(svn r5070) Merged the bridge branch

-Feature: Bridges can now be placed above:
	Any railway track combination (excluding depots and waypoints)
	Any road combination (excluding depots)
	Clear tiles (duh), including fields
	Tunnel entrances
	Bridge heads

Thanks to Tron for idea and implementation, KUDr for the yapf synchronization and many others for hours of testing

There are still a number of visual problems remaining, especially when electric railways are on or under the bridge.
DO NOT REPORT THOSE BUGS FOR THE TIME BEING please.

1 files changed, 36 insertions, 30 deletions

diff --git a/elrail.c b/elrail.c
index f0476d210..24bd2415a 100644
--- a/elrail.c
+++ b/elrail.c
@@ -91,18 +91,10 @@ static TrackBits GetRailTrackBitsUniversal(TileIndex t, byte *override)
 				return DiagDirToAxis(GetTunnelDirection(t)) == AXIS_X ? TRACK_BIT_X : TRACK_BIT_Y;
 			} else {
 				if (GetRailType(t) != RAILTYPE_ELECTRIC) return 0;
-				if (IsBridgeMiddle(t)) {
-					if (IsTransportUnderBridge(t) &&
-						GetTransportTypeUnderBridge(t) == TRANSPORT_RAIL) {
-						return GetRailBitsUnderBridge(t);
-					} else {
-						return 0;
-					}
-				} else {
-					if (override != NULL && DistanceMax(t, GetOtherBridgeEnd(t)) > 1) *override = 1 << GetBridgeRampDirection(t);
-
-					return DiagDirToAxis(GetBridgeRampDirection(t)) == AXIS_X ? TRACK_BIT_X : TRACK_BIT_Y;
+				if (override != NULL && DistanceMax(t, GetOtherBridgeEnd(t)) > 1) {
+					*override = 1 << GetBridgeRampDirection(t);
 				}
+				return DiagDirToAxis(GetBridgeRampDirection(t)) == AXIS_X ? TRACK_BIT_X : TRACK_BIT_Y;
 			}
 		case MP_STREET:
 			if (GetRoadTileType(t) != ROAD_TILE_CROSSING) return 0;
@@ -125,7 +117,7 @@ static TrackBits GetRailTrackBitsUniversal(TileIndex t, byte *override)
 static void AdjustTileh(TileIndex tile, Slope* tileh)
 {
 	if (IsTunnelTile(tile)) *tileh = SLOPE_FLAT;
-	if (IsBridgeTile(tile) && IsBridgeRamp(tile)) {
+	if (IsBridgeTile(tile)) {
 		if (*tileh != SLOPE_FLAT) {
 			*tileh = SLOPE_FLAT;
 		} else {
@@ -193,9 +185,10 @@ static void DrawCatenaryRailway(const TileInfo *ti)
 		for (k = 0; k < NUM_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 (TrackSourceTile[i][k] == TS_NEIGHBOUR &&
-			    IsBridgeTile(neighbour) && IsBridgeRamp(neighbour) &&
-			    GetBridgeRampDirection(neighbour) == ReverseDiagDir(i)
-			   ) continue;
+			    IsBridgeTile(neighbour) &&
+			    GetBridgeRampDirection(neighbour) == ReverseDiagDir(i)) {
+				continue;
+			}
 
 			/* We check whether the track in question (k) is present in the tile
 			   (TrackSourceTile) */
@@ -219,7 +212,7 @@ static void DrawCatenaryRailway(const TileInfo *ti)
 
 		/* 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)) {
+		if (IsBridgeTile(neighbour)) {
 			foundation = GetBridgeFoundation(tileh[TS_NEIGHBOUR], DiagDirToAxis(GetBridgeRampDirection(neighbour)));
 		}
 
@@ -247,6 +240,14 @@ static void DrawCatenaryRailway(const TileInfo *ti)
 		   Remove those (simply by ANDing with allowed, since these markers are never allowed) */
 		if ( (PPPallowed[i] & PPPpreferred[i]) != 0) PPPallowed[i] &= PPPpreferred[i];
 
