Beispiel #1
0
map::map(std::vector<itype*> *itptr, std::vector<itype_id> (*miptr)[num_itloc],
         std::vector<trap*> *trptr)
{
    nulter = t_null;
    nultrap = tr_null;
    itypes = itptr;
    mapitems = miptr;
    traps = trptr;
    for (int i = 0; i < SEEX * 3; i++) {
        for (int j = 0; j < SEEY * 3; j++) {
            tr_at(i, j) = tr_null;
            radiation(i, j) = 0;
        }
    }
}
Beispiel #2
0
bool map::process_fields_in_submap(game *g, int gridn)
{
 bool found_field = false;
 field *cur;
 field_id curtype;
 for (int locx = 0; locx < SEEX; locx++) {
  for (int locy = 0; locy < SEEY; locy++) {
   cur = &(grid[gridn].fld[locx][locy]);
   int x = locx + SEEX * (gridn % my_MAPSIZE),
       y = locy + SEEY * int(gridn / my_MAPSIZE);

   curtype = cur->type;
   if (!found_field && curtype != fd_null)
    found_field = true;
   if (cur->density > 3 || cur->density < 1)
    debugmsg("Whoooooa density of %d", cur->density);

  if (cur->age == 0)	// Don't process "newborn" fields
   curtype = fd_null;

  int part;
  vehicle *veh;
  switch (curtype) {

   case fd_null:
    break;	// Do nothing, obviously.  OBVIOUSLY.

   case fd_blood:
   case fd_bile:
    if (has_flag(swimmable, x, y))	// Dissipate faster in water
     cur->age += 250;
    break;

   case fd_acid:
    if (has_flag(swimmable, x, y))	// Dissipate faster in water
     cur->age += 20;
    for (int i = 0; i < i_at(x, y).size(); i++) {
     item *melting = &(i_at(x, y)[i]);
     if (melting->made_of(LIQUID) || melting->made_of(VEGGY)   ||
         melting->made_of(FLESH)  || melting->made_of(POWDER)  ||
         melting->made_of(COTTON) || melting->made_of(WOOL)    ||
         melting->made_of(PAPER)  || melting->made_of(PLASTIC) ||
         (melting->made_of(GLASS) && !one_in(3)) || one_in(4)) {
// Acid destructable objects here
      melting->damage++;
      if (melting->damage >= 5 ||
          (melting->made_of(PAPER) && melting->damage >= 3)) {
       cur->age += melting->volume();
       for (int m = 0; m < i_at(x, y)[i].contents.size(); m++)
        i_at(x, y).push_back( i_at(x, y)[i].contents[m] );
       i_at(x, y).erase(i_at(x, y).begin() + i);
       i--;
      }
     }
    }
    break;

   case fd_sap:
    break; // It doesn't do anything.

   case fd_fire: {
// Consume items as fuel to help us grow/last longer.
    bool destroyed = false;
    int vol = 0, smoke = 0, consumed = 0;
    for (int i = 0; i < i_at(x, y).size() && consumed < cur->density * 2; i++) {
     destroyed = false;
     vol = i_at(x, y)[i].volume();
     item *it = &(i_at(x, y)[i]);

     if (it->is_ammo() && it->ammo_type() != AT_BATT &&
         it->ammo_type() != AT_NAIL && it->ammo_type() != AT_BB &&
         it->ammo_type() != AT_BOLT && it->ammo_type() != AT_ARROW) {
      cur->age /= 2;
      cur->age -= 600;
      destroyed = true;
      smoke += 6;
      consumed++;

     } else if (it->made_of(PAPER)) {
      destroyed = it->burn(cur->density * 3);
      consumed++;
      if (cur->density == 1)
       cur->age -= vol * 10;
      if (vol >= 4)
       smoke++;

     } else if ((it->made_of(WOOD) || it->made_of(VEGGY))) {
      if (vol <= cur->density * 10 || cur->density == 3) {
       cur->age -= 4;
       destroyed = it->burn(cur->density);
       smoke++;
       consumed++;
      } else if (it->burnt < cur->density) {
       destroyed = it->burn(1);
       smoke++;
      }

     } else if ((it->made_of(COTTON) || it->made_of(WOOL))) {
      if (vol <= cur->density * 5 || cur->density == 3) {
       cur->age--;
       destroyed = it->burn(cur->density);
       smoke++;
       consumed++;
      } else if (it->burnt < cur->density) {
       destroyed = it->burn(1);
       smoke++;
      }

     } else if (it->made_of(FLESH)) {
      if (vol <= cur->density * 5 || (cur->density == 3 && one_in(vol / 20))) {
       cur->age--;
       destroyed = it->burn(cur->density);
       smoke += 3;
       consumed++;
      } else if (it->burnt < cur->density * 5 || cur->density >= 2) {
       destroyed = it->burn(1);
       smoke++;
      }

     } else if (it->made_of(LIQUID)) {
      switch (it->type->id) { // TODO: Make this be not a hack.
       case itm_whiskey:
       case itm_vodka:
       case itm_rum:
       case itm_tequila:
        cur->age -= 300;
        smoke += 6;
        break;
       default:
        cur->age += rng(80 * vol, 300 * vol);
        smoke++;
      }
      destroyed = true;
      consumed++;

     } else if (it->made_of(POWDER)) {
      cur->age -= vol;
      destroyed = true;
      smoke += 2;

     } else if (it->made_of(PLASTIC)) {
      smoke += 3;
      if (it->burnt <= cur->density * 2 || (cur->density == 3 && one_in(vol))) {
       destroyed = it->burn(cur->density);
       if (one_in(vol + it->burnt))
        cur->age--;
      }
     }

     if (destroyed) {
      for (int m = 0; m < i_at(x, y)[i].contents.size(); m++)
       i_at(x, y).push_back( i_at(x, y)[i].contents[m] );
      i_at(x, y).erase(i_at(x, y).begin() + i);
      i--;
     }
    }

    veh = &(veh_at(x, y, part));
    if (veh->type != veh_null && (veh->parts[part].flags & VHP_FUEL_TANK) && veh->fuel_type == AT_GAS)
    {
        if (cur->density > 1 && one_in (8) && veh->fuel > 0)
            veh->explode (g, x, y);
    }
// Consume the terrain we're on
    if (has_flag(explodes, x, y)) {
     ter(x, y) = ter_id(int(ter(x, y)) + 1);
     cur->age = 0;
     cur->density = 3;
     g->explosion(x, y, 40, 0, true);

    } else if (has_flag(inflammable, x, y) && one_in(32 - cur->density * 10)) {
     cur->age -= cur->density * cur->density * 40;
     smoke += 15;
     if (cur->density == 3)
      ter(x, y) = t_ash;
    } else if (has_flag(flammable,  x, y) && one_in(32 - cur->density * 10)) {
     cur->age -= cur->density * cur->density * 40;
     smoke += 15;
     if (cur->density == 3)
      ter(x, y) = t_rubble;
    } else if (has_flag(meltable,  x, y) && one_in(32 - cur->density * 10)) {
     cur->age -= cur->density * cur->density * 40;
     if (cur->density == 3)
      ter(x, y) = t_b_metal;
    } else if (terlist[ter(x, y)].flags & mfb(swimmable))
     cur->age += 800;	// Flames die quickly on water

// If we consumed a lot, the flames grow higher
    while (cur->density < 3 && cur->age < 0) {
     cur->age += 300;
     cur->density++;
    }
// If the flames are in a pit, it can't spread to non-pit
    bool in_pit = (ter(x, y) == t_pit);
// If the flames are REALLY big, they contribute to adjacent flames
    if (cur->density == 3 && cur->age < 0) {
// Randomly offset our x/y shifts by 0-2, to randomly pick a square to spread to
     int starti = rng(0, 2);
     int startj = rng(0, 2);
     for (int i = 0; i < 3 && cur->age < 0; i++) {
      for (int j = 0; j < 3 && cur->age < 0; j++) {
       int fx = x + ((i + starti) % 3) - 1, fy = y + ((j + startj) % 3) - 1;
       if (field_at(fx, fy).type == fd_fire && field_at(fx, fy).density < 3 &&
           (!in_pit || ter(fx, fy) == t_pit)) {
        field_at(fx, fy).density++;
        field_at(fx, fy).age = 0;
        cur->age = 0;
       }
      }
     }
    }
// Consume adjacent fuel / terrain to spread.
// Randomly offset our x/y shifts by 0-2, to randomly pick a square to spread to
    int starti = rng(0, 2);
    int startj = rng(0, 2);
    for (int i = 0; i < 3; i++) {
     for (int j = 0; j < 3; j++) {
      int fx = x + ((i + starti) % 3) - 1, fy = y + ((j + startj) % 3) - 1;
      if (INBOUNDS(fx, fy)) {
       int spread_chance = 20 * (cur->density - 1) + 10 * smoke;
       if (has_flag(explodes, fx, fy) && one_in(8 - cur->density)) {
        ter(fx, fy) = ter_id(int(ter(fx, fy)) + 1);
        g->explosion(fx, fy, 40, 0, true);
       } else if ((i != 0 || j != 0) && rng(1, 100) < spread_chance &&
                  (!in_pit || ter(fx, fy) == t_pit) &&
                  ((cur->density == 3 &&
                    (has_flag(flammable, fx, fy) || one_in(20))) ||
                   flammable_items_at(fx, fy) ||
                   field_at(fx, fy).type == fd_web)) {
        if (field_at(fx, fy).type == fd_smoke ||
            field_at(fx, fy).type == fd_web)
         field_at(fx, fy) = field(fd_fire, 1, 0);
        else
         add_field(g, fx, fy, fd_fire, 1);
       } else {
        bool nosmoke = true;
        for (int ii = -1; ii <= 1; ii++) {
         for (int jj = -1; jj <= 1; jj++) {
          if (field_at(x+ii, y+jj).type == fd_fire &&
              field_at(x+ii, y+jj).density == 3)
           smoke++;
          else if (field_at(x+ii, y+jj).type == fd_smoke)
           nosmoke = false;
         }
        }
// If we're not spreading, maybe we'll stick out some smoke, huh?
        if (move_cost(fx, fy) > 0 &&
            (!one_in(smoke) || (nosmoke && one_in(40))) &&
            rng(3, 35) < cur->density * 10 && cur->age < 1000) {
         smoke--;
         add_field(g, fx, fy, fd_smoke, rng(1, cur->density));
        }
       }
      }
     }
    }
   } break;

   case fd_smoke:
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++)
      g->scent(x+i, y+j) = 0;
    }
    if (is_outside(x, y))
     cur->age += 50;
    if (one_in(2)) {
     std::vector <point> spread;
     for (int a = -1; a <= 1; a++) {
      for (int b = -1; b <= 1; b++) {
       if ((field_at(x+a, y+b).type == fd_smoke &&
             field_at(x+a, y+b).density < 3       ) ||
           (field_at(x+a, y+b).is_null() && move_cost(x+a, y+b) > 0))
        spread.push_back(point(x+a, y+b));
      }
     }
     if (cur->density > 0 && cur->age > 0 && spread.size() > 0) {
      point p = spread[rng(0, spread.size() - 1)];
      if (field_at(p.x, p.y).type == fd_smoke &&
          field_at(p.x, p.y).density < 3) {
        field_at(p.x, p.y).density++;
        cur->density--;
      } else if (cur->density > 0 && move_cost(p.x, p.y) > 0 &&
                 add_field(g, p.x, p.y, fd_smoke, 1)){
       cur->density--;
       field_at(p.x, p.y).age = cur->age;
      }
     }
    }
   break;

   case fd_tear_gas:
// Reset nearby scents to zero
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++)
      g->scent(x+i, y+j) = 0;
    }
    if (is_outside(x, y))
     cur->age += 30;
// One in three chance that it spreads (less than smoke!)
    if (one_in(3)) {
     std::vector <point> spread;
// Pick all eligible points to spread to
     for (int a = -1; a <= 1; a++) {
      for (int b = -1; b <= 1; b++) {
       if (((field_at(x+a, y+b).type == fd_smoke ||
             field_at(x+a, y+b).type == fd_tear_gas) &&
             field_at(x+a, y+b).density < 3            )      ||
           (field_at(x+a, y+b).is_null() && move_cost(x+a, y+b) > 0))
        spread.push_back(point(x+a, y+b));
      }
     }
// Then, spread to a nearby point
     if (cur->density > 0 && cur->age > 0 && spread.size() > 0) {
      point p = spread[rng(0, spread.size() - 1)];
// Nearby teargas grows thicker
      if (field_at(p.x, p.y).type == fd_tear_gas &&
          field_at(p.x, p.y).density < 3) {
        field_at(p.x, p.y).density++;
        cur->density--;
// Nearby smoke is converted into teargas
      } else if (field_at(p.x, p.y).type == fd_smoke) {
       field_at(p.x, p.y).type = fd_tear_gas;
// Or, just create a new field.
      } else if (cur->density > 0 && move_cost(p.x, p.y) > 0 &&
                 add_field(g, p.x, p.y, fd_tear_gas, 1)) {
       cur->density--;
       field_at(p.x, p.y).age = cur->age;
      }
     }
    }
    break;

   case fd_toxic_gas:
// Reset nearby scents to zero
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++)
      g->scent(x+i, y+j) = 0;
    }
    if (is_outside(x, y))
     cur->age += 40;
    if (one_in(2)) {
     std::vector <point> spread;
// Pick all eligible points to spread to
     for (int a = -1; a <= 1; a++) {
      for (int b = -1; b <= 1; b++) {
       if (((field_at(x+a, y+b).type == fd_smoke ||
             field_at(x+a, y+b).type == fd_tear_gas ||
             field_at(x+a, y+b).type == fd_toxic_gas ||
             field_at(x+a, y+b).type == fd_nuke_gas   ) &&
             field_at(x+a, y+b).density < 3            )      ||
           (field_at(x+a, y+b).is_null() && move_cost(x+a, y+b) > 0))
        spread.push_back(point(x+a, y+b));
      }
     }
// Then, spread to a nearby point
     if (cur->density > 0 && cur->age > 0 && spread.size() > 0) {
      point p = spread[rng(0, spread.size() - 1)];
// Nearby toxic gas grows thicker
      if (field_at(p.x, p.y).type == fd_toxic_gas &&
          field_at(p.x, p.y).density < 3) {
        field_at(p.x, p.y).density++;
        cur->density--;
// Nearby smoke & teargas is converted into toxic gas
      } else if (field_at(p.x, p.y).type == fd_smoke ||
                 field_at(p.x, p.y).type == fd_tear_gas) {
       field_at(p.x, p.y).type = fd_toxic_gas;
// Or, just create a new field.
      } else if (cur->density > 0 && move_cost(p.x, p.y) > 0 &&
                 add_field(g, p.x, p.y, fd_toxic_gas, 1)) {
       cur->density--;
       field_at(p.x, p.y).age = cur->age;
      }
     }
    }
    break;


   case fd_nuke_gas:
// Reset nearby scents to zero
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++)
      g->scent(x+i, y+j) = 0;
    }
    if (is_outside(x, y))
     cur->age += 40;
// Increase long-term radiation in the land underneath
    radiation(x, y) += rng(0, cur->density);
    if (one_in(2)) {
     std::vector <point> spread;
// Pick all eligible points to spread to
     for (int a = -1; a <= 1; a++) {
      for (int b = -1; b <= 1; b++) {
       if (((field_at(x+a, y+b).type == fd_smoke ||
             field_at(x+a, y+b).type == fd_tear_gas ||
             field_at(x+a, y+b).type == fd_toxic_gas ||
             field_at(x+a, y+b).type == fd_nuke_gas   ) &&
             field_at(x+a, y+b).density < 3            )      ||
           (field_at(x+a, y+b).is_null() && move_cost(x+a, y+b) > 0))
        spread.push_back(point(x+a, y+b));
      }
     }
// Then, spread to a nearby point
     if (cur->density > 0 && cur->age > 0 && spread.size() > 0) {
      point p = spread[rng(0, spread.size() - 1)];
// Nearby nukegas grows thicker
      if (field_at(p.x, p.y).type == fd_nuke_gas &&
          field_at(p.x, p.y).density < 3) {
        field_at(p.x, p.y).density++;
        cur->density--;
// Nearby smoke, tear, and toxic gas is converted into nukegas
      } else if (field_at(p.x, p.y).type == fd_smoke ||
                 field_at(p.x, p.y).type == fd_toxic_gas ||
                 field_at(p.x, p.y).type == fd_tear_gas) {
       field_at(p.x, p.y).type = fd_nuke_gas;
// Or, just create a new field.
      } else if (cur->density > 0 && move_cost(p.x, p.y) > 0 &&
                 add_field(g, p.x, p.y, fd_nuke_gas, 1)) {
       cur->density--;
       field_at(p.x, p.y).age = cur->age;
      }
     }
    }
    break;

   case fd_gas_vent:
    for (int i = x - 1; i <= x + 1; i++) {
     for (int j = y - 1; j <= y + 1; j++) {
      if (field_at(i, j).type == fd_toxic_gas && field_at(i, j).density < 3)
       field_at(i, j).density++;
      else
       add_field(g, i, j, fd_toxic_gas, 3);
     }
    }
    break;

   case fd_fire_vent:
    if (cur->density > 1) {
     if (one_in(3))
      cur->density--;
    } else {
     cur->type = fd_flame_burst;
     cur->density = 3;
    }
    break;

   case fd_flame_burst:
    if (cur->density > 1)
     cur->density--;
    else {
     cur->type = fd_fire_vent;
     cur->density = 3;
    }
    break;

   case fd_electricity:
    if (!one_in(5)) {	// 4 in 5 chance to spread
     std::vector<point> valid;
     if (move_cost(x, y) == 0 && cur->density > 1) { // We're grounded
      int tries = 0;
      while (tries < 10 && cur->age < 50) {
       int cx = x + rng(-1, 1), cy = y + rng(-1, 1);
       if (move_cost(cx, cy) != 0 && field_at(cx, cy).is_null()) {
        add_field(g, cx, cy, fd_electricity, 1);
        cur->density--;
        tries = 0;
       } else
        tries++;
      }
     } else {	// We're not grounded; attempt to ground
      for (int a = -1; a <= 1; a++) {
       for (int b = -1; b <= 1; b++) {
        if (move_cost(x + a, y + b) == 0 && // Grounded tiles first
            field_at(x + a, y + b).is_null())
         valid.push_back(point(x + a, y + b));
       }
      }
      if (valid.size() == 0) {	// Spread to adjacent space, then
       int px = x + rng(-1, 1), py = y + rng(-1, 1);
       if (move_cost(px, py) > 0 && field_at(px, py).type == fd_electricity &&
           field_at(px, py).density < 3)
        field_at(px, py).density++;
       else if (move_cost(px, py) > 0)
        add_field(g, px, py, fd_electricity, 1);
       cur->density--;
      }
      while (valid.size() > 0 && cur->density > 0) {
       int index = rng(0, valid.size() - 1);
       add_field(g, valid[index].x, valid[index].y, fd_electricity, 1);
       cur->density--;
       valid.erase(valid.begin() + index);
      }
     }
    }
    break;

