/* Compute the fraction of corridor tiles with litter, of the parcels owned by the given player. */
static int l_map_get_litter_fraction(lua_State *L)
{
    THMap* pMap = luaT_testuserdata<THMap>(L);
    int owner = static_cast<int>(luaL_checkinteger(L, 2));
    if (owner == 0)
    {
        lua_pushnumber(L, 0.0); // Outside has no litter.
        return 1;
    }

    double tile_count = 0;
    double litter_count = 0;
    for (int x = 0; x < pMap->getWidth(); x++)
    {
        for (int y = 0; y < pMap->getHeight(); y++)
        {
            const THMapNode* pNode = pMap->getNodeUnchecked(x, y);
            if (pNode->iParcelId == 0 || owner != pMap->getParcelOwner(pNode->iParcelId) ||
                pNode->iRoomId != 0)
            {
                continue;
            }

            tile_count++;
            for(auto iter = pNode->objects.begin(); iter != pNode->objects.end(); iter++)
            {
                if(*iter == THObjectType::litter)
                {
                    litter_count++;
                    break;
                }
            }
        }
    }

    double fraction = (tile_count == 0) ? 0.0 : litter_count / tile_count;
    lua_pushnumber(L, fraction);
    return 1;
}
static int l_map_get_parcel_owner(lua_State *L)
{
    THMap* pMap = luaT_testuserdata<THMap>(L);
    lua_pushinteger(L, pMap->getParcelOwner(static_cast<int>(luaL_checkinteger(L, 2))));
    return 1;
}