/**
* Check if the monster can occupy a grid safely
*/
static bool monster_hates_grid(struct chunk *c, struct monster *mon, int y,
int x)
{
/* Only some creatures can handle damaging terrain */
if (square_isdamaging(c, y, x) &&
!rf_has(mon->race->flags, square_feat(c, y, x)->resist_flag)) {
return true;
}
return false;
}
/**
* This will push objects off a square.
*
* The methodology is to load all objects on the square into a queue. Replace
* the previous square with a type that does not allow for objects. Drop the
* objects. Last, put the square back to its original type.
*/
void push_object(int y, int x)
{
/* Save the original terrain feature */
struct feature *feat_old = square_feat(cave, y, x);
struct object *obj = square_object(cave, y, x);
struct queue *queue = q_new(z_info->floor_size);
bool glyph = square_iswarded(cave, y, x);
/* Push all objects on the square, stripped of pile info, into the queue */
while (obj) {
struct object *next = obj->next;
q_push_ptr(queue, obj);
/* Orphan the object */
obj->next = NULL;
obj->prev = NULL;
obj->iy = 0;
obj->ix = 0;
/* Next object */
obj = next;
}
/* Disassociate the objects from the square */
cave->squares[y][x].obj = NULL;
/* Set feature to an open door */
square_force_floor(cave, y, x);
square_add_door(cave, y, x, false);
/* Drop objects back onto the floor */
while (q_len(queue) > 0) {
/* Take object from the queue */
obj = q_pop_ptr(queue);
/* Drop the object */
drop_near(cave, &obj, 0, y, x, false);
}
/* Reset cave feature and rune if needed */
square_set_feat(cave, y, x, feat_old->fidx);
if (glyph)
square_add_ward(cave, y, x);
q_free(queue);
}
/**
* Determine if a cave grid is allowed to have player traps in it.
*/
bool square_player_trap_allowed(struct chunk *c, int y, int x)
{
/*
* We currently forbid multiple traps in a grid under normal conditions.
* If this changes, various bits of code elsewhere will have to change too.
*/
if (square_istrap(c, y, x))
return false;
/* We currently forbid traps in a grid with objects. */
if (square_object(c, y, x))
return false;
/* Check the feature trap flag */
return (tf_has(square_feat(c, y, x)->flags, TF_TRAP));
}
/**
* Choose a "safe" location near a monster for it to run toward.
*
* A location is "safe" if it can be reached quickly and the player
* is not able to fire into it (it isn't a "clean shot"). So, this will
* cause monsters to "duck" behind walls. Hopefully, monsters will also
* try to run towards corridor openings if they are in a room.
*
* This function may take lots of CPU time if lots of monsters are fleeing.
*
* Return true if a safe location is available.
*/
static bool get_move_find_safety(struct chunk *c, struct monster *mon)
{
int fy = mon->fy;
int fx = mon->fx;
int py = player->py;
int px = player->px;
int i, y, x, dy, dx, d, dis;
int gy = 0, gx = 0, gdis = 0;
const int *y_offsets;
const int *x_offsets;
/* Start with adjacent locations, spread further */
for (d = 1; d < 10; d++) {
/* Get the lists of points with a distance d from (fx, fy) */
y_offsets = dist_offsets_y[d];
x_offsets = dist_offsets_x[d];
/* Check the locations */
for (i = 0, dx = x_offsets[0], dy = y_offsets[0];
dx != 0 || dy != 0;
i++, dx = x_offsets[i], dy = y_offsets[i]) {
y = fy + dy;
x = fx + dx;
/* Skip illegal locations */
if (!square_in_bounds_fully(c, y, x)) continue;
/* Skip locations in a wall */
if (!square_ispassable(c, y, x)) continue;
/* Ignore too-distant grids */
if (c->noise.grids[y][x] > c->noise.grids[fy][fx] + 2 * d)
continue;
/* Ignore damaging terrain if they can't handle it */
if (square_isdamaging(c, y, x) &&
!rf_has(mon->race->flags, square_feat(c, y, x)->resist_flag))
continue;
/* Check for absence of shot (more or less) */
if (!square_isview(c, y, x)) {
/* Calculate distance from player */
dis = distance(loc(x, y), loc(px, py));
/* Remember if further than previous */
if (dis > gdis) {
gy = y;
gx = x;
gdis = dis;
}
}
}
/* Check for success */
if (gdis > 0) {
/* Good location */
mon->target.grid = loc(gx, gy);
return (true);
}
}
/* No safe place */
return (false);
}
