(svn r4150) -Feature: Merged elrails into trunk. Thanks to Tron for lots of code and proofreading, thanks to peter1138 for another lot of code and ideas.

1 files changed, 352 insertions, 0 deletions

diff --git a/elrail.c b/elrail.c
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+/* $Id$ */
+/** @file elrail.c
+  * This file deals with displaying wires and pylons for electric railway systems.
+<h2>Basics</h2>
+
+<h3>Tile Types</h3>
+
+We have two different types of tiles in the drawing code:
+Normal Railway Tiles (NRTs) which can have more than one track on it, and
+Special Railways tiles (SRTs) which have only one track (like crossings, depots
+stations, etc).
+
+<h3>Location Categories</h3>
+
+All tiles are categorized into three location groups (TLG):
+Group 0: Tiles with both an even X coordinate and an even Y coordinate
+Group 1: Tiles with an even X and an odd Y coordinate
+Group 2: Tiles with an odd X and an even Y coordinate
+Group 3: Tiles with both an odd X and Y coordnate.
+
+<h3>Pylon Points</h3>
+<h4>Control Points</h4>
+A Pylon Control Point (PCP) is a position where a wire (or rather two)
+is mounted onto a pylon.
+Each NRT does contain 4 PCPs which are mapped to a byte
+variable and are represented by the DiagDirection enum:
+
+A wire that ends on the PCP has a dark ending, otherwise the end is bright.<p>
+
+Now on each edge there are two PCPs: One from each adjacent tile. Both PCPs are merged
+using an OR matrix (i. e. if one tile needs a PCP at the postion in question, both
+tiles get it).
+
+<h4>Position Points</h4>
+A Pylon Position Point (PPP) is a position where a pylon is located on the ground.
+Each PCP owns 8 in (45 degree steps) PPPs that are located around it. PPPs are numbered
+0 to 7 with 0 starting north and numbering in clockwise direction. Each track bit has PPPs
+that are impossible (because the pylon would be situated on the track), preferred (because
+the pylon would be rectangular to the track). PPPs are represented by the Direction enum.
+
+<img src="../../elrail_tile.png">
+<img src="../../elrail_track.png">
+
+  */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "tile.h"
+#include "viewport.h"
+#include "functions.h" /* We should REALLY get rid of this goddamn file, as it is butt-ugly */
+#include "variables.h" /* ... same here */
+#include "rail.h"
+#include "debug.h"
+#include "tunnel_map.h"
+#include "road_map.h"
+#include "bridge_map.h"
+#include "bridge.h"
+#include "rail_map.h"
+#include "table/sprites.h"
+#include "table/elrail_data.h"
+
+static inline TLG GetTLG(TileIndex t)
+{
+	return (HASBIT(TileX(t), 0) << 1) + HASBIT(TileY(t), 0);
+}
+
+/** Finds which Rail Bits are present on a given tile. For bridge tiles,
+  * returns track bits under the bridge
+  */
+static TrackBits GetRailTrackBitsUniversal(TileIndex t, byte *override)
+{
+	switch (GetTileType(t)) {
+		case MP_RAILWAY:
+			if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;
+			switch (GetRailTileType(t)) {
+				case RAIL_TYPE_NORMAL: case RAIL_TYPE_SIGNALS:
+					return GetTrackBits(t);
+				default:
+					return 0;
+			}
+			break;
+		case MP_TUNNELBRIDGE:
+			if (IsTunnel(t)) {
+				if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;
+				if (override != NULL) *override = 1 << GetTunnelDirection(t);
+				return (_m[t].m5 & 1) ? TRACK_BIT_Y : TRACK_BIT_X;
+			} else {
+				if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;
+				if (
+					IsBridgeMiddle(t) &&
+					IsTransportUnderBridge(t) &&
+					GetTransportTypeUnderBridge(t) == TRANSPORT_RAIL) {
+					return GetRailBitsUnderBridge(t);
+				} else {
+					if (override != NULL && DistanceMax(t, GetOtherBridgeEnd(t)) > 1) *override = 1 << GetBridgeRampDirection(t);
+
+					return GetBridgeAxis(t) == AXIS_X ? TRACK_BIT_X : TRACK_BIT_Y;
+				}
+			}
+		case MP_STREET:
+			if ((_m[t].m4 & 0xF) != RAILTYPE_ELECTRIC) return 0;
+			return GetCrossingRailBits(t);
+		case MP_STATION:
+			if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;
+			return _m[t].m5 & 1 ? TRACK_BIT_Y : TRACK_BIT_X;
+		default:
+			return 0;
+	}
+}
+
+/** Draws wires and, if required, pylons on a given tile
+  * @param ti The Tileinfo to draw the tile for
+  * @todo Currently, each pylon is drawn twice (once for each neighbouring tiles use OwnedPPPonPCP for this)
+  */
+static void DrawCatenaryRailway(const TileInfo *ti)
+{
+	/* Pylons are placed on a tile edge, so we need to take into account
+	   the track configuration of 2 adjacent tiles. trackconfig[0] stores the
+	   current tile (home tile) while [1] holds the neighbour */
+	TrackBits trackconfig[TS_END];
+	bool isflat[TS_END];
+	/* Note that ti->tileh has already been adjusted for Foundations */
+	uint tileh[TS_END] = {ti->tileh, 0};
+
+	TLG tlg = GetTLG(ti->tile);
+	byte PCPstatus = 0;
+	byte OverridePCP = 0;
+	byte PPPpreferred[DIAGDIR_END] = {0xFF, 0xFF, 0xFF, 0xFF};
+	byte PPPallowed[DIAGDIR_END] = {AllowedPPPonPCP[0], AllowedPPPonPCP[1], AllowedPPPonPCP[2], AllowedPPPonPCP[3]};
+	byte PPPbuffer[DIAGDIR_END];
+	DiagDirection i;
+	Track t;
+
+	/* Find which rail bits are present, and select the override points.
+	   We don't draw a pylon:
+	   1) INSIDE a tunnel (we wouldn't see it anyway)
+	   2) on the "far" end of a bridge head (the one that connects to bridge middle),
+	      because that one is drawn on the bridge. Exception is for length 0 bridges
+	      which have no middle tiles */
+	trackconfig[TS_HOME] = GetRailTrackBitsUniversal(ti->tile, &OverridePCP);
+	/* If a track bit is present that is not in the main direction, the track is level */
+	isflat[TS_HOME] = trackconfig[TS_HOME] & (TRACK_BIT_UPPER | TRACK_BIT_LOWER | TRACK_BIT_LEFT | TRACK_BIT_RIGHT);
+
+	if (IsTunnelTile(ti->tile)) tileh[TS_HOME] = 0;
+	if (IsBridgeTile(ti->tile) && IsBridgeRamp(ti->tile)) {
+		if (tileh[TS_HOME] != 0) {
+			tileh[TS_HOME] = 0;
+		} else {
+			switch (GetBridgeRampDirection(ti->tile)) {
+				case DIAGDIR_NE: tileh[TS_HOME] = 12; break;
+				case DIAGDIR_SE: tileh[TS_HOME] =  6; break;
+				case DIAGDIR_SW: tileh[TS_HOME] =  3; break;
+				case DIAGDIR_NW: tileh[TS_HOME] =  9; break;
+				default: break;
+			}
+		}
+	}
+
+	for (i = DIAGDIR_NE; i < DIAGDIR_END; i++) {
+		extern const TileIndexDiffC _tileoffs_by_dir[];
+		TileIndex neighbour = ti->tile + TileOffsByDir(i);
+		uint foundation = 0;
+		int k;
+
+		/* Here's one of the main headaches. GetTileSlope does not correct for possibly
+		   existing foundataions, so we do have to do that manually later on.*/
+		tileh[TS_NEIGHBOUR] = GetTileSlope(neighbour, NULL);
+		trackconfig[TS_NEIGHBOUR] = GetRailTrackBitsUniversal(neighbour, NULL);
+		isflat[TS_NEIGHBOUR] = trackconfig[TS_NEIGHBOUR] & (TRACK_BIT_UPPER | TRACK_BIT_LOWER | TRACK_BIT_LEFT | TRACK_BIT_RIGHT);
+
+		/* We cycle through all the existing tracks at a PCP and see what
+		   PPPs we want to have, or may not have at all */
+		for (k = 0; k < TRACKS_AT_PCP; k++) {
+			/* Next to us, we have a bridge head, don't worry about that one, if it shows away from us */
+			if (
+					trackorigin[i][k] == TS_NEIGHBOUR &&
+					IsBridgeTile(neighbour) && IsBridgeRamp(neighbour) &&
+					GetBridgeRampDirection(neighbour) == ReverseDiagDir(i)
+			   ) continue;
+
+			if (HASBIT(trackconfig[trackorigin[i][k]], PPPtracks[i][k])) {
+				DiagDirection PCPpos = (trackorigin[i][k] == 0) ? i : ReverseDiagDir(i);
+				PCPstatus |= 1 << i; /* This PCP is in use */
+				PPPpreferred[i] &= PreferredPPPofTrackBitAtPCP[PPPtracks[i][k]][PCPpos];
+				PPPallowed[i] &= ~DisallowedPPPofTrackBitAtPCP[PPPtracks[i][k]][PCPpos];
+			}
+		}
+
+		/* Deactivate all PPPs if PCP is not used */
+		PPPpreferred[i] *= HASBIT(PCPstatus, i);
+		PPPallowed[i] *= HASBIT(PCPstatus, i);
+
+		/* Station on a non-flat tile means foundation. add one height level and adjust tileh */
+		if (IsTileType(neighbour, MP_STATION) && tileh[TS_NEIGHBOUR] != 0) tileh[TS_NEIGHBOUR] = 0;
+
+		/* Read the foundataions if they are present, and adjust the tileh */
+		if (IsTileType(neighbour, MP_RAILWAY)) foundation = GetRailFoundation(tileh[TS_NEIGHBOUR], trackconfig[TS_NEIGHBOUR]);
+		if (IsBridgeTile(neighbour) && IsBridgeRamp(neighbour)) foundation = GetBridgeFoundation(tileh[TS_NEIGHBOUR], GetBridgeAxis(neighbour));
+		if (foundation != 0) {
