# HG changeset patch
# User frosch <frosch@openttd.org>
# Date 2010-11-21 17:42:18
# Node ID 27c24a3260350f94ee75d3680de17cdfdf94bd24
# Parent  b9e4f67cdda1c3bef7f67f4e7f76d12b0e61565a

(svn r21289) -Fix [FS#4133]: Make terraforming and tunnel-excavation handle DC_AUTO-clearable multitile objects.

diff --git a/src/terraform_cmd.cpp b/src/terraform_cmd.cpp
--- a/src/terraform_cmd.cpp
+++ b/src/terraform_cmd.cpp
@@ -17,6 +17,7 @@
 #include "functions.h"
 #include "economy_func.h"
 #include "genworld.h"
+#include "object_base.h"
 
 #include "table/strings.h"
 
@@ -275,8 +276,10 @@ CommandCost CmdTerraformLand(TileIndex t
 		total_cost.AddCost(cost);
 	}
 
-	/* Check if the terraforming is valid wrt. tunnels, bridges and objects on the surface */
-	{
+	/* Check if the terraforming is valid wrt. tunnels, bridges and objects on the surface
+	 * Pass == 0: Collect tileareas which are caused to be auto-cleared.
+	 * Pass == 1: Collect the actual cost. */
+	for (int pass = 0; pass < 2; pass++) {
 		TileIndex *ti = ts.tile_table;
 
 		for (int count = ts.tile_table_count; count != 0; count--, ti++) {
@@ -315,16 +318,31 @@ CommandCost CmdTerraformLand(TileIndex t
 				_terraform_err_tile = tile; // highlight the tile above the tunnel
 				return_cmd_error(STR_ERROR_EXCAVATION_WOULD_DAMAGE);
 			}
+
+			/* Is the tile already cleared? */
+			const ClearedObjectArea *coa = FindClearedObject(tile);
+			bool indirectly_cleared = coa != NULL && coa->first_tile != tile;
+
 			/* Check tiletype-specific things, and add extra-cost */
 			const bool curr_gen = _generating_world;
 			if (_game_mode == GM_EDITOR) _generating_world = true; // used to create green terraformed land
-			CommandCost cost = _tile_type_procs[GetTileType(tile)]->terraform_tile_proc(tile, flags | DC_AUTO | DC_FORCE_CLEAR_TILE, z_min * TILE_HEIGHT, tileh);
+			DoCommandFlag tile_flags = flags | DC_AUTO | DC_FORCE_CLEAR_TILE;
+			if (pass == 0) {
+				tile_flags &= ~DC_EXEC;
+				tile_flags |= DC_NO_MODIFY_TOWN_RATING;
+			}
+			CommandCost cost;
+			if (indirectly_cleared) {
+				cost = DoCommand(tile, 0, 0, tile_flags, CMD_LANDSCAPE_CLEAR);
+			} else {
+				cost = _tile_type_procs[GetTileType(tile)]->terraform_tile_proc(tile, tile_flags, z_min * TILE_HEIGHT, tileh);
+			}
 			_generating_world = curr_gen;
 			if (cost.Failed()) {
 				_terraform_err_tile = tile;
 				return cost;
 			}
-			total_cost.AddCost(cost);
+			if (pass == 1) total_cost.AddCost(cost);
 		}
 	}
 
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -38,6 +38,7 @@
 #include "pbs.h"
 #include "company_base.h"
 #include "newgrf_railtype.h"
+#include "object_base.h"
 
 #include "table/sprites.h"
 #include "table/strings.h"
@@ -583,23 +584,31 @@ CommandCost CmdBuildTunnel(TileIndex sta
 
 	if (IsWaterTile(end_tile)) return_cmd_error(STR_ERROR_CAN_T_BUILD_ON_WATER);
 
+	/* Clear the tile in any case */
+	ret = DoCommand(end_tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+	if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
+	cost.AddCost(ret);
+
 	/* slope of end tile must be complementary to the slope of the start tile */
 	if (end_tileh != ComplementSlope(start_tileh)) {
-		/* Check if there is a structure on the terraformed tile. Do not add the cost, that will be done by the terraforming
-		 * Note: Currently the town rating is also affected by this clearing-test. So effectivly the player is punished twice for clearing
-		 *       the tree on end_tile.
-		 */
-		ret = DoCommand(end_tile, 0, 0, DC_AUTO, CMD_LANDSCAPE_CLEAR);
+		/* Mark the tile as already cleared for the terraform command.
+		 * Do this for all tiles (like trees), not only objects. */
+		ClearedObjectArea *coa = FindClearedObject(end_tile);
+		if (coa == NULL) {
+			coa = _cleared_object_areas.Append();
+			coa->first_tile = end_tile;
+			coa->area = TileArea(end_tile, 1, 1);
+		}
+
+		/* Hide the tile from the terraforming command */
+		TileIndex old_first_tile = coa->first_tile;
+		coa->first_tile = INVALID_TILE;
+		ret = DoCommand(end_tile, end_tileh & start_tileh, 0, flags, CMD_TERRAFORM_LAND);
+		coa->first_tile = old_first_tile;
 		if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
-
-		ret = DoCommand(end_tile, end_tileh & start_tileh, 0, flags, CMD_TERRAFORM_LAND);
-		if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
-	} else {
-		ret = DoCommand(end_tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
-		if (ret.Failed()) return ret;
+		cost.AddCost(ret);
 	}
 	cost.AddCost(_price[PR_BUILD_TUNNEL]);
-	cost.AddCost(ret);
 
 	/* Pay for the rail/road in the tunnel including entrances */
 	switch (transport_type) {