object_cmd.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "stdafx.h"
#include "landscape.h"
#include "command_func.h"
#include "viewport_func.h"
#include "company_base.h"
#include "town.h"
#include "bridge_map.h"
#include "genworld.h"
#include "autoslope.h"
#include "clear_func.h"
#include "water.h"
#include "window_func.h"
#include "company_gui.h"
#include "cheat_type.h"
#include "object.h"
#include "cargopacket.h"
#include "core/random_func.hpp"
#include "core/pool_func.hpp"
#include "object_map.h"
#include "object_base.h"
#include "newgrf_config.h"
#include "newgrf_object.h"
#include "date_func.h"
#include "newgrf_debug.h"
#include "vehicle_func.h"
#include "station_func.h"
#include "object_cmd.h"
#include "landscape_cmd.h"
 
#include "table/strings.h"
#include "table/object_land.h"
 
#include "safeguards.h"
 
ObjectPool _object_pool("Object");
INSTANTIATE_POOL_METHODS(Object)
uint16 Object::counts[NUM_OBJECTS];
 
/* static */ Object *Object::GetByTile(TileIndex tile)
{
  return Object::Get(GetObjectIndex(tile));
}
 
ObjectType GetObjectType(TileIndex t)
{
  assert(IsTileType(t, MP_OBJECT));
  return Object::GetByTile(t)->type;
}
 
void InitializeObjects()
{
  Object::ResetTypeCounts();
}
 
void BuildObject(ObjectType type, TileIndex tile, CompanyID owner, Town *town, uint8 view)
{
  const ObjectSpec *spec = ObjectSpec::Get(type);
 
  TileArea ta(tile, GB(spec->size, HasBit(view, 0) ? 4 : 0, 4), GB(spec->size, HasBit(view, 0) ? 0 : 4, 4));
  Object *o = new Object();
  o->type          = type;
  o->location      = ta;
  o->town          = town == nullptr ? CalcClosestTownFromTile(tile) : town;
  o->build_date    = _date;
  o->view          = view;
 
  /* If nothing owns the object, the colour will be random. Otherwise
   * get the colour from the company's livery settings. */
  if (owner == OWNER_NONE) {
    o->colour = Random();
  } else {
    const Livery *l = Company::Get(owner)->livery;
    o->colour = l->colour1 + l->colour2 * 16;
  }
 
  /* If the object wants only one colour, then give it that colour. */
  if ((spec->flags & OBJECT_FLAG_2CC_COLOUR) == 0) o->colour &= 0xF;
 
  if (HasBit(spec->callback_mask, CBM_OBJ_COLOUR)) {
    uint16 res = GetObjectCallback(CBID_OBJECT_COLOUR, o->colour, 0, spec, o, tile);
    if (res != CALLBACK_FAILED) {
      if (res >= 0x100) ErrorUnknownCallbackResult(spec->grf_prop.grffile->grfid, CBID_OBJECT_COLOUR, res);
      o->colour = GB(res, 0, 8);
    }
  }
 
  assert(o->town != nullptr);
 
  for (TileIndex t : ta) {
    WaterClass wc = (IsWaterTile(t) ? GetWaterClass(t) : WATER_CLASS_INVALID);
    /* Update company infrastructure counts for objects build on canals owned by nobody. */
    if (wc == WATER_CLASS_CANAL && owner != OWNER_NONE && (IsTileOwner(t, OWNER_NONE) || IsTileOwner(t, OWNER_WATER))) {
      Company::Get(owner)->infrastructure.water++;
      DirtyCompanyInfrastructureWindows(owner);
    }
    bool remove = IsDockingTile(t);
    MakeObject(t, owner, o->index, wc, Random());
    if (remove) RemoveDockingTile(t);
    MarkTileDirtyByTile(t);
  }
 
  Object::IncTypeCount(type);
  if (spec->flags & OBJECT_FLAG_ANIMATION) TriggerObjectAnimation(o, OAT_BUILT, spec);
}
 
static void IncreaseAnimationStage(TileIndex tile)
{
  TileArea ta = Object::GetByTile(tile)->location;
  for (TileIndex t : ta) {
    SetAnimationFrame(t, GetAnimationFrame(t) + 1);
    MarkTileDirtyByTile(t);
  }
}
 
#define GetCompanyHQSize GetAnimationFrame
 
#define IncreaseCompanyHQSize IncreaseAnimationStage
 
void UpdateCompanyHQ(TileIndex tile, uint score)
{
  if (tile == INVALID_TILE) return;
 
  byte val = 0;
  if (score >= 170) val++;
  if (score >= 350) val++;
  if (score >= 520) val++;
  if (score >= 720) val++;
 
  while (GetCompanyHQSize(tile) < val) {
    IncreaseCompanyHQSize(tile);
  }
}
 
void UpdateObjectColours(const Company *c)
{
  for (Object *obj : Object::Iterate()) {
    Owner owner = GetTileOwner(obj->location.tile);
    /* Not the current owner, so colour doesn't change. */
    if (owner != c->index) continue;
 
    const ObjectSpec *spec = ObjectSpec::GetByTile(obj->location.tile);
    /* Using the object colour callback, so not using company colour. */
    if (HasBit(spec->callback_mask, CBM_OBJ_COLOUR)) continue;
 
    const Livery *l = c->livery;
    obj->colour = ((spec->flags & OBJECT_FLAG_2CC_COLOUR) ? (l->colour2 * 16) : 0) + l->colour1;
  }
}
 
extern CommandCost CheckBuildableTile(TileIndex tile, uint invalid_dirs, int &allowed_z, bool allow_steep, bool check_bridge);
static CommandCost ClearTile_Object(TileIndex tile, DoCommandFlag flags);
 
CommandCost CmdBuildObject(DoCommandFlag flags, TileIndex tile, ObjectType type, uint8 view)
{
  CommandCost cost(EXPENSES_CONSTRUCTION);
 
  if (type >= NUM_OBJECTS) return CMD_ERROR;
  const ObjectSpec *spec = ObjectSpec::Get(type);
  if (_game_mode == GM_NORMAL && !spec->IsAvailable() && !_generating_world) return CMD_ERROR;
  if ((_game_mode == GM_EDITOR || _generating_world) && !spec->WasEverAvailable()) return CMD_ERROR;
 
  if ((spec->flags & OBJECT_FLAG_ONLY_IN_SCENEDIT) != 0 && ((!_generating_world && _game_mode != GM_EDITOR) || _current_company != OWNER_NONE)) return CMD_ERROR;
  if ((spec->flags & OBJECT_FLAG_ONLY_IN_GAME) != 0 && (_generating_world || _game_mode != GM_NORMAL || _current_company > MAX_COMPANIES)) return CMD_ERROR;
  if (view >= spec->views) return CMD_ERROR;
 
  if (!Object::CanAllocateItem()) return_cmd_error(STR_ERROR_TOO_MANY_OBJECTS);
  if (Town::GetNumItems() == 0) return_cmd_error(STR_ERROR_MUST_FOUND_TOWN_FIRST);
 
  int size_x = GB(spec->size, HasBit(view, 0) ? 4 : 0, 4);
  int size_y = GB(spec->size, HasBit(view, 0) ? 0 : 4, 4);
  TileArea ta(tile, size_x, size_y);
  for (TileIndex t : ta) {
    if (!IsValidTile(t)) return_cmd_error(STR_ERROR_TOO_CLOSE_TO_EDGE_OF_MAP_SUB); // Might be off the map
  }
 
  if (type == OBJECT_OWNED_LAND) {
    /* Owned land is special as it can be placed on any slope. */
    cost.AddCost(Command<CMD_LANDSCAPE_CLEAR>::Do(flags, tile));
  } else {
    /* Check the surface to build on. At this time we can't actually execute the
     * the CLEAR_TILE commands since the newgrf callback later on can check
     * some information about the tiles. */
    bool allow_water = (spec->flags & (OBJECT_FLAG_BUILT_ON_WATER | OBJECT_FLAG_NOT_ON_LAND)) != 0;
    bool allow_ground = (spec->flags & OBJECT_FLAG_NOT_ON_LAND) == 0;
    for (TileIndex t : ta) {
      if (HasTileWaterGround(t)) {
        if (!allow_water) return_cmd_error(STR_ERROR_CAN_T_BUILD_ON_WATER);
        if (!IsWaterTile(t)) {
          /* Normal water tiles don't have to be cleared. For all other tile types clear
           * the tile but leave the water. */
          cost.AddCost(Command<CMD_LANDSCAPE_CLEAR>::Do(flags & ~DC_NO_WATER & ~DC_EXEC, t));
        } else {
          /* Can't build on water owned by another company. */
          Owner o = GetTileOwner(t);
          if (o != OWNER_NONE && o != OWNER_WATER) cost.AddCost(CheckOwnership(o, t));
 
          /* However, the tile has to be clear of vehicles. */
          cost.AddCost(EnsureNoVehicleOnGround(t));
        }
      } else {
        if (!allow_ground) return_cmd_error(STR_ERROR_MUST_BE_BUILT_ON_WATER);
        /* For non-water tiles, we'll have to clear it before building. */
 
