ // y!=y1
if (!can_move(md, x, y, x, y + dy))
break;
y += dy;
wpd->path[i++] = (dy > 0) ? DIR::S : DIR::N;
}
if (x == x1 && y == y1)
{
wpd->path_len = i;
wpd->path_pos = 0;
wpd->path_half = 0;
return 0;
}
}
if (flag & 1)
return -1;
struct tmp_path tp[MAX_WALKPATH * MAX_WALKPATH] {};
i = calc_index(x0, y0);
tp[i].x = x0;
tp[i].y = y0;
tp[i].dist = 0;
tp[i].dir = DIR::S;
tp[i].before = 0;
tp[i].cost = calc_cost(&tp[i], x1, y1);
tp[i].flag = 0;
heap[0] = 0;
push_heap_path(heap, tp, calc_index(x0, y0));
while (1)
{
int e = 0;
if (heap[0] == 0)
return -1;
rp = pop_heap_path(heap, tp);
x = tp[rp].x;
y = tp[rp].y;
if (x == x1 && y == y1)
{
int len, j;
for (len = 0, i = rp; len < 100 && i != calc_index(x0, y0);
i = tp[i].before, len++);
if (len == 100 || len >= sizeof(wpd->path))
return -1;
wpd->path_len = len;
wpd->path_pos = 0;
wpd->path_half = 0;
for (i = rp, j = len - 1; j >= 0; i = tp[i].before, j--)
wpd->path[j] = tp[i].dir;
return 0;
}
if (can_move(md, x, y, x + 1, y - 1))
e += add_path(heap, tp, x + 1, y - 1, tp[rp].dist + 14, DIR::NE, rp, x1, y1);
if (can_move(md, x, y, x + 1, y))
e += add_path(heap, tp, x + 1, y, tp[rp].dist + 10, DIR::E, rp, x1, y1);
if (can_move(md, x, y, x + 1, y + 1))
e += add_path(heap, tp, x + 1, y + 1, tp[rp].dist + 14, DIR::SE, rp, x1, y1);
if (can_move(md, x, y, x, y + 1))
e += add_path(heap, tp, x, y + 1, tp[rp].dist + 10, DIR::S, rp, x1, y1);
if (can_move(md, x, y, x - 1, y + 1))
e += add_path(heap, tp, x - 1, y + 1, tp[rp].dist + 14, DIR::SW, rp, x1, y1);
if (can_move(md, x, y, x - 1, y))
e += add_path(heap, tp, x - 1, y, tp[rp].dist + 10, DIR::W, rp, x1, y1);
if (can_move(md, x, y, x - 1, y - 1))
e += add_path(heap, tp, x - 1, y - 1, tp[rp].dist + 14, DIR::NW, rp, x1, y1);
if (can_move(md, x, y, x, y - 1))
e += add_path(heap, tp, x, y - 1, tp[rp].dist + 10, DIR::N, rp, x1, y1);
tp[rp].flag = 1;
if (e || heap[0] >= MAX_HEAP - 5)
return -1;
}
}