(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, 46 insertions, 100 deletions

diff --git a/bridge_map.h b/bridge_map.h
index f2b5d4ee4..9470204e0 100644
--- a/bridge_map.h
+++ b/bridge_map.h
@@ -11,6 +11,9 @@
 #include "tile.h"
 
 
+void DrawBridgeMiddle(const TileInfo* ti); // XXX
+
+
 static inline bool IsBridge(TileIndex t)
 {
 	assert(IsTileType(t, MP_TUNNELBRIDGE));
@@ -23,28 +26,38 @@ static inline bool IsBridgeTile(TileIndex t)
 }
 
 
-static inline bool IsBridgeRamp(TileIndex t)
+static inline bool MayHaveBridgeAbove(TileIndex t)
 {
-	assert(IsBridgeTile(t));
-	return !HASBIT(_m[t].m5, 6);
+	return
+		IsTileType(t, MP_CLEAR) ||
+		IsTileType(t, MP_RAILWAY) ||
+		IsTileType(t, MP_STREET) ||
+		IsTileType(t, MP_WATER) ||
+		IsTileType(t, MP_TUNNELBRIDGE);
 }
 
-static inline bool IsBridgeMiddle(TileIndex t)
+
+static inline bool IsXBridgeAbove(TileIndex t)
 {
-	assert(IsBridgeTile(t));
-	return HASBIT(_m[t].m5, 6);
+	assert(MayHaveBridgeAbove(t));
+	return GB(_m[t].extra, 6, 1) != 0;
+}
+
+static inline bool IsYBridgeAbove(TileIndex t)
+{
+	assert(MayHaveBridgeAbove(t));
+	return GB(_m[t].extra, 7, 1) != 0;
 }
 
+static inline bool IsBridgeOfAxis(TileIndex t, Axis a)
+{
+	if (a == AXIS_X) return IsXBridgeAbove(t);
+	return IsYBridgeAbove(t);
+}
 
-/**
- * Determines which piece of a bridge is contained in the current tile
- * @param tile The tile to analyze
- * @return the piece
- */
-static inline uint GetBridgePiece(TileIndex t)
+static inline bool IsBridgeAbove(TileIndex t)
 {
-	assert(IsBridgeMiddle(t));
-	return GB(_m[t].m2, 0, 4);
+	return (IsXBridgeAbove(t) || IsYBridgeAbove(t));
 }
 
 
@@ -65,7 +78,6 @@ static inline uint GetBridgeType(TileIndex t)
  */
 static inline DiagDirection GetBridgeRampDirection(TileIndex t)
 {
-	assert(IsBridgeRamp(t));
 	/* Heavy wizardry to convert the X/Y (bit 0) + N/S (bit 5) encoding of
 	 * bridges to a DiagDirection
 	 */
@@ -75,8 +87,9 @@ static inline DiagDirection GetBridgeRampDirection(TileIndex t)
 
 static inline Axis GetBridgeAxis(TileIndex t)
 {
-	assert(IsBridgeMiddle(t));
-	return (Axis)GB(_m[t].m5, 0, 1);
+	static const Axis BridgeAxis[] = {AXIS_END, AXIS_X, AXIS_Y, AXIS_END};
+	assert(IsBridgeAbove(t));
+	return BridgeAxis[GB(_m[t].extra, 6, 2)];
 }
 
 
@@ -87,50 +100,17 @@ static inline TransportType GetBridgeTransportType(TileIndex t)
 }
 
 
-static inline bool IsClearUnderBridge(TileIndex t)
-{
-	assert(IsBridgeMiddle(t));
-	return GB(_m[t].m5, 3, 3) == 0;
-}
-
-static inline bool IsWaterUnderBridge(TileIndex t)
-{
-	assert(IsBridgeMiddle(t));
-	return GB(_m[t].m5, 3, 3) == 1;
-}
-
-
-static inline bool IsTransportUnderBridge(TileIndex t)
-{
-	assert(IsBridgeMiddle(t));
-	return HASBIT(_m[t].m5, 5);
-}
-
-static inline TransportType GetTransportTypeUnderBridge(TileIndex t)
-{
-	assert(IsTransportUnderBridge(t));
-	return (TransportType)GB(_m[t].m5, 3, 2);
-}
-
-static inline RoadBits GetRoadBitsUnderBridge(TileIndex t)
-{
-	assert(GetTransportTypeUnderBridge(t) == TRANSPORT_ROAD);
-	return GetBridgeAxis(t) == AXIS_X ? ROAD_Y : ROAD_X;
-}
-
-static inline TrackBits GetRailBitsUnderBridge(TileIndex t)
-{
-	assert(GetTransportTypeUnderBridge(t) == TRANSPORT_RAIL);
-	return GetBridgeAxis(t) == AXIS_X ? TRACK_BIT_Y : TRACK_BIT_X;
-}
-
-
 /**
  * Finds the end of a bridge in the specified direction starting at a middle tile
  */
 TileIndex GetBridgeEnd(TileIndex, DiagDirection);
 