+		if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile)) {
+			Track bridgetrack = GetBridgeAxis(ti->tile) == AXIS_X ? TRACK_X : TRACK_Y;
+			uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile), GetBridgeAxis(ti->tile));
+
+			if ((height <= TilePixelHeight(ti->tile) + TILE_HEIGHT) &&
+			(i == PCPpositions[bridgetrack][0] || i == PCPpositions[bridgetrack][1])) SETBIT(OverridePCP, i);
+		}
+
 		if (PPPallowed[i] != 0 && HASBIT(PCPstatus, i) && !HASBIT(OverridePCP, i)) {
 			for (k = 0; k < DIR_END; k++) {
 				byte temp = PPPorder[i][GetTLG(ti->tile)][k];
@@ -279,12 +280,11 @@ static void DrawCatenaryRailway(const TileInfo *ti)
 			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(ti->tile) <= TilePixelHeight(ti->tile)
-			   ) return;
+			if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile) && !(_display_opt & DO_TRANS_BUILDINGS)) {
+				uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile), GetBridgeAxis(ti->tile));
+
+				if (height <= TilePixelHeight(ti->tile) + TILE_HEIGHT) 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(!IsSteepSlope(tileh[TS_HOME]));
@@ -320,30 +320,37 @@ static void DrawCatenaryOnBridge(const TileInfo *ti)
 	}
 
 	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);
+			sss->x_size, sss->y_size, sss->z_size, GetBridgeHeight(end, axis) + sss->z_offset);
 
 	/* Finished with wires, draw pylons */
 	/* every other tile needs a pylon on the northern end */
 	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) + TILE_HEIGHT);
+			AddSortableSpriteToDraw( pylons_bridge[0 + HASBIT(tlg, 0)], ti->x, ti->y + 4 + 8 * HASBIT(tlg, 0), 1, 1, 10, GetBridgeHeight(end, axis));
 		} else {
-			AddSortableSpriteToDraw( pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y, 1, 1, 10, GetBridgeHeight(ti->tile) + TILE_HEIGHT);
+			AddSortableSpriteToDraw( pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y, 1, 1, 10, GetBridgeHeight(end, axis));
 		}
 	}
 
 	/* need a pylon on the southern end of the bridge */
 	if (DistanceMax(ti->tile, start) == length) {
 		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) + TILE_HEIGHT);
+			AddSortableSpriteToDraw( pylons_bridge[0 + HASBIT(tlg, 0)], ti->x + 16, ti->y + 4 + 8 * HASBIT(tlg, 0), 1, 1, 10, GetBridgeHeight(end, axis));
 		} else {
-			AddSortableSpriteToDraw( pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y + 16, 1, 1, 10, GetBridgeHeight(ti->tile) + TILE_HEIGHT);
+			AddSortableSpriteToDraw( pylons_bridge[2 + HASBIT(tlg, 1)], ti->x + 4 + 8 * HASBIT(tlg, 1), ti->y + 16, 1, 1, 10, GetBridgeHeight(end, axis));
 		}
 	}
 }
 
 void DrawCatenary(const TileInfo *ti)
 {
+	if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile)) {
+		TileIndex head = GetNorthernBridgeEnd(ti->tile);
+
+		if (GetBridgeTransportType(head) == TRANSPORT_RAIL && GetRailType(head) == RAILTYPE_ELECTRIC) {
+			DrawCatenaryOnBridge(ti);
+		}
+	}
 	switch (GetTileType(ti->tile)) {
 		case MP_RAILWAY:
 			if (GetRailTileType(ti->tile) == RAIL_TILE_DEPOT_WAYPOINT && GetRailTileSubtype(ti->tile) == RAIL_SUBTYPE_DEPOT) {
@@ -354,9 +361,8 @@ void DrawCatenary(const TileInfo *ti)
 			}
 			/* 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:
+		case MP_STREET:
+		case MP_STATION:
 			DrawCatenaryRailway(ti);
 			break;
 		default: