Fedhas rework part 2: Wall of Briars ability

A 2* ability that encircles the player with summoned briar patches. The
player can fire through these plants, and the briars damage monsters
that attack them. Monster AI is changed so that hostile monsters always
try to attack briars that are friendly to the player.

Only floor or shallow water tiles that have no monsters are viable
summon locations. The briar patches' HP scale with Invocations by adding
1 HD with each level of this skill.

crawl-ref/source/ability-type.h

@@ -178,6 +178,7 @@ enum ability_type
     ABIL_FEDHAS_PLANT_RING,
     ABIL_FEDHAS_SPAWN_SPORES,
     ABIL_FEDHAS_EVOLUTION,
+    ABIL_FEDHAS_WALL_OF_BRIARS,
     // Cheibriados
     ABIL_CHEIBRIADOS_TIME_STEP = 1151,
     ABIL_CHEIBRIADOS_TIME_BEND,

crawl-ref/source/ability.cc

@@ -524,6 +524,8 @@ static const ability_def Ability_List[] =
       4, 0, 100, 1, {fail_basis::invo, 60, 4, 25}, abflag::none },
     { ABIL_FEDHAS_RAIN, "Rain",
       4, 0, 150, 4, {fail_basis::invo, 70, 4, 25}, abflag::none },
+    { ABIL_FEDHAS_WALL_OF_BRIARS, "Wall of Briars",
+      3, 0, 50, 2, {fail_basis::invo, 30, 6, 20}, abflag::none},
 
     // Cheibriados
     { ABIL_CHEIBRIADOS_TIME_BEND, "Bend Time",
@@ -2871,6 +2873,12 @@ static spret _do_ability(const ability_def& abil, bool fail)
             return spret::abort;
         break;
 
+    case ABIL_FEDHAS_WALL_OF_BRIARS:
+        fail_check();
+        if (!fedhas_wall_of_briars())
+            return spret::abort;
+        break;
+
     case ABIL_FEDHAS_RAIN:
         fail_check();
         if (!fedhas_rain(you.pos()))

crawl-ref/source/dat/descript/ability.txt

@@ -481,6 +481,11 @@ Bring an orc corpse back to life. The orc will be an ally, even if it was not
 already one before it died.
 %%%%
 # Fedhas
+Wall of Briars ability
+
+Grow short-lived briar patches around you. Monsters attacking these briars will
+be damaged by sharp thorns. Invocations skill increases the briars' health.
+%%%%
 Sunlight ability
 
 Calls sunlight down over a small area of the dungeon. Monsters illuminated by

crawl-ref/source/mon-act.cc

@@ -2990,6 +2990,7 @@ static bool _may_cutdown(monster* mons, monster* targ)
     // (but don't try to attack briars unless their damage will be insignificant)
     return mons_is_firewood(*targ)
         && (targ->type != MONS_BRIAR_PATCH
+            || (targ->friendly() && !mons_aligned(mons, targ))
             || mons->type == MONS_THORN_HUNTER
             || mons->armour_class() * mons->hit_points >= 400);
 }

crawl-ref/source/religion.cc

@@ -264,6 +264,7 @@ const vector<god_power> god_powers[NUM_GODS] =
     // Fedhas
     {
       { 1, ABIL_FEDHAS_SUNLIGHT, "call sunshine" },
+      { 2, ABIL_FEDHAS_WALL_OF_BRIARS, "encircle yourself with summoned briar patches"},
       { 2, ABIL_FEDHAS_EVOLUTION, "induce evolution" },
       { 3, ABIL_FEDHAS_PLANT_RING, "cause a ring of plants to grow" },
       { 4, ABIL_FEDHAS_SPAWN_SPORES, "spawn explosive spores" },

crawl-ref/source/rltiles/dc-invocations.txt

@@ -25,6 +25,7 @@ fedhas_plant_ring ABILITY_FEDHAS_PLANT_RING
 fedhas_rain ABILITY_FEDHAS_RAIN
 fedhas_spawn_spores ABILITY_FEDHAS_SPAWN_SPORES
 fedhas_sunlight ABILITY_FEDHAS_SUNLIGHT
+fedhas_wall_of_briars ABILITY_FEDHAS_WALL_OF_BRIARS
 gozag_potion_petition ABILITY_GOZAG_POTION_PETITION
 gozag_call_merchant ABILITY_GOZAG_CALL_MERCHANT
 gozag_bribe_branch ABILITY_GOZAG_BRIBE_BRANCH

crawl-ref/source/spl-summoning.cc

@@ -3473,3 +3473,54 @@ int count_summons(const actor *summoner, spell_type spell)
 
     return count;
 }
+
+static bool _create_briar_patch(coord_def& target)
+{
+    mgen_data mgen = mgen_data(MONS_BRIAR_PATCH, BEH_FRIENDLY, target,
+            MHITNOT, MG_FORCE_PLACE, GOD_FEDHAS);
+    mgen.hd = mons_class_hit_dice(MONS_BRIAR_PATCH) +
+        you.skill_rdiv(SK_INVOCATIONS);
+    mgen.set_summoned(&you, 3 + you.skill_rdiv(SK_INVOCATIONS, 1, 6),
+            SPELL_NO_SPELL);
+
+    if (create_monster(mgen))
+    {
+        mpr("A briar patch grows up from the ground.");
+        return true;
+    }
+
+    return false;
+}
+
+bool fedhas_wall_of_briars()
+{
+    // How many adjacent open spaces are there?
+    vector<coord_def> adjacent;
+    for (adjacent_iterator adj_it(you.pos()); adj_it; ++adj_it)
+    {
+        if (monster_habitable_grid(MONS_BRIAR_PATCH, env.grid(*adj_it))
+            && !actor_at(*adj_it))
+        {
+            adjacent.push_back(*adj_it);
+        }
+    }
+
+    // Don't prompt if we can't do anything.
+    if (adjacent.empty())
+    {
+        mpr("No empty adjacent squares.");
+        return false;
+    }
+
+    int created_count = 0;
+    for (auto p : adjacent)
+    {
+        if (_create_briar_patch(p))
+            created_count++;
+    }
+
+    if (!created_count)
+        canned_msg(MSG_NOTHING_HAPPENS);
+
+    return created_count;
+}

crawl-ref/source/spl-summoning.h

@@ -125,3 +125,5 @@ void summoned_monster(const monster* mons, const actor* caster,
 bool summons_are_capped(spell_type spell);
 int summons_limit(spell_type spell);
 int count_summons(const actor *summoner, spell_type spell);
+
+bool fedhas_wall_of_briars();

crawl-ref/source/tilepick.cc

@@ -3513,6 +3513,8 @@ tileidx_t tileidx_ability(const ability_type ability)
     case ABIL_JIYVA_CURE_BAD_MUTATION:
         return TILEG_ABILITY_JIYVA_CURE_BAD_MUTATIONS;
     // Fedhas
+    case ABIL_FEDHAS_WALL_OF_BRIARS:
+        return TILEG_ABILITY_FEDHAS_WALL_OF_BRIARS;
     case ABIL_FEDHAS_SUNLIGHT:
         return TILEG_ABILITY_FEDHAS_SUNLIGHT;
     case ABIL_FEDHAS_RAIN: