From 071ef2c88fbcfc9d1c9db111ec0ff628efc4002a Mon Sep 17 00:00:00 2001
From: Timmy Weerwag <timmy@timmyweerwag.nl>
Date: Mon, 23 Mar 2015 00:34:00 +0100
Subject: [PATCH] Fixed an original bug in bridge footpath building

Affects starting to build a footpath bridge on a sloped tile. The original code
was horribly broken. I think this is the most intuitive solution considering
the height of the arrow when selecting the tile.
---
 src/windows/footpath.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/windows/footpath.c b/src/windows/footpath.c
index d60ab4d6ed..5bf53d8c8c 100644
--- a/src/windows/footpath.c
+++ b/src/windows/footpath.c
@@ -756,14 +756,18 @@ static void window_footpath_start_bridge_at_point(int screenX, int screenY)
 		return;
 
 	if (map_element_get_type(mapElement) == MAP_ELEMENT_TYPE_SURFACE) {
-		// ?
-		uint8 dl = ((mapElement->properties.surface.slope & 0x0F) << direction) & 0xFF;
-		uint8 dh = dl;
-		dl = (dl >> 4) & 0x0F;
-		dh = (dh & 0x0F) | dl;
+		// If we start the path on a slope, the arrow is slightly raised, so we
+		// expect the path to be slightly raised as well.
+		uint8_t slope = mapElement->properties.surface.slope;
 		z = mapElement->base_height;
-		if ((dh & 0x0C) == 0x0C)
+		if (slope & 0x10) {
+			// Steep diagonal slope
+			z += 4;
+		}
+		else if (slope & 0x0f) {
+			// Normal slope
 			z += 2;
+		}
 	} else {
 		z = mapElement->base_height;
 		if (map_element_get_type(mapElement) == MAP_ELEMENT_TYPE_PATH) {