27

/*

    28

 * In one terraforming command all four corners of a initial tile can be raised/lowered (though this is not available to the player).

    29

 * The maximal amount of height modifications is archieved when raising a complete flat land from sea level to MAX_TILE_HEIGHT or vice versa.

    30

 * This affects all corners with a manhatten distance smaller than MAX_TILE_HEIGHT to one of the initial 4 corners.

    31

 * Their maximal amount is computed to 4 * \sum_{i=1}^{h_max} i  =  2 * h_max * (h_max + 1).

    32

 */

    33

static const int TERRAFORMER_MODHEIGHT_SIZE = 2 * MAX_TILE_HEIGHT * (MAX_TILE_HEIGHT + 1);

    34

    35

/*

    36

 * The maximal amount of affected tiles (i.e. the tiles that incident with one of the corners above, is computed similiar to

    37

 * 1 + 4 * \sum_{i=1}^{h_max} (i+1)  =  1 + 2 * h_max + (h_max + 3).

    38

 */

    39

static const int TERRAFORMER_TILE_TABLE_SIZE = 1 + 2 * MAX_TILE_HEIGHT * (MAX_TILE_HEIGHT + 3);

    40

    42

	TileIndex tile;   ///< Referenced tile.

    43

	byte height;      ///< New TileHeight (height of north corner) of the tile.

    47

	int modheight_count;                                         ///< amount of entries in "modheight".

    48

	int tile_table_count;                                        ///< amount of entries in "tile_table".

    50

	TileIndex tile_table[TERRAFORMER_TILE_TABLE_SIZE];           ///< Dirty tiles, i.e. at least one corner changed.

    51

	TerraformerHeightMod modheight[TERRAFORMER_MODHEIGHT_SIZE];  ///< Height modifications.

    54

/**

    55

 * Gets the TileHeight (height of north corner) of a tile as of current terraforming progress.

    56

 *

    57

 * @param ts TerraformerState.

    58

 * @param tile Tile.

    59

 * @return TileHeight.

    60

 */

    70

	/* TileHeight unchanged so far, read value from map. */

    74

/**

    75

 * Stores the TileHeight (height of north corner) of a tile in a TerraformerState.

    76

 *

    77

 * @param ts TerraformerState.

    78

 * @param tile Tile.

    79

 * @param height New TileHeight.

    80

 */

    81

static void TerraformSetHeightOfTile(TerraformerState *ts, TileIndex tile, int height)

    82

{

    83

	/* Find tile in the "modheight" table.

    84

	 * Note: In a normal user-terraform command the tile will not be found in the "modheight" table.

    85

	 *       But during house- or industry-construction multiple corners can be terraformed at once. */

    86

	TerraformerHeightMod *mod = ts->modheight;

    87

	int count = ts->modheight_count;

    88

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

    89

		mod++;

    90

		count--;

    91

	}

    92

    93

	/* New entry? */

    94

	if (count == 0) {

    95

		assert(ts->modheight_count < TERRAFORMER_MODHEIGHT_SIZE);

    96

		ts->modheight_count++;

    97

	}

    98

    99

	/* Finally store the new value */

   100

	mod->tile = tile;

   101

	mod->height = (byte)height;

   102

}

   103

   104

/**

   105

 * Adds a tile to the "tile_table" in a TerraformerState.

   106

 *

   107

 * @param ts TerraformerState.

   108

 * @param tile Tile.

   109

 */

   121

	assert(ts->tile_table_count < TERRAFORMER_TILE_TABLE_SIZE);

   122

   126

/**

   127

 * Adds all tiles that incident with the north corner of a specific tile to the "tile_table" in a TerraformerState.

   128

 *

   129

 * @param ts TerraformerState.

   130

 * @param tile Tile.

   131

 */

   140

/**

   141

 * Terraform the north corner of a tile to a specific height.

   142

 *

   143

 * @param ts TerraformerState.

   144

 * @param tile Tile.

   145

 * @param height Aimed height.

   146

 * @param return Error code or cost.

   147

 */

   148

static CommandCost TerraformTileHeight(TerraformerState *ts, TileIndex tile, int height)

   150

	CommandCost total_cost = CommandCost();

   154

	/* Check range of destination height */

   155

	if (height < 0) return_cmd_error(STR_1003_ALREADY_AT_SEA_LEVEL);

   156

	if (height > MAX_TILE_HEIGHT) return_cmd_error(STR_1004_TOO_HIGH);

   158

	/*

   159

	 * Check if the terraforming has any effect.

   160

	 * This can only be true, if multiple corners of the start-tile are terraformed (i.e. the terraforming is done by towns/industries etc.).

   161

	 * In this case the terraforming should fail. (Don't know why.)

