Allow webs to be placed without a giant spider on them

Allow creating webs without spiders in the lua level scripts:

des.trap({ type = "web", spider_on_web = 0 });

Based on xNetHack commit by copperwater <aosdict@gmail.com>.

Also changes the Spider nest themed room to generate without
spiders when the level difficulty is 8 or less.

dat/themerms.lua

@@ -101,22 +101,21 @@ themerooms = {
    },
 
    -- Spider nest
-   {
+   function()
-      mindiff = 10,
+      des.room({ type = "themed",
-      contents = function()
-         des.room({ type = "themed",
                   contents = function(rm)
+                     local spooders = nh.level_difficulty() > 8;
                      for x = 0, rm.width - 1 do
                         for y = 0, rm.height - 1 do
                            if (percent(30)) then
-                              des.trap("web", x, y);
+                              des.trap({ type = "web", x = x, y = y,
+                                   spider_on_web = spooders and percent(80) });
                            end
                         end
                      end
                   end
-         });
+      });
-      end
+   end,
-   },
 
    -- Trap room
    function()

include/hack.h

@@ -475,6 +475,11 @@ enum bodypart_types {
 #define TELEDS_ALLOW_DRAG 1
 #define TELEDS_TELEPORT   2
 
+/* flags for mktrap() */
+#define MKTRAP_NOFLAGS       0x0
+#define MKTRAP_MAZEFLAG      0x1 /* trap placed on coords as if in maze */
+#define MKTRAP_NOSPIDERONWEB 0x2 /* web will not generate a spider */
+
 #define MON_POLE_DIST 5 /* How far monsters can use pole-weapons */
 #define PET_MISSILE_RANGE2 36 /* Square of distance within which pets shoot */
 

include/sp_lev.h

@@ -127,6 +127,7 @@ typedef struct {
 typedef struct {
     packed_coord coord;
     xchar x, y, type;
+    boolean spider_on_web;
 } spltrap;
 
 typedef struct {

src/mklev.c

@@ -769,7 +769,7 @@ fill_ordinary_room(struct mkroom *croom)
     if (x <= 1)
         x = 2;
     while (!rn2(x) && (++trycnt < 1000))
-        mktrap(0, 0, croom, (coord *) 0);
+        mktrap(0, MKTRAP_NOFLAGS, croom, (coord *) 0);
     if (!rn2(3) && somexyspace(croom, &pos))
         (void) mkgold(0L, pos.x, pos.y);
     if (Is_rogue_level(&u.uz))
@@ -1322,7 +1322,7 @@ occupied(register xchar x, register xchar y)
 /* make a trap somewhere (in croom if mazeflag = 0 && !tm) */
 /* if tm != null, make trap at that location */
 void
-mktrap(int num, int mazeflag, struct mkroom *croom, coord *tm)
+mktrap(int num, int mktrapflags, struct mkroom *croom, coord *tm)
 {
     register int kind;
     struct trap *t;
@@ -1390,7 +1390,7 @@ mktrap(int num, int mazeflag, struct mkroom *croom, coord *tm)
                     kind = NO_TRAP;
                 break;
             case WEB:
-                if (lvl < 7)
+                if (lvl < 7 && !(mktrapflags & MKTRAP_NOSPIDERONWEB))
                     kind = NO_TRAP;
                 break;
             case STATUE_TRAP:
@@ -1427,7 +1427,7 @@ mktrap(int num, int mazeflag, struct mkroom *croom, coord *tm)
         do {
             if (++tryct > 200)
                 return;
-            if (mazeflag)
+            if (mktrapflags & MKTRAP_MAZEFLAG)
                 mazexy(&m);
             else if (!somexy(croom, &m))
                 return;
@@ -1440,7 +1440,7 @@ mktrap(int num, int mazeflag, struct mkroom *croom, coord *tm)
        should prevent cases where that might not happen) but be paranoid */
     kind = t ? t->ttyp : NO_TRAP;
 
-    if (kind == WEB)
+    if (kind == WEB && !(mktrapflags & MKTRAP_NOSPIDERONWEB))
         (void) makemon(&mons[PM_GIANT_SPIDER], m.x, m.y, NO_MM_FLAGS);
 
     /* The hero isn't the only person who's entered the dungeon in

src/mkmaze.c

@@ -1062,7 +1062,7 @@ makemaz(const char *s)
         (void) mkgold(0L, mm.x, mm.y);
     }
     for (x = rn1(6, 7); x; x--)
-        mktrap(0, 1, (struct mkroom *) 0, (coord *) 0);
+        mktrap(0, MKTRAP_MAZEFLAG, (struct mkroom *) 0, (coord *) 0);
 }
 
 #ifdef MICRO

src/sp_lev.c

@@ -1686,6 +1686,7 @@ create_trap(spltrap* t, struct mkroom* croom)
 {
     xchar x = -1, y = -1;
     coord tm;
+    int mktrap_flags = MKTRAP_MAZEFLAG;
 
     if (croom) {
         get_free_room_loc(&x, &y, croom, t->coord);
@@ -1700,10 +1701,13 @@ create_trap(spltrap* t, struct mkroom* croom)
             return;
     }
 
+    if (!t->spider_on_web)
+        mktrap_flags |= MKTRAP_NOSPIDERONWEB;
+
     tm.x = x;
     tm.y = y;
 
-    mktrap(t->type, 1, (struct mkroom *) 0, &tm);
+    mktrap(t->type, mktrap_flags, (struct mkroom *) 0, &tm);
 }
 
 /*
@@ -3995,6 +3999,7 @@ get_traptype_byname(const char *trapname)
 }
 
 /* trap({ type = "hole", x = 1, y = 1 }); */
+/* trap({ type = "web", spider_on_web = 0 }); */
 /* trap("hole", 3, 4); */
 /* trap("level teleport", {5, 8}); */
 /* trap("rust") */
@@ -4008,6 +4013,8 @@ lspo_trap(lua_State* L)
 
     create_des_coder();
 
+    tmptrap.spider_on_web = TRUE;
+
     if (argc == 1 && lua_type(L, 1) == LUA_TSTRING) {
         const char *trapstr = luaL_checkstring(L, 1);
 
@@ -4030,6 +4037,8 @@ lspo_trap(lua_State* L)
 
         get_table_xy_or_coord(L, &x, &y);
         tmptrap.type = get_table_traptype_opt(L, "type", -1);
+        tmptrap.spider_on_web
+            = get_table_boolean_opt(L, "spider_on_web", 1);
     }
 
     if (tmptrap.type == NO_TRAP)