(svn r11107) -Feature: some tool so one can still build tunnels under rails (and other structures) when the owner of the structure built it on foundations and if you have enough "empty" space ofcourse. One could use the tool for some other construction needs too. Patch by frosch.

1 files changed, 42 insertions, 3 deletions

diff --git a/src/road_cmd.cpp b/src/road_cmd.cpp
index cf2ae3638..003cf3348 100644
--- a/src/road_cmd.cpp
+++ b/src/road_cmd.cpp
@@ -32,6 +32,12 @@
 #include "station_map.h"
 #include "tunnel_map.h"
 #include "misc/autoptr.hpp"
+#include "autoslope.h"
+
+#define M(x) (1 << (x))
+/* Level crossings may only be built on these slopes */
+static const uint32 VALID_LEVEL_CROSSING_SLOPES = (M(SLOPE_SEN) | M(SLOPE_ENW) | M(SLOPE_NWS) | M(SLOPE_NS) | M(SLOPE_WSE) | M(SLOPE_EW) | M(SLOPE_FLAT));
+#undef M
 
 bool CheckAllowRemoveRoad(TileIndex tile, RoadBits remove, Owner owner, bool *edge_road, RoadType rt)
 {
@@ -405,12 +411,10 @@ CommandCost CmdBuildRoad(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 				return_cmd_error(STR_1000_LAND_SLOPED_IN_WRONG_DIRECTION);
 			}
 
-#define M(x) (1 << (x))
 			/* Level crossings may only be built on these slopes */
-			if (!HASBIT(M(SLOPE_SEN) | M(SLOPE_ENW) | M(SLOPE_NWS) | M(SLOPE_NS) | M(SLOPE_WSE) | M(SLOPE_EW) | M(SLOPE_FLAT), tileh)) {
+			if (!HASBIT(VALID_LEVEL_CROSSING_SLOPES, tileh)) {
 				return_cmd_error(STR_1000_LAND_SLOPED_IN_WRONG_DIRECTION);
 			}
-#undef M
 
 			if (GetRailTileType(tile) != RAIL_TILE_NORMAL) goto do_clear;
 			switch (GetTrackBits(tile)) {
@@ -1372,6 +1376,41 @@ static void ChangeTileOwner_Road(TileIndex tile, PlayerID old_player, PlayerID n
 
 static CommandCost TerraformTile_Road(TileIndex tile, uint32 flags, uint z_new, Slope tileh_new)
 {
+	if (_patches.build_on_slopes && AutoslopeEnabled()) {
+		switch (GetRoadTileType(tile)) {
+			case ROAD_TILE_CROSSING:
+				if (!IsSteepSlope(tileh_new) && (GetTileMaxZ(tile) == z_new + GetSlopeMaxZ(tileh_new)) && HASBIT(VALID_LEVEL_CROSSING_SLOPES, tileh_new)) return _price.terraform;
+				break;
+
+			case ROAD_TILE_DEPOT:
+				if (AutoslopeCheckForEntranceEdge(tile, z_new, tileh_new, GetRoadDepotDirection(tile))) return _price.terraform;
+				break;
+
+			case ROAD_TILE_NORMAL: {
+				RoadBits bits = GetAllRoadBits(tile);
+				RoadBits bits_copy = bits;
+				/* Check if the slope-road_bits combination is valid at all, i.e. it is save to call GetRoadFoundation(). */
+				if (!CmdFailed(CheckRoadSlope(tileh_new, &bits_copy, ROAD_NONE))) {
+					/* CheckRoadSlope() sometimes changes the road_bits, if it does not agree with them. */
+					if (bits == bits_copy) {
+						uint z_old;
+						Slope tileh_old = GetTileSlope(tile, &z_old);
+
+						/* Get the slope on top of the foundation */
+						z_old += ApplyFoundationToSlope(GetRoadFoundation(tileh_old, bits), &tileh_old);
+						z_new += ApplyFoundationToSlope(GetRoadFoundation(tileh_new, bits), &tileh_new);
+
+						/* The surface slope must not be changed */
+						if ((z_old == z_new) && (tileh_old == tileh_new)) return _price.terraform;
+					}
+				}
+				break;
+			}
+
+			default: NOT_REACHED();
+		}
+	}
+
 	return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 }