Merge branch 'custom_bridgeheads' into jgrpp

# Conflicts:
#	docs/landscape_grid.html
#	src/roadveh_cmd.cpp
#	src/saveload/afterload.cpp
#	src/saveload/extended_ver_sl.cpp
#	src/saveload/extended_ver_sl.h
#	src/settings_gui.cpp
#	src/settings_type.h
#	src/tunnelbridge_cmd.cpp
#	src/tunnelbridge_map.h

docs/landscape.html

@@ -1453,6 +1453,36 @@
     <ul>
      <li style="color: blue">m1 bit 7: bit 4 of <a href="#TrackType">track type</a> for railway (more rail types patch)</li>
      <li>m1 bits 4..0: <a href="#OwnershipInfo">owner</a></li>
+     <li style="color: blue">m2 bits 7..0: custom road bridge heads (flat bridge heads only)<br>
+      Road/tram bits below are XORed with the axial bridge direction road bits.<br>
+      A non-custom bridge head configuration will have a value of 0.
+      <ul>
+       <li>m2 bits 7..4: Road bits<br>
+           Valid only if m7 bit 6 is set
+       </li>
+       <li>m2 bits 3..0: Tram bits<br>
+           Valid only if m7 bit 7 is set
+       </li>
+      </ul>
+      <table style="color: blue">
+       <tr>
+        <td align=left>bit 0: </td>
+        <td>NW piece</td>
+       </tr>
+       <tr>
+        <td align=left>bit 1: </td>
+        <td>SW piece</td>
+       </tr>
+       <tr>
+        <td align=left>bit 2: </td>
+        <td>SE piece</td>
+       </tr>
+       <tr>
+        <td align=left>bit 3: </td>
+        <td>NE piece</td>
+       </tr>
+      </table>
+     </li>
      <li>m3 bits 7..4: <a href="#OwnershipInfo">owner</a> of tram</li>
      <li style="color: purple">m3 bits 3..0: bits 3..0 of <a href="#TrackType">track type</a> for railway</li>
      <li>m5 bit 4: pbs reservation state for railway</li>

src/bridge_map.h

@@ -186,4 +186,72 @@ static inline void MakeAqueductBridgeRamp(TileIndex t, Owner o, DiagDirection d)
 	MakeBridgeRamp(t, o, 0, d, TRANSPORT_WATER, 0);
 }
 
+/**
+ * Checks if this road bridge head is a custom bridge head
+ * @param t The tile to analyze
+ * @pre IsBridgeTile(t) && GetTunnelBridgeTransportType(t) == TRANSPORT_ROAD
+ * @return true if it is a custom bridge head
+ */
+static inline bool IsRoadCustomBridgeHead(TileIndex t)
+{
+	assert(IsBridgeTile(t) && (TransportType)GB(_m[t].m5, 2, 2) == TRANSPORT_ROAD);
+	return GB(_m[t].m2, 0, 8) != 0;
+}
+
+/**
+ * Checks if this tile is a road bridge head with a custom bridge head
+ * @param t The tile to analyze
+ * @return true if it is a road bridge head with a custom bridge head
+ */
+static inline bool IsRoadCustomBridgeHeadTile(TileIndex t)
+{
+	return IsBridgeTile(t) && (TransportType)GB(_m[t].m5, 2, 2) == TRANSPORT_ROAD && IsRoadCustomBridgeHead(t);
+}
+
+/**
+ * Returns the road bits for a (possibly custom) road bridge head
+ * @param t The tile to analyze
+ * @param rt Road type.
+ * @pre IsBridgeTile(t) && GetTunnelBridgeTransportType(t) == TRANSPORT_ROAD
+ * @return road bits for the bridge head
+ */
+static inline RoadBits GetCustomBridgeHeadRoadBits(TileIndex t, RoadType rt)
+{
+	assert(IsBridgeTile(t));
+	if (!HasTileRoadType(t, rt)) return (RoadBits) 0;
+	RoadBits bits = (GB(_m[t].m5, 0, 1) ? ROAD_Y : ROAD_X) ^ (RoadBits) GB(_m[t].m2, rt == ROADTYPE_TRAM ? 4 : 0, 4);
+	return bits;
+}
+
+/**
+ * Returns the road bits for a (possibly custom) road bridge head, for all road types
+ * @param t The tile to analyze
+ * @pre IsBridgeTile(t) && GetTunnelBridgeTransportType(t) == TRANSPORT_ROAD
+ * @return road bits for the bridge head
+ */
+static inline RoadBits GetCustomBridgeHeadAllRoadBits(TileIndex t)
+{
+	return GetCustomBridgeHeadRoadBits(t, ROADTYPE_ROAD) | GetCustomBridgeHeadRoadBits(t, ROADTYPE_TRAM);
+}
+
+/**
+ * Sets the road bits for a (possibly custom) road bridge head
+ * @param t The tile to modify
+ * @param rt Road type.
+ * @param bits The road bits.
+ * @pre IsBridgeTile(t) && GetTunnelBridgeTransportType(t) == TRANSPORT_ROAD
+ * @pre HasTileRoadType() must be set correctly before calling this
+ */
+static inline void SetCustomBridgeHeadRoadBits(TileIndex t, RoadType rt, RoadBits bits)
+{
+	assert(IsBridgeTile(t));
+	if (HasTileRoadType(t, rt)) {
+		assert(bits != ROAD_NONE);
+		SB(_m[t].m2, rt == ROADTYPE_TRAM ? 4 : 0, 4, bits ^ (GB(_m[t].m5, 0, 1) ? ROAD_Y : ROAD_X));
+	} else {
+		assert(bits == ROAD_NONE);
+		SB(_m[t].m2, rt == ROADTYPE_TRAM ? 4 : 0, 4, 0);
+	}
+}
+
 #endif /* BRIDGE_MAP_H */

src/company_gui.cpp

@@ -2478,6 +2478,15 @@ void DirtyCompanyInfrastructureWindows(CompanyID company)
 	SetWindowDirty(WC_COMPANY_INFRASTRUCTURE, company);
 }
 
+/**
+ * Redraw all windows with all company infrastructure counts.
+ */
+void DirtyAllCompanyInfrastructureWindows()
+{
+	SetWindowClassesDirty(WC_COMPANY);
+	SetWindowClassesDirty(WC_COMPANY_INFRASTRUCTURE);
+}
+
 struct BuyCompanyWindow : Window {
 	BuyCompanyWindow(WindowDesc *desc, WindowNumber window_number) : Window(desc)
 	{

src/company_gui.h

@@ -25,5 +25,6 @@ void ShowCompany(CompanyID company);
 void InvalidateCompanyWindows(const Company *c);
 void DeleteCompanyWindows(CompanyID company);
 void DirtyCompanyInfrastructureWindows(CompanyID company);
+void DirtyAllCompanyInfrastructureWindows();
 
 #endif /* COMPANY_GUI_H */

src/landscape.cpp

@@ -30,6 +30,7 @@
 #include "core/random_func.hpp"
 #include "object_base.h"
 #include "company_func.h"
+#include "tunnelbridge_map.h"
 #include "pathfinder/npf/aystar.h"
 #include "saveload/saveload.h"
 #include <deque>
@@ -351,6 +352,8 @@ Slope GetFoundationSlope(TileIndex tile, int *z)
 
 bool HasFoundationNW(TileIndex tile, Slope slope_here, uint z_here)
 {
+	if (IsRoadCustomBridgeHeadTile(tile) && GetTunnelBridgeDirection(tile) == DIAGDIR_NW) return false;
+
 	int z;
 
 	int z_W_here = z_here;
@@ -368,6 +371,8 @@ bool HasFoundationNW(TileIndex tile, Slope slope_here, uint z_here)
 
 bool HasFoundationNE(TileIndex tile, Slope slope_here, uint z_here)
 {
+	if (IsRoadCustomBridgeHeadTile(tile) && GetTunnelBridgeDirection(tile) == DIAGDIR_NE) return false;
+
 	int z;
 
 	int z_E_here = z_here;

src/lang/english.txt

@@ -1832,6 +1832,9 @@ STR_CONFIG_SETTING_PATHFINDER_FOR_SHIPS_HELPTEXT                :Path finder to
 STR_CONFIG_SETTING_REVERSE_AT_SIGNALS                           :Automatic reversing at signals: {STRING2}
 STR_CONFIG_SETTING_REVERSE_AT_SIGNALS_HELPTEXT                  :Allow trains to reverse on a signal, if they waited there a long time
 
+STR_CONFIG_SETTING_ENABLE_ROAD_CUSTOM_BRIDGE_HEADS              :Enable road custom bridge heads: {STRING2}
+STR_CONFIG_SETTING_ENABLE_ROAD_CUSTOM_BRIDGE_HEADS_HELPTEXT     :Allow road bridges to have custom, non-straight flat entry/exit tiles
+
 STR_CONFIG_SETTING_QUERY_CAPTION                                :{WHITE}Change setting value
 
 STR_CONFIG_SETTING_ADJACENT_CROSSINGS                           :Close adjacent level crossings: {STRING2}

src/pathfinder/follow_track.hpp

@@ -102,8 +102,9 @@ struct CFollowTrackT
 	{
 		assert(IsTram()); // this function shouldn't be called in other cases
 
-		if (IsNormalRoadTile(tile)) {
-			RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
+		const bool is_bridge = IsRoadCustomBridgeHeadTile(tile);
+		if (is_bridge || IsNormalRoadTile(tile)) {
+			RoadBits rb = is_bridge ? GetCustomBridgeHeadRoadBits(tile, ROADTYPE_TRAM) : GetRoadBits(tile, ROADTYPE_TRAM);
 			switch (rb) {
 				case ROAD_NW: return DIAGDIR_NW;
 				case ROAD_SW: return DIAGDIR_SW;
@@ -216,7 +217,7 @@ protected:
 				m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
 				return;
 			}
-			assert(ReverseDiagDir(enterdir) == m_exitdir);
+			if (!IsRoadCustomBridgeHeadTile(m_old_tile)) assert(ReverseDiagDir(enterdir) == m_exitdir);
 		}
 
 		/* normal or station tile, do one step */
@@ -370,7 +371,12 @@ protected:
 					}
 				}
 			} else { // IsBridge(m_new_tile)
-				if (!m_is_bridge) {
+				if (!m_is_bridge && IsRoadTT() && IsRoadCustomBridgeHeadTile(m_new_tile)) {
+					if (!(DiagDirToRoadBits(ReverseDiagDir(m_exitdir)) & GetCustomBridgeHeadRoadBits(m_new_tile, IsTram() ? ROADTYPE_TRAM : ROADTYPE_ROAD))) {
+						m_err = EC_NO_WAY;
+						return false;
+					}
+				} else if (!m_is_bridge) {
 					DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
 					if (ramp_enderdir != m_exitdir) {
 						m_err = EC_NO_WAY;

src/pathfinder/yapf/yapf_road.cpp

@@ -112,7 +112,10 @@ public:
 	 */
 	inline bool PfCalcCost(Node &n, const TrackFollower *tf)
 	{
-		int segment_cost = 0;
+		/* this is to handle the case where the starting tile is a junction custom bridge head,
+		 * and we have advanced across the bridge in the initial step */
+		int segment_cost = tf->m_tiles_skipped * YAPF_TILE_LENGTH;
+
 		uint tiles = 0;
 		/* start at n.m_key.m_tile / n.m_key.m_td and walk to the end of segment */
 		TileIndex tile = n.m_key.m_tile;
@@ -135,6 +138,11 @@ public:
 			TrackFollower F(Yapf().GetVehicle());
 			if (!F.Follow(tile, trackdir)) break;
 
+			/* if we skipped some tunnel tiles, add their cost */
+			/* with custom bridge heads, this cost must be added before checking if the segment has ended */
+			segment_cost += F.m_tiles_skipped * YAPF_TILE_LENGTH;
+			tiles += F.m_tiles_skipped + 1;
+
 			/* if there are more trackdirs available & reachable, we are at the end of segment */
 			if (KillFirstBit(F.m_new_td_bits) != TRACKDIR_BIT_NONE) break;
 
@@ -143,10 +151,6 @@ public:
 			/* stop if RV is on simple loop with no junctions */
 			if (F.m_new_tile == n.m_key.m_tile && new_td == n.m_key.m_td) return false;
 
-			/* if we skipped some tunnel tiles, add their cost */
-			segment_cost += F.m_tiles_skipped * YAPF_TILE_LENGTH;
-			tiles += F.m_tiles_skipped + 1;
-
 			/* add hilly terrain penalty */
 			segment_cost += Yapf().SlopeCost(tile, F.m_new_tile, trackdir);
 

src/road_cmd.cpp

@@ -53,7 +53,7 @@ bool RoadVehiclesAreBuilt()
 }
 
 /** Invalid RoadBits on slopes.  */
-static const RoadBits _invalid_tileh_slopes_road[2][15] = {
+extern const RoadBits _invalid_tileh_slopes_road[2][15] = {
 	/* The inverse of the mixable RoadBits on a leveled slope */
 	{
 		ROAD_NONE,         // SLOPE_FLAT
@@ -213,36 +213,75 @@ static CommandCost RemoveRoad(TileIndex tile, DoCommandFlag flags, RoadBits piec
 	if (ret.Failed()) return ret;
 
 	if (!IsTileType(tile, MP_ROAD)) {
+		const bool custom_bridge_head = IsBridgeTile(tile) &&
+				HasBridgeFlatRamp(GetTileSlope(tile), DiagDirToAxis(GetTunnelBridgeDirection(tile))) &&
+				(_settings_game.construction.road_custom_bridge_heads || IsRoadCustomBridgeHead(tile));
+
 		/* If it's the last roadtype, just clear the whole tile */
-		if (rts == RoadTypeToRoadTypes(rt)) return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+		if (!custom_bridge_head && rts == RoadTypeToRoadTypes(rt)) return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 
 		CommandCost cost(EXPENSES_CONSTRUCTION);
 		if (IsTileType(tile, MP_TUNNELBRIDGE)) {
+			const RoadBits entrance_piece = DiagDirToRoadBits(GetTunnelBridgeDirection(tile));
+			const RoadBits axial_pieces = AxisToRoadBits(DiagDirToAxis(GetTunnelBridgeDirection(tile)));
+			const RoadBits existing = IsBridge(tile) ? GetCustomBridgeHeadRoadBits(tile, rt) : axial_pieces;
+			const RoadType other_rt = (rt == ROADTYPE_ROAD) ? ROADTYPE_TRAM : ROADTYPE_ROAD;
+
+			/* handle case where we would otherwise leave a single bridge entrance piece */
+			if ((existing & ~pieces) == entrance_piece) {
+				pieces |= entrance_piece;
+			}
+
 			/* Removing any roadbit in the bridge axis removes the roadtype (that's the behaviour remove-long-roads needs) */
-			if ((AxisToRoadBits(DiagDirToAxis(GetTunnelBridgeDirection(tile))) & pieces) == ROAD_NONE) return_cmd_error(rt == ROADTYPE_TRAM ? STR_ERROR_THERE_IS_NO_TRAMWAY : STR_ERROR_THERE_IS_NO_ROAD);
+			if ((existing & pieces) == ROAD_NONE) return_cmd_error(rt == ROADTYPE_TRAM ? STR_ERROR_THERE_IS_NO_TRAMWAY : STR_ERROR_THERE_IS_NO_ROAD);
+
+			if (!custom_bridge_head) pieces |= axial_pieces;
+
+			const TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
+			const uint middle_len = GetTunnelBridgeLength(other_end, tile);
+			uint pieces_count = 0;
+
+			const RoadBits other_end_existing = IsBridge(other_end) ? GetCustomBridgeHeadRoadBits(other_end, rt) : axial_pieces;
+			RoadBits other_end_pieces = ROAD_NONE;
+			if (pieces & entrance_piece) {
+				other_end_pieces |= MirrorRoadBits(entrance_piece);
+				/* if removing the other end entrance would only leave one piece, remove that too */
+				if (CountBits(other_end_existing & ~other_end_pieces) == 1) {
+					other_end_pieces |= other_end_existing;
+				}
+				pieces_count += middle_len * 2;
+				if ((GetCustomBridgeHeadRoadBits(tile, other_rt) & entrance_piece) == ROAD_NONE) {
+					/* can't leave no entrance pieces for any road type */
+					return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+				}
+			}
+			pieces_count += CountBits(pieces & existing);
+			pieces_count += CountBits(other_end_pieces & other_end_existing);
 
-			TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
-			/* Pay for *every* tile of the bridge or tunnel */
-			uint len = GetTunnelBridgeLength(other_end, tile) + 2;
-			cost.AddCost(len * _price[PR_CLEAR_ROAD]);
+			cost.AddCost(pieces_count * _price[PR_CLEAR_ROAD]);
 			if (flags & DC_EXEC) {
-				Company *c = Company::GetIfValid(GetRoadOwner(tile, rt));
-				if (c != NULL) {
-					/* A full diagonal road tile has two road bits. */
-					c->infrastructure.road[rt] -= len * 2 * TUNNELBRIDGE_TRACKBIT_FACTOR;
-					DirtyCompanyInfrastructureWindows(c->index);
+				SubtractRoadTunnelBridgeInfrastructure(tile, other_end);
+
+				const RoadBits bits = existing & ~pieces;
+				const RoadBits other_bits = other_end_existing & ~other_end_pieces;
+
+				if (bits == ROAD_NONE) SetRoadTypes(tile, GetRoadTypes(tile) & ~RoadTypeToRoadTypes(rt));
+				if (other_bits == ROAD_NONE) SetRoadTypes(other_end, GetRoadTypes(other_end) & ~RoadTypeToRoadTypes(rt));
+
+				if (IsBridge(tile)) {
+					SetCustomBridgeHeadRoadBits(tile, rt, bits);
+					SetCustomBridgeHeadRoadBits(other_end, rt, other_bits);
 				}
 
-				SetRoadTypes(other_end, GetRoadTypes(other_end) & ~RoadTypeToRoadTypes(rt));
-				SetRoadTypes(tile, GetRoadTypes(tile) & ~RoadTypeToRoadTypes(rt));
+				if (bits == ROAD_NONE && other_bits == ROAD_NONE) {
+					/* If the owner of the bridge sells all its road, also move the ownership
+					 * to the owner of the other roadtype, unless the bridge owner is a town. */
 
-				/* If the owner of the bridge sells all its road, also move the ownership
-				 * to the owner of the other roadtype, unless the bridge owner is a town. */
-				RoadType other_rt = (rt == ROADTYPE_ROAD) ? ROADTYPE_TRAM : ROADTYPE_ROAD;
-				Owner other_owner = GetRoadOwner(tile, other_rt);
-				if (!IsTileOwner(tile, other_owner) && !IsTileOwner(tile, OWNER_TOWN)) {
-					SetTileOwner(tile, other_owner);
-					SetTileOwner(other_end, other_owner);
+					Owner other_owner = GetRoadOwner(tile, other_rt);
+					if (!IsTileOwner(tile, other_owner) && !IsTileOwner(tile, OWNER_TOWN)) {
+						SetTileOwner(tile, other_owner);
+						SetTileOwner(other_end, other_owner);
+					}
 				}
 