        /* When relocating HQ, allow it to be relocated (partial) on itself. */
        if (!(type == OBJECT_HQ &&
            IsTileType(t, MP_OBJECT) &&
            IsTileOwner(t, _current_company) &&
            IsObjectType(t, OBJECT_HQ))) {
          cost.AddCost(Command<CMD_LANDSCAPE_CLEAR>::Do(flags & ~DC_EXEC, t));
        }
      }
    }
 
    /* So, now the surface is checked... check the slope of said surface. */
    int allowed_z;
    if (GetTileSlope(tile, &allowed_z) != SLOPE_FLAT) allowed_z++;
 
    for (TileIndex t : ta) {
      uint16 callback = CALLBACK_FAILED;
      if (HasBit(spec->callback_mask, CBM_OBJ_SLOPE_CHECK)) {
        TileIndex diff = t - tile;
        callback = GetObjectCallback(CBID_OBJECT_LAND_SLOPE_CHECK, GetTileSlope(t), TileY(diff) << 4 | TileX(diff), spec, nullptr, t, view);
      }
 
      if (callback == CALLBACK_FAILED) {
        cost.AddCost(CheckBuildableTile(t, 0, allowed_z, false, false));
      } else {
        /* The meaning of bit 10 is inverted for a grf version < 8. */
        if (spec->grf_prop.grffile->grf_version < 8) ToggleBit(callback, 10);
        CommandCost ret = GetErrorMessageFromLocationCallbackResult(callback, spec->grf_prop.grffile, STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
        if (ret.Failed()) return ret;
      }
    }
 
    if (flags & DC_EXEC) {
      /* This is basically a copy of the loop above with the exception that we now
       * execute the commands and don't check for errors, since that's already done. */
      for (TileIndex t : ta) {
        if (HasTileWaterGround(t)) {
          if (!IsWaterTile(t)) {
            Command<CMD_LANDSCAPE_CLEAR>::Do((flags & ~DC_NO_WATER) | DC_NO_MODIFY_TOWN_RATING, t);
          }
        } else {
          Command<CMD_LANDSCAPE_CLEAR>::Do(flags | DC_NO_MODIFY_TOWN_RATING, t);
        }
      }
    }
  }
  if (cost.Failed()) return cost;
 
  /* Finally do a check for bridges. */
  for (TileIndex t : ta) {
    if (IsBridgeAbove(t) && (
        !(spec->flags & OBJECT_FLAG_ALLOW_UNDER_BRIDGE) ||
        (GetTileMaxZ(t) + spec->height >= GetBridgeHeight(GetSouthernBridgeEnd(t))))) {
      return_cmd_error(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
    }
  }
 
  int hq_score = 0;
  uint build_object_size = 1;
  switch (type) {
    case OBJECT_TRANSMITTER:
    case OBJECT_LIGHTHOUSE:
      if (!IsTileFlat(tile)) return_cmd_error(STR_ERROR_FLAT_LAND_REQUIRED);
      break;
 
    case OBJECT_OWNED_LAND:
      if (IsTileType(tile, MP_OBJECT) &&
          IsTileOwner(tile, _current_company) &&
          IsObjectType(tile, OBJECT_OWNED_LAND)) {
        return_cmd_error(STR_ERROR_YOU_ALREADY_OWN_IT);
      }
      break;
 
    case OBJECT_HQ: {
      Company *c = Company::Get(_current_company);
      if (c->location_of_HQ != INVALID_TILE) {
        /* Don't relocate HQ on the same location. */
        if (c->location_of_HQ == tile) return_cmd_error(STR_ERROR_ALREADY_BUILT);
        /* We need to persuade a bit harder to remove the old HQ. */
        _current_company = OWNER_WATER;
        cost.AddCost(ClearTile_Object(c->location_of_HQ, flags));
        _current_company = c->index;
      }
 
      if (flags & DC_EXEC) {
        hq_score = UpdateCompanyRatingAndValue(c, false);
        c->location_of_HQ = tile;
        SetWindowDirty(WC_COMPANY, c->index);
      }
      break;
    }
 
    case OBJECT_STATUE:
      /* This may never be constructed using this method. */
      return CMD_ERROR;
 
    default: // i.e. NewGRF provided.
      build_object_size = size_x * size_y;
      break;
  }
 
  /* Don't allow building more objects if the company has reached its limit. */
  Company *c = Company::GetIfValid(_current_company);
  if (c != nullptr && GB(c->build_object_limit, 16, 16) < build_object_size) {
    return_cmd_error(STR_ERROR_BUILD_OBJECT_LIMIT_REACHED);
  }
 
  if (flags & DC_EXEC) {
    BuildObject(type, tile, _current_company == OWNER_DEITY ? OWNER_NONE : _current_company, nullptr, view);
 
    /* Make sure the HQ starts at the right size. */
    if (type == OBJECT_HQ) UpdateCompanyHQ(tile, hq_score);
 
    /* Subtract the tile from the build limit. */
    if (c != nullptr) c->build_object_limit -= build_object_size << 16;
  }
 
  cost.AddCost(spec->GetBuildCost() * build_object_size);
  return cost;
}
 
CommandCost CmdBuildObjectArea(DoCommandFlag flags, TileIndex tile, TileIndex start_tile, ObjectType type, uint8 view, bool diagonal)
{
  if (start_tile >= MapSize()) return CMD_ERROR;
 
  if (type >= NUM_OBJECTS) return CMD_ERROR;
  const ObjectSpec *spec = ObjectSpec::Get(type);
  if (view >= spec->views) return CMD_ERROR;
 
  if (spec->size != OBJECT_SIZE_1X1) return CMD_ERROR;
 
  Money money = GetAvailableMoneyForCommand();
  CommandCost cost(EXPENSES_CONSTRUCTION);
  CommandCost last_error = CMD_ERROR;
  bool had_success = false;
 
  const Company *c = Company::GetIfValid(_current_company);
  int limit = (c == nullptr ? INT32_MAX : GB(c->build_object_limit, 16, 16));
 
  TileIterator *iter = diagonal ? (TileIterator *)new DiagonalTileIterator(tile, start_tile) : new OrthogonalTileIterator(tile, start_tile);
  for (; *iter != INVALID_TILE; ++(*iter)) {
    TileIndex t = *iter;
    CommandCost ret = Command<CMD_BUILD_OBJECT>::Do(flags & ~DC_EXEC, t, type, view);
 
    /* If we've reached the limit, stop building (or testing). */
    if (c != nullptr && limit-- <= 0) break;
 
    if (ret.Failed()) {
      last_error = ret;
      continue;
    }
 
    had_success = true;
    if (flags & DC_EXEC) {
      money -= ret.GetCost();
 
      /* If we run out of money, stop building. */
      if (ret.GetCost() > 0 && money < 0) break;
      Command<CMD_BUILD_OBJECT>::Do(flags, t, type, view);
    }
    cost.AddCost(ret);
  }
 
  delete iter;
  return had_success ? cost : last_error;
}
 
static Foundation GetFoundation_Object(TileIndex tile, Slope tileh);
 
static void DrawTile_Object(TileInfo *ti)
{
  ObjectType type = GetObjectType(ti->tile);
  const ObjectSpec *spec = ObjectSpec::Get(type);
 
  /* Fall back for when the object doesn't exist anymore. */
  if (!spec->enabled) type = OBJECT_TRANSMITTER;
 
  if ((spec->flags & OBJECT_FLAG_HAS_NO_FOUNDATION) == 0) DrawFoundation(ti, GetFoundation_Object(ti->tile, ti->tileh));
 
  if (type < NEW_OBJECT_OFFSET) {
    const DrawTileSprites *dts = nullptr;
    Owner to = GetTileOwner(ti->tile);
    PaletteID palette = to == OWNER_NONE ? PAL_NONE : COMPANY_SPRITE_COLOUR(to);
 
    if (type == OBJECT_HQ) {
      TileIndex diff = ti->tile - Object::GetByTile(ti->tile)->location.tile;
      dts = &_object_hq[GetCompanyHQSize(ti->tile) << 2 | TileY(diff) << 1 | TileX(diff)];
    } else {
      dts = &_objects[type];
    }
 
    if (spec->flags & OBJECT_FLAG_HAS_NO_FOUNDATION) {
      /* If an object has no foundation, but tries to draw a (flat) ground
       * type... we have to be nice and convert that for them. */
      switch (dts->ground.sprite) {
        case SPR_FLAT_BARE_LAND:          DrawClearLandTile(ti, 0); break;
        case SPR_FLAT_1_THIRD_GRASS_TILE: DrawClearLandTile(ti, 1); break;
        case SPR_FLAT_2_THIRD_GRASS_TILE: DrawClearLandTile(ti, 2); break;
        case SPR_FLAT_GRASS_TILE:         DrawClearLandTile(ti, 3); break;
        default: DrawGroundSprite(dts->ground.sprite, palette);     break;
      }
    } else {
      DrawGroundSprite(dts->ground.sprite, palette);
    }
 
    if (!IsInvisibilitySet(TO_STRUCTURES)) {
      const DrawTileSeqStruct *dtss;
      foreach_draw_tile_seq(dtss, dts->seq) {
        AddSortableSpriteToDraw(
          dtss->image.sprite, palette,
          ti->x + dtss->delta_x, ti->y + dtss->delta_y,
          dtss->size_x, dtss->size_y,
          dtss->size_z, ti->z + dtss->delta_z,
          IsTransparencySet(TO_STRUCTURES)
        );
      }
    }
  } else {
    DrawNewObjectTile(ti, spec);
  }
 
  DrawBridgeMiddle(ti);
}
 
static int GetSlopePixelZ_Object(TileIndex tile, uint x, uint y)
{
  if (IsObjectType(tile, OBJECT_OWNED_LAND)) {
    int z;
    Slope tileh = GetTilePixelSlope(tile, &z);
 
    return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
  } else {
    return GetTileMaxPixelZ(tile);
  }
}
 
static Foundation GetFoundation_Object(TileIndex tile, Slope tileh)
{
  return IsObjectType(tile, OBJECT_OWNED_LAND) ? FOUNDATION_NONE : FlatteningFoundation(tileh);
}
 
static void ReallyClearObjectTile(Object *o)
{
  Object::DecTypeCount(o->type);
  for (TileIndex tile_cur : o->location) {
    DeleteNewGRFInspectWindow(GSF_OBJECTS, tile_cur);
 
    MakeWaterKeepingClass(tile_cur, GetTileOwner(tile_cur));
  }
  delete o;
}
 
std::vector<ClearedObjectArea> _cleared_object_areas;
 
ClearedObjectArea *FindClearedObject(TileIndex tile)
{
  TileArea ta = TileArea(tile, 1, 1);
 
  for (ClearedObjectArea &coa : _cleared_object_areas) {
    if (coa.area.Intersects(ta)) return &coa;
  }
 
  return nullptr;
}
 
static CommandCost ClearTile_Object(TileIndex tile, DoCommandFlag flags)
{
  /* Get to the northern most tile. */
  Object *o = Object::GetByTile(tile);
  TileArea ta = o->location;
 
  ObjectType type = o->type;
  const ObjectSpec *spec = ObjectSpec::Get(type);
 
  CommandCost cost(EXPENSES_CONSTRUCTION, spec->GetClearCost() * ta.w * ta.h / 5);
  if (spec->flags & OBJECT_FLAG_CLEAR_INCOME) cost.MultiplyCost(-1); // They get an income!
 
  /* Towns can't remove any objects. */
  if (_current_company == OWNER_TOWN) return CMD_ERROR;
 
  /* Water can remove everything! */
  if (_current_company != OWNER_WATER) {
    if ((flags & DC_NO_WATER) && IsTileOnWater(tile)) {
      /* There is water under the object, treat it as water tile. */
      return_cmd_error(STR_ERROR_CAN_T_BUILD_ON_WATER);
    } else if (!(spec->flags & OBJECT_FLAG_AUTOREMOVE) && (flags & DC_AUTO)) {
      /* No automatic removal by overbuilding stuff. */
      return_cmd_error(type == OBJECT_HQ ? STR_ERROR_COMPANY_HEADQUARTERS_IN : STR_ERROR_OBJECT_IN_THE_WAY);
    } else if (_game_mode == GM_EDITOR) {
      /* No further limitations for the editor. */
    } else if (GetTileOwner(tile) == OWNER_NONE) {
      /* Owned by nobody and unremovable, so we can only remove it with brute force! */
      if (!_cheats.magic_bulldozer.value && (spec->flags & OBJECT_FLAG_CANNOT_REMOVE) != 0) return CMD_ERROR;
    } else if (CheckTileOwnership(tile).Failed()) {
      /* We don't own it!. */
      return_cmd_error(STR_ERROR_OWNED_BY);
    } else if ((spec->flags & OBJECT_FLAG_CANNOT_REMOVE) != 0 && (spec->flags & OBJECT_FLAG_AUTOREMOVE) == 0) {
      /* In the game editor or with cheats we can remove, otherwise we can't. */
      if (!_cheats.magic_bulldozer.value) {
        if (type == OBJECT_HQ) return_cmd_error(STR_ERROR_COMPANY_HEADQUARTERS_IN);
        return CMD_ERROR;
      }
 
      /* Removing with the cheat costs more in TTDPatch / the specs. */
      cost.MultiplyCost(25);
    }
  } else if ((spec->flags & (OBJECT_FLAG_BUILT_ON_WATER | OBJECT_FLAG_NOT_ON_LAND)) != 0) {
    /* Water can't remove objects that are buildable on water. */
    return CMD_ERROR;
  }
 
  switch (type) {
    case OBJECT_HQ: {
      Company *c = Company::Get(GetTileOwner(tile));
      if (flags & DC_EXEC) {
        c->location_of_HQ = INVALID_TILE; // reset HQ position
        SetWindowDirty(WC_COMPANY, c->index);
        CargoPacket::InvalidateAllFrom(ST_HEADQUARTERS, c->index);
      }
 
      /* cost of relocating company is 1% of company value */
      cost = CommandCost(EXPENSES_CONSTRUCTION, CalculateCompanyValue(c) / 100);
      break;
    }
 
    case OBJECT_STATUE:
      if (flags & DC_EXEC) {
        Town *town = o->town;
        ClrBit(town->statues, GetTileOwner(tile));
        SetWindowDirty(WC_TOWN_AUTHORITY, town->index);
      }
      break;
 
    default:
      break;
  }
 
  _cleared_object_areas.push_back({tile, ta});
 
  if (flags & DC_EXEC) ReallyClearObjectTile(o);
 
  return cost;
}
 
static void AddAcceptedCargo_Object(TileIndex tile, CargoArray &acceptance, CargoTypes *always_accepted)
{
  if (!IsObjectType(tile, OBJECT_HQ)) return;
 
  /* HQ accepts passenger and mail; but we have to divide the values
   * between 4 tiles it occupies! */
 
  /* HQ level (depends on company performance) in the range 1..5. */
  uint level = GetCompanyHQSize(tile) + 1;
 
  /* Top town building generates 10, so to make HQ interesting, the top
   * type makes 20. */
  acceptance[CT_PASSENGERS] += std::max(1U, level);
  SetBit(*always_accepted, CT_PASSENGERS);
 
  /* Top town building generates 4, HQ can make up to 8. The
   * proportion passengers:mail is different because such a huge
   * commercial building generates unusually high amount of mail
   * correspondence per physical visitor. */
  acceptance[CT_MAIL] += std::max(1U, level / 2);
  SetBit(*always_accepted, CT_MAIL);
}
 
static void AddProducedCargo_Object(TileIndex tile, CargoArray &produced)
{
  if (!IsObjectType(tile, OBJECT_HQ)) return;
 
  produced[CT_PASSENGERS]++;
  produced[CT_MAIL]++;
}
 
 
static void GetTileDesc_Object(TileIndex tile, TileDesc *td)
{
  const ObjectSpec *spec = ObjectSpec::GetByTile(tile);
  td->str = spec->name;
  td->owner[0] = GetTileOwner(tile);
  td->build_date = Object::GetByTile(tile)->build_date;
 
  if (spec->grf_prop.grffile != nullptr) {
    td->grf = GetGRFConfig(spec->grf_prop.grffile->grfid)->GetName();
  }
}
 
static void TileLoop_Object(TileIndex tile)
{
  const ObjectSpec *spec = ObjectSpec::GetByTile(tile);
  if (spec->flags & OBJECT_FLAG_ANIMATION) {
    Object *o = Object::GetByTile(tile);
    TriggerObjectTileAnimation(o, tile, OAT_TILELOOP, spec);
    if (o->location.tile == tile) TriggerObjectAnimation(o, OAT_256_TICKS, spec);
  }
 
  if (IsTileOnWater(tile)) TileLoop_Water(tile);
 
  if (!IsObjectType(tile, OBJECT_HQ)) return;
 
  /* HQ accepts passenger and mail; but we have to divide the values
   * between 4 tiles it occupies! */
 
  /* HQ level (depends on company performance) in the range 1..5. */
  uint level = GetCompanyHQSize(tile) + 1;
  assert(level < 6);
 
  StationFinder stations(TileArea(tile, 2, 2));
 
  uint r = Random();
  /* Top town buildings generate 250, so the top HQ type makes 256. */
  if (GB(r, 0, 8) < (256 / 4 / (6 - level))) {
    uint amt = GB(r, 0, 8) / 8 / 4 + 1;
    if (EconomyIsInRecession()) amt = (amt + 1) >> 1;
    MoveGoodsToStation(CT_PASSENGERS, amt, ST_HEADQUARTERS, GetTileOwner(tile), stations.GetStations());
  }
 
  /* Top town building generates 90, HQ can make up to 196. The
   * proportion passengers:mail is about the same as in the acceptance
   * equations. */
  if (GB(r, 8, 8) < (196 / 4 / (6 - level))) {
    uint amt = GB(r, 8, 8) / 8 / 4 + 1;
    if (EconomyIsInRecession()) amt = (amt + 1) >> 1;
    MoveGoodsToStation(CT_MAIL, amt, ST_HEADQUARTERS, GetTileOwner(tile), stations.GetStations());
  }
}
 
 
static TrackStatus GetTileTrackStatus_Object(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side)
{
  return 0;
}
 
static bool ClickTile_Object(TileIndex tile)
{
  if (!IsObjectType(tile, OBJECT_HQ)) return false;
 
  ShowCompany(GetTileOwner(tile));
  return true;
}
 
static void AnimateTile_Object(TileIndex tile)
{
  AnimateNewObjectTile(tile);
}
 
static bool HasTransmitter(TileIndex tile, void *user)
{
  return IsObjectTypeTile(tile, OBJECT_TRANSMITTER);
}
 
static bool TryBuildLightHouse()
{
  uint maxx = MapMaxX();
  uint maxy = MapMaxY();
  uint r = Random();
 
  /* Scatter the lighthouses more evenly around the perimeter */
  int perimeter = (GB(r, 16, 16) % (2 * (maxx + maxy))) - maxy;
  DiagDirection dir;
  for (dir = DIAGDIR_NE; perimeter > 0; dir++) {
    perimeter -= (DiagDirToAxis(dir) == AXIS_X) ? maxx : maxy;
  }
 
  TileIndex tile;
  switch (dir) {
    default:
    case DIAGDIR_NE: tile = TileXY(maxx - 1, r % maxy); break;
    case DIAGDIR_SE: tile = TileXY(r % maxx, 1); break;
    case DIAGDIR_SW: tile = TileXY(1,        r % maxy); break;
    case DIAGDIR_NW: tile = TileXY(r % maxx, maxy - 1); break;
  }
 
  /* Only build lighthouses at tiles where the border is sea. */
  if (!IsTileType(tile, MP_WATER)) return false;
 
  for (int j = 0; j < 19; j++) {
    int h;
    if (IsTileType(tile, MP_CLEAR) && IsTileFlat(tile, &h) && h <= 2 && !IsBridgeAbove(tile)) {
      BuildObject(OBJECT_LIGHTHOUSE, tile);
      assert(tile < MapSize());
      return true;
    }
    tile += TileOffsByDiagDir(dir);
    if (!IsValidTile(tile)) return false;
  }
  return false;
}
 
static bool TryBuildTransmitter()
{
  TileIndex tile = RandomTile();
  int h;
  if (IsTileType(tile, MP_CLEAR) && IsTileFlat(tile, &h) && h >= 4 && !IsBridgeAbove(tile)) {
    TileIndex t = tile;
    if (CircularTileSearch(&t, 9, HasTransmitter, nullptr)) return false;
 
    BuildObject(OBJECT_TRANSMITTER, tile);
    return true;
  }
  return false;
}
 
void GenerateObjects()
{
  /* Set a guestimate on how much we progress */
  SetGeneratingWorldProgress(GWP_OBJECT, NUM_OBJECTS);
 
  /* Determine number of water tiles at map border needed for freeform_edges */
  uint num_water_tiles = 0;
  if (_settings_game.construction.freeform_edges) {
    for (uint x = 0; x < MapMaxX(); x++) {
      if (IsTileType(TileXY(x, 1), MP_WATER)) num_water_tiles++;
      if (IsTileType(TileXY(x, MapMaxY() - 1), MP_WATER)) num_water_tiles++;
    }
    for (uint y = 1; y < MapMaxY() - 1; y++) {
      if (IsTileType(TileXY(1, y), MP_WATER)) num_water_tiles++;
      if (IsTileType(TileXY(MapMaxX() - 1, y), MP_WATER)) num_water_tiles++;
    }
  }
 
  /* Iterate over all possible object types */
  for (uint i = 0; i < NUM_OBJECTS; i++) {
    const ObjectSpec *spec = ObjectSpec::Get(i);
 
    /* Continue, if the object was never available till now or shall not be placed */
    if (!spec->WasEverAvailable() || spec->generate_amount == 0) continue;
 
    uint16 amount = spec->generate_amount;
 
    /* Scale by map size */
    if ((spec->flags & OBJECT_FLAG_SCALE_BY_WATER) && _settings_game.construction.freeform_edges) {
      /* Scale the amount of lighthouses with the amount of land at the borders.
       * The -6 is because the top borders are MP_VOID (-2) and all corners
       * are counted twice (-4). */
      amount = ScaleByMapSize1D(amount * num_water_tiles) / (2 * MapMaxY() + 2 * MapMaxX() - 6);
    } else if (spec->flags & OBJECT_FLAG_SCALE_BY_WATER) {
      amount = ScaleByMapSize1D(amount);
    } else {
      amount = ScaleByMapSize(amount);
    }
 
    /* Now try to place the requested amount of this object */
    for (uint j = ScaleByMapSize(1000); j != 0 && amount != 0 && Object::CanAllocateItem(); j--) {
      switch (i) {
        case OBJECT_TRANSMITTER:
          if (TryBuildTransmitter()) amount--;
          break;
 
        case OBJECT_LIGHTHOUSE:
          if (TryBuildLightHouse()) amount--;
          break;
 
        default:
          uint8 view = RandomRange(spec->views);
          if (CmdBuildObject(DC_EXEC | DC_AUTO | DC_NO_TEST_TOWN_RATING | DC_NO_MODIFY_TOWN_RATING, RandomTile(), i, view).Succeeded()) amount--;
          break;
      }
    }
    IncreaseGeneratingWorldProgress(GWP_OBJECT);
  }
}
 
static void ChangeTileOwner_Object(TileIndex tile, Owner old_owner, Owner new_owner)
{
  if (!IsTileOwner(tile, old_owner)) return;
 
  bool do_clear = false;
 
  ObjectType type = GetObjectType(tile);
  if ((type == OBJECT_OWNED_LAND || type >= NEW_OBJECT_OFFSET) && new_owner != INVALID_OWNER) {
    SetTileOwner(tile, new_owner);
  } else if (type == OBJECT_STATUE) {
    Town *t = Object::GetByTile(tile)->town;
    ClrBit(t->statues, old_owner);
    if (new_owner != INVALID_OWNER && !HasBit(t->statues, new_owner)) {
      /* Transfer ownership to the new company */
      SetBit(t->statues, new_owner);
      SetTileOwner(tile, new_owner);
    } else {
      do_clear = true;
    }
 
    SetWindowDirty(WC_TOWN_AUTHORITY, t->index);
  } else {
    do_clear = true;
  }
 
  if (do_clear) {
    ReallyClearObjectTile(Object::GetByTile(tile));
    /* When clearing objects, they may turn into canal, which may require transferring ownership. */
    ChangeTileOwner(tile, old_owner, new_owner);
  }
}
 
static CommandCost TerraformTile_Object(TileIndex tile, DoCommandFlag flags, int z_new, Slope tileh_new)
{
  ObjectType type = GetObjectType(tile);
 
  if (type == OBJECT_OWNED_LAND) {
    /* Owned land remains unsold */
    CommandCost ret = CheckTileOwnership(tile);
    if (ret.Succeeded()) return CommandCost();
  } else if (AutoslopeEnabled() && type != OBJECT_TRANSMITTER && type != OBJECT_LIGHTHOUSE) {
    /* Behaviour:
     *  - Both new and old slope must not be steep.
     *  - TileMaxZ must not be changed.
     *  - Allow autoslope by default.
     *  - Disallow autoslope if callback succeeds and returns non-zero.
     */
    Slope tileh_old = GetTileSlope(tile);
    /* TileMaxZ must not be changed. Slopes must not be steep. */
    if (!IsSteepSlope(tileh_old) && !IsSteepSlope(tileh_new) && (GetTileMaxZ(tile) == z_new + GetSlopeMaxZ(tileh_new))) {
      const ObjectSpec *spec = ObjectSpec::Get(type);
 
      /* Call callback 'disable autosloping for objects'. */
      if (HasBit(spec->callback_mask, CBM_OBJ_AUTOSLOPE)) {
        /* If the callback fails, allow autoslope. */
        uint16 res = GetObjectCallback(CBID_OBJECT_AUTOSLOPE, 0, 0, spec, Object::GetByTile(tile), tile);
        if (res == CALLBACK_FAILED || !ConvertBooleanCallback(spec->grf_prop.grffile, CBID_OBJECT_AUTOSLOPE, res)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
      } else if (spec->enabled) {
        /* allow autoslope */
        return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
      }
    }
  }
 
  return Command<CMD_LANDSCAPE_CLEAR>::Do(flags, tile);
}
 
extern const TileTypeProcs _tile_type_object_procs = {
  DrawTile_Object,             // draw_tile_proc
  GetSlopePixelZ_Object,       // get_slope_z_proc
  ClearTile_Object,            // clear_tile_proc
  AddAcceptedCargo_Object,     // add_accepted_cargo_proc
  GetTileDesc_Object,          // get_tile_desc_proc
  GetTileTrackStatus_Object,   // get_tile_track_status_proc
  ClickTile_Object,            // click_tile_proc
  AnimateTile_Object,          // animate_tile_proc
  TileLoop_Object,             // tile_loop_proc
  ChangeTileOwner_Object,      // change_tile_owner_proc
  AddProducedCargo_Object,     // add_produced_cargo_proc
  nullptr,                        // vehicle_enter_tile_proc
  GetFoundation_Object,        // get_foundation_proc
  TerraformTile_Object,        // terraform_tile_proc
};