   162

	 */

   163

	if (height == TerraformGetHeightOfTile(ts, tile)) return CMD_ERROR;

   165

	/* Check "too close to edge of map" */

   166

	uint x = TileX(tile);

   167

	uint y = TileY(tile);

   168

	if ((x <= 1) || (y <= 1) || (x >= MapMaxX() - 1) || (y >= MapMaxY() - 1)) {

   169

		/*

   170

		 * Determine a sensible error tile

   171

		 * Note: If x and y are both zero this will disable the error tile. (Tile 0 cannot be highlighted :( )

   172

		 */

   173

		if ((x == 1) && (y != 0)) x = 0;

   174

		if ((y == 1) && (x != 0)) y = 0;

   175

		_terraform_err_tile = TileXY(x, y);

   176

		return_cmd_error(STR_0002_TOO_CLOSE_TO_EDGE_OF_MAP);

   179

	/* Mark incident tiles, that are involved in the terraforming */

   180

	TerraformAddDirtyTileAround(ts, tile);

   182

	/* Store the height modification */

   183

	TerraformSetHeightOfTile(ts, tile, height);

   185

	/* Increment cost */

   186

	total_cost.AddCost(_price.terraform);

   188

	/* Recurse to neighboured corners if height difference is larger than 1 */

   193

			{ 1,  0}, // move to tile in SE

   194

			{-2,  0}, // undo last move, and move to tile in NW

   195

			{ 1,  1}, // undo last move, and move to tile in SW

   196

			{ 0, -2}  // undo last move, and move to tile in NE

   202

			/* Get TileHeight of neighboured tile as of current terraform progress */

   203

			int r = TerraformGetHeightOfTile(ts, tile);

   204

			int height_diff = height - r;

   205

   206

			/* Is the height difference to the neighboured corner greater than 1? */

   207

			if (abs(height_diff) > 1) {

   208

				/* Terraform the neighboured corner. The resulting height difference should be 1. */

   209

				height_diff += (height_diff < 0 ? 1 : -1);

   210

				CommandCost cost = TerraformTileHeight(ts, tile, r + height_diff);

   211

				if (CmdFailed(cost)) return cost;

   212

				total_cost.AddCost(cost);

   217

	return total_cost;

   223

 * @param p1 corners to terraform (SLOPE_xxx)

   224

 * @param p2 direction; eg up (non-zero) or down (zero)

   230

	CommandCost total_cost = CommandCost();

   231

	int direction = (p2 != 0 ? 1 : -1);

   242

	/* Compute the costs and the terraforming result in a model of the landscape */

   243

	if ((p1 & SLOPE_W) != 0) {

   244

		TileIndex t = tile + TileDiffXY(1, 0);

   245

		CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);

   246

		if (CmdFailed(cost)) return cost;

   247

		total_cost.AddCost(cost);

   250

	if ((p1 & SLOPE_S) != 0) {

   251

		TileIndex t = tile + TileDiffXY(1, 1);

   252

		CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);

   253

		if (CmdFailed(cost)) return cost;

   254

		total_cost.AddCost(cost);

   257

	if ((p1 & SLOPE_E) != 0) {

   258

		TileIndex t = tile + TileDiffXY(0, 1);

   259

		CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);

   260

		if (CmdFailed(cost)) return cost;

   261

		total_cost.AddCost(cost);

   264

	if ((p1 & SLOPE_N) != 0) {

   265

		TileIndex t = tile + TileDiffXY(0, 0);

   266

		CommandCost cost = TerraformTileHeight(&ts, t, TileHeight(t) + direction);

   267

		if (CmdFailed(cost)) return cost;

   268

		total_cost.AddCost(cost);

   269

	}

   270

   271

	/* Check if the terraforming is valid wrt. tunnels, bridges and objects on the surface */

   279

			/* Find new heights of tile corners */

   280

			uint z_N = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 0));

   281

			uint z_W = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 0));

   282

			uint z_S = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 1));

   283

			uint z_E = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 1));

   285

			/* Find min and max height of tile */

   286

			uint z_min = min(min(z_N, z_W), min(z_S, z_E));

   287

			uint z_max = max(max(z_N, z_W), max(z_S, z_E));

   288

   289

			/* Compute tile slope */

   290

			uint tileh = (z_max > z_min + 1 ? SLOPE_STEEP : SLOPE_FLAT);

   291

			if (z_W > z_min) tileh += SLOPE_W;

   292

			if (z_S > z_min) tileh += SLOPE_S;

   293

			if (z_E > z_min) tileh += SLOPE_E;

   294

			if (z_N > z_min) tileh += SLOPE_N;

   295

   296

			/* Check if bridge would take damage */

   299

				_terraform_err_tile = tile; // highlight the tile under the bridge

   302

			/* Check if tunnel would take damage */

   304

				_terraform_err_tile = tile; // highlight the tile above the tunnel

   307

			/* Check tiletype-specific things, and add extra-cost */

   308

			CommandCost cost = _tile_type_procs[GetTileType(tile)]->terraform_tile_proc(tile, flags, z_min * TILE_HEIGHT, (Slope) tileh);

   309

			if (CmdFailed(cost)) {

   310

				_terraform_err_tile = tile;

   311

				return cost;

   312

			}

   313

			total_cost.AddCost(cost);

   340

	return total_cost;

   386

			ret = DoCommand(tile2, SLOPE_N, (curh > h) ? 0 : 1, flags & ~DC_EXEC, CMD_TERRAFORM_LAND);

   395

				DoCommand(tile2, SLOPE_N, (curh > h) ? 0 : 1, flags, CMD_TERRAFORM_LAND);