+			if (foundation < 15) {
+				tileh[TS_NEIGHBOUR] = 0;
+			} else {
+				tileh[TS_NEIGHBOUR] = _inclined_tileh[foundation - 15];
+			}
+		}
+
+		/* Convert the real tileh into a pseudo-tileh for the track */
+		if (IsTunnelTile(neighbour)) tileh[TS_NEIGHBOUR] = 0;
+		if (IsBridgeTile(neighbour) && IsBridgeRamp(neighbour)) {
+			if (tileh[TS_NEIGHBOUR] != 0) {
+				tileh[TS_NEIGHBOUR] = 0;
+			} else {
+				switch (GetBridgeRampDirection(neighbour)) {
+					case DIAGDIR_NE: tileh[TS_NEIGHBOUR] = 12; break;
+					case DIAGDIR_SE: tileh[TS_NEIGHBOUR] =  6; break;
+					case DIAGDIR_SW: tileh[TS_NEIGHBOUR] =  3; break;
+					case DIAGDIR_NW: tileh[TS_NEIGHBOUR] =  9; break;
+					default: break;
+				}
+			}
+		}
+
+		/* If we have a straight (and level) track, we want a pylon only every 2 tiles
+		   Delete the PCP if this is the case. */
+		/* Level means that the slope is the same, or the track is flat */
+		if (tileh[TS_HOME] == tileh[TS_NEIGHBOUR] || (isflat[TS_HOME] && isflat[TS_NEIGHBOUR])) {
+			for (k = 0; k < NUM_IGNORE_GROUPS; k++)
+				if (PPPpreferred[i] == IgnoredPCP[k][tlg][i]) PCPstatus &= ~(1 << i);
+		}
+
+		/* Now decide where we draw our tiles. First try the preferred PPPs, but they may not exist.
+		   In that case, we try the any of the allowed ones. if they don't exist either, don't draw
+		   anything */
+		if (PPPpreferred[i] != 0) {
+			/* Some of the preferred PPPs (the ones in direct extension of the track bit)
+			   have been used as an "end of line" marker. As these are not ALLOWED, this operation
+			   cancles them out */
+			PPPbuffer[i] = PPPpreferred[i] & PPPallowed[i];
+			/* We haven't any buffer yet, so try something else. Fixes 90° curves */
+			if (PPPbuffer[i] == 0) PPPbuffer[i] = PPPallowed[i];
+		} else {
+			PPPbuffer[i] = PPPallowed[i];
+		}
+
+		if (PPPbuffer[i] != 0 && HASBIT(PCPstatus, i) && !HASBIT(OverridePCP, i)) {
+			for (k = 0; k < DIR_END; k++) {
+				byte temp = PPPorder[i][GetTLG(ti->tile)][k];
+				if (HASBIT(PPPbuffer[i], temp)) {
+					uint x  = ti->x + x_pcp_offsets[i] + x_ppp_offsets[temp];
+					uint y  = ti->y + y_pcp_offsets[i] + y_ppp_offsets[temp];
+
+					/* Don't build the pylon if it would be outside the tile */
+					if (!HASBIT(OwnedPPPonPCP[i], temp)) {
+						/* We have a neighour that will draw it, bail out */
+						if (trackconfig[TS_NEIGHBOUR] != 0) break;
+						continue; /* No neighbour, go looking for a better position */
+					}
+
+					AddSortableSpriteToDraw(pylons_normal[temp], x, y, 1, 1, 10,
+							GetSlopeZ(ti->x + x_pcp_offsets[i], ti->y + y_pcp_offsets[i]));
+					break; /* We already have drawn a pylon, bail out */
+				}
+			}
+		}
+	}
+
+	/* Drawing of pylons is finished, now draw the wires */
+	for (t = 0; t < TRACK_END; t++) {
+		if (HASBIT(trackconfig[TS_HOME], t)) {
+
+			byte PCPconfig = HASBIT(PCPstatus, PCPpositions[t][0]) +
+				(HASBIT(PCPstatus, PCPpositions[t][1]) << 1);
+
+			const SortableSpriteStruct *sss;
+			int tileh_selector = !(tileh[TS_HOME] % 3) * tileh[TS_HOME] / 3; /* tileh for the slopes, 0 otherwise */
+
+			if ( /* We are not drawing a wire under a low bridge */
+					IsBridgeTile(ti->tile) &&
+					IsBridgeMiddle(ti->tile) &&
+					!(_display_opt & DO_TRANS_BUILDINGS) &&
+					GetBridgeHeight(t) <= TilePixelHeight(t)
+			   ) return;
+
+			assert(PCPconfig != 0); /* We have a pylon on neither end of the wire, that doesn't work (since we have no sprites for that) */
+			assert(!IsSteepTileh(tileh[TS_HOME]));
+			sss = &CatenarySpriteData[Wires[tileh_selector][t][PCPconfig]];
+
+			AddSortableSpriteToDraw( sss->image, ti->x + sss->x_offset, ti->y + sss->y_offset,
+				sss->x_size, sss->y_size, sss->z_size, GetSlopeZ(ti->x + min(sss->x_offset, 15), ti->y + min(sss->y_offset, 15)) + sss->z_offset);
+		}
+	}
+}
+
+static void DrawCatenaryOnBridge(const TileInfo *ti)
+{
+	TileIndex start = GetOtherBridgeEnd(GetSouthernBridgeEnd(ti->tile));
+	uint length = GetBridgeLength(GetSouthernBridgeEnd(ti->tile), GetOtherBridgeEnd(GetSouthernBridgeEnd(ti->tile)));
+	uint num = DistanceMax(ti->tile, start);
+	const SortableSpriteStruct *sss;
+	Axis axis = GetBridgeAxis(ti->tile);
+	TLG tlg = GetTLG(ti->tile);
+
+	CatenarySprite offset = axis == AXIS_X ? 0 : WIRE_Y_FLAT_BOTH - WIRE_X_FLAT_BOTH;
+
+	if ((length % 2) && num == length) {
+		sss = &CatenarySpriteData[WIRE_X_FLAT_BOTH + offset];
+	} else {
+		sss = &CatenarySpriteData[WIRE_X_FLAT_SW + (num % 2) + offset];
+	}
+
+	if (num % 2) {
+		if (axis == AXIS_X) {
+			AddSortableSpriteToDraw( pylons_bridge[0 + HASBIT(tlg, 0)], ti->x, ti->y + 4 + 8 * HASBIT(tlg, 0), 1, 1, 10, GetBridgeHeight(ti->tile) + 8);
+		} else {
+			AddSortableSpriteToDraw( pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y, 1, 1, 10, GetBridgeHeight(ti->tile) + 8);
+		}
+	}
+
+	if (DistanceMax(ti->tile, start) == length) { /* need a pylon here (the southern end) */
+		if (axis == AXIS_X) {
+			AddSortableSpriteToDraw( pylons_bridge[0 + HASBIT(tlg, 0)], ti->x + 16, ti->y + 4 + 8 * HASBIT(tlg, 0), 1, 1, 10, GetBridgeHeight(ti->tile) + 8);
+		} else {
+			AddSortableSpriteToDraw( pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y + 16, 1, 1, 10, GetBridgeHeight(ti->tile) + 8);
+		}
+	}
+
+	AddSortableSpriteToDraw( sss->image, ti->x + sss->x_offset, ti->y + sss->y_offset,
+			sss->x_size, sss->y_size, sss->z_size, GetBridgeHeight(ti->tile) + sss->z_offset + 8);
+}
+
+void DrawCatenary(const TileInfo *ti)
+{
+	switch (GetTileType(ti->tile)) {
+		case MP_RAILWAY:
+			if (GetRailTileType(ti->tile) == RAIL_TYPE_DEPOT_WAYPOINT && GetRailTileSubtype(ti->tile) == RAIL_SUBTYPE_DEPOT) {
+				const SortableSpriteStruct *sss = &CatenarySpriteData[WIRE_DEPOT_SW + ReverseDiagDir(GetRailDepotDirection(ti->tile))];
+				AddSortableSpriteToDraw( sss->image, ti->x + sss->x_offset, ti->y + sss->y_offset,
+					sss->x_size, sss->y_size, sss->z_size, GetSlopeZ(ti->x, ti->y) + sss->z_offset);
+				return;
+			}
+			/* Fall through */
+		case MP_TUNNELBRIDGE:
+			if (IsBridgeTile(ti->tile) && IsBridgeMiddle(ti->tile) && GetRailTypeOnBridge(ti->tile) == RAILTYPE_ELECTRIC) DrawCatenaryOnBridge(ti);
+			/* Fall further */
+		case MP_STREET: case MP_STATION:
+			DrawCatenaryRailway(ti);
+			break;
+		default:
+			break;
+	}
+}
+