Lua: Allow creating gas clouds

Use the gas clouds in the Clouds themeroom.
Use the existing visible_region_at() in the vision code.

dat/themerms.lua

@@ -43,10 +43,10 @@ themeroom_fills = {
    -- Cloud room
    function(rm)
       local fog = selection.room();
-      des.terrain(fog, "C");
       for i = 1, (fog:numpoints() / 4) do
          des.monster({ id = "fog cloud", asleep = true });
       end
+      des.gas_cloud({ selection = fog });
    end,
 
    -- Boulder room

doc/lua.adoc

@@ -569,6 +569,21 @@ Example:
  des.finalize_level();
 
 
+=== gas_cloud
+
+Create a gas cloud.
+The `damage` and `ttl` fields are optional.
+Defaults to non-poisonous and infinite lifetime.
+
+Example:
+
+ des.gas_cloud({ x = XX, y = YY });
+ des.gas_cloud({ coord = { XX, YY } });
+ des.gas_cloud({ selection = SEL });
+ des.gas_cloud({ selection = SEL, damage = 5 });
+ des.gas_cloud({ selection = SEL, damage = 5, ttl = 200 });
+
+
 === gold
 
 Create a pile of gold.

include/extern.h

@@ -2560,6 +2560,7 @@ extern void save_regions(NHFILE *) NONNULLARG1;
 extern void rest_regions(NHFILE *) NONNULLARG1;
 extern void region_stats(const char *, char *, long *, long *) NONNULLPTRS;
 extern NhRegion *create_gas_cloud(coordxy, coordxy, int, int);
+extern NhRegion *create_gas_cloud_selection(struct selectionvar *, int);
 extern boolean region_danger(void);
 extern void region_safety(void);
 

src/region.c

@@ -1189,6 +1189,44 @@ create_gas_cloud(coordxy x, coordxy y, int cloudsize, int damage)
     return cloud;
 }
 
+/* create a single gas cloud from selection */
+NhRegion *
+create_gas_cloud_selection(struct selectionvar *sel, int damage)
+{
+    NhRegion *cloud;
+    NhRect tmprect;
+    coordxy x, y;
+    NhRect r;
+    boolean inside_cloud = is_hero_inside_gas_cloud();
+
+    selection_getbounds(sel, &r);
+
+    cloud = create_region((NhRect *) 0, 0);
+    for (x = r.lx; x <= r.hx; x++)
+        for (y = r.ly; y <= r.hy; y++)
+            if (selection_getpoint(x, y, sel)) {
+                tmprect.lx = tmprect.hx = x;
+                tmprect.ly = tmprect.hy = y;
+                add_rect_to_reg(cloud, &tmprect);
+            }
+
+    if (!gi.in_mklev && !gc.context.mon_moving)
+        set_heros_fault(cloud); /* assume player has created it */
+    cloud->inside_f = INSIDE_GAS_CLOUD;
+    cloud->expire_f = EXPIRE_GAS_CLOUD;
+    cloud->arg = cg.zeroany;
+    cloud->arg.a_int = damage;
+    cloud->visible = TRUE;
+    cloud->glyph = cmap_to_glyph(damage ? S_poisoncloud : S_cloud);
+    add_region(cloud);
+
+    if (!gi.in_mklev && !inside_cloud && is_hero_inside_gas_cloud())
+        You("are enveloped in a cloud of %s!",
+            damage ? "noxious gas" : "steam");
+    return cloud;
+}
+
+
 /* for checking troubles during prayer; is hero at risk? */
 boolean
 region_danger(void)

src/sp_lev.c

@@ -159,6 +159,7 @@ int lspo_finalize_level(lua_State *);
 int lspo_room(lua_State *);
 int lspo_stair(lua_State *);
 int lspo_teleport_region(lua_State *);
+int lspo_gas_cloud(lua_State *);
 int lspo_terrain(lua_State *);
 int lspo_trap(lua_State *);
 int lspo_wall_property(lua_State *);
@@ -5545,6 +5546,49 @@ lspo_feature(lua_State *L)
     return 0;
 }
 
+/* gas_cloud({ selection=SELECTION }); */
+/* gas_cloud({ selection=SELECTION, damage=N }); */
+/* gas_cloud({ selection=SELECTION, damage=N, ttl=N }); */
+int
+lspo_gas_cloud(lua_State *L)
+{
+    coordxy x = 0, y = 0;
+    struct selectionvar *sel = NULL;
+    int argc = lua_gettop(L);
+    int damage = 0;
+    int ttl = -2;
+
+    create_des_coder();
+
+    if (argc == 1 && lua_type(L, 1) == LUA_TTABLE) {
+        lua_Integer tx, ty;
+        NhRegion *reg;
+
+        lcheck_param_table(L);
+
+        get_table_xy_or_coord(L, &tx, &ty);
+        x = tx, y = ty;
+        if (tx == -1 && ty == -1) {
+            lua_getfield(L, 1, "selection");
+            sel = l_selection_check(L, -1);
+            lua_pop(L, 1);
+        }
+        damage = get_table_int_opt(L, "damage", 0);
+        ttl = get_table_int_opt(L, "ttl", -2);
+        if (!sel) {
+            reg = create_gas_cloud(x, y, 1, damage);
+        } else
+            reg = create_gas_cloud_selection(sel, damage);
+        if (ttl > -2)
+            reg->ttl = ttl;
+    } else {
+        nhl_error(L, "wrong parameters");
+    }
+
+    return 0;
+}
+
+
 /*
  * [lit_state: 1 On, 0 Off, -1 random, -2 leave as-is]
  * terrain({ x=NN, y=NN, typ=MAPCHAR, lit=lit_state });
@@ -6995,6 +7039,7 @@ static const struct luaL_Reg nhl_functions[] = {
     { "teleport_region", lspo_teleport_region },
     { "reset_level", lspo_reset_level },
     { "finalize_level", lspo_finalize_level },
+    { "gas_cloud", lspo_gas_cloud },
     /* TODO: { "branch", lspo_branch }, */
     /* TODO: { "portal", lspo_portal }, */
     { NULL, NULL }

src/vision.c

@@ -141,7 +141,6 @@ does_block(int x, int y, struct rm *lev)
 {
     struct obj *obj;
     struct monst *mon;
-    int i;
 
 #ifdef DEBUG
     /* set DEBUGFILES=seethru in environment to see through bubbles */
@@ -181,14 +180,8 @@ does_block(int x, int y, struct rm *lev)
     if (gs.seethru != 1) {
 #endif
     /* Clouds (poisonous or not) block light. */
-    for (i = 0; i < gn.n_regions; i++) {
+    if (visible_region_at(x, y))
-        /* Ignore regions with ttl == 0 - expire_gas_cloud must unblock its
+        return 1;
-         * points prior to being removed itself. */
-        if (gr.regions[i]->ttl > 0 && gr.regions[i]->visible
-            && inside_region(gr.regions[i], x, y)) {
-            return 1;
-        }
-    }
 #ifdef DEBUG
     } /* gs.seethru */
 #endif