(svn r21493) -Codechange: don't use the full 32 bits of the level land command to tell whether to raise, lower or keep the level of the first selected tile

1 files changed, 11 insertions, 3 deletions

diff --git a/src/terraform_cmd.cpp b/src/terraform_cmd.cpp
index 1b58a91da..406bdf5be 100644
--- a/src/terraform_cmd.cpp
+++ b/src/terraform_cmd.cpp
@@ -378,7 +378,8 @@ CommandCost CmdTerraformLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
  * @param tile end tile of area-drag
  * @param flags for this command type
  * @param p1 start tile of area drag
- * @param p2 height difference; eg raise (+1), lower (-1) or level (0)
+ * @param p2 various bitstuffed data.
+ *  bits 1 - 2: Mode of leveling \c LevelMode.
  * @param text unused
  * @return the cost of this operation or an error
  */
@@ -392,14 +393,21 @@ CommandCost CmdLevelLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 	uint oldh = TileHeight(p1);
 
 	/* compute new height */
-	uint h = oldh + (int8)p2;
+	uint h = oldh;
+	LevelMode lm = (LevelMode)GB(p2, 1, 2);
+	switch (lm) {
+		case LM_LEVEL: break;
+		case LM_RAISE: h++; break;
+		case LM_LOWER: h--; break;
+		default: return CMD_ERROR;
+	}
 
 	/* Check range of destination height */
 	if (h > MAX_TILE_HEIGHT) return_cmd_error((oldh == 0) ? STR_ERROR_ALREADY_AT_SEA_LEVEL : STR_ERROR_TOO_HIGH);
 
 	Money money = GetAvailableMoneyForCommand();
 	CommandCost cost(EXPENSES_CONSTRUCTION);
-	CommandCost last_error((p2 == 0) ? STR_ERROR_ALREADY_LEVELLED : INVALID_STRING_ID);
+	CommandCost last_error(lm == LM_LEVEL ? STR_ERROR_ALREADY_LEVELLED : INVALID_STRING_ID);
 	bool had_success = false;
 
 	TileArea ta(tile, p1);