(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.

2 files changed, 21 insertions, 22 deletions

diff --git a/src/tile.cpp b/src/tile.cpp
index 128c16128..449156465 100644
--- a/src/tile.cpp
+++ b/src/tile.cpp
@@ -23,11 +23,11 @@ Slope GetTileSlope(TileIndex tile, uint *h)
 
 	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 *h)
 
 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;
-
-	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;
+	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) return 0;
+
+	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
index 8d75735b6..593d3fe6b 100644
--- a/src/tunnel_map.cpp
+++ b/src/tunnel_map.cpp
@@ -64,8 +64,6 @@ bool IsTunnelInWayDir(TileIndex tile, uint z, DiagDirection dir)
 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);
 }