 				/* Mark tiles dirty that have been repaved */
@@ -252,6 +291,9 @@ static CommandCost RemoveRoad(TileIndex tile, DoCommandFlag flags, RoadBits piec
 					MarkTileDirtyByTile(tile);
 					MarkTileDirtyByTile(other_end);
 				}
+
+				AddRoadTunnelBridgeInfrastructure(tile, other_end);
+				DirtyAllCompanyInfrastructureWindows();
 			}
 		} else {
 			assert(IsDriveThroughStopTile(tile));
@@ -670,12 +712,95 @@ CommandCost CmdBuildRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 
 		case MP_TUNNELBRIDGE: {
 			if (GetTunnelBridgeTransportType(tile) != TRANSPORT_ROAD) goto do_clear;
-			/* Only allow building the outern roadbit, so building long roads stops at existing bridges */
-			if (MirrorRoadBits(DiagDirToRoadBits(GetTunnelBridgeDirection(tile))) != pieces) goto do_clear;
-			if (HasTileRoadType(tile, rt)) return_cmd_error(STR_ERROR_ALREADY_BUILT);
-			/* Don't allow adding roadtype to the bridge/tunnel when vehicles are already driving on it */
-			CommandCost ret = TunnelBridgeIsFree(tile, GetOtherTunnelBridgeEnd(tile));
-			if (ret.Failed()) return ret;
+
+			const TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
+
+			if (IsBridge(tile)) {
+				const DiagDirection entrance_dir = GetTunnelBridgeDirection(tile);
+				const RoadBits entrance_piece = DiagDirToRoadBits(entrance_dir);
+				const RoadBits axial_pieces = AxisToRoadBits(DiagDirToAxis(entrance_dir));
+				existing = GetCustomBridgeHeadRoadBits(tile, rt);
+
+				if (!(_settings_game.construction.road_custom_bridge_heads && HasBridgeFlatRamp(tileh, DiagDirToAxis(entrance_dir)))) {
+					/* Ordinary bridge heads only */
+					/* Only allow building the outer roadbit, so building long roads stops at existing bridges */
+					if (MirrorRoadBits(entrance_piece) != pieces) goto do_clear;
+					pieces = axial_pieces;
+				}
+				if ((existing & pieces) == pieces) return_cmd_error(STR_ERROR_ALREADY_BUILT);
+				if ((pieces & ~axial_pieces) && !_settings_game.construction.build_on_slopes) {
+					return_cmd_error(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
+				}
+				if ((_invalid_tileh_slopes_road[0][tileh] & (pieces & ~entrance_piece)) != ROAD_NONE) {
+					return_cmd_error(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
+				}
+
+				/* Don't allow adding roadtype to the bridge/tunnel when vehicles are already driving on it */
+				CommandCost ret = TunnelBridgeIsFree(tile, other_end);
+				if (ret.Failed()) return ret;
+
+
+				if ((existing | pieces) == entrance_piece) {
+					/*
+					 * Don't allow the custom bridge head bits to be only the entrance piece
+					 * as this makes road vehicles go haywire
+					 */
+					pieces = axial_pieces;
+				}
+
+				RoadBits added_pieces = (existing | pieces) & ~existing;
+				uint added_pieces_count = CountBits(added_pieces);
+				RoadBits other_end_added_pieces = ROAD_NONE;
+				RoadBits other_end_existing = ROAD_NONE;
+
+				if (added_pieces & entrance_piece) {
+					/* adding road to whole bridge */
+
+					other_end_added_pieces = MirrorRoadBits(entrance_piece);
+					added_pieces_count += 1 + (GetTunnelBridgeLength(tile, other_end) * 2);
+
+					other_end_existing = GetCustomBridgeHeadRoadBits(other_end, rt);
+					assert((other_end_added_pieces & other_end_existing) == ROAD_NONE);
+
+					if (other_end_existing == ROAD_NONE) {
+						/*
+						 * Don't allow the other end custom bridge head bits to be only the entrance piece
+						 * as this makes road vehicles go haywire
+						 */
+						other_end_added_pieces = axial_pieces;
+						added_pieces_count++;
+					}
+				}
+
+				cost.AddCost(added_pieces_count * _price[PR_BUILD_ROAD]);
+
+				if (flags & DC_EXEC) {
+					SubtractRoadTunnelBridgeInfrastructure(tile, other_end);
+
+					SetRoadTypes(tile, GetRoadTypes(tile) | RoadTypeToRoadTypes(rt));
+					if (!existing) SetRoadOwner(tile, rt, company);
+					SetCustomBridgeHeadRoadBits(tile, rt, existing | pieces);
+					if (other_end_added_pieces) {
+						SetRoadTypes(other_end, GetRoadTypes(other_end) | RoadTypeToRoadTypes(rt));
+						if (!other_end_existing) SetRoadOwner(other_end, rt, company);
+						SetCustomBridgeHeadRoadBits(other_end, rt, other_end_existing | other_end_added_pieces);
+					}
+
+					MarkBridgeDirty(tile);
+
+					AddRoadTunnelBridgeInfrastructure(tile, other_end);
+					DirtyAllCompanyInfrastructureWindows();
+				}
+
+				return cost;
+			} else { // IsTunnel(tile)
+				/* Only allow building the outer roadbit, so building long roads stops at existing bridges */
+				if (MirrorRoadBits(DiagDirToRoadBits(GetTunnelBridgeDirection(tile))) != pieces) goto do_clear;
+				if (HasTileRoadType(tile, rt)) return_cmd_error(STR_ERROR_ALREADY_BUILT);
+				/* Don't allow adding roadtype to the bridge/tunnel when vehicles are already driving on it */
+				CommandCost ret = TunnelBridgeIsFree(tile, other_end);
+				if (ret.Failed()) return ret;
+			}
 			break;
 		}
 
@@ -762,7 +887,7 @@ do_clear:;
 
 				/* Mark tiles dirty that have been repaved */
 				if (IsBridge(tile)) {
-					MarkBridgeDirty(tile);
+					NOT_REACHED();
 				} else {
 					MarkTileDirtyByTile(other_end);
 					MarkTileDirtyByTile(tile);
@@ -864,8 +989,6 @@ CommandCost CmdBuildLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32 p
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 	CommandCost last_error = CMD_ERROR;
 	TileIndex tile = start_tile;
-	bool had_bridge = false;
-	bool had_tunnel = false;
 	bool had_success = false;
 	bool is_ai = HasBit(p2, 6);
 
@@ -896,27 +1019,21 @@ CommandCost CmdBuildLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32 p
 			}
 		} else {
 			had_success = true;
-			/* Only pay for the upgrade on one side of the bridges and tunnels */
-			if (IsTileType(tile, MP_TUNNELBRIDGE)) {
-				if (IsBridge(tile)) {
-					if (!had_bridge || GetTunnelBridgeDirection(tile) == dir) {
-						cost.AddCost(ret);
-					}
-					had_bridge = true;
-				} else { // IsTunnel(tile)
-					if (!had_tunnel || GetTunnelBridgeDirection(tile) == dir) {
-						cost.AddCost(ret);
-					}
-					had_tunnel = true;
-				}
-			} else {
-				cost.AddCost(ret);
-			}
+			cost.AddCost(ret);
+		}
+		/* Do not run into or across bridges/tunnels */
+		if (IsTileType(tile, MP_TUNNELBRIDGE)) {
+			if (GetTunnelBridgeDirection(tile) == dir) break;
 		}
 
 		if (tile == end_tile) break;
 
 		tile += TileOffsByDiagDir(dir);
+
+		/* Do not run onto a bridge/tunnel tile from below/above */
+		if (IsTileType(tile, MP_TUNNELBRIDGE)) {
+			if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(dir)) break;
+		}
 	}
 
 	return had_success ? cost : last_error;
@@ -1239,16 +1356,17 @@ static void DrawRoadDetail(SpriteID img, const TileInfo *ti, int dx, int dy, int
  * Draw ground sprite and road pieces
  * @param ti TileInfo
  */
-static void DrawRoadBits(TileInfo *ti)
+void DrawRoadBits(TileInfo *ti)
 {
-	RoadBits road = GetRoadBits(ti->tile, ROADTYPE_ROAD);
-	RoadBits tram = GetRoadBits(ti->tile, ROADTYPE_TRAM);
+	const bool is_bridge = IsTileType(ti->tile, MP_TUNNELBRIDGE);
+	RoadBits road = is_bridge ? GetCustomBridgeHeadRoadBits(ti->tile, ROADTYPE_ROAD) : GetRoadBits(ti->tile, ROADTYPE_ROAD);
+	RoadBits tram = is_bridge ? GetCustomBridgeHeadRoadBits(ti->tile, ROADTYPE_TRAM) : GetRoadBits(ti->tile, ROADTYPE_TRAM);
 
