# HG changeset patch
# User rubidium <rubidium@openttd.org>
# Date 2007-07-25 15:45:46
# Node ID a531c9f4c784b622dbc203e678b23561faa5f70d
# Parent  d89111d78bff1e4813ba5c179780c792fa8a199d

(svn r10686) -Fix [FS#1058]: determining whether there is a tunnel going under the lowered area is only needed in two directions instead of all four, so take the directions (one for each axis) to the nearest border (along the given axis). Furthermore GetTileZ did much more than absolutely necessary.

diff --git a/src/tile.cpp b/src/tile.cpp
--- a/src/tile.cpp
+++ b/src/tile.cpp
@@ -23,11 +23,11 @@ Slope GetTileSlope(TileIndex tile, uint 
 
 	min = a = TileHeight(tile);
 	b = TileHeight(tile + TileDiffXY(1, 0));
-	if (min >= b) min = b;
+	if (min > b) min = b;
 	c = TileHeight(tile + TileDiffXY(0, 1));
-	if (min >= c) min = c;
+	if (min > c) min = c;
 	d = TileHeight(tile + TileDiffXY(1, 1));
-	if (min >= d) min = d;
+	if (min > d) min = d;
 
 	r = SLOPE_FLAT;
 	if ((a -= min) != 0) r += (--a << 4) + SLOPE_N;
@@ -42,24 +42,25 @@ Slope GetTileSlope(TileIndex tile, uint 
 
 uint GetTileZ(TileIndex tile)
 {
-	uint h;
-	GetTileSlope(tile, &h);
-	return h;
+	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) return 0;
+
+	uint h = TileHeight(tile);
+	h = min(h, TileHeight(tile + TileDiffXY(1, 0)));
+	h = min(h, TileHeight(tile + TileDiffXY(0, 1)));
+	h = min(h, TileHeight(tile + TileDiffXY(1, 1)));
+
+	return h * TILE_HEIGHT;
 }
 
 
 uint GetTileMaxZ(TileIndex t)
 {
-	uint max;
-	uint h;
+	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) return 0;
 
-	h = TileHeight(t);
-	max = h;
-	h = TileHeight(t + TileDiffXY(1, 0));
-	if (h > max) max = h;
-	h = TileHeight(t + TileDiffXY(0, 1));
-	if (h > max) max = h;
-	h = TileHeight(t + TileDiffXY(1, 1));
-	if (h > max) max = h;
-	return max * 8;
+	uint h = TileHeight(t);
+	h = max(h, TileHeight(t + TileDiffXY(1, 0)));
+	h = max(h, TileHeight(t + TileDiffXY(0, 1)));
+	h = max(h, TileHeight(t + TileDiffXY(1, 1)));
+
+	return h * TILE_HEIGHT;
 }
diff --git a/src/tunnel_map.cpp b/src/tunnel_map.cpp
--- a/src/tunnel_map.cpp
+++ b/src/tunnel_map.cpp
@@ -64,8 +64,6 @@ bool IsTunnelInWayDir(TileIndex tile, ui
 bool IsTunnelInWay(TileIndex tile, uint z)
 {
 	return
-		IsTunnelInWayDir(tile, z, DIAGDIR_NE) ||
-		IsTunnelInWayDir(tile, z, DIAGDIR_SE) ||
-		IsTunnelInWayDir(tile, z, DIAGDIR_SW) ||
-		IsTunnelInWayDir(tile, z, DIAGDIR_NW);
+		IsTunnelInWayDir(tile, z, (TileX(tile) > (MapMaxX() / 2)) ? DIAGDIR_NE : DIAGDIR_SW) ||
+		IsTunnelInWayDir(tile, z, (TileY(tile) > (MapMaxY() / 2)) ? DIAGDIR_NW : DIAGDIR_SE);
 }