   case fd_fatigue:
    if (cur->density < 3 && int(g->turn) % 3600 == 0 && one_in(10))
     cur->density++;
    else if (cur->density == 3 && one_in(600)) { // Spawn nether creature!
     mon_id type = mon_id(rng(mon_flying_polyp, mon_blank));
     monster creature(g->mtypes[type]);
     creature.spawn(x + rng(-3, 3), y + rng(-3, 3));
     g->z.push_back(creature);
    }
    break;
   }

   cur->age++;
   if (fieldlist[cur->type].halflife > 0) {
    if (cur->age > 0 &&
        dice(3, cur->age) > dice(3, fieldlist[cur->type].halflife)) {
     cur->age = 0;
     cur->density--;
    }
    if (cur->density <= 0) { // Totally dissapated.
     grid[gridn].field_count--;
     grid[gridn].fld[locx][locy] = field();
    }
   }
  }
 }
 return found_field;
}
// solve vegetation model
void modifiedVegetationModel::solve(volVectorField& U, volScalarField& T, volScalarField& w)
{
    // solve radiation within vegetation
    radiation();

    const double p_ = 101325;

    // Magnitude of velocity
    volScalarField magU("magU", mag(U));

    // Bounding velocity
    bound(magU, UMin_);

    // solve aerodynamic, stomatal resistance
    volScalarField new_Tl("new_Tl", Tl_);

    // info
    Info << "    max leaf temp tl=" << max(T.internalField())
         << "k, iteration i=0" << endl;

    scalar maxError, maxRelError;
    int i;

    // solve leaf temperature, iteratively.
    int maxIter = 500;
    for (i=1; i<=maxIter; i++)
    {
        // Solve aerodynamc, stomatal resistance
        resistance(magU, T, w, new_Tl);

        forAll(LAD_, cellI)
        {
            if (LAD_[cellI] > 10*SMALL)
            {
                // Initial leaf temperature
                if (i==1)
                    Tl_[cellI];// = T[cellI];//*0. + 300.;//T[cellI];

                // Calculate saturated density, specific humidity
                rhosat_[cellI] = calc_rhosat(Tl_[cellI]);
                evsat_[cellI] = calc_evsat(Tl_[cellI]);
                wsat_[cellI] = 0.621945*(evsat_[cellI]/(p_-evsat_[cellI])); // ASHRAE 1, eq.23

                // Calculate transpiration rate]);
                E_[cellI] = nEvapSides_.value()*LAD_[cellI]*rhoa_.value()*(wsat_[cellI]-w[cellI])/(ra_[cellI]+rs_[cellI]);
                //E_[cellI] = 0.0; // No evapotranspiration

                // Calculate latent heat flux
                Ql_[cellI] = lambda_.value()*E_[cellI];

                // Calculate new leaf temperature
                new_Tl[cellI] = T[cellI] + (Rn_[cellI] - Ql_[cellI])*(ra_[cellI]/(2.0*rhoa_.value()*cpa_.value()*LAD_[cellI]));

            }
        }

        // info
        Info << "    max leaf temp tl=" << gMax(new_Tl.internalField())
             << " K, iteration i="   << i << endl;

        // Check rel. L-infinity error
        maxError = gMax(mag(new_Tl.internalField()-Tl_.internalField()));
        maxRelError = maxError/gMax(mag(new_Tl.internalField()));

        // update leaf temp.
        forAll(Tl_, cellI)
            Tl_[cellI] = 0.5*Tl_[cellI]+0.5*new_Tl[cellI];

         // convergence check
         if (maxRelError < 1e-8)
             break;
    }
    Tl_.correctBoundaryConditions();

    // Iteration info
    Info << "Vegetation model:  Solving for Tl, Final residual = " << maxError
         << ", Final relative residual = " << maxRelError
         << ", No Iterations " << i << endl;

    Info << "temperature parameters: max Tl = " << gMax(Tl_)
         << ", min T = " << gMin(T) << ", max T = " << gMax(T) << endl;

    Info << "resistances: max rs = " << gMax(rs_)
         << ", max ra = " << gMax(ra_) << endl;

    // Final: Solve aerodynamc, stomatal resistance
    resistance(magU, T, w, Tl_);

    // Final: Update sensible and latent heat flux
    forAll(LAD_, cellI)
    {
        if (LAD_[cellI] > 10*SMALL)
        {
            // Calculate saturated density, specific humidity
            rhosat_[cellI] = calc_rhosat(Tl_[cellI]);
            evsat_[cellI] = calc_evsat(Tl_[cellI]);
            wsat_[cellI] = 0.621945*(evsat_[cellI]/(p_-evsat_[cellI])); // ASHRAE 1, eq.23

            // Calculate transpiration rate
            E_[cellI] = nEvapSides_.value()*LAD_[cellI]*rhoa_.value()*(wsat_[cellI]-w[cellI])/(ra_[cellI]+rs_[cellI]); // todo: implement switch for double or single side

            // Calculate latent heat flux
            Ql_[cellI] = lambda_.value()*E_[cellI];

            // Calculate sensible heat flux
            Qs_[cellI] = 2.0*rhoa_.value()*cpa_.value()*LAD_[cellI]*(Tl_[cellI]-T[cellI])/ra_[cellI];
        }
    }
    rhosat_.correctBoundaryConditions();
    wsat_.correctBoundaryConditions();
    E_.correctBoundaryConditions();
    Ql_.correctBoundaryConditions();
    Qs_.correctBoundaryConditions();


}
Beispiel #4
0
bool map::process_fields(game *g)
{
 bool found_field = false;
 field *cur;
 field_id curtype;
 for (int x = 0; x < SEEX * 3; x++) {
  for (int y = 0; y < SEEY * 3; y++) {
   cur = &field_at(x, y);
   curtype = cur->type;
   if (!found_field && curtype != fd_null)
    found_field = true;
   if (cur->density > 3)
    debugmsg("Whoooooa density of %d", cur->density);

  if (cur->age == 0)	// Don't process "newborn" fields
   curtype = fd_null;

  switch (curtype) {

   case fd_null:
    break;	// Do nothing, obviously.  OBVIOUSLY.

   case fd_blood:
   case fd_bile:
    if (has_flag(swimmable, x, y))	// Dissipate faster in water
     cur->age += 250;
    break;

   case fd_acid:
    if (has_flag(swimmable, x, y))	// Dissipate faster in water
     cur->age += 20;
    for (int i = 0; i < i_at(x, y).size(); i++) {
     item *melting = &(i_at(x, y)[i]);
     if (melting->made_of(LIQUID) || melting->made_of(VEGGY)   ||
         melting->made_of(FLESH)  || melting->made_of(POWDER)  ||
         melting->made_of(COTTON) || melting->made_of(WOOL)    ||
         melting->made_of(PAPER)  || melting->made_of(PLASTIC) ||
         (melting->made_of(GLASS) && !one_in(3)) || one_in(4)) {
// Acid destructable objects here
      melting->damage++;
      if (melting->damage >= 5 ||
          (melting->made_of(PAPER) && melting->damage >= 3)) {
       cur->age += melting->volume();
       for (int m = 0; m < i_at(x, y)[i].contents.size(); m++)
        i_at(x, y).push_back( i_at(x, y)[i].contents[m] );
       i_at(x, y).erase(i_at(x, y).begin() + i);
       i--;
      }
     }
    }
    break;

   case fd_fire:
// Consume items as fuel to help us grow/last longer.
    bool destroyed;
    int vol;
    for (int i = 0; i < i_at(x, y).size(); i++) {
     destroyed = false;
     vol = i_at(x, y)[i].volume();
     if (i_at(x, y)[i].is_ammo()) {
      cur->age /= 2;
      cur->age -= 300;
      destroyed = true;
     } else if (i_at(x, y)[i].made_of(PAPER)) {
      cur->age -= vol * 10;
      destroyed = true;
     } else if ((i_at(x, y)[i].made_of(WOOD) || i_at(x, y)[i].made_of(VEGGY)) &&
                (vol <= cur->density*10-(cur->age>0 ? rng(0,cur->age/10) : 0) ||
                 cur->density == 3)) {
      cur->age -= vol * 10;
      destroyed = true;
     } else if ((i_at(x, y)[i].made_of(COTTON) || i_at(x, y)[i].made_of(FLESH)||
                 i_at(x, y)[i].made_of(WOOL)) &&
                (vol <= cur->density*2 || (cur->density == 3 && one_in(vol)))) {
      cur->age -= vol * 5;
      destroyed = true;
     } else if (i_at(x, y)[i].made_of(LIQUID) || i_at(x, y)[i].made_of(POWDER)||
                i_at(x, y)[i].made_of(PLASTIC)||
                (cur->density >= 2 && i_at(x, y)[i].made_of(GLASS)) ||
                (cur->density == 3 && i_at(x, y)[i].made_of(IRON))) {
      switch (i_at(x, y)[i].type->id) { // TODO: Make this be not a hack.
       case itm_whiskey:
       case itm_vodka:
       case itm_rum:
       case itm_tequila:
        cur->age -= 220;
        break;
      }
      destroyed = true;
     }
     if (destroyed) {
      for (int m = 0; m < i_at(x, y)[i].contents.size(); m++)
       i_at(x, y).push_back( i_at(x, y)[i].contents[m] );
      i_at(x, y).erase(i_at(x, y).begin() + i);
      i--;
     }
    }
// Consume the terrain we're on
    if (terlist[ter(x, y)].flags & mfb(flammable) && one_in(8 - cur->density)) {
     cur->age -= cur->density * cur->density * 40;
     if (cur->density == 3)
      ter(x, y) = t_rubble;
    } else if (terlist[ter(x, y)].flags & mfb(explodes)) {
     ter(x, y) = ter_id(int(ter(x, y)) + 1);
     cur->age = 0;
     cur->density = 3;
     g->explosion(x, y, 40, 0, true);
    } else if (terlist[ter(x, y)].flags & mfb(swimmable))
     cur->age += 800;	// Flames die quickly on water
// If we consumed a lot, the flames grow higher
    while (cur->density < 3 && cur->age < 0) {
     cur->age += 300;
     cur->density++;
    }
// If the flames are REALLY big, they contribute to adjacent flames
    if (cur->density == 3 && cur->age < 0) {
// If the flames are in a pit, it can't spread to non-pit
     bool in_pit = (ter(x, y) == t_pit);
// Randomly offset our x/y shifts by 0-2, to randomly pick a square to spread to
     int starti = rng(0, 2);
     int startj = rng(0, 2);
     for (int i = 0; i < 3 && cur->age < 0; i++) {
      for (int j = 0; j < 3 && cur->age < 0; j++) {
       if (field_at(x+((i+starti)%3), y+((j+startj)%3)).type == fd_fire &&
           field_at(x+((i+starti)%3), y+((j+startj)%3)).density < 3 &&
           (!in_pit || ter(x+((i+starti)%3), y+((j+startj)%3)) == t_pit)) {
        field_at(x+((i+starti)%3), y+((j+startj)%3)).density++; 
        field_at(x+((i+starti)%3), y+((j+startj)%3)).age = 0;
        cur->age = 0;
       }
      }
     }
    }
// Consume adjacent fuel / terrain to spread.
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++) {
      if (x+i >= 0 && y+j >= 0 && x+i < SEEX * 3 && y+j <= SEEY * 3) {
       if (has_flag(explodes, x + i, y + j) && one_in(8 - cur->density)) {
        ter(x + i, y + i) = ter_id(int(ter(x + i, y + i)) + 1);
        g->explosion(x+i, y+j, 40, 0, true);
       } else if ((i != 0 || j != 0) && (i_at(x+i, y+j).size() > 0 ||
                  rng(15, 120) < cur->density * 10)) {
        if (field_at(x+i, y+j).type == fd_smoke)
         field_at(x+i, y+j) = field(fd_fire, 1, 0);
// Fire in pits can only spread to adjacent pits
        else if (ter(x, y) != t_pit || ter(x + i, y + j) == t_pit)
         add_field(g, x+i, y+j, fd_fire, 1);
// If we're not spreading, maybe we'll stick out some smoke, huh?
       } else if (move_cost(x+i, y+j) > 0 &&
                  rng(7, 40) < cur->density * 10 && cur->age < 1000) {
        add_field(g, x+i, y+j, fd_smoke, rng(1, cur->density));
       }
      }
     }
    }
   break;
  
   case fd_smoke:
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++)
      g->scent(x+i, y+j) = 0;
    }
    if (is_outside(x, y))
     cur->age += 50;
    if (one_in(2)) {
     std::vector <point> spread;
     for (int a = -1; a <= 1; a++) {
      for (int b = -1; b <= 1; b++) {
       if ((field_at(x+a, y+b).type == fd_smoke &&
             field_at(x+a, y+b).density < 3)      ||
           (field_at(x+a, y+b).is_null() && move_cost(x+a, y+b) > 0))
        spread.push_back(point(x+a, y+b));
      }
     }
     if (cur->density > 0 && cur->age > 0 && spread.size() > 0) {
      point p = spread[rng(0, spread.size() - 1)];
      if (field_at(p.x, p.y).type == fd_smoke &&
          field_at(p.x, p.y).density < 3) {
        field_at(p.x, p.y).density++;
        cur->density--;
      } else if (cur->density > 0 && move_cost(p.x, p.y) > 0 &&
                 add_field(g, p.x, p.y, fd_smoke, 1)){
       cur->density--;
       field_at(p.x, p.y).age = cur->age;
      }
     }
    }
   break;

   case fd_tear_gas:
// Reset nearby scents to zero
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++)
      g->scent(x+i, y+j) = 0;
    }
    if (is_outside(x, y))
     cur->age += 30;
// One in three chance that it spreads (less than smoke!)
    if (one_in(3)) {
     std::vector <point> spread;
// Pick all eligible points to spread to
     for (int a = -1; a <= 1; a++) {
      for (int b = -1; b <= 1; b++) {
       if (((field_at(x+a, y+b).type == fd_smoke ||
             field_at(x+a, y+b).type == fd_tear_gas) &&
             field_at(x+a, y+b).density < 3            )      ||
           (field_at(x+a, y+b).is_null() && move_cost(x+a, y+b) > 0))
        spread.push_back(point(x+a, y+b));
      }
     }
// Then, spread to a nearby point
     if (cur->density > 0 && cur->age > 0 && spread.size() > 0) {
      point p = spread[rng(0, spread.size() - 1)];
// Nearby teargas grows thicker
      if (field_at(p.x, p.y).type == fd_tear_gas &&
          field_at(p.x, p.y).density < 3) {
        field_at(p.x, p.y).density++;
        cur->density--;
// Nearby smoke is converted into teargas
      } else if (field_at(p.x, p.y).type == fd_smoke) {
       field_at(p.x, p.y).type = fd_tear_gas;
// Or, just create a new field.
      } else if (cur->density > 0 && move_cost(p.x, p.y) > 0 &&
                 add_field(g, p.x, p.y, fd_tear_gas, 1)) {
       cur->density--;
       field_at(p.x, p.y).age = cur->age;
      }
     }
    }
    break;

