Function FootpathIsConnectedToMapEdgeHelper

src/openrct2/world/Footpath.cpp:1087–1283

* * rct2: 0x0069AC1A * @param flags (1 << 0): Ignore queues * (1 << 5): Unown * (1 << 7): Ignore no entry signs */

     *              (1 << 7): Ignore no entry signs
     */
    static int32_t FootpathIsConnectedToMapEdgeHelper(CoordsXYZ footpathPos, int32_t direction, int32_t flags)
    {
        int32_t returnVal = FOOTPATH_SEARCH_INCOMPLETE;

        struct TileState
        {
            bool processed = false;
            CoordsXYZ footpathPos;
            int32_t direction;
            int32_t level;
            int32_t distanceFromJunction;
            int32_t junctionTolerance;
        };

        // Vector of all of the child tile elements for us to explore
        std::vector<TileState> tiles;
        TileElement* tileElement = nullptr;
        int numPendingTiles = 0;

        TileState currentTile = { false, footpathPos, direction, 0, 0, 16 };

        // Captures the current state of the variables and stores them in tiles vector for iteration later
        auto CaptureCurrentTileState = [&tiles, &numPendingTiles](TileState t_currentTile) -> void {
            // Search for an entry of this tile in our list already
            for (const TileState& tile : tiles)
            {
                if (tile.footpathPos == t_currentTile.footpathPos && tile.direction == t_currentTile.direction)
                    return;
            }

            // If we get here we did not find it, so insert the tile into our list
            tiles.push_back(t_currentTile);
            ++numPendingTiles;
        };

        // Loads the next tile to visit into our variables
        auto LoadNextTileElement = [&tiles, &numPendingTiles](TileState& t_currentTile) -> void {
            // Do not continue if there are no tiles in the list
            if (tiles.empty())
                return;

            // Find the next unprocessed tile
            for (size_t tileIndex = tiles.size() - 1; tileIndex > 0; --tileIndex)
            {
                if (tiles[tileIndex].processed)
                    continue;
                --numPendingTiles;
                t_currentTile = tiles[tileIndex];
                tiles[tileIndex].processed = true;
                return;
            }
            // Default to tile 0
            --numPendingTiles;
            t_currentTile = tiles[0];
            tiles[0].processed = true;
        };

        // Encapsulate the tile skipping logic to make do-while more readable