terraform_cmd.cpp

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/* $Id: terraform_cmd.cpp 14754 2008-12-28 14:37:19Z rubidium $ */

#include "stdafx.h"
#include "openttd.h"
#include "strings_type.h"
#include "command_func.h"
#include "tile_map.h"
#include "tunnel_map.h"
#include "bridge_map.h"
#include "variables.h"
#include "functions.h"
#include "economy_func.h"

#include "table/strings.h"

/*
 * In one terraforming command all four corners of a initial tile can be raised/lowered (though this is not available to the player).
 * The maximal amount of height modifications is archieved when raising a complete flat land from sea level to MAX_TILE_HEIGHT or vice versa.
 * This affects all corners with a manhatten distance smaller than MAX_TILE_HEIGHT to one of the initial 4 corners.
 * Their maximal amount is computed to 4 * \sum_{i=1}^{h_max} i  =  2 * h_max * (h_max + 1).
 */
static const int TERRAFORMER_MODHEIGHT_SIZE = 2 * MAX_TILE_HEIGHT * (MAX_TILE_HEIGHT + 1);

/*
 * The maximal amount of affected tiles (i.e. the tiles that incident with one of the corners above, is computed similiar to
 * 1 + 4 * \sum_{i=1}^{h_max} (i+1)  =  1 + 2 * h_max + (h_max + 3).
 */
static const int TERRAFORMER_TILE_TABLE_SIZE = 1 + 2 * MAX_TILE_HEIGHT * (MAX_TILE_HEIGHT + 3);

struct TerraformerHeightMod {
  TileIndex tile;   
  byte height;      
};

struct TerraformerState {
  int modheight_count;  
  int tile_table_count; 

  TileIndex tile_table[TERRAFORMER_TILE_TABLE_SIZE];
  TerraformerHeightMod modheight[TERRAFORMER_MODHEIGHT_SIZE];  
};

TileIndex _terraform_err_tile; 

static int TerraformGetHeightOfTile(const TerraformerState *ts, TileIndex tile)
{
  const TerraformerHeightMod *mod = ts->modheight;

  for (int count = ts->modheight_count; count != 0; count--, mod++) {
    if (mod->tile == tile) return mod->height;
  }

  /* TileHeight unchanged so far, read value from map. */
  return TileHeight(tile);
}

static void TerraformSetHeightOfTile(TerraformerState *ts, TileIndex tile, int height)
{
  /* Find tile in the "modheight" table.
   * Note: In a normal user-terraform command the tile will not be found in the "modheight" table.
   *       But during house- or industry-construction multiple corners can be terraformed at once. */
  TerraformerHeightMod *mod = ts->modheight;
  int count = ts->modheight_count;

  while ((count > 0) && (mod->tile != tile)) {
    mod++;
    count--;
  }

  /* New entry? */
  if (count == 0) {
    assert(ts->modheight_count < TERRAFORMER_MODHEIGHT_SIZE);
    ts->modheight_count++;
  }

  /* Finally store the new value */
  mod->tile = tile;
  mod->height = (byte)height;
}

static void TerraformAddDirtyTile(TerraformerState *ts, TileIndex tile)
{
  int count = ts->tile_table_count;

  for (TileIndex *t = ts->tile_table; count != 0; count--, t++) {
    if (*t == tile) return;
  }

  assert(ts->tile_table_count < TERRAFORMER_TILE_TABLE_SIZE);

  ts->tile_table[ts->tile_table_count++] = tile;
}

static void TerraformAddDirtyTileAround(TerraformerState *ts, TileIndex tile)
{
  TerraformAddDirtyTile(ts, tile + TileDiffXY( 0, -1));
  TerraformAddDirtyTile(ts, tile + TileDiffXY(-1, -1));
  TerraformAddDirtyTile(ts, tile + TileDiffXY(-1,  0));
  TerraformAddDirtyTile(ts, tile);
}

static CommandCost TerraformTileHeight(TerraformerState *ts, TileIndex tile, int height)
{
  assert(tile < MapSize());

  /* Check range of destination height */
  if (height < 0) return_cmd_error(STR_1003_ALREADY_AT_SEA_LEVEL);
  if (height > MAX_TILE_HEIGHT) return_cmd_error(STR_1004_TOO_HIGH);

  /*
   * Check if the terraforming has any effect.
   * This can only be true, if multiple corners of the start-tile are terraformed (i.e. the terraforming is done by towns/industries etc.).
   * In this case the terraforming should fail. (Don't know why.)
   */
  if (height == TerraformGetHeightOfTile(ts, tile)) return CMD_ERROR;

