1

/* $Id$ */

     2

/** @file elrail.c

     3

 * This file deals with displaying wires and pylons for electric railways.

     4

 * <h2>Basics</h2>

     5

 *

     6

 * <h3>Tile Types</h3>

     7

 *

     8

 * We have two different types of tiles in the drawing code:

     9

 * Normal Railway Tiles (NRTs) which can have more than one track on it, and

    10

 * Special Railways tiles (SRTs) which have only one track (like crossings, depots

    11

 * stations, etc).

    12

 *

    13

 * <h3>Location Categories</h3>

    14

 *

    15

 * All tiles are categorized into three location groups (TLG):

    16

 * Group 0: Tiles with both an even X coordinate and an even Y coordinate

    17

 * Group 1: Tiles with an even X and an odd Y coordinate

    18

 * Group 2: Tiles with an odd X and an even Y coordinate

    19

 * Group 3: Tiles with both an odd X and Y coordnate.

    20

 *

    21

 * <h3>Pylon Points</h3>

    22

 * <h4>Control Points</h4>

    23

 * A Pylon Control Point (PCP) is a position where a wire (or rather two)

    24

 * is mounted onto a pylon.

    25

 * Each NRT does contain 4 PCPs which are bitmapped to a byte

    26

 * variable and are represented by the DiagDirection enum

    27

 *

    28

 * Each track ends on two PCPs and thus requires one pylon on each end. However,

    29

 * there is one exception: Straight-and-level tracks only have one pylon every

    30

 * other tile.

    31

 *

    32

 * Now on each edge there are two PCPs: One from each adjacent tile. Both PCPs

    33

 * are merged using an OR operation (i. e. if one tile needs a PCP at the postion

    34

 * in question, both tiles get it).

    35

 *

    36

 * <h4>Position Points</h4>

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 * A Pylon Position Point (PPP) is a position where a pylon is located on the

    38

 * ground.  Each PCP owns 8 in (45 degree steps) PPPs that are located around

    39

 * it. PPPs are represented using the Direction enum. Each track bit has PPPs

    40

 * that are impossible (because the pylon would be situated on the track) and

    41

 * some that are preferred (because the pylon would be rectangular to the track).

    42

 *

    43

 * <img src="../../elrail_tile.png">

    44

 * <img src="../../elrail_track.png">

    45

 *

    46

 */

    47

    48

#include "stdafx.h"

    49

#include "openttd.h"

    50

#include "station_map.h"

    51

#include "tile.h"

    52

#include "viewport.h"

    53

#include "functions.h" /* We should REALLY get rid of this goddamn file, as it is butt-ugly */

    54

#include "variables.h" /* ... same here */

    55

#include "rail.h"

    56

#include "debug.h"

    57

#include "tunnel_map.h"

    58

#include "road_map.h"

    59

#include "bridge_map.h"

    60

#include "bridge.h"

    61

#include "rail_map.h"

    62

#include "table/sprites.h"

    63

#include "table/elrail_data.h"

    64

    65

static inline TLG GetTLG(TileIndex t)

    66

{

    67

	return (HASBIT(TileX(t), 0) << 1) + HASBIT(TileY(t), 0);

    68

}

    69

    70

/** Finds which Rail Bits are present on a given tile. For bridge tiles,

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 * returns track bits under the bridge

    72

 */

    73

static TrackBits GetRailTrackBitsUniversal(TileIndex t, byte *override)

    74

{

    75

	switch (GetTileType(t)) {

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		case MP_RAILWAY:

    77

			if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;

    78

			switch (GetRailTileType(t)) {

    79

				case RAIL_TILE_NORMAL: case RAIL_TILE_SIGNALS:

    80

					return GetTrackBits(t);

    81

				case RAIL_TILE_DEPOT_WAYPOINT:

    82

					if (GetRailTileSubtype(t) == RAIL_SUBTYPE_WAYPOINT) return GetRailWaypointBits(t);

    83

				default:

    84

					return 0;

    85

			}

    86

			break;

    87

    88

		case MP_TUNNELBRIDGE:

    89

			if (IsTunnel(t)) {

    90

				if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;

    91

				if (override != NULL) *override = 1 << GetTunnelDirection(t);

    92

				return AxisToTrackBits(DiagDirToAxis(GetTunnelDirection(t)));

    93

			} else {

    94

				if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;

    95

				if (IsBridgeMiddle(t)) {

    96

					if (IsTransportUnderBridge(t) &&

    97

						GetTransportTypeUnderBridge(t) == TRANSPORT_RAIL) {

    98

						return GetRailBitsUnderBridge(t);

    99

					} else {

   100

						return 0;

   101

					}

   102

				} else {

   103

					if (override != NULL && DistanceMax(t, GetOtherBridgeEnd(t)) > 1) *override = 1 << GetBridgeRampDirection(t);

   104

   105

					return AxisToTrackBits(DiagDirToAxis(GetBridgeRampDirection(t)));

   106

				}

   107

			}

   108

   109

		case MP_STREET:

   110

			if (GetRoadTileType(t) != ROAD_TILE_CROSSING) return 0;

   111

			if (GetRailTypeCrossing(t) != RAILTYPE_ELECTRIC) return 0;

   112

			return GetCrossingRailBits(t);

   113

   114

		case MP_STATION:

   115

			if (!IsRailwayStation(t)) return 0;

   116

			if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;

   117

			if (!IsStationTileElectrifiable(t)) return 0;

   118

			return TrackToTrackBits(GetRailStationTrack(t));

   119

   120

		default:

   121

			return 0;

   122

	}

   123

}

   124

   125

/** Corrects the tileh for certain tile types. Returns an effective tileh for the track on the tile.

   126

 * @param tile The tile to analyse

   127

 * @param *tileh the tileh

   128

 */

   129

static void AdjustTileh(TileIndex tile, Slope *tileh)

   130

{

   131

	if (IsTileType(tile, MP_TUNNELBRIDGE)) {

   132

		if (IsTunnel(tile)) {

   133

			*tileh = SLOPE_FLAT;

   134

		} else {

   135

			if (IsBridgeRamp(tile)) {

   136

				if (*tileh != SLOPE_FLAT) {

   137

					*tileh = SLOPE_FLAT;

   138

				} else {

   139

					switch (GetBridgeRampDirection(tile)) {

   140

						case DIAGDIR_NE: *tileh = SLOPE_NE; break;

   141

						case DIAGDIR_SE: *tileh = SLOPE_SE; break;

   142

						case DIAGDIR_SW: *tileh = SLOPE_SW; break;

   143

						case DIAGDIR_NW: *tileh = SLOPE_NW; break;

   144

						default: break;

   145

					}

   146

				}

   147

			}

   148

		}

   149

	}

   150

}

   151

   152

/** Draws wires and, if required, pylons on a given tile

   153

 * @param ti The Tileinfo to draw the tile for

   154

 */

   155

static void DrawCatenaryRailway(const TileInfo *ti)

   156

{

   157

	/* Pylons are placed on a tile edge, so we need to take into account

   158

	 * the track configuration of 2 adjacent tiles. trackconfig[0] stores the

   159

	 * current tile (home tile) while [1] holds the neighbour */

   160

	TrackBits trackconfig[TS_END];

   161

	bool isflat[TS_END];

   162

	/* Note that ti->tileh has already been adjusted for Foundations */

   163

	Slope tileh[TS_END] = { ti->tileh, SLOPE_FLAT };

   164

   165

	TLG tlg = GetTLG(ti->tile);

   166

	byte PCPstatus = 0;

   167

	byte OverridePCP = 0;

   168

	byte PPPpreferred[DIAGDIR_END];

   169

	byte PPPallowed[DIAGDIR_END];

   170

	DiagDirection i;

   171

	Track t;

   172

   173

	/* Find which rail bits are present, and select the override points.

