Function TerraformTile_Road

src/road_cmd.cpp:2367–2404

}

static CommandCost TerraformTile_Road(TileIndex tile, DoCommandFlags flags, int z_new, Slope tileh_new)
{
	if (_settings_game.construction.build_on_slopes && AutoslopeEnabled()) {
		switch (GetRoadTileType(tile)) {
			case RoadTileType::Crossing:
				if (!IsSteepSlope(tileh_new) && (GetTileMaxZ(tile) == z_new + GetSlopeMaxZ(tileh_new)) && HasBit(VALID_LEVEL_CROSSING_SLOPES, tileh_new)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
				break;

			case RoadTileType::Depot:
				if (AutoslopeCheckForEntranceEdge(tile, z_new, tileh_new, GetRoadDepotDirection(tile))) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
				break;

			case RoadTileType::Normal: {
				RoadBits bits = GetAllRoadBits(tile);
				RoadBits bits_copy = bits;
				/* Check if the slope-road_bits combination is valid at all, i.e. it is safe to call GetRoadFoundation(). */
				if (CheckRoadSlope(tileh_new, &bits_copy, ROAD_NONE, ROAD_NONE).Succeeded()) {
					/* CheckRoadSlope() sometimes changes the road_bits, if it does not agree with them. */
					if (bits == bits_copy) {
						auto [tileh_old, z_old] = GetTileSlopeZ(tile);

						/* Get the slope on top of the foundation */
						z_old += ApplyFoundationToSlope(GetRoadFoundation(tileh_old, bits), tileh_old);
						z_new += ApplyFoundationToSlope(GetRoadFoundation(tileh_new, bits), tileh_new);

						/* The surface slope must not be changed */
						if ((z_old == z_new) && (tileh_old == tileh_new)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
					}
				}
				break;
			}

			default: NOT_REACHED();
		}
	}

	return Command<CMD_LANDSCAPE_CLEAR>::Do(flags, tile);
}

/**
 * Checks the tile and returns whether the current player is allowed to convert the roadtype to another roadtype without taking ownership