   case fd_nuke_gas:
// Reset nearby scents to zero
    for (int i = -1; i <= 1; i++) {
     for (int j = -1; j <= 1; j++)
      g->scent(x+i, y+j) = 0;
    }
    if (is_outside(x, y))
     cur->age += 40;
// Increase long-term radiation in the land underneath
    radiation(x, y) += rng(0, cur->density);
    if (one_in(2)) {
     std::vector <point> spread;
// Pick all eligible points to spread to
     for (int a = -1; a <= 1; a++) {
      for (int b = -1; b <= 1; b++) {
       if (((field_at(x+a, y+b).type == fd_smoke ||
             field_at(x+a, y+b).type == fd_tear_gas ||
             field_at(x+a, y+b).type == fd_nuke_gas   ) &&
             field_at(x+a, y+b).density < 3            )      ||
           (field_at(x+a, y+b).is_null() && move_cost(x+a, y+b) > 0))
        spread.push_back(point(x+a, y+b));
      }
     }
// Then, spread to a nearby point
     if (cur->density > 0 && cur->age > 0 && spread.size() > 0) {
      point p = spread[rng(0, spread.size() - 1)];
// Nearby nukegas grows thicker
      if (field_at(p.x, p.y).type == fd_nuke_gas &&
          field_at(p.x, p.y).density < 3) {
        field_at(p.x, p.y).density++;
        cur->density--;
// Nearby smoke & teargas is converted into nukegas
      } else if (field_at(p.x, p.y).type == fd_smoke ||
                 field_at(p.x, p.y).type == fd_tear_gas) {
       field_at(p.x, p.y).type = fd_nuke_gas;
// Or, just create a new field.
      } else if (cur->density > 0 && move_cost(p.x, p.y) > 0 &&
                 add_field(g, p.x, p.y, fd_nuke_gas, 1)) {
       cur->density--;
       field_at(p.x, p.y).age = cur->age;
      }
     }
    }
    break;

   case fd_electricity:
    if (!one_in(5)) {	// 4 in 5 chance to spread
     std::vector<point> valid;
     if (move_cost(x, y) == 0 && cur->density > 1) { // We're grounded
      int tries = 0;
      while (tries < 10 && cur->age < 50) {
       int cx = x + rng(-1, 1), cy = y + rng(-1, 1);
       if (move_cost(cx, cy) != 0 && field_at(cx, cy).is_null()) {
        add_field(g, cx, cy, fd_electricity, 1);
        cur->density--;
        tries = 0;
       } else
        tries++;
      }
     } else {	// We're not grounded; attempt to ground
      for (int a = -1; a <= 1; a++) {
       for (int b = -1; b <= 1; b++) {
        if (move_cost(x + a, y + b) == 0 && // Grounded tiles first
            field_at(x + a, y + b).is_null())
         valid.push_back(point(x + a, y + b));
       }
      }
      if (valid.size() == 0) {	// Spread to adjacent space, then
       int px = x + rng(-1, 1), py = y + rng(-1, 1);
       if (move_cost(px, py) > 0 && field_at(px, py).type == fd_electricity &&
           field_at(px, py).density < 3)
        field_at(px, py).density++;
       else if (move_cost(px, py) > 0)
        add_field(g, px, py, fd_electricity, 1);
       cur->density--;
      }
      while (valid.size() > 0 && cur->density > 0) {
       int index = rng(0, valid.size() - 1);
       add_field(g, valid[index].x, valid[index].y, fd_electricity, 1);
       cur->density--;
       valid.erase(valid.begin() + index);
      }
     }
    }
    break;

   case fd_fatigue:
    if (cur->density < 3 && g->turn % 3600 == 0 && one_in(10))
     cur->density++;
    else if (cur->density == 3 && one_in(3600)) { // Spawn nether creature!
     mon_id type = mon_id(rng(mon_flying_polyp, mon_blank));
     monster creature(g->mtypes[type]);
     creature.spawn(x + rng(-3, 3), y + rng(-3, 3));
     g->z.push_back(creature);
    }
    break;
   }
  
   if (fieldlist[cur->type].halflife > 0) {
    cur->age++;
    if (cur->age > 0 &&
        dice(3, cur->age) > dice(3, fieldlist[cur->type].halflife)) {
     cur->age = 0;
     cur->density--;
    }
    if (cur->density <= 0) // Totally dissapated.
     field_at(x, y) = field();
   }
  }
 }
 return found_field;
}