(svn r22960) -Feature: Allow depots, standard roadstops and airports on steep slopes.

1 files changed, 12 insertions, 13 deletions

diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index 452dbe9da..5f140365b 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -672,10 +672,11 @@ CommandCost ClearTile_Station(TileIndex tile, DoCommandFlag flags);
  * @param tile TileIndex to check.
  * @param invalid_dirs Prohibited directions for slopes (set of #DiagDirection).
  * @param allowed_z Height allowed for the tile. If allowed_z is negative, it will be set to the height of this tile.
+ * @param allow_steep Whether steep slopes are allowed.
  * @param check_bridge Check for the existance of a bridge.
  * @return The cost in case of success, or an error code if it failed.
  */
-CommandCost CheckBuildableTile(TileIndex tile, uint invalid_dirs, int &allowed_z, bool check_bridge = true)
+CommandCost CheckBuildableTile(TileIndex tile, uint invalid_dirs, int &allowed_z, bool allow_steep, bool check_bridge = true)
 {
 	if (check_bridge && MayHaveBridgeAbove(tile) && IsBridgeAbove(tile)) {
 		return_cmd_error(STR_ERROR_MUST_DEMOLISH_BRIDGE_FIRST);
@@ -691,23 +692,21 @@ CommandCost CheckBuildableTile(TileIndex tile, uint invalid_dirs, int &allowed_z
 	 *   1) The tile is "steep" (i.e. stretches two height levels).
 	 *   2) The tile is non-flat and the build_on_slopes switch is disabled.
 	 */
-	if (IsSteepSlope(tileh) ||
+	if ((!allow_steep && IsSteepSlope(tileh)) ||
 			((!_settings_game.construction.build_on_slopes) && tileh != SLOPE_FLAT)) {
 		return_cmd_error(STR_ERROR_FLAT_LAND_REQUIRED);
 	}
 
 	CommandCost cost(EXPENSES_CONSTRUCTION);
-	int flat_z = z;
+	int flat_z = z + GetSlopeMaxZ(tileh);
 	if (tileh != SLOPE_FLAT) {
 		/* Forbid building if the tile faces a slope in a invalid direction. */
-		if ((HasBit(invalid_dirs, DIAGDIR_NE) && !(tileh & SLOPE_NE)) ||
-		    (HasBit(invalid_dirs, DIAGDIR_SE) && !(tileh & SLOPE_SE)) ||
-		    (HasBit(invalid_dirs, DIAGDIR_SW) && !(tileh & SLOPE_SW)) ||
-		    (HasBit(invalid_dirs, DIAGDIR_NW) && !(tileh & SLOPE_NW))) {
-			return_cmd_error(STR_ERROR_FLAT_LAND_REQUIRED);
+		for (DiagDirection dir = DIAGDIR_BEGIN; dir != DIAGDIR_END; dir++) {
+			if (HasBit(invalid_dirs, dir) && !CanBuildDepotByTileh(dir, tileh)) {
+				return_cmd_error(STR_ERROR_FLAT_LAND_REQUIRED);
+			}
 		}
 		cost.AddCost(_price[PR_BUILD_FOUNDATION]);
-		flat_z += TILE_HEIGHT;
 	}
 
 	/* The level of this tile must be equal to allowed_z. */
@@ -733,7 +732,7 @@ CommandCost CheckFlatLand(TileArea tile_area, DoCommandFlag flags)
 	int allowed_z = -1;
 
 	TILE_AREA_LOOP(tile_cur, tile_area) {
-		CommandCost ret = CheckBuildableTile(tile_cur, 0, allowed_z);
+		CommandCost ret = CheckBuildableTile(tile_cur, 0, allowed_z, true);
 		if (ret.Failed()) return ret;
 		cost.AddCost(ret);
 
@@ -769,7 +768,7 @@ static CommandCost CheckFlatLandRailStation(TileArea tile_area, DoCommandFlag fl
 	bool slope_cb = statspec != NULL && HasBit(statspec->callback_mask, CBM_STATION_SLOPE_CHECK);
 
 	TILE_AREA_LOOP(tile_cur, tile_area) {
-		CommandCost ret = CheckBuildableTile(tile_cur, invalid_dirs, allowed_z);
+		CommandCost ret = CheckBuildableTile(tile_cur, invalid_dirs, allowed_z, false);
 		if (ret.Failed()) return ret;
 		cost.AddCost(ret);
 
@@ -851,7 +850,7 @@ static CommandCost CheckFlatLandRoadStop(TileArea tile_area, DoCommandFlag flags
 	int allowed_z = -1;
 
 	TILE_AREA_LOOP(cur_tile, tile_area) {
-		CommandCost ret = CheckBuildableTile(cur_tile, invalid_dirs, allowed_z);
+		CommandCost ret = CheckBuildableTile(cur_tile, invalid_dirs, allowed_z, !is_drive_through);
 		if (ret.Failed()) return ret;
 		cost.AddCost(ret);
 
@@ -3586,7 +3585,7 @@ static CommandCost TerraformTile_Station(TileIndex tile, DoCommandFlag flags, ui
 		/* TODO: If you implement newgrf callback 149 'land slope check', you have to decide what to do with it here.
 		 *       TTDP does not call it.
 		 */
-		if (!IsSteepSlope(tileh_new) && (GetTileMaxZ(tile) == z_new + GetSlopeMaxZ(tileh_new))) {
+		if (GetTileMaxZ(tile) == z_new + GetSlopeMaxZ(tileh_new)) {
 			switch (GetStationType(tile)) {
 				case STATION_WAYPOINT:
 				case STATION_RAIL: {