 /**
+ * Finds the northern end of a bridge starting at a middle tile
+ */
+TileIndex GetNorthernBridgeEnd(TileIndex t);
+
+/**
  * Finds the southern end of a bridge starting at a middle tile
  */
 TileIndex GetSouthernBridgeEnd(TileIndex t);
@@ -141,38 +121,26 @@ TileIndex GetSouthernBridgeEnd(TileIndex t);
  */
 TileIndex GetOtherBridgeEnd(TileIndex);
 
-uint GetBridgeHeight(TileIndex t);
+uint GetBridgeHeight(TileIndex tile, Axis a);
+uint GetBridgeFoundation(Slope tileh, Axis axis);
 
-static inline void SetClearUnderBridge(TileIndex t)
+static inline void ClearSingleBridgeMiddle(TileIndex t, Axis a)
 {
-	assert(IsBridgeMiddle(t));
-	SetTileOwner(t, OWNER_NONE);
-	SB(_m[t].m5, 3, 3, 0 << 2 | 0);
-	SB(_m[t].m3, 0, 4, 0);
+	assert(MayHaveBridgeAbove(t));
+	CLRBIT(_m[t].extra, 6 + a);
 }
 
-static inline void SetWaterUnderBridge(TileIndex t)
-{
-	assert(IsBridgeMiddle(t));
-	SetTileOwner(t, OWNER_WATER);
-	SB(_m[t].m5, 3, 3, 0 << 2 | 1);
-	SB(_m[t].m3, 0, 4, 0);
-}
 
-static inline void SetRailUnderBridge(TileIndex t, Owner o, RailType r)
+static inline void ClearBridgeMiddle(TileIndex t)
 {
-	assert(IsBridgeMiddle(t));
-	SetTileOwner(t, o);
-	SB(_m[t].m5, 3, 3, 1 << 2 | TRANSPORT_RAIL);
-	SB(_m[t].m3, 0, 4, r);
+	ClearSingleBridgeMiddle(t, AXIS_X);
+	ClearSingleBridgeMiddle(t, AXIS_Y);
 }
 
-static inline void SetRoadUnderBridge(TileIndex t, Owner o)
+static inline void SetBridgeMiddle(TileIndex t, Axis a)
 {
-	assert(IsBridgeMiddle(t));
-	SetTileOwner(t, o);
-	SB(_m[t].m5, 3, 3, 1 << 2 | TRANSPORT_ROAD);
-	SB(_m[t].m3, 0, 4, 0);
+	assert(MayHaveBridgeAbove(t));
+	SETBIT(_m[t].extra, 6 + a);
 }
 
 
@@ -200,26 +168,4 @@ static inline void MakeRailBridgeRamp(TileIndex t, Owner o, uint bridgetype, Dia
 }
 
 
-static inline void MakeBridgeMiddle(TileIndex t, uint bridgetype, uint piece, Axis a, TransportType tt)
-{
-	SetTileType(t, MP_TUNNELBRIDGE);
-	SetTileOwner(t, OWNER_NONE);
-	_m[t].m2 = bridgetype << 4 | piece;
-	_m[t].m3 = 0;
-	_m[t].m4 = 0;
-	_m[t].m5 = 1 << 7 | 1 << 6 | 0 << 5 | 0 << 3 | tt << 1 | a;
-}
-
-static inline void MakeRoadBridgeMiddle(TileIndex t, uint bridgetype, uint piece, Axis a)
-{
-	MakeBridgeMiddle(t, bridgetype, piece, a, TRANSPORT_ROAD);
-}
-
-static inline void MakeRailBridgeMiddle(TileIndex t, uint bridgetype, uint piece, Axis a, RailType r)
-{
-	MakeBridgeMiddle(t, bridgetype, piece, a, TRANSPORT_RAIL);
-	SB(_m[t].m3, 4, 4, r);
-}
-
-
 #endif