Add rolling boulder traps in Sokoban to reduce wrist strain

When playtesting NetHack heavily, I observed that most of the time
it wasn't placing much strain on my wrists, but Sokoban was an
exception: travel, farmove, etc. can normally be used to avoid the
need to spam keys, but they don't work while pushing a boulder, and
the boulders often need to be pushed along precise routes, so you
have to tap out every movement. This becomes particularly straining
when pushing in the last few boulders, as you have to push them a
long way along the goal corridor.

This commit adds rolling boulder traps to Sokoban that will
automatically roll boulders along the goal corridor, meaning that
you don't have to push them there manually. This considerably
reduces the number of keystrokes needed to solve Sokoban, without
making any significant change to the difficulty of the levels.
Some of the designs had to change slightly in order to make room
for them, but not in a way that meaningfully changes the solution.

dat/soko1-1.lua

@@ -60,9 +60,10 @@ des.object("boulder", 09, 12);
 des.object("boulder", 03, 14);
 
 -- prevent monster generation over the (filled) holes
-des.exclusion({ type = "monster-generation", region = { 08,01, 23,01 } });
+des.exclusion({ type = "monster-generation", region = { 07,01, 23,01 } });
 -- Traps
-des.trap("hole", 08, 01);
+des.trap("hole", 07, 01);
+des.trap("rolling boulder", 08, 01);
 des.trap("hole", 09, 01);
 des.trap("hole", 10, 01);
 des.trap("hole", 11, 01);

dat/soko1-2.lua

@@ -61,9 +61,9 @@ des.object("boulder",12,09);
 des.object("boulder",11,10);
 
 -- prevent monster generation over the (filled) holes
-des.exclusion({ type = "monster-generation", region = { 05,01, 22,01 } });
+des.exclusion({ type = "monster-generation", region = { 05,01, 23,01 } });
 -- Traps
-des.trap("hole",05,01)
+des.trap("rolling boulder",05,01)
 des.trap("hole",06,01)
 des.trap("hole",07,01)
 des.trap("hole",08,01)
@@ -81,6 +81,7 @@ des.trap("hole",19,01)
 des.trap("hole",20,01)
 des.trap("hole",21,01)
 des.trap("hole",22,01)
+des.trap("hole",23,01)
 
 des.monster({ id = "giant mimic", appear_as = "obj:boulder" });
 des.monster({ id = "giant mimic", appear_as = "obj:boulder" });

dat/soko2-1.lua

@@ -49,6 +49,7 @@ des.object("boulder",06,06)
 -- prevent monster generation over the (filled) holes
 des.exclusion({ type = "monster-generation", region = { 07,09, 18,09 } });
 -- Traps
+des.trap("rolling boulder",07,09)
 des.trap("hole",08,09)
 des.trap("hole",09,09)
 des.trap("hole",10,09)

dat/soko2-2.lua

@@ -7,26 +7,27 @@ des.level_init({ style = "solidfill", fg = " " });
 des.level_flags("mazelevel", "noteleport", "premapped", "sokoban", "solidify");
 
 des.map([[
-  --------          
---|.|....|          
-|........|----------
-|.-...-..|.|.......|
-|...-......|.......|
-|.-....|...|.......|
-|....-.--.-|.......|
-|..........|.......|
-|.--...|...|.......|
-|....-.|---|.......|
---|....|----------+|
-  |................|
-  ------------------
+  --------            
+--|.|....|            
+|........|----------  
+|.-...-..|.|.......|  
+|...-......|.......|  
+|.-....|...|.......|  
+|....-.--.-|.......|  
+|..........|.......|  
+|.--...|...|.......---
+|....-.|---|.......+.|
+--|....|------------.|
+  |................+.|
+  --------------------
 ]]);
 des.stair("down", 06,11)
 des.stair("up", 15,06)
-des.door("locked",18,10)
-des.region(selection.area(00,00,19,12), "lit");
-des.non_diggable(selection.area(00,00,19,12));
-des.non_passwall(selection.area(00,00,19,12));
+des.door("locked",19,09)
+des.door("locked",19,11)
+des.region(selection.area(00,00,21,12), "lit");
+des.non_diggable(selection.area(00,00,21,12));
+des.non_passwall(selection.area(00,00,21,12));
 
 -- Boulders
 des.object("boulder",04,02)
@@ -49,7 +50,7 @@ des.object("boulder",05,11)
 -- prevent monster generation over the (filled) holes
 des.exclusion({ type = "monster-generation", region = { 06,11, 18,11 } });
 -- Traps
-des.trap("hole",07,11)
+des.trap("rolling boulder",07,11)
 des.trap("hole",08,11)
 des.trap("hole",09,11)
 des.trap("hole",10,11)
@@ -60,6 +61,7 @@ des.trap("hole",14,11)
 des.trap("hole",15,11)
 des.trap("hole",16,11)
 des.trap("hole",17,11)
+des.trap("hole",18,11)
 
 -- Random objects
 des.object({ class = "%" });

dat/soko3-1.lua

@@ -55,6 +55,7 @@ des.object("boulder",10,10)
 -- prevent monster generation over the (filled) holes
 des.exclusion({ type = "monster-generation", region = { 11,10, 27,10 } });
 -- Traps
+des.trap("rolling boulder",11,10)
 des.trap("hole",12,10)
 des.trap("hole",13,10)
 des.trap("hole",14,10)

dat/soko3-2.lua

@@ -48,8 +48,9 @@ des.object("boulder",10,10)
 des.object("boulder",03,11)
 
 -- prevent monster generation over the (filled) holes
-des.exclusion({ type = "monster-generation", region = { 12,10, 24,10 } });
+des.exclusion({ type = "monster-generation", region = { 11,10, 24,10 } });
 -- Traps
+des.trap("rolling boulder",11,10)
 des.trap("hole",12,10)
 des.trap("hole",13,10)
 des.trap("hole",14,10)

dat/soko4-1.lua

@@ -74,16 +74,21 @@ des.object("boulder",10,10)
 
 -- prevent monster generation over the (filled) pits
 des.exclusion({ type = "monster-generation", region = { 01,06, 07,11 } });
+
 -- Traps
-des.trap("pit",03,06)
 des.trap("pit",04,06)
-des.trap("pit",05,06)
+
+des.trap("pit",02,06)
+des.trap("pit",02,07)
 des.trap("pit",02,08)
-des.trap("pit",02,09)
+des.trap("rolling boulder",02,09)
+
+des.trap("pit",02,10)
+des.trap("pit",03,10)
 des.trap("pit",04,10)
 des.trap("pit",05,10)
 des.trap("pit",06,10)
-des.trap("pit",07,10)
+des.trap("rolling boulder",07,10)
 
 -- A little help
 des.object("scroll of earth",02,11)

dat/soko4-2.lua

@@ -50,11 +50,14 @@ des.trap("pit",01,03)
 des.trap("pit",01,04)
 des.trap("pit",01,05)
 des.trap("pit",01,06)
-des.trap("pit",01,07)
+des.trap("rolling boulder",01,07)
+
+des.trap("pit",01,08)
+des.trap("pit",02,08)
 des.trap("pit",03,08)
 des.trap("pit",04,08)
 des.trap("pit",05,08)
-des.trap("pit",06,08)
+des.trap("rolling boulder",06,08)
 
 -- A little help
 des.object("scroll of earth",01,09)

src/trap.c

@@ -2820,6 +2820,8 @@ immune_to_trap(struct monst *mon, unsigned ttype)
            hanging to the ceiling */
         if (Sokoban && (is_pit(ttype) || is_hole(ttype)))
             return TRAP_NOT_IMMUNE;
+        if (In_sokoban(&u.uz) && ttype == ROLLING_BOULDER_TRAP)
+            return TRAP_CLEARLY_IMMUNE; /* not dangerous in Sokoban */
         if (is_floater(pm) || is_flyer(pm)
             || (is_clinger(pm) && has_ceiling(&u.uz)))
             return TRAP_CLEARLY_IMMUNE;
@@ -3589,7 +3591,7 @@ find_random_launch_coord(struct trap *ttmp, coord *cc)
     coordxy dx, dy;
     coordxy x, y;
 
-    if (!ttmp || !cc)
+    if (!ttmp || !cc || Sokoban)
         return FALSE;
 
     x = ttmp->tx;