From 372b9cb8270ac467bf06bdcd586285c819bfaf2f Mon Sep 17 00:00:00 2001
From: tron <tron@openttd.org>
Date: Thu, 27 Jan 2005 12:52:20 +0000
Subject: [PATCH] (svn r1696) Use GetTileSlope() instead of
 FindLandscapeHeightByTile() where it is sufficient.
 FindLandscapeHeightByTile() uses GetTileSlope() internally and adds some more
 info, which is discarded in these cases. While touching the code make a bit
 more clear how GetBridgeHeight() works.

---
 train_cmd.c        |  8 ++++----
 tunnelbridge_cmd.c | 16 +++++-----------
 vehicle.c          |  5 +----
 3 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/train_cmd.c b/train_cmd.c
index 5853116b1c..1ce1631ee8 100644
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -2049,13 +2049,13 @@ static bool CheckCompatibleRail(const Vehicle *v, TileIndex tile)
 
 		case MP_TUNNELBRIDGE:
 			if ((_map5[tile] & 0xC0) == 0xC0) { // is bridge middle part?
-				TileInfo ti;
-				FindLandscapeHeightByTile(&ti, tile);
+				uint height;
+				uint tileh = GetTileSlope(tile, &height);
 
 				// correct Z position of a train going under a bridge on slopes
-				if (CORRECT_Z(ti.tileh)) ti.z += 8;
+				if (CORRECT_Z(tileh)) height += 8;
 
-				if (v->z_pos != ti.z) return true; // train is going over bridge
+				if (v->z_pos != height) return true; // train is going over bridge
 			}
 			break;
 
diff --git a/tunnelbridge_cmd.c b/tunnelbridge_cmd.c
index 156ea8a23c..62418e2d30 100644
--- a/tunnelbridge_cmd.c
+++ b/tunnelbridge_cmd.c
@@ -905,9 +905,7 @@ int32 DoConvertTunnelBridgeRail(uint tile, uint totype, bool exec)
 static uint GetBridgeHeight(const TileInfo *ti)
 {
 	uint delta;
-	TileInfo ti_end;
-	uint tile = ti->tile;
-	uint z_correction = 0;
+	TileIndex tile = ti->tile;
 
 	// find the end tile of the bridge.
 	delta = (_map5[tile] & 1) ? TILE_XY(0,1) : TILE_XY(1,0);
@@ -916,14 +914,10 @@ static uint GetBridgeHeight(const TileInfo *ti)
 		tile += delta;
 	} while (_map5[tile] & 0x40);	// while bridge middle parts
 
-	// if the end of the bridge is on a tileh 7, the z coordinate is 1 tile too low
-	// correct it.
-	FindLandscapeHeightByTile(&ti_end, tile);
-	if (HASBIT(1 << 7, ti_end.tileh))
-		z_correction += 8;
-
-	// return the height there (the height of the NORTH CORNER)
-	return TilePixelHeight(tile) + z_correction;
+	/* Return the height there (the height of the NORTH CORNER)
+	 * If the end of the bridge is on a tileh 7 (all raised, except north corner),
+	 * the z coordinate is 1 height level too low. Compensate for that */
+	return TilePixelHeight(tile) + (GetTileSlope(tile, NULL) == 7 ? 8 : 0);
 }
 
 static const byte _bridge_foundations[2][16] = {
diff --git a/vehicle.c b/vehicle.c
index ffe2e392e1..915da38da4 100644
--- a/vehicle.c
+++ b/vehicle.c
@@ -82,10 +82,7 @@ static inline uint Correct_Z(uint tileh)
 
 uint GetCorrectTileHeight(TileIndex tile)
 {
-	TileInfo ti;
-
-	FindLandscapeHeightByTile(&ti, tile);
-	return Correct_Z(ti.tileh);
+	return Correct_Z(GetTileSlope(tile, NULL));
 }
 
 bool EnsureNoVehicleZ(TileIndex tile, byte z)