   174

	 * We don't draw a pylon:

   175

	 * 1) INSIDE a tunnel (we wouldn't see it anyway)

   176

	 * 2) on the "far" end of a bridge head (the one that connects to bridge middle),

   177

	 *    because that one is drawn on the bridge. Exception is for length 0 bridges

   178

	 *    which have no middle tiles */

   179

	trackconfig[TS_HOME] = GetRailTrackBitsUniversal(ti->tile, &OverridePCP);

   180

	/* If a track bit is present that is not in the main direction, the track is level */

   181

	isflat[TS_HOME] = trackconfig[TS_HOME] & (TRACK_BIT_HORZ | TRACK_BIT_VERT);

   182

   183

	AdjustTileh(ti->tile, &tileh[TS_HOME]);

   184

   185

	for (i = DIAGDIR_NE; i < DIAGDIR_END; i++) {

   186

		TileIndex neighbour = ti->tile + TileOffsByDiagDir(i);

   187

		uint foundation = 0;

   188

		int k;

   189

   190

		/* Here's one of the main headaches. GetTileSlope does not correct for possibly

   191

		 * existing foundataions, so we do have to do that manually later on.*/

   192

		tileh[TS_NEIGHBOUR] = GetTileSlope(neighbour, NULL);

   193

		trackconfig[TS_NEIGHBOUR] = GetRailTrackBitsUniversal(neighbour, NULL);

   194

		if (IsTunnelTile(neighbour) && i != GetTunnelDirection(neighbour)) trackconfig[TS_NEIGHBOUR] = 0;

   195

		isflat[TS_NEIGHBOUR] = trackconfig[TS_NEIGHBOUR] & (TRACK_BIT_HORZ | TRACK_BIT_VERT);

   196

   197

		PPPpreferred[i] = 0xFF; /* We start with preferring everything (end-of-line in any direction) */

   198

		PPPallowed[i] = AllowedPPPonPCP[i];

   199

   200

		/* We cycle through all the existing tracks at a PCP and see what

   201

		 * PPPs we want to have, or may not have at all */

   202

		for (k = 0; k < NUM_TRACKS_AT_PCP; k++) {

   203

			/* Next to us, we have a bridge head, don't worry about that one, if it shows away from us */

   204

			if (TrackSourceTile[i][k] == TS_NEIGHBOUR &&

   205

			    IsBridgeTile(neighbour) && IsBridgeRamp(neighbour) &&

   206

			    GetBridgeRampDirection(neighbour) == ReverseDiagDir(i)) {

   207

				continue;

   208

			}

   209

   210

			/* We check whether the track in question (k) is present in the tile

   211

			 * (TrackSourceTile) */

   212

			if (HASBIT(trackconfig[TrackSourceTile[i][k]], TracksAtPCP[i][k])) {

   213

				/* track found, if track is in the neighbour tile, adjust the number

   214

				 * of the PCP for preferred/allowed determination*/

   215

				DiagDirection PCPpos = (TrackSourceTile[i][k] == TS_HOME) ? i : ReverseDiagDir(i);

   216

				SETBIT(PCPstatus, i); /* This PCP is in use */

   217

   218

				PPPpreferred[i] &= PreferredPPPofTrackAtPCP[TracksAtPCP[i][k]][PCPpos];

   219

				PPPallowed[i] &= ~DisallowedPPPofTrackAtPCP[TracksAtPCP[i][k]][PCPpos];

   220

			}

   221

		}

   222

   223

		/* Deactivate all PPPs if PCP is not used */

   224

		PPPpreferred[i] *= HASBIT(PCPstatus, i);

   225

		PPPallowed[i] *= HASBIT(PCPstatus, i);

   226

   227

		/* A station is always "flat", so adjust the tileh accordingly */

   228

		if (IsTileType(neighbour, MP_STATION)) tileh[TS_NEIGHBOUR] = SLOPE_FLAT;

   229

   230

		/* Read the foundataions if they are present, and adjust the tileh */

   231

		if (IsTileType(neighbour, MP_RAILWAY) && GetRailType(neighbour) == RAILTYPE_ELECTRIC) foundation = GetRailFoundation(tileh[TS_NEIGHBOUR], trackconfig[TS_NEIGHBOUR]);

   232

		if (IsBridgeTile(neighbour) && IsBridgeRamp(neighbour)) {

   233

			foundation = GetBridgeFoundation(tileh[TS_NEIGHBOUR], DiagDirToAxis(GetBridgeRampDirection(neighbour)));

   234

		}

   235

   236

		if (foundation != 0) {

   237

			if (foundation < 15) {

   238

				tileh[TS_NEIGHBOUR] = SLOPE_FLAT;

   239

			} else {

   240

				tileh[TS_NEIGHBOUR] = _inclined_tileh[foundation - 15];

   241

			}

   242

		}

   243

   244

		AdjustTileh(neighbour, &tileh[TS_NEIGHBOUR]);

   245

   246

		/* If we have a straight (and level) track, we want a pylon only every 2 tiles

   247

		 * Delete the PCP if this is the case. */

   248

		/* Level means that the slope is the same, or the track is flat */

   249

		if (tileh[TS_HOME] == tileh[TS_NEIGHBOUR] || (isflat[TS_HOME] && isflat[TS_NEIGHBOUR])) {

   250

			for (k = 0; k < NUM_IGNORE_GROUPS; k++)

   251

				if (PPPpreferred[i] == IgnoredPCP[k][tlg][i]) CLRBIT(PCPstatus, i);

   252

		}

   253

   254

		/* Now decide where we draw our pylons. First try the preferred PPPs, but they may not exist.

   255

		 * In that case, we try the any of the allowed ones. if they don't exist either, don't draw

   256

		 * anything. Note that the preferred PPPs still contain the end-of-line markers.

   257

		 * Remove those (simply by ANDing with allowed, since these markers are never allowed) */

   258

		if ((PPPallowed[i] & PPPpreferred[i]) != 0) PPPallowed[i] &= PPPpreferred[i];

   259

   260

		if (PPPallowed[i] != 0 && HASBIT(PCPstatus, i) && !HASBIT(OverridePCP, i)) {

   261

			for (k = 0; k < DIR_END; k++) {

   262

				byte temp = PPPorder[i][GetTLG(ti->tile)][k];

   263

   264

				if (HASBIT(PPPallowed[i], temp)) {

   265

					uint x  = ti->x + x_pcp_offsets[i] + x_ppp_offsets[temp];

   266

					uint y  = ti->y + y_pcp_offsets[i] + y_ppp_offsets[temp];

   267

   268

					/* Don't build the pylon if it would be outside the tile */

   269

					if (!HASBIT(OwnedPPPonPCP[i], temp)) {

   270

						/* We have a neighour that will draw it, bail out */

   271

						if (trackconfig[TS_NEIGHBOUR] != 0) break;

   272

						continue; /* No neighbour, go looking for a better position */

   273

					}

   274

   275

					AddSortableSpriteToDraw(pylons_normal[temp], x, y, 1, 1, 10,

   276

							GetSlopeZ(ti->x + x_pcp_offsets[i], ti->y + y_pcp_offsets[i]));

   277

					break; /* We already have drawn a pylon, bail out */

   278

				}

   279

			}

   280

		}

   281

	}

   282

   283

	/* Don't draw a wire under a low bridge */

   284

	if (IsBridgeTile(ti->tile) &&

   285

			IsBridgeMiddle(ti->tile) &&

   286

			!(_display_opt & DO_TRANS_BUILDINGS) &&

   287

			GetBridgeHeight(ti->tile) <= TilePixelHeight(ti->tile) + TILE_HEIGHT) {

   288

		return;

   289

	}

   290

   291

	/* Drawing of pylons is finished, now draw the wires */

   292

	for (t = 0; t < TRACK_END; t++) {

   293

		if (HASBIT(trackconfig[TS_HOME], t)) {

   294

   295

			byte PCPconfig = HASBIT(PCPstatus, PCPpositions[t][0]) +

   296

				(HASBIT(PCPstatus, PCPpositions[t][1]) << 1);

   297

   298

			const SortableSpriteStruct *sss;

   299

			int tileh_selector = !(tileh[TS_HOME] % 3) * tileh[TS_HOME] / 3; /* tileh for the slopes, 0 otherwise */

   300

   301

			assert(PCPconfig != 0); /* We have a pylon on neither end of the wire, that doesn't work (since we have no sprites for that) */

   302

			assert(!IsSteepSlope(tileh[TS_HOME]));

   303

			sss = &CatenarySpriteData[Wires[tileh_selector][t][PCPconfig]];

   304

   305

			AddSortableSpriteToDraw( sss->image, ti->x + sss->x_offset, ti->y + sss->y_offset,

   306

				sss->x_size, sss->y_size, sss->z_size, GetSlopeZ(ti->x + min(sss->x_offset, TILE_SIZE - 1), ti->y + min(sss->y_offset, TILE_SIZE - 1)) + sss->z_offset);

   307

		}

   308

	}

   309

}

   310

   311

static void DrawCatenaryOnBridge(const TileInfo *ti)

   312

{

   313

	TileIndex end = GetSouthernBridgeEnd(ti->tile);

   314

	TileIndex start = GetOtherBridgeEnd(end);

   315

   316

	uint length = GetBridgeLength(start, end);

   317

	uint num = DistanceMax(ti->tile, start);

   318

	uint height;

   319

   320

	const SortableSpriteStruct *sss;

   321

	Axis axis = GetBridgeAxis(ti->tile);

   322

	TLG tlg = GetTLG(ti->tile);

   323

   324

	CatenarySprite offset = axis == AXIS_X ? 0 : WIRE_Y_FLAT_BOTH - WIRE_X_FLAT_BOTH;

   325

   326

	if ((length % 2) && num == length) {

   327

		/* Draw the "short" wire on the southern end of the bridge

   328

		 * only needed if the length of the bridge is odd */

   329

		sss = &CatenarySpriteData[WIRE_X_FLAT_BOTH + offset];

   330

	} else {

   331

		/* Draw "long" wires on all other tiles of the bridge (one pylon every two tiles) */

   332

		sss = &CatenarySpriteData[WIRE_X_FLAT_SW + (num % 2) + offset];

   333

	}

   334

   335

	height = GetBridgeHeight(ti->tile);

   336

   337

	AddSortableSpriteToDraw( sss->image, ti->x + sss->x_offset, ti->y + sss->y_offset,

   338

		sss->x_size, sss->y_size, sss->z_size, height + sss->z_offset

   339

	);

   340

   341

	/* Finished with wires, draw pylons */

   342

	/* every other tile needs a pylon on the northern end */

   343

	if (num % 2) {

   344

		if (axis == AXIS_X) {

   345

			AddSortableSpriteToDraw(pylons_bridge[0 + HASBIT(tlg, 0)], ti->x, ti->y + 4 + 8 * HASBIT(tlg, 0), 1, 1, 10, height);

   346

		} else {

   347

			AddSortableSpriteToDraw(pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y, 1, 1, 10, height);

   348

		}

   349

	}

   350

   351

	/* need a pylon on the southern end of the bridge */

   352

	if (DistanceMax(ti->tile, start) == length) {

   353

		if (axis == AXIS_X) {

   354

			AddSortableSpriteToDraw(pylons_bridge[0 + HASBIT(tlg, 0)], ti->x + 16, ti->y + 4 + 8 * HASBIT(tlg, 0), 1, 1, 10, height);

   355

		} else {

   356

			AddSortableSpriteToDraw(pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y + 16, 1, 1, 10, height);

   357

		}

   358

	}

   359

}

   360

   361

void DrawCatenary(const TileInfo *ti)

   362

{

   363

	switch (GetTileType(ti->tile)) {

   364

		case MP_RAILWAY:

   365

			if (IsRailDepot(ti->tile)) {

   366

				const SortableSpriteStruct* sss = &CatenarySpriteData_Depot[GetRailDepotDirection(ti->tile)];

   367

   368

				AddSortableSpriteToDraw(

   369

					sss->image, ti->x + sss->x_offset, ti->y + sss->y_offset,

   370

					sss->x_size, sss->y_size, sss->z_size,

   371

					GetTileMaxZ(ti->tile) + sss->z_offset

   372

				);

   373

				return;

   374

			}

   375

			break;

   376

   377

		case MP_TUNNELBRIDGE:

   378

			if (IsBridge(ti->tile) && IsBridgeMiddle(ti->tile) && GetRailTypeOnBridge(ti->tile) == RAILTYPE_ELECTRIC) DrawCatenaryOnBridge(ti);

   379

			break;

   380

   381

		case MP_STREET:  break;

   382

		case MP_STATION: break;

   383

   384

		default: return;

   385

	}

   386

	DrawCatenaryRailway(ti);

   387

}