 	SpriteID image = 0;
 	PaletteID pal = PAL_NONE;
 
 	if (ti->tileh != SLOPE_FLAT) {
-		DrawFoundation(ti, GetRoadFoundation(ti->tileh, road | tram));
+		DrawFoundation(ti, is_bridge ? FOUNDATION_LEVELED : GetRoadFoundation(ti->tileh, road | tram));
 
 		/* DrawFoundation() modifies ti.
 		 * Default sloped sprites.. */
@@ -1257,7 +1375,7 @@ static void DrawRoadBits(TileInfo *ti)
 
 	if (image == 0) image = _road_tile_sprites_1[road != ROAD_NONE ? road : tram];
 
-	Roadside roadside = GetRoadside(ti->tile);
+	Roadside roadside = is_bridge ? ROADSIDE_PAVED : GetRoadside(ti->tile);
 
 	if (DrawRoadAsSnowDesert(ti->tile, roadside)) {
 		image += 19;
@@ -1285,14 +1403,14 @@ static void DrawRoadBits(TileInfo *ti)
 		DrawGroundSprite(image, pal);
 	}
 
-	if (road != ROAD_NONE) {
+	if (!is_bridge && road != ROAD_NONE) {
 		DisallowedRoadDirections drd = GetDisallowedRoadDirections(ti->tile);
 		if (drd != DRD_NONE) {
 			DrawGroundSpriteAt(SPR_ONEWAY_BASE + drd - 1 + ((road == ROAD_X) ? 0 : 3), PAL_NONE, 8, 8, GetPartialPixelZ(8, 8, ti->tileh));
 		}
 	}
 
-	if (HasRoadWorks(ti->tile)) {
+	if (!is_bridge && HasRoadWorks(ti->tile)) {
 		/* Road works */
 		DrawGroundSprite((road | tram) & ROAD_X ? SPR_EXCAVATION_X : SPR_EXCAVATION_Y, PAL_NONE);
 		return;
@@ -1587,7 +1705,7 @@ static bool ClickTile_Road(TileIndex tile)
 }
 
 /* Converts RoadBits to TrackBits */
-static const TrackBits _road_trackbits[16] = {
+extern const TrackBits _road_trackbits[16] = {
 	TRACK_BIT_NONE,                                  // ROAD_NONE
 	TRACK_BIT_NONE,                                  // ROAD_NW
 	TRACK_BIT_NONE,                                  // ROAD_SW

src/road_map.cpp

@@ -52,6 +52,7 @@ RoadBits GetAnyRoadBits(TileIndex tile, RoadType rt, bool straight_tunnel_bridge
 
 		case MP_TUNNELBRIDGE:
 			if (GetTunnelBridgeTransportType(tile) != TRANSPORT_ROAD) return ROAD_NONE;
+			if (IsRoadCustomBridgeHeadTile(tile)) return GetCustomBridgeHeadRoadBits(tile, rt);
 			return straight_tunnel_bridge_entrance ?
 					AxisToRoadBits(DiagDirToAxis(GetTunnelBridgeDirection(tile))) :
 					DiagDirToRoadBits(ReverseDiagDir(GetTunnelBridgeDirection(tile)));

src/roadveh_cmd.cpp

@@ -1151,6 +1151,8 @@ bool IndividualRoadVehicleController(RoadVehicle *v, const RoadVehicle *prev)
 	 * by the previous vehicle in the chain when it gets to the right place. */
 	if (v->IsInDepot()) return true;
 
+	bool no_advance_tile = false;
+
 	if (v->state == RVSB_WORMHOLE) {
 		/* Vehicle is entering a depot or is on a bridge or in a tunnel */
 		GetNewVehiclePosResult gp = GetNewVehiclePos(v);
@@ -1164,19 +1166,24 @@ bool IndividualRoadVehicleController(RoadVehicle *v, const RoadVehicle *prev)
 		}
 
 		if (IsTileType(gp.new_tile, MP_TUNNELBRIDGE) && HasBit(VehicleEnterTile(v, gp.new_tile, gp.x, gp.y), VETS_ENTERED_WORMHOLE)) {
-			/* Vehicle has just entered a bridge or tunnel */
+			if (IsRoadCustomBridgeHeadTile(gp.new_tile)) {
+				v->frame = 15;
+				no_advance_tile = true;
+			} else {
+				/* Vehicle has just entered a bridge or tunnel */
+				v->x_pos = gp.x;
+				v->y_pos = gp.y;
+				v->UpdatePosition();
+				v->UpdateInclination(true, true);
+				return true;
+			}
+		} else {
 			v->x_pos = gp.x;
 			v->y_pos = gp.y;
 			v->UpdatePosition();
-			v->UpdateInclination(true, true);
+			if ((v->vehstatus & VS_HIDDEN) == 0) v->Vehicle::UpdateViewport(true);
 			return true;
 		}
-
-		v->x_pos = gp.x;
-		v->y_pos = gp.y;
-		v->UpdatePosition();
-		if (v->IsDrawn()) v->Vehicle::UpdateViewport(true);
-		return true;
 	}
 
 	/* Get move position data for next frame.
@@ -1187,12 +1194,16 @@ bool IndividualRoadVehicleController(RoadVehicle *v, const RoadVehicle *prev)
 		(_settings_game.vehicle.road_side << RVS_DRIVE_SIDE)) ^ v->overtaking][v->frame + 1];
 
 	if (rd.x & RDE_NEXT_TILE) {
-		TileIndex tile = v->tile + TileOffsByDiagDir((DiagDirection)(rd.x & 3));
+		TileIndex tile = v->tile;
+		if (!no_advance_tile) tile += TileOffsByDiagDir((DiagDirection)(rd.x & 3));
 		Trackdir dir;
 
 		if (v->IsFrontEngine()) {
 			/* If this is the front engine, look for the right path. */
 			dir = RoadFindPathToDest(v, tile, (DiagDirection)(rd.x & 3));
+		} else if (no_advance_tile) {
+			/* Follow previous vehicle out of custom bridge wormhole */
+			dir = (Trackdir) prev->state;
 		} else {
 			dir = FollowPreviousRoadVehicle(v, prev, tile, (DiagDirection)(rd.x & 3), false);
 		}
@@ -1209,6 +1220,10 @@ again:
 			/* When turning around we can't be overtaking. */
 			v->overtaking = 0;
 
