63 lines
2 KiB
C
63 lines
2 KiB
C
#include "dijkstra.h"
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#include <stddef.h>
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static int passable(uint8_t t) {
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return t == T_FLOOR || t == T_CORRIDOR || t == T_DOOR || t == T_BRIDGE
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|| t == T_STAIRS_UP || t == T_STAIRS_DOWN;
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}
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void bfs_from(grid_t g, int sx, int sy, dist_map_t dist,
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int extra_passable_x, int extra_passable_y) {
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for (int y = 0; y < DROWS; y++)
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for (int x = 0; x < DCOLS; x++)
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dist[y][x] = DIST_UNREACHABLE;
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if (!grid_in_bounds(sx, sy)) return;
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static const int dx4[4] = {1, -1, 0, 0};
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static const int dy4[4] = {0, 0, 1, -1};
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int qx[DCOLS * DROWS];
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int qy[DCOLS * DROWS];
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int head = 0, tail = 0;
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dist[sy][sx] = 0;
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qx[tail] = sx; qy[tail] = sy; tail++;
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while (head < tail) {
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int cx = qx[head], cy = qy[head]; head++;
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int16_t d = dist[cy][cx];
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for (int i = 0; i < 4; i++) {
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int nx = cx + dx4[i], ny = cy + dy4[i];
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if (!grid_in_bounds(nx, ny)) continue;
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int is_extra = (nx == extra_passable_x && ny == extra_passable_y);
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if (!is_extra && !passable(g[ny][nx].terrain)) continue;
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if (dist[ny][nx] <= d + 1) continue;
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dist[ny][nx] = d + 1;
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qx[tail] = nx; qy[tail] = ny; tail++;
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}
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}
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}
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int is_connected(grid_t g, int *out_unreached) {
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int sx = -1, sy = -1, total = 0;
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for (int y = 0; y < DROWS; y++) {
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for (int x = 0; x < DCOLS; x++) {
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if (passable(g[y][x].terrain)) {
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if (sx < 0) { sx = x; sy = y; }
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total++;
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}
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}
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}
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if (total == 0) { if (out_unreached) *out_unreached = 0; return 1; }
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static dist_map_t dist;
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bfs_from(g, sx, sy, dist, -1, -1);
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int reached = 0;
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for (int y = 0; y < DROWS; y++)
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for (int x = 0; x < DCOLS; x++)
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if (passable(g[y][x].terrain) && dist[y][x] != DIST_UNREACHABLE)
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reached++;
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if (out_unreached) *out_unreached = total - reached;
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return reached == total;
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}
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