+ lua_rawseti(L, -2, ++i);
+ individual_count[c]++;
+ }
+ }
+ lua_newtable(L);
+ for (std::set<content_t>::const_iterator it = filter.begin();
+ it != filter.end(); ++it) {
+ lua_pushnumber(L, individual_count[*it]);
+ lua_setfield(L, -2, ndef->get(*it).name.c_str());
+ }
+ return 2;
+}
+
+// find_nodes_in_area_under_air(minp, maxp, nodenames) -> list of positions
+// nodenames: e.g. {"ignore", "group:tree"} or "default:dirt"
+int ModApiEnvMod::l_find_nodes_in_area_under_air(lua_State *L)
+{
+ /* Note: A similar but generalized (and therefore slower) version of this
+ * function could be created -- e.g. find_nodes_in_area_under -- which
+ * would accept a node name (or ID?) or list of names that the "above node"
+ * should be.
+ * TODO
+ */
+
+ GET_ENV_PTR;
+
+ INodeDefManager *ndef = getServer(L)->ndef();
+ v3s16 minp = read_v3s16(L, 1);
+ v3s16 maxp = read_v3s16(L, 2);
+ sortBoxVerticies(minp, maxp);
+
+ v3s16 cube = maxp - minp + 1;
+
+ /* Limit for too large areas, assume default values
+ * and give tolerances of 1 node on each side
+ * (chunksize * MAP_BLOCKSIZE + 2)^3 = 551368
+ */
+ if ((u64)cube.X * (u64)cube.Y * (u64)cube.Z > 551368) {
+ luaL_error(L, "find_nodes_in_area_under_air(): area volume"
+ " exceeds allowed value of 551368");
+ return 0;
+ }
+
+ std::set<content_t> filter;
+
+ if (lua_istable(L, 3)) {
+ lua_pushnil(L);
+ while (lua_next(L, 3) != 0) {
+ // key at index -2 and value at index -1
+ luaL_checktype(L, -1, LUA_TSTRING);
+ ndef->getIds(lua_tostring(L, -1), filter);
+ // removes value, keeps key for next iteration
+ lua_pop(L, 1);
+ }
+ } else if (lua_isstring(L, 3)) {
+ ndef->getIds(lua_tostring(L, 3), filter);
+ }
+
+ lua_newtable(L);
+ u64 i = 0;
+ for (s16 x = minp.X; x <= maxp.X; x++)
+ for (s16 z = minp.Z; z <= maxp.Z; z++) {
+ s16 y = minp.Y;
+ v3s16 p(x, y, z);
+ content_t c = env->getMap().getNodeNoEx(p).getContent();
+ for (; y <= maxp.Y; y++) {
+ v3s16 psurf(x, y + 1, z);
+ content_t csurf = env->getMap().getNodeNoEx(psurf).getContent();
+ if (c != CONTENT_AIR && csurf == CONTENT_AIR &&
+ filter.count(c) != 0) {
+ push_v3s16(L, v3s16(x, y, z));
+ lua_rawseti(L, -2, ++i);
+ }
+ c = csurf;