+			if (no_advance_tile) {
+				DEBUG(misc, 0, "Road vehicle attempted to turn around on a single road piece bridge head");
+			}
+
 			/* Turning around */
 			if (v->roadtype == ROADTYPE_TRAM) {
 				/* Determine the road bits the tram needs to be able to turn around
@@ -1221,9 +1236,16 @@ again:
 					case TRACKDIR_RVREV_SW: needed = ROAD_NE; break;
 					case TRACKDIR_RVREV_NW: needed = ROAD_SE; break;
 				}
-				if ((v->Previous() != NULL && v->Previous()->tile == tile) ||
-						(v->IsFrontEngine() && IsNormalRoadTile(tile) && !HasRoadWorks(tile) &&
-							(needed & GetRoadBits(tile, ROADTYPE_TRAM)) != ROAD_NONE)) {
+				auto tile_turn_ok = [&]() -> bool {
+					if (IsNormalRoadTile(tile)) {
+						return !HasRoadWorks(tile) && (needed & GetRoadBits(tile, ROADTYPE_TRAM)) != ROAD_NONE;
+					} else if (IsRoadCustomBridgeHeadTile(tile)) {
+						return (needed & GetCustomBridgeHeadRoadBits(tile, ROADTYPE_TRAM)) != ROAD_NONE;
+					} else {
+						return false;
+					}
+				};
+				if ((v->Previous() != NULL && v->Previous()->tile == tile) || tile_turn_ok()) {
 					/*
 					 * Taking the 'big' corner for trams only happens when:
 					 * - The previous vehicle in this (articulated) tram chain is

src/saveload/afterload.cpp

@@ -3268,6 +3268,15 @@ bool AfterLoadGame()
 		}
 	}
 
+	if (SlXvIsFeatureMissing(XSLFI_CUSTOM_BRIDGE_HEADS)) {
+		/* ensure that previously unused custom bridge-head bits are cleared */
+		for (TileIndex t = 0; t < map_size; t++) {
+			if (IsBridgeTile(t) && GetTunnelBridgeTransportType(t) == TRANSPORT_ROAD) {
+				SB(_m[t].m2, 0, 8, 0);
+			}
+		}
+	}
+
 	/* Station acceptance is some kind of cache */
 	if (IsSavegameVersionBefore(127)) {
 		Station *st;

src/saveload/company_sl.cpp

@@ -200,7 +200,8 @@ void AfterLoadCompanyStats()
 				if (tile < other_end) {
 					/* Count each tunnel/bridge TUNNELBRIDGE_TRACKBIT_FACTOR times to simulate
 					 * the higher structural maintenance needs, and don't forget the end tiles. */
-					uint len = (GetTunnelBridgeLength(tile, other_end) + 2) * TUNNELBRIDGE_TRACKBIT_FACTOR;
+					const uint middle_len = GetTunnelBridgeLength(tile, other_end) * TUNNELBRIDGE_TRACKBIT_FACTOR;
+					const uint len = middle_len + (2 * TUNNELBRIDGE_TRACKBIT_FACTOR);
 
 					switch (GetTunnelBridgeTransportType(tile)) {
 						case TRANSPORT_RAIL:
@@ -214,12 +215,7 @@ void AfterLoadCompanyStats()
 							break;
 
 						case TRANSPORT_ROAD: {
-							/* Iterate all present road types as each can have a different owner. */
-							RoadType rt;
-							FOR_EACH_SET_ROADTYPE(rt, GetRoadTypes(tile)) {
-								c = Company::GetIfValid(GetRoadOwner(tile, rt));
-								if (c != NULL) c->infrastructure.road[rt] += len * 2; // A full diagonal road has two road bits.
-							}
+							AddRoadTunnelBridgeInfrastructure(tile, other_end);
 							break;
 						}
 

src/saveload/extended_ver_sl.cpp

@@ -73,6 +73,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_CARGO_TYPE_ORDERS,      XSCF_NULL,                2,   2, "cargo_type_orders",         NULL, NULL, "ORDX,VEOX" },
 	{ XSLFI_EXTENDED_GAMELOG,       XSCF_NULL,                1,   1, "extended_gamelog",          NULL, NULL, NULL        },
 	{ XSLFI_STATION_CATCHMENT_INC,  XSCF_NULL,                1,   1, "station_catchment_inc",     NULL, NULL, NULL        },
+	{ XSLFI_CUSTOM_BRIDGE_HEADS,    XSCF_NULL,                1,   1, "custom_bridge_heads",       NULL, NULL, NULL        },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, NULL, NULL, NULL, NULL },// This is the end marker
 };
 

src/saveload/extended_ver_sl.h

@@ -47,6 +47,7 @@ enum SlXvFeatureIndex {
 	XSLFI_CARGO_TYPE_ORDERS,                      ///< Cargo-specific load/unload order flags
 	XSLFI_EXTENDED_GAMELOG,                       ///< Extended gamelog
 	XSLFI_STATION_CATCHMENT_INC,                  ///< Station catchment radius increase
+	XSLFI_CUSTOM_BRIDGE_HEADS,                    ///< Custom bridge heads
 
 	XSLFI_RIFF_HEADER_60_BIT,                     ///< Size field in RIFF chunk header is 60 bit
 	XSLFI_HEIGHT_8_BIT,                           ///< Map tile height is 8 bit instead of 4 bit, but savegame version may be before this became true in trunk

src/settings_gui.cpp

@@ -1715,6 +1715,7 @@ static SettingsContainer &GetSettingsTree()
 			limitations->Add(new SettingEntry("vehicle.disable_elrails"));
 			limitations->Add(new SettingEntry("construction.maximum_signal_evaluations"));
 			limitations->Add(new SettingEntry("construction.enable_build_river"));
+			limitations->Add(new SettingEntry("construction.road_custom_bridge_heads"));
 		}
 
 		SettingsPage *disasters = main->Add(new SettingsPage(STR_CONFIG_SETTING_ACCIDENTS));

src/settings_type.h

@@ -354,6 +354,7 @@ struct ConstructionSettings {
 	uint16 maximum_signal_evaluations;       ///< maximum number of programmable signals which may be evaluated in one pass
 	byte   simulated_wormhole_signals;       ///< simulate signals in tunnel
 	bool   enable_build_river;               ///< enable building rivers in-game
+	uint8  road_custom_bridge_heads;         ///< allow construction of road custom bridge heads
 
 	uint32 terraform_per_64k_frames;         ///< how many tile heights may, over a long period, be terraformed per 65536 frames?
 	uint16 terraform_frame_burst;            ///< how many tile heights may, over a short period, be terraformed?

