Make hero polyed into fog cloud emit clouds

Also prevent cloud creation giving a message, if it was a single
cloud on hero and deals no damage.

include/extern.h

@@ -1827,6 +1827,7 @@ extern void mon_track_add(struct monst *, coordxy, coordxy) NONNULLARG1;
 extern void mon_track_clear(struct monst *) NONNULLARG1;
 extern boolean monhaskey(struct monst *, boolean) NONNULLARG1;
 extern void mon_regen(struct monst *, boolean) NONNULLARG1;
+extern void m_everyturn_effect(struct monst *) NONNULLARG1;
 extern void m_postmove_effect(struct monst *) NONNULLARG1;
 extern int dochugw(struct monst *, boolean) NONNULLARG1;
 extern boolean onscary(coordxy, coordxy, struct monst *) NONNULLARG3;

src/allmain.c

@@ -439,6 +439,8 @@ moveloop_core(void)
         curs_on_u();
     }
 
+    m_everyturn_effect(&gy.youmonst);
+
     gc.context.move = 1;
 
     if (gm.multi >= 0 && go.occupation) {

src/mon.c

@@ -1016,12 +1016,7 @@ movemon_singlemon(struct monst *mtmp)
     if (mon_offmap(mtmp))
         return FALSE;
 
-    if (mtmp->data == &mons[PM_FOG_CLOUD]) {
+    m_everyturn_effect(mtmp);
-        NhRegion *reg = visible_region_at(mtmp->mx, mtmp->my);
-
-        if (!reg)
-            create_gas_cloud(mtmp->mx, mtmp->my, 1, 0); /* harmless vapor */
-    }
 
     /* Find a monster that we have not treated yet. */
     if (mtmp->movement < NORMAL_SPEED)

src/monmove.c

@@ -593,6 +593,23 @@ mind_blast(struct monst *mtmp)
     }
 }
 
+/* called every turn for each living monster on the map,
+   and the hero */
+void
+m_everyturn_effect(struct monst *mtmp)
+{
+    boolean is_u = (mtmp == &gy.youmonst) ? TRUE : FALSE;
+    coordxy x = is_u ? u.ux : mtmp->mx,
+        y = is_u ? u.uy : mtmp->my;
+
+    if (mtmp->data == &mons[PM_FOG_CLOUD]) {
+        NhRegion *reg = visible_region_at(x, y);
+
+        if (!reg)
+            create_gas_cloud(x, y, 1, 0); /* harmless vapor */
+    }
+}
+
 /* do whatever effects monster has after moving.
    called for both monsters and polyed hero.
    for hero, called after location changes,

src/region.c

@@ -1143,6 +1143,13 @@ create_gas_cloud(coordxy x, coordxy y, int cloudsize, int damage)
     int newidx = 1; /* initial spot is already taken */
     boolean inside_cloud = is_hero_inside_gas_cloud();
 
+    /* a single-point cloud on hero and it deals no damage.
+       probably a natural cause of being polyed. don't message about it */
+    if (!gc.context.mon_moving && u_at(x, y) && cloudsize == 1
+        && (!damage
+            || (damage && m_poisongas_ok(&gy.youmonst) == M_POISONGAS_OK)))
+        inside_cloud = TRUE;
+
     if (cloudsize > MAX_CLOUD_SIZE) {
         impossible("create_gas_cloud: cloud too large (%d)!", cloudsize);
         cloudsize = MAX_CLOUD_SIZE;