--- /tmp/viewport.cpp
+++ /home/zigieteusz/Programowanie/OpenTTD/clean/trunk/src/viewport.cpp
@@ -1504,27 +1504,21 @@
 				 * for x and y. */
 				int x = (row - column) / 2;
 				int y = (row + column) / 2;
-				tile_info.x = x;
-				tile_info.y = y;
-
-				/* For some strange reason, those fields inside tile_info are uints. However,
-				 * in the old code their copies in an int variable where compared against zero. */
-				if (IsInsideMM(x, _settings_game.construction.freeform_edges ? 1 : 0, MapMaxX()) &&
-						IsInsideMM(y, _settings_game.construction.freeform_edges ? 1 : 0, MapMaxY())) {
-					/* We are inside the map => paint landscape. */
-					tile_info.tile = TileXY(tile_info.x, tile_info.y);
-					tile_info.tileh = GetTilePixelSlope(tile_info.tile, &tile_info.z);
+
+				if (IsInsideMM(x, 0, MapSizeX()) && IsInsideMM(y, 0, MapSizeY())) {
+					tile_info.tile = TileXY(x, y);
 					tile_type = GetTileType(tile_info.tile);
 				} else {
-					/* We are outside the map => paint black. */
 					tile_info.tile = INVALID_TILE;
-					tile_info.tileh = GetTilePixelSlopeOutsideMap(tile_info.x, tile_info.y, &tile_info.z);
 					tile_type = MP_VOID;
 				}
 
-				/* Scale to 16x16 tiles, needed for the drawing procedures called below. */
-				tile_info.x *= TILE_SIZE;
-				tile_info.y *= TILE_SIZE;
+				tile_info.tileh = (tile_type != MP_VOID) ?
+						GetTilePixelSlope(tile_info.tile, &tile_info.z) :
+						GetTilePixelSlopeOutsideMap(x, y, &tile_info.z);
+
+				tile_info.x = x * TILE_SIZE;
+				tile_info.y = y * TILE_SIZE;
 
 				_vd.foundation_part = FOUNDATION_PART_NONE;
 				_vd.foundation[0] = -1;
@@ -1533,7 +1527,7 @@
 				_vd.last_foundation_child[1] = NULL;
 
 				_tile_type_procs[tile_type]->draw_tile_proc(&tile_info);
-				DrawTileSelection(&tile_info);
+				if (tile_info.tile != INVALID_TILE) DrawTileSelection(&tile_info);
 			}
 		}
 	}