src/table/settings.ini

@@ -1413,6 +1413,15 @@ str      = STR_CONFIG_SETTING_STOP_ON_COMPETITOR_ROAD
 strhelp  = STR_CONFIG_SETTING_STOP_ON_COMPETITOR_ROAD_HELPTEXT
 cat      = SC_BASIC
 
+[SDT_BOOL]
+base     = GameSettings
+var      = construction.road_custom_bridge_heads
+def      = true
+cat      = SC_BASIC
+str      = STR_CONFIG_SETTING_ENABLE_ROAD_CUSTOM_BRIDGE_HEADS
+strhelp  = STR_CONFIG_SETTING_ENABLE_ROAD_CUSTOM_BRIDGE_HEADS_HELPTEXT
+patxname = ""custom_bridge_heads.construction.road_custom_bridge_heads""
+
 [SDT_BOOL]
 base     = GameSettings
 var      = station.adjacent_stations

src/tunnelbridge_cmd.cpp

@@ -55,6 +55,8 @@ TileIndex _build_tunnel_endtile; ///< The end of a tunnel; as hidden return from
 /** Z position of the bridge sprites relative to bridge height (downwards) */
 static const int BRIDGE_Z_START = 3;
 
+extern void DrawRoadBits(TileInfo *ti);
+extern const RoadBits _invalid_tileh_slopes_road[2][15];
 
 /**
  * Mark bridge tiles dirty.
@@ -962,19 +964,11 @@ static CommandCost DoClearBridge(TileIndex tile, DoCommandFlag flags)
 				}
 			}
 		} else if (GetTunnelBridgeTransportType(tile) == TRANSPORT_ROAD) {
-			RoadType rt;
-			FOR_EACH_SET_ROADTYPE(rt, GetRoadTypes(tile)) {
-				Company *c = Company::GetIfValid(GetRoadOwner(tile, rt));
-				if (c != NULL) {
-					/* A full diagonal road tile has two road bits. */
-					c->infrastructure.road[rt] -= len * 2 * TUNNELBRIDGE_TRACKBIT_FACTOR;
-					DirtyCompanyInfrastructureWindows(c->index);
-				}
-			}
+			SubtractRoadTunnelBridgeInfrastructure(tile, endtile);
 		} else { // Aqueduct
 			if (Company::IsValidID(owner)) Company::Get(owner)->infrastructure.water -= len * TUNNELBRIDGE_TRACKBIT_FACTOR;
 		}
-		DirtyCompanyInfrastructureWindows(owner);
+		DirtyAllCompanyInfrastructureWindows();
 
 		if (IsTunnelBridgeSignalSimulationEntrance(tile)) ClearBridgeEntranceSimulatedSignals(tile);
 		if (IsTunnelBridgeSignalSimulationEntrance(endtile)) ClearBridgeEntranceSimulatedSignals(endtile);
@@ -1403,6 +1397,12 @@ static void DrawTile_TunnelBridge(TileInfo *ti)
 
 		DrawBridgeMiddle(ti);
 	} else { // IsBridge(ti->tile)
+		if (transport_type == TRANSPORT_ROAD && IsRoadCustomBridgeHead(ti->tile)) {
+			DrawRoadBits(ti);
+			DrawBridgeMiddle(ti);
+			return;
+		}
+
 		const PalSpriteID *psid;
 		int base_offset;
 		bool ice = HasTunnelBridgeSnowOrDesert(ti->tile);
@@ -1627,11 +1627,19 @@ void DrawBridgeMiddle(const TileInfo *ti)
 	psid++;
 
 	if (transport_type == TRANSPORT_ROAD) {
-		RoadTypes rts = GetRoadTypes(rampsouth);
+		const RoadTypes rts = GetRoadTypes(rampsouth);
+
+		bool has_tram = HasBit(rts, ROADTYPE_TRAM);
+		bool has_road = HasBit(rts, ROADTYPE_ROAD);
+		if (IsRoadCustomBridgeHeadTile(rampsouth)) {
+			RoadBits entrance_bit = DiagDirToRoadBits(GetTunnelBridgeDirection(rampsouth));
+			has_tram = has_tram && (GetCustomBridgeHeadRoadBits(rampsouth, ROADTYPE_TRAM) & entrance_bit);
+			has_road = has_road && (GetCustomBridgeHeadRoadBits(rampsouth, ROADTYPE_ROAD) & entrance_bit);
+		}
 
-		if (HasBit(rts, ROADTYPE_TRAM)) {
+		if (has_tram) {
 			/* DrawBridgeTramBits() calls EndSpriteCombine() and StartSpriteCombine() */
-			DrawBridgeTramBits(x, y, bridge_z, axis ^ 1, HasBit(rts, ROADTYPE_ROAD), false);
+			DrawBridgeTramBits(x, y, bridge_z, axis ^ 1, has_road, false);
 		} else {
 			EndSpriteCombine();
 			StartSpriteCombine();
@@ -1716,6 +1724,10 @@ static int GetSlopePixelZ_TunnelBridge(TileIndex tile, uint x, uint y)
 		/* In the tunnel entrance? */
 		if (5 <= pos && pos <= 10) return z;
 	} else { // IsBridge(tile)
+		if (IsRoadCustomBridgeHeadTile(tile)) {
+			return z + TILE_HEIGHT;
+		}
+
 		DiagDirection dir = GetTunnelBridgeDirection(tile);
 		uint pos = (DiagDirToAxis(dir) == AXIS_X ? y : x);
 
@@ -1743,6 +1755,7 @@ static int GetSlopePixelZ_TunnelBridge(TileIndex tile, uint x, uint y)
 
 static Foundation GetFoundation_TunnelBridge(TileIndex tile, Slope tileh)
 {
+	if (IsRoadCustomBridgeHeadTile(tile)) return FOUNDATION_LEVELED;
 	return IsTunnel(tile) ? FOUNDATION_NONE : GetBridgeFoundation(tileh, DiagDirToAxis(GetTunnelBridgeDirection(tile)));
 }
 
@@ -1843,42 +1856,102 @@ static bool ClickTile_TunnelBridge(TileIndex tile)
 	return false;
 }
 
+extern const TrackBits _road_trackbits[16];
+
 static TrackStatus GetTileTrackStatus_TunnelBridge(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side)
 {
 	TransportType transport_type = GetTunnelBridgeTransportType(tile);
 	if (transport_type != mode || (transport_type == TRANSPORT_ROAD && (GetRoadTypes(tile) & sub_mode) == 0)) return 0;
 
