--- a/src/newgrf_house.cpp	Mon Mar 31 07:25:49 2008 +0000
+++ b/src/newgrf_house.cpp	Mon Mar 31 15:10:24 2008 +0000
@@ -216,7 +216,7 @@
 
 	switch (variable) {
 		/* Construction stage. */
-		case 0x40: return (IsTileType(tile, MP_HOUSE) ? GetHouseBuildingStage(tile) : 0) | OriginalTileRandomiser(TileX(tile), TileY(tile)) << 2;
+		case 0x40: return (IsTileType(tile, MP_HOUSE) ? GetHouseBuildingStage(tile) : 0) | TileHash2Bit(TileX(tile), TileY(tile)) << 2;
 
 		/* Building age. */
 		case 0x41: return Clamp(_cur_year - GetHouseConstructionYear(tile), 0, 0xFF);
@@ -340,7 +340,7 @@
 						pal = HasBit(callback, 14) ? GB(callback, 0, 8) + SPR_2CCMAP_BASE : callback;
 					}
 				} else {
-					pal = hs->random_colour[OriginalTileRandomiser(ti->x, ti->y)] + PALETTE_RECOLOR_START;
+					pal = hs->random_colour[TileHash2Bit(ti->x, ti->y)] + PALETTE_RECOLOR_START;
 				}
 			}
 		} else {

--- a/src/town.h	Mon Mar 31 07:25:49 2008 +0000
+++ b/src/town.h	Mon Mar 31 15:10:24 2008 +0000
@@ -314,7 +314,7 @@
 extern Town *_cleared_town;
 extern int _cleared_town_rating;
 
-uint OriginalTileRandomiser(uint x, uint y);
+uint TileHash2Bit(uint x, uint y);
 void ResetHouses();
 
 void ClearTownHouse(Town *t, TileIndex tile);

--- a/src/town_cmd.cpp	Mon Mar 31 07:25:49 2008 +0000
+++ b/src/town_cmd.cpp	Mon Mar 31 15:10:24 2008 +0000
@@ -129,15 +129,21 @@
 	TownDrawHouseLift
 };
 
-uint OriginalTileRandomiser(uint x, uint y)
+/**
+ * Calculate a hash value from a tile position
+ *
+ * @param x The X coordinate
+ * @param y The Y coordinate
+ * @return The hash of the tile
+ */
+uint TileHash2Bit(uint x, uint y)
 {
-	uint variant;
-	variant  = x >> 4;
-	variant ^= x >> 6;
-	variant ^= y >> 4;
-	variant -= y >> 6;
-	variant &= 3;
-	return variant;
+	uint hash = x >> 4;
+	hash ^= x >> 6;
+	hash ^= y >> 4;
+	hash -= y >> 6;
+	hash &= 3;
+	return hash;
 }
 
 /**
@@ -175,7 +181,7 @@
 	}
 
 	/* Retrieve pointer to the draw town tile struct */
-	dcts = &_town_draw_tile_data[house_id << 4 | OriginalTileRandomiser(ti->x, ti->y) << 2 | GetHouseBuildingStage(ti->tile)];
+	dcts = &_town_draw_tile_data[house_id << 4 | TileHash2Bit(ti->x, ti->y) << 2 | GetHouseBuildingStage(ti->tile)];
 
 	if (ti->tileh != SLOPE_FLAT) DrawFoundation(ti, FOUNDATION_LEVELED);