  /* Check "too close to edge of map" */
  uint x = TileX(tile);
  uint y = TileY(tile);
  if ((x <= 1) || (y <= 1) || (x >= MapMaxX() - 1) || (y >= MapMaxY() - 1)) {
    /*
     * Determine a sensible error tile
     * Note: If x and y are both zero this will disable the error tile. (Tile 0 cannot be highlighted :( )
     */
    if ((x == 1) && (y != 0)) x = 0;
    if ((y == 1) && (x != 0)) y = 0;
    _terraform_err_tile = TileXY(x, y);
    return_cmd_error(STR_0002_TOO_CLOSE_TO_EDGE_OF_MAP);
  }

  /* Mark incident tiles, that are involved in the terraforming */
  TerraformAddDirtyTileAround(ts, tile);

  /* Store the height modification */
  TerraformSetHeightOfTile(ts, tile, height);

  CommandCost total_cost(EXPENSES_CONSTRUCTION);

  /* Increment cost */
  total_cost.AddCost(_price.terraform);

  /* Recurse to neighboured corners if height difference is larger than 1 */
  {
    const TileIndexDiffC *ttm;

    static const TileIndexDiffC _terraform_tilepos[] = {
      { 1,  0}, // move to tile in SE
      {-2,  0}, // undo last move, and move to tile in NW
      { 1,  1}, // undo last move, and move to tile in SW
      { 0, -2}  // undo last move, and move to tile in NE
    };

    for (ttm = _terraform_tilepos; ttm != endof(_terraform_tilepos); ttm++) {
      tile += ToTileIndexDiff(*ttm);

      /* Get TileHeight of neighboured tile as of current terraform progress */
      int r = TerraformGetHeightOfTile(ts, tile);
      int height_diff = height - r;

      /* Is the height difference to the neighboured corner greater than 1? */
      if (abs(height_diff) > 1) {
        /* Terraform the neighboured corner. The resulting height difference should be 1. */
        height_diff += (height_diff < 0 ? 1 : -1);
        CommandCost cost = TerraformTileHeight(ts, tile, r + height_diff);
        if (CmdFailed(cost)) return cost;
        total_cost.AddCost(cost);
      }
    }
  }

  return total_cost;
}

CommandCost CmdTerraformLand(TileIndex tile, uint32 flags, uint32 p1, uint32 p2, const char *text)
{
  /* Make an extra check for map-bounds cause we add tiles to the originating tile */
  if (tile + TileDiffXY(1, 1) >= MapSize()) return CMD_ERROR;

  _terraform_err_tile = INVALID_TILE;

  CommandCost total_cost(EXPENSES_CONSTRUCTION);
  int direction = (p2 != 0 ? 1 : -1);
  TerraformerState ts;

  ts.modheight_count = ts.tile_table_count = 0;

  /* Compute the costs and the terraforming result in a model of the landscape */
  if ((p1 & SLOPE_W) != 0) {
    TileIndex t = tile + TileDiffXY(1, 0);
    CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);
    if (CmdFailed(cost)) return cost;
    total_cost.AddCost(cost);
  }

  if ((p1 & SLOPE_S) != 0) {
    TileIndex t = tile + TileDiffXY(1, 1);
    CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);
    if (CmdFailed(cost)) return cost;
    total_cost.AddCost(cost);
  }

  if ((p1 & SLOPE_E) != 0) {
    TileIndex t = tile + TileDiffXY(0, 1);
    CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);
    if (CmdFailed(cost)) return cost;
    total_cost.AddCost(cost);
  }

  if ((p1 & SLOPE_N) != 0) {
    TileIndex t = tile + TileDiffXY(0, 0);
    CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);
    if (CmdFailed(cost)) return cost;
    total_cost.AddCost(cost);
  }

  /* Check if the terraforming is valid wrt. tunnels, bridges and objects on the surface */
  {
    TileIndex *ti = ts.tile_table;

    for (int count = ts.tile_table_count; count != 0; count--, ti++) {
      TileIndex tile = *ti;

      /* Find new heights of tile corners */
      uint z_N = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 0));
      uint z_W = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 0));
      uint z_S = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 1));
      uint z_E = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 1));

      /* Find min and max height of tile */
      uint z_min = min(min(z_N, z_W), min(z_S, z_E));
      uint z_max = max(max(z_N, z_W), max(z_S, z_E));