 	DiagDirection dir = GetTunnelBridgeDirection(tile);
+
+	if (mode == TRANSPORT_ROAD && IsRoadCustomBridgeHeadTile(tile)) {
+		if (side != INVALID_DIAGDIR && side == dir) return 0;
+		TrackBits bits = TRACK_BIT_NONE;
+		if (sub_mode & ROADTYPES_TRAM) bits |= _road_trackbits[GetCustomBridgeHeadRoadBits(tile, ROADTYPE_TRAM)];
+		if (sub_mode & ROADTYPES_ROAD) bits |= _road_trackbits[GetCustomBridgeHeadRoadBits(tile, ROADTYPE_ROAD)];
+		return CombineTrackStatus(TrackBitsToTrackdirBits(bits), TRACKDIR_BIT_NONE);
+	}
 	if (side != INVALID_DIAGDIR && side != ReverseDiagDir(dir)) return 0;
 	return CombineTrackStatus(TrackBitsToTrackdirBits(DiagDirToDiagTrackBits(dir)), TRACKDIR_BIT_NONE);
 }
 
+static void UpdateRoadTunnelBridgeInfrastructure(TileIndex begin, TileIndex end, bool add) {
+	/* A full diagonal road has two road bits. */
+	const uint middle_len = 2 * GetTunnelBridgeLength(begin, end) * TUNNELBRIDGE_TRACKBIT_FACTOR;
+	const uint len = middle_len + (2 * TUNNELBRIDGE_TRACKBIT_FACTOR);
+
+	/* Iterate all present road types as each can have a different owner. */
+	RoadType rt;
+	FOR_EACH_SET_ROADTYPE(rt, GetRoadTypes(begin)) {
+		Company * const c = Company::GetIfValid(GetRoadOwner(begin, rt));
+		if (c != NULL) {
+			uint infra = 0;
+			if (IsBridge(begin)) {
+				const RoadBits bits = GetCustomBridgeHeadRoadBits(begin, rt);
+				infra += CountBits(bits) * TUNNELBRIDGE_TRACKBIT_FACTOR;
+				if (bits & DiagDirToRoadBits(GetTunnelBridgeDirection(begin))) {
+					infra += middle_len;
+				}
+			} else {
+				infra += len;
+			}
+			if (add) {
+				c->infrastructure.road[rt] += infra;
+			} else {
+				c->infrastructure.road[rt] -= infra;
+			}
+		}
+	}
+	FOR_EACH_SET_ROADTYPE(rt, GetRoadTypes(end)) {
+		Company * const c = Company::GetIfValid(GetRoadOwner(end, rt));
+		if (c != NULL) {
+			uint infra = 0;
+			if (IsBridge(end)) {
+				const RoadBits bits = GetCustomBridgeHeadRoadBits(end, rt);
+				infra += CountBits(bits) * TUNNELBRIDGE_TRACKBIT_FACTOR;
+			}
+			if (add) {
+				c->infrastructure.road[rt] += infra;
+			} else {
+				c->infrastructure.road[rt] -= infra;
+			}
+		}
+	}
+}
+
+void AddRoadTunnelBridgeInfrastructure(TileIndex begin, TileIndex end) {
+	UpdateRoadTunnelBridgeInfrastructure(begin, end, true);
+}
+
+void SubtractRoadTunnelBridgeInfrastructure(TileIndex begin, TileIndex end) {
+	UpdateRoadTunnelBridgeInfrastructure(begin, end, false);
+}
+
 static void ChangeTileOwner_TunnelBridge(TileIndex tile, Owner old_owner, Owner new_owner)
 {
-	TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
+	const TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
 	/* Set number of pieces to zero if it's the southern tile as we
 	 * don't want to update the infrastructure counts twice. */
-	uint num_pieces = tile < other_end ? (GetTunnelBridgeLength(tile, other_end) + 2) * TUNNELBRIDGE_TRACKBIT_FACTOR : 0;
+	const uint num_pieces = tile < other_end ? (GetTunnelBridgeLength(tile, other_end) + 2) * TUNNELBRIDGE_TRACKBIT_FACTOR : 0;
+	const TransportType tt = GetTunnelBridgeTransportType(tile);
+
+	if (tt == TRANSPORT_ROAD) SubtractRoadTunnelBridgeInfrastructure(tile, other_end);
 
 	for (RoadType rt = ROADTYPE_ROAD; rt < ROADTYPE_END; rt++) {
 		/* Update all roadtypes, no matter if they are present */
 		if (GetRoadOwner(tile, rt) == old_owner) {
-			if (HasBit(GetRoadTypes(tile), rt)) {
-				/* Update company infrastructure counts. A full diagonal road tile has two road bits.
-				 * No need to dirty windows here, we'll redraw the whole screen anyway. */
-				Company::Get(old_owner)->infrastructure.road[rt] -= num_pieces * 2;
-				if (new_owner != INVALID_OWNER) Company::Get(new_owner)->infrastructure.road[rt] += num_pieces * 2;
-			}
-
 			SetRoadOwner(tile, rt, new_owner == INVALID_OWNER ? OWNER_NONE : new_owner);
 		}
 	}
 
+	if (tt == TRANSPORT_ROAD) AddRoadTunnelBridgeInfrastructure(tile, other_end);
+
 	if (!IsTileOwner(tile, old_owner)) return;
 
 	/* Update company infrastructure counts for rail and water as well.
 	 * No need to dirty windows here, we'll redraw the whole screen anyway. */
-	TransportType tt = GetTunnelBridgeTransportType(tile);
+
 	Company *old = Company::Get(old_owner);
 	if (tt == TRANSPORT_RAIL) {
 		old->infrastructure.rail[GetRailType(tile)] -= num_pieces;
@@ -2082,6 +2155,14 @@ static CommandCost TerraformTile_TunnelBridge(TileIndex tile, DoCommandFlag flag
 		int z_old;
 		Slope tileh_old = GetTileSlope(tile, &z_old);
 
+		if (IsRoadCustomBridgeHeadTile(tile)) {
+			const RoadBits pieces = GetCustomBridgeHeadAllRoadBits(tile);
+			const RoadBits entrance_piece = DiagDirToRoadBits(direction);
+			if ((_invalid_tileh_slopes_road[0][tileh_new] & (pieces & ~entrance_piece)) != ROAD_NONE) {
+				return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+			}
+		}
+
 		/* Check if new slope is valid for bridges in general (so we can safely call GetBridgeFoundation()) */
 		if ((direction == DIAGDIR_NW) || (direction == DIAGDIR_NE)) {
 			CheckBridgeSlopeSouth(axis, &tileh_old, &z_old);

src/tunnelbridge_map.h

@@ -260,4 +260,7 @@ static inline void SetTunnelBridgePBS(TileIndex t, bool is_pbs)
 	SB(_me[t].m6, 6, 1, is_pbs ? 1 : 0);
 }
 
+void AddRoadTunnelBridgeInfrastructure(TileIndex begin, TileIndex end);
+void SubtractRoadTunnelBridgeInfrastructure(TileIndex begin, TileIndex end);
+
 #endif /* TUNNELBRIDGE_MAP_H */