Add edge flood behaviour for land ground objects with no foundations

docs/newgrf-additions-nml.html

@@ -304,7 +304,7 @@
 	<tr><td>use_land_ground</td><td>0 or 1</td><td>
 		Sets whether to use the underlying ground as the object ground sprite, ignoring the ground sprite provided in the sprite layout.<br />
 		When enabled, the ground sprite will be bare ground, grass, snow, desert, etc. as if it were a clear ground tile.<br />
-		In edge foundation mode, the ground may be coast/shore when flooded.
+		In edge foundation mode, or when foundations are disabled, the ground may be coast/shore when flooded.
 	</td></tr>
 	<tr><td>edge_foundation_mode</td><td>[mode0, mode1, mode2, mode3]</td><td>
 		Enables edge foundation mode for the object.<br />

docs/newgrf-additions.html

@@ -583,7 +583,7 @@
 	<h4 id="object_use_land_ground">Object uses land ground sprite (mappable property: object_use_land_ground)</h4>
 	<p>This property sets whether to use the underlying ground as the object ground sprite, ignoring the ground sprite provided in the sprite layout.<br />
 	When enabled, the ground sprite will be bare ground, grass, snow, desert, etc. as if it were a clear ground tile.<br />
-	In edge foundation mode, the ground may be coast/shore when flooded.<br />
+	In edge foundation mode, or when foundations are disabled, the ground may be coast/shore when flooded.<br />
 	The property length is 1 byte. 0 is disabled (default). 1 is enabled.</p>
 	<p>This is indicated by the feature name: <font face="monospace">action0_object_use_land_ground</font>, version 1</p>
 	<h4 id="object_edge_foundation_mode">Enable object edge foundation mode (mappable property: object_edge_foundation_mode)</h4>

src/water_cmd.cpp

@@ -1247,6 +1247,11 @@ void DoFloodTile(TileIndex target)
 					SetObjectGroundTypeDensity(target, OBJECT_GROUND_SHORE, 3);
 					MarkTileDirtyByTile(target, VMDF_NOT_MAP_MODE);
 					flooded = true;
+				} else if ((spec->ctrl_flags & OBJECT_CTRL_FLAG_USE_LAND_GROUND) && (spec->flags & OBJECT_FLAG_HAS_NO_FOUNDATION)) {
+					SetWaterClass(target, WATER_CLASS_SEA);
+					SetObjectGroundTypeDensity(target, OBJECT_GROUND_SHORE, 3);
+					MarkTileDirtyByTile(target, VMDF_NOT_MAP_MODE);
+					flooded = true;
 				}
 				break;
 			}