      /* Compute tile slope */
      Slope tileh = (z_max > z_min + 1 ? SLOPE_STEEP : SLOPE_FLAT);
      if (z_W > z_min) tileh |= SLOPE_W;
      if (z_S > z_min) tileh |= SLOPE_S;
      if (z_E > z_min) tileh |= SLOPE_E;
      if (z_N > z_min) tileh |= SLOPE_N;

      /* Check if bridge would take damage */
      if (direction == 1 && MayHaveBridgeAbove(tile) && IsBridgeAbove(tile) &&
          GetBridgeHeight(GetSouthernBridgeEnd(tile)) <= z_max * TILE_HEIGHT) {
        _terraform_err_tile = tile; // highlight the tile under the bridge
        return_cmd_error(STR_5007_MUST_DEMOLISH_BRIDGE_FIRST);
      }
      /* Check if tunnel would take damage */
      if (direction == -1 && IsTunnelInWay(tile, z_min * TILE_HEIGHT)) {
        _terraform_err_tile = tile; // highlight the tile above the tunnel
        return_cmd_error(STR_1002_EXCAVATION_WOULD_DAMAGE);
      }
      /* Check tiletype-specific things, and add extra-cost */
      const bool curr_gen = _generating_world;
      if (_game_mode == GM_EDITOR) _generating_world = true; // used to create green terraformed land
      CommandCost cost = _tile_type_procs[GetTileType(tile)]->terraform_tile_proc(tile, flags | DC_AUTO, z_min * TILE_HEIGHT, tileh);
      _generating_world = curr_gen;
      if (CmdFailed(cost)) {
        _terraform_err_tile = tile;
        return cost;
      }
      total_cost.AddCost(cost);
    }
  }

  if (flags & DC_EXEC) {
    /* change the height */
    {
      int count;
      TerraformerHeightMod *mod;

      mod = ts.modheight;
      for (count = ts.modheight_count; count != 0; count--, mod++) {
        TileIndex til = mod->tile;

        SetTileHeight(til, mod->height);
      }
    }

    /* finally mark the dirty tiles dirty */
    {
      int count;
      TileIndex *ti = ts.tile_table;
      for (count = ts.tile_table_count; count != 0; count--, ti++) {
        MarkTileDirtyByTile(*ti);
      }
    }
  }
  return total_cost;
}


CommandCost CmdLevelLand(TileIndex tile, uint32 flags, uint32 p1, uint32 p2, const char *text)
{
  if (p1 >= MapSize()) return CMD_ERROR;

  /* remember level height */
  uint oldh = TileHeight(p1);

  /* compute new height */
  uint h = oldh + p2;

  /* Check range of destination height */
  if (h > MAX_TILE_HEIGHT) return_cmd_error((oldh == 0) ? STR_1003_ALREADY_AT_SEA_LEVEL : STR_1004_TOO_HIGH);
  if (p2 == 0) _error_message = STR_ALREADY_LEVELLED;

  /* make sure sx,sy are smaller than ex,ey */
  int ex = TileX(tile);
  int ey = TileY(tile);
  int sx = TileX(p1);
  int sy = TileY(p1);
  if (ex < sx) Swap(ex, sx);
  if (ey < sy) Swap(ey, sy);
  tile = TileXY(sx, sy);

  int size_x = ex - sx + 1;
  int size_y = ey - sy + 1;

  Money money = GetAvailableMoneyForCommand();
  CommandCost cost(EXPENSES_CONSTRUCTION);

  BEGIN_TILE_LOOP(tile2, size_x, size_y, tile) {
    uint curh = TileHeight(tile2);
    while (curh != h) {
      CommandCost ret = DoCommand(tile2, SLOPE_N, (curh > h) ? 0 : 1, flags & ~DC_EXEC, CMD_TERRAFORM_LAND);
      if (CmdFailed(ret)) break;

      if (flags & DC_EXEC) {
        money -= ret.GetCost();
        if (money < 0) {
          _additional_cash_required = ret.GetCost();
          return cost;
        }
        DoCommand(tile2, SLOPE_N, (curh > h) ? 0 : 1, flags, CMD_TERRAFORM_LAND);
      }

      cost.AddCost(ret);
      curh += (curh > h) ? -1 : 1;
    }
  } END_TILE_LOOP(tile2, size_x, size_y, tile)

  return (cost.GetCost() == 0) ? CMD_ERROR : cost;
}