restrict where the engraving symbol shows up

rooms and corridor locations that have been seen
don't hide stairs

include/engrave.h

@@ -39,4 +39,10 @@ struct engr {
 #define engraving_to_defsym(ep) \
     (levl[(ep)->engr_x][(ep)->engr_y].typ == CORR ? S_engrcorr : S_engroom)
 
+#define spot_shows_engravings(x,y)      \
+    (levl[(x)][(y)].typ == CORR         \
+     || levl[(x)][(y)].typ == SCORR     \
+     || levl[(x)][(y)].typ == ICE       \
+     || levl[(x)][(y)].typ == ROOM )
+
 #endif /* ENGRAVE_H */

src/display.c

@@ -416,12 +416,14 @@ unmap_object(register coordxy x, register coordxy y)
 
     if ((trap = t_at(x, y)) != 0 && trap->tseen && !covers_traps(x, y)) {
         map_trap(trap, 0);
-    } else if ((ep = engr_at(x, y)) != 0 && !covers_traps(x, y)) {
-        map_engraving(ep, 0);
     } else if (levl[x][y].seenv) {
         struct rm *lev = &levl[x][y];
 
-        map_background(x, y, 0);
+        if (spot_shows_engravings(x, y)
+               && (ep = engr_at(x, y)) != 0 && !covers_traps(x, y))
+            map_engraving(ep, 0);
+        else
+            map_background(x, y, 0);
 
         /* turn remembered dark room squares dark */
         if (!lev->waslit && lev->glyph == cmap_to_glyph(S_room)
@@ -450,7 +452,9 @@ unmap_object(register coordxy x, register coordxy y)
             map_object(obj, show);                                          \
         else if ((trap = t_at(x, y)) && trap->tseen && !covers_traps(x, y)) \
             map_trap(trap, show);                                           \
-        else if ((ep = engr_at(x, y)) && !covers_traps(x, y))  \
+        else if (spot_shows_engravings(x, y)                                \
+                 && (ep = engr_at(x, y)) != 0                               \
+                 && !covers_traps(x, y))                                    \
             map_engraving(ep, show);                                        \
         else                                                                \
             map_background(x, y, show);                                     \

src/engrave.c

@@ -317,8 +317,13 @@ void
 read_engr_at(coordxy x, coordxy y)
 {
     struct engr *ep = engr_at(x, y);
+    const char *eloc = surface(x, y);
     int sensed = 0;
 
+    if (!spot_shows_engravings(x, y)) {
+        if (On_stairs(x, y))
+            eloc = "stairs";
+    }
     /* Sensing an engraving does not require sight,
      * nor does it necessarily imply comprehension (literacy).
      */
@@ -335,21 +340,20 @@ read_engr_at(coordxy x, coordxy y)
         case HEADSTONE:
             if (!Blind || can_reach_floor(TRUE)) {
                 sensed = 1;
-                pline("%s is engraved here on the %s.", Something,
+                pline("%s is engraved here on the %s.", Something, eloc);
-                      surface(x, y));
             }
             break;
         case BURN:
             if (!Blind || can_reach_floor(TRUE)) {
                 sensed = 1;
                 pline("Some text has been %s into the %s here.",
-                      is_ice(x, y) ? "melted" : "burned", surface(x, y));
+                      is_ice(x, y) ? "melted" : "burned", eloc);
             }
             break;
         case MARK:
             if (!Blind) {
                 sensed = 1;
-                pline("There's some graffiti on the %s here.", surface(x, y));
+                pline("There's some graffiti on the %s here.", eloc);
             }
             break;
         case ENGR_BLOOD:
@@ -1052,6 +1056,10 @@ doengrave(void)
     }
 
     eloc = surface(u.ux, u.uy);
+    if (!spot_shows_engravings(u.ux, u.uy)) {
+        if (On_stairs(u.ux, u.uy))
+            eloc = "stairs";
+    }
     adding = (oep && !eow);
     switch (type) {
     default: