/*
         * public functions
         */
        /// <summary>
        /// A*, modified to find a nearest path in case of failure
        /// </summary>
        /// <param name="map">The Map</param>
        /// <param name="startNode">The starting Node</param>
        /// <param name="endNode">The ending Node</param>
        /// <returns>The path as a list of waypoints</returns>
        public static List<Node> findPath(NodeMap map, Node startNode, Node endNode)
        {
            // initialize data
            PQueue open = new PQueue();
            open.enqueue(startNode);
            List<Node> adjacentNodes = new List<Node>();

            // good ol' A*
            while (open.Count > 0)
            {
                // find the open Node with the lowest Fscore and remove it from the open PQueue
                Node current = open.dequeue();

                // if this is our destination Node, we're done; otherwise, close it so we don't travel to it again
                if (current == endNode)
                    return reconstruct(endNode);
                current.close();

                // find every valid Node adjacent to the current Node
                adjacentNodes = map.getAdjacentNodes(current);

                // iterate over all of them
                for (int i = 0; i < adjacentNodes.Count; i++)
                {
                    // grab an adjacent Node and calculate a new GScore and HScore for it
                    Node adjacent = adjacentNodes[i];
                    int tempGScore = current.Gscore + map.pathDistance(current, adjacent);
                    int tempHScore = map.pathDistance(adjacent, endNode);

                    // if we have not opened this Cell, give it new stats and open it
                    if (!adjacent.isOpen)
                    {
                        setAdjacentStats(adjacent, current, tempGScore, tempHScore);
                        open.enqueue(adjacent);
                    }

                    // otherwise, if we have opened it but the new path to it is shorter than the old one, give it new stats and reset its position in the open PQueue
                    else if (tempGScore < adjacent.Gscore)
                    {
                        setAdjacentStats(adjacent, current, tempGScore, tempHScore);
                        //open.resetPosition(adjacent);
                    }
                }
            }

            // no valid path exists, so find the nearest path
            List<Node> closed = createClosed(map);
            Node nearestNode = closed[0];

            // find the closed Node with the lowest Hscore (distance from the intended end); return a path to that Node
            if (closed.Count > 0)
            {
                for (int i = 1; i < closed.Count; i++)
                {
                    if (closed[i].Hscore < nearestNode.Hscore)
                        nearestNode = closed[i];
                }
            }
            return reconstruct(nearestNode);
        }
 /// <summary>
 /// Copy constructor
 /// </summary>
 public PQueue(PQueue p)
 {
     for (int i = 0; i < p.pq.Count(); i++)
     {
         pq.Add(p.pq[i]);
     }
 }
 /// <summary>
 /// Copy constructor
 /// </summary>
 /// <param name="p">The PQueue to copy</param>
 public PQueue(PQueue p)
 {
     this.pq.Clear();
     for (int i = 0; i < p.pq.Count; i++)
     {
         this.pq.Add(p.pq[i]);
     }
     recomputeStats();
 }
 /// <summary>
 /// Copy constructor
 /// </summary>
 /// <param name="p">The PQueue to copy</param>
 public PQueue(PQueue p)
 {
     this.pq.Clear();
     for (int i = 0; i < p.pq.Count; i++)
     {
         this.pq.Add(p.pq[i]);
     }
     recomputeStats();
 }
Esempio n. 5
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        /*
         * public functions
         */

        /// <summary>
        /// Given an invalid Node, returns the approximate nearest valid Node.
        /// </summary>
        /// <param name="end"></param>
        /// <returns></returns>
        public static Node nearestValidEnd(NodeMap map, Node start, Node end)
        {
            int    max  = Math.Max(map.height, map.width);
            PQueue ring = new PQueue();

            // iterate outward from the end Node in progressively larger rings, putting all valid Nodes into a PQueue.
            // Continue until we find a ring with a valid Node.
            for (int i = 1; i < max; i++)
            {
                ring = getRing(map, end, i);
                if (ring.Count != 0)
                {
                    break;
                }
            }

            // find the valid Node nearest the intended end
            Node newEnd = ring.peek(0);

            // if the PQueue has a lead tie (i.e. there are 2+ nodes of equal distance from the center node),
            // pick the one closest to the intended start Node.
            if (ring.hasLeadTie)
            {
                int distToStart = map.pathDistance(start, newEnd);
                int distToEnd   = map.pathDistance(end, newEnd);
                for (int i = 1; i < ring.Count; i++)
                {
                    if (map.pathDistance(ring.peek(i), end) > distToEnd)
                    {
                        break;
                    }
                    int currentDist = map.pathDistance(ring.peek(i), start);
                    if (currentDist < distToStart)
                    {
                        distToStart = currentDist;
                        newEnd      = ring.peek(i);
                    }
                }
            }

            // clean all enqueued Nodes so they can be properly used by the pathfinder
            for (int i = 0; i < ring.Count; i++)
            {
                ring.peek(i).clean();
            }

            return(newEnd);
        }
        /*
         * public functions
         */
        /// <summary>
        /// Given an invalid Node, returns the approximate nearest valid Node.
        /// </summary>
        /// <param name="end"></param>
        /// <returns></returns>
        public static Node nearestValidEnd(NodeMap map, Node start, Node end)
        {
            int max = Math.Max(map.height, map.width);
            PQueue ring = new PQueue();

            // iterate outward from the end Node in progressively larger rings, putting all valid Nodes into a PQueue.
            // Continue until we find a ring with a valid Node.
            for (int i = 1; i < max; i++)
            {
                ring = getRing(map, end, i);
                if (ring.Count != 0)
                    break;
            }

            // if this is a completely invalid NodeMap (yeah, right, I know), return null
            if (ring.Count == 0)
                return null;

            // find the valid Node nearest the intended end
            Node newEnd = ring.peek(0);

            // if the PQueue has a lead tie (i.e. there are 2+ nodes of equal distance from the center node),
            // pick the one closest to the intended start Node.
            if (ring.hasLeadTie)
            {
                int distToStart = map.pathDistance(start, newEnd);
                int distToEnd = map.pathDistance(end, newEnd);
                for (int i = 1; i < ring.Count; i++)
                {
                    if (map.pathDistance(ring.peek(i), end) > distToEnd)
                        break;
                    int currentDist = map.pathDistance(ring.peek(i), start);
                    if (currentDist < distToStart)
                    {
                        distToStart = currentDist;
                        newEnd = ring.peek(i);
                    }
                }
            }

            // clean the FScores of all enqueued Nodes so they can be properly used by the pathfinder
            for (int i = 0; i < ring.Count; i++)
                ring.peek(i).Fscore = 0;

            return newEnd;
        }
        /*
         * helper functions
         */
        /// <summary>
        /// Enqueues all valid Nodes in a ring around a center Node, offset from the center by [offset] Nodes.
        /// For example, an offset of 2 searches a 5x5 ring (x+-2, y+-2) around the center Node.
        /// Since modifying the Node's Fscores is necessary for enqueueing, each enqueued node's Fscore must be reset after use.
        /// </summary>
        /// <param name="map">The NodeMap to search over</param>
        /// <param name="center">The center Node to search around</param>
        /// <param name="offset">The ring "radius"</param>
        /// <returns>A PQueue containing all valid Nodes found in the ring</returns>
        private static PQueue getRing(NodeMap map, Node center, int offset)
        {
            PQueue ring = new PQueue();
            int x = center.Xcoord;
            int y = center.Ycoord;

            // grab left and right columns
            for (int i = y - offset; i <= y + offset; i++)
            {
                Node Xmin = map.getNode(x - offset, i);
                Node Xmax = map.getNode(x + offset, i);
                if (Xmin.isValid)
                {
                    Xmin.Fscore = map.pathDistance(Xmin, center);
                    ring.enqueue(Xmin);
                }
                if (Xmax.isValid)
                {
                    Xmax.Fscore = map.pathDistance(Xmax, center);
                    ring.enqueue(Xmax);
                }
            }

            // grab remainder of top and bottom rows
            for (int i = x - offset + 1; i < x + offset; i++)
            {
                Node Ymin = map.getNode(i, y - offset);
                Node Ymax = map.getNode(i, y + offset);
                if (Ymin.isValid)
                {
                    Ymin.Fscore = map.pathDistance(Ymin, center);
                    ring.enqueue(Ymin);
                }
                if (Ymax.isValid)
                {
                    Ymax.Fscore = map.pathDistance(Ymax, center);
                    ring.enqueue(Ymax);
                }
            }

            return ring;
        }
Esempio n. 8
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        /*
         * helper functions
         */

        /// <summary>
        /// Enqueues all valid Nodes in a ring around a center Node, offset from the center by [offset] Nodes.
        /// For example, an offset of 2 searches a 5x5 ring (x+-2, y+-2) around the center Node.
        /// Since modifying the Node's Fscores is necessary for enqueueing, each enqueued node's Fscore must be reset after use.
        /// </summary>
        /// <param name="map">The NodeMap to search over</param>
        /// <param name="center">The center Node to search around</param>
        /// <param name="offset">The ring "radius"</param>
        /// <returns>A PQueue containing all valid Nodes found in the ring</returns>
        private static PQueue getRing(NodeMap map, Node center, int offset)
        {
            PQueue ring = new PQueue();
            int    x    = center.X;
            int    y    = center.Y;

            // grab left and right columns
            for (int i = Math.Max(y - offset, 0); i <= y + offset; i++)
            {
                Node Xmin = map.getNode(x - offset, i);
                Node Xmax = map.getNode(x + offset, i);
                if (Xmin != null && Xmin.isValid)
                {
                    Xmin.Fscore = map.pathDistance(Xmin, center);
                    ring.enqueue(Xmin);
                }
                if (Xmax != null && Xmax.isValid)
                {
                    Xmax.Fscore = map.pathDistance(Xmax, center);
                    ring.enqueue(Xmax);
                }
            }

            // grab remainder of top and bottom rows
            for (int i = x - offset + 1; i < x + offset; i++)
            {
                Node Ymin = map.getNode(i, Math.Max(0, y - offset));
                Node Ymax = map.getNode(i, Math.Min(map.width - 1, y + offset));
                if (Ymin != null && Ymin.isValid)
                {
                    Ymin.Fscore = map.pathDistance(Ymin, center);
                    ring.enqueue(Ymin);
                }
                if (Ymax != null && Ymax.isValid)
                {
                    Ymax.Fscore = map.pathDistance(Ymax, center);
                    ring.enqueue(Ymax);
                }
            }

            return(ring);
        }
		/*
		 * helper functions
		 */

        /// <summary>
        /// Enqueues all valid Nodes in a ring around a center Node, offset from the center by [offset] Nodes.
        /// For example, an offset of 2 searches a 5x5 ring (x+-2, y+-2) around the center Node.
        /// Since modifying the Node's Fscores is necessary for enqueueing, each enqueued node's Fscore must be reset after use.
        /// </summary>
        /// <param name="map">The NodeMap to search over</param>
        /// <param name="center">The center Node to search around</param>
        /// <param name="offset">The ring "radius"</param>
        /// <returns>A PQueue containing all valid Nodes found in the ring</returns>
        private static PQueue getRing(NodeMap map, Node center, int offset)
        {
            PQueue ring = new PQueue();
            int x = center.Xcoord;
            int y = center.Ycoord;

            // grab left and right columns
            for (int i = y - offset; i <= y + offset; i++)
            {
                Node Xmin = map.getNode(x - offset, i);
                Node Xmax = map.getNode(x + offset, i);
                if (Xmin.isValid)
                {
                    Xmin.Fscore = map.pathDistance(Xmin, center);
                    ring.enqueue(Xmin);
                }
                if (Xmax.isValid)
                {
                    Xmax.Fscore = map.pathDistance(Xmax, center);
                    ring.enqueue(Xmax);
                }
            }

            // grab remainder of top and bottom rows
            for (int i = x - offset + 1; i < x + offset; i++)
            {
                Node Ymin = map.getNode(i, y - offset);
                Node Ymax = map.getNode(i, y + offset);
                if (Ymin.isValid)
                {
                    Ymin.Fscore = map.pathDistance(Ymin, center);
                    ring.enqueue(Ymin);
                }
                if (Ymax.isValid)
                {
                    Ymax.Fscore = map.pathDistance(Ymax, center);
                    ring.enqueue(Ymax);
                }
            }

            return ring;
        }
        /*
         * public functions
         */
        /// <summary>
        /// A*, modified to find a nearest path in case of failure
        /// </summary>
        /// <param name="map">The Map</param>
        /// <param name="startCell">The starting Cell</param>
        /// <param name="endCell">The ending Cell</param>
        /// <returns>The path as a list of waypoints</returns>
        public static List<Cell> findPath(Map map, Cell startCell, Cell endCell)
        {
            /*
             * Terminology
             *		Gscore			cumulative calculated distance from the start Cell to the given Cell
             *		Hscore			estimated distance from the given Cell to the end Cell.
             *							Overestimating this can result in the calculation of an incorrect (inefficient) path,
             *							but the more it is underestimated, the longer correct path calculation will take
             *		Fscore			Gscore + Hscore; estimated total distance from start to end on a path through the given Cell.
             *							Priority queues (PQueues) are ordered by ascending Fscore, so shortest estimated paths are examined first
             *		open list		A PQueue of Cells to be examined.  Initially contains the start Cell
             *		closed list		A List<Cell> of Cells that have been examined
             *		adjacent list	A PQueue of Cells adjacent to the current Cell
             */

            // initialize the lists
            PQueue open = new PQueue();
            open.enqueue(startCell);
            List<Cell> closed = new List<Cell>();
            PQueue adjacentCells = new PQueue();
            iterations = 0;

            // good ol' A*
            while (open.count() > 0)											    // iterate until we have examined every appropriate Cell
            {
                //open.print("Open", true);
                Cell currentCell = open.dequeue();								    // look at the Cell with the lowest Fscore and remove it from the open list
                if (currentCell == endCell)										    // if this is our destination Cell, we're done!
                    return reconstruct(endCell);									    // so return the path
                closed.Add(currentCell);										    // otherwise, close this Cell so we don't travel to it again
                adjacentCells = getAdjacentCells(map, open, closed, currentCell);	// now find every valid Cell adjacent to the current Cell
                //adjacentCells.print("Adjacent", false);
                while (adjacentCells.count() != 0)                                  // iterate over all of them, from lowest to highest Fscore
                {
                    Cell adjacentCell = adjacentCells.dequeue();									// grab the current adjacent Cell
                    int tempGScore = currentCell.Gscore + pathDistance(currentCell, adjacentCell);	// calculate a temporary Gscore as if we were traveling to this Cell from the current Cell
                    if (!open.contains(adjacentCell) || tempGScore < adjacentCell.Gscore)			// if this Cell has not been added to the open list, or if tempGscore is less than the Cell's current Gscore
                    {
                        int h = pathDistance(adjacentCell, endCell);									// estimate the Cell's Hscore
                        adjacentCell.prev = currentCell;												// set the Cell's prev pointer to the current Cell
                        adjacentCell.Hscore = h;														// set the Cell's Hscore
                        adjacentCell.Gscore = tempGScore;												// set the Cell's Gscore
                        adjacentCell.Fscore = tempGScore + h;											// set the Cell's Fscore
                    }
                    if (!open.contains(adjacentCell))												// if the adjacent Cell we just examined is not yet on the open list, add it
                        open.enqueue(adjacentCell);
                }
                iterations++;
            }

            // no valid path exists, so find the nearest path
            closed.RemoveAt(0);										// remove the start Cell from the closed List
            if (closed.Count > 0)									// if there are still Cells on the closed list
            {
                Cell nearestCell = closed[0];							// find the closed Cell with the lowest Hscore;
                for (int i = 1; i < closed.Count; i++)					// this should be the Cell closest to the desired destination,
                {														// so return a path ending with that Cell.
                    if (closed[i].Hscore < nearestCell.Hscore)
                        nearestCell = closed[i];
                }
                return reconstruct(nearestCell);
            }
            else
            {
                List<Cell> path = new List<Cell>();					// otherwise, our only path was the start Cell (i.e. we are completely trapped);
                path.Add(endCell);									// so return a path with just that Cell.
                return path;
            }
        }
        /*
         * helper functions
         */
        /// <summary>
        /// Puts all valid Cells adjacent to the given Cell in a PQueue and returns it
        /// </summary>
        /// <param name="map">The Map</param>
        /// <param name="closed">The closed list</param>
        /// <param name="currentCell">The current (center) Cell</param>
        /// <returns>A PQueue of all traversable adjacent Cells</returns>
        private static PQueue getAdjacentCells(Map map, PQueue open, List<Cell> closed, Cell currentCell)
        {
            int x = currentCell.Xcoord;
            int y = currentCell.Ycoord;
            List<Cell> immediate = new List<Cell>();
            List<Cell> diagonal = new List<Cell>();
            PQueue adjacentCells = new PQueue();

            // grab all adjacent Cells (or null values) and store them here
            Cell[,] temp = map.getCells(x - 1, y - 1, 3, 3);

            // iterate over all adjacent Cells; add the ones that are open and in bounds to the appropriate List<Cell>
            for (int j = 0; j < 3; j++)
            {
                for (int i = 0; i < 3; i++)
                {
                    if (temp[i, j] != null && !closed.Contains(temp[i, j]))
                    {
                        // if the Cell is horizontally or vertically adjacent,
                        // add the Cell to the list of immediately adjacent Cells
                        if (Math.Abs(2 - i - j) == 1)
                            immediate.Add(temp[i, j]);

                        // otherwise, if the Cell is valid, add it to the list of diagonally adjacent Cells
                        else if (temp[i, j].isValid)
                            diagonal.Add(temp[i, j]);
                    }
                }
            }

            // iterate over all immediately adjacent Cells.  If they are valid, enqueue them;
            // otherwise, remove the neighboring diagonally adjacent Cells from the diagonal List
            for (int i = 0; i < immediate.Count(); i++)
            {
                if (!immediate[i].isValid)
                {
                    Cell one, two = null;
                    if (immediate[i].Xcoord == x)   // the Cell is vertically adjacent
                    {
                        one = map.getCell(x + 1, immediate[i].Ycoord);
                        two = map.getCell(x - 1, immediate[i].Ycoord);
                    }
                    else                            // the Cell is horizontally adjacent
                    {
                        one = map.getCell(immediate[i].Xcoord, y - 1);
                        two = map.getCell(immediate[i].Xcoord, y + 1);
                    }
                    if (one != null)
                        diagonal.Remove(one);
                    if (two != null)
                        diagonal.Remove(two);
                }
                else {
                    adjacentCells.enqueue(immediate[i]);
                }
            }

            // enqueue all remaining diagonally adjacent Cells
            for (int i = 0; i < diagonal.Count(); i++)
                adjacentCells.enqueue(diagonal[i]);

            // return the finished PQueue
            return adjacentCells;
        }
        /*
         * public functions
         */

        /// <summary>
        /// A*, modified to find a nearest path in case of failure
        /// </summary>
        /// <param name="map">The Map</param>
        /// <param name="startNode">The starting Node</param>
        /// <param name="endNode">The ending Node</param>
        /// <returns>The path as a list of waypoints</returns>
        public static List <Node> findPath(NodeMap map, Node startNode, Node endNode)
        {
            // initialize data
            PQueue open = new PQueue();

            open.enqueue(startNode);
            List <Node> adjacentNodes = new List <Node>();

            // good ol' A*
            while (open.Count > 0)
            {
                // find the open Node with the lowest Fscore and remove it from the open PQueue
                Node current = open.dequeue();

                // if this is our destination Node, we're done; otherwise, close it so we don't travel to it again
                if (current == endNode)
                {
                    return(reconstruct(endNode));
                }
                current.close();

                // find every valid Node adjacent to the current Node
                adjacentNodes = map.getAdjacentNodes(current);

                // iterate over all of them
                for (int i = 0; i < adjacentNodes.Count; i++)
                {
                    // grab an adjacent Node and calculate a new GScore and HScore for it
                    Node adjacent   = adjacentNodes[i];
                    int  tempGScore = current.Gscore + map.pathDistance(current, adjacent);
                    int  tempHScore = map.pathDistance(adjacent, endNode);

                    // if we have not opened this Cell, give it new stats and open it
                    if (!adjacent.isOpen)
                    {
                        setAdjacentStats(adjacent, current, tempGScore, tempHScore);
                        open.enqueue(adjacent);
                    }

                    // otherwise, if we have opened it but the new path to it is shorter than the old one, give it new stats and reset its position in the open PQueue
                    else if (tempGScore < adjacent.Gscore)
                    {
                        setAdjacentStats(adjacent, current, tempGScore, tempHScore);
                        //open.resetPosition(adjacent);
                    }
                }
            }

            // no valid path exists, so find the nearest path
            List <Node> closed      = createClosed(map);
            Node        nearestNode = closed[0];

            // find the closed Node with the lowest Hscore (distance from the intended end); return a path to that Node
            if (closed.Count > 0)
            {
                for (int i = 1; i < closed.Count; i++)
                {
                    if (closed[i].Hscore < nearestNode.Hscore)
                    {
                        nearestNode = closed[i];
                    }
                }
            }
            return(reconstruct(nearestNode));
        }
Esempio n. 13
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        /*
         * public functions
         */

        /// <summary>
        /// A*, modified to find a nearest path in case of failure
        /// </summary>
        /// <param name="map">The Map</param>
        /// <param name="startCell">The starting Cell</param>
        /// <param name="endCell">The ending Cell</param>
        /// <returns>The path as a list of waypoints</returns>
        public static List <Cell> findPath(Map map, Cell startCell, Cell endCell)
        {
            /*
             * Terminology
             *		Gscore			cumulative calculated distance from the start Cell to the given Cell
             *		Hscore			estimated distance from the given Cell to the end Cell.
             *							Overestimating this can result in the calculation of an incorrect (inefficient) path,
             *							but the more it is underestimated, the longer correct path calculation will take
             *		Fscore			Gscore + Hscore; estimated total distance from start to end on a path through the given Cell.
             *							Priority queues (PQueues) are ordered by ascending Fscore, so shortest estimated paths are examined first
             *		open list		A PQueue of Cells to be examined.  Initially contains the start Cell
             *		closed list		A List<Cell> of Cells that have been examined
             *		adjacent list	A PQueue of Cells adjacent to the current Cell
             */

            // initialize the lists
            PQueue open = new PQueue();

            open.enqueue(startCell);
            List <Cell> closed        = new List <Cell>();
            PQueue      adjacentCells = new PQueue();

            iterations = 0;

            // good ol' A*
            while (open.count() > 0)                                                                                                        // iterate until we have examined every appropriate Cell
            {
                //open.print("Open", true);
                Cell currentCell = open.dequeue();                                                    // look at the Cell with the lowest Fscore and remove it from the open list
                if (currentCell == endCell)                                                           // if this is our destination Cell, we're done!
                {
                    return(reconstruct(endCell));                                                     // so return the path
                }
                closed.Add(currentCell);                                                              // otherwise, close this Cell so we don't travel to it again
                adjacentCells = getAdjacentCells(map, open, closed, currentCell);                     // now find every valid Cell adjacent to the current Cell
                //adjacentCells.print("Adjacent", false);
                while (adjacentCells.count() != 0)                                                    // iterate over all of them, from lowest to highest Fscore
                {
                    Cell adjacentCell = adjacentCells.dequeue();                                      // grab the current adjacent Cell
                    int  tempGScore   = currentCell.Gscore + pathDistance(currentCell, adjacentCell); // calculate a temporary Gscore as if we were traveling to this Cell from the current Cell
                    if (!open.contains(adjacentCell) || tempGScore < adjacentCell.Gscore)             // if this Cell has not been added to the open list, or if tempGscore is less than the Cell's current Gscore
                    {
                        int h = pathDistance(adjacentCell, endCell);                                  // estimate the Cell's Hscore
                        adjacentCell.prev   = currentCell;                                            // set the Cell's prev pointer to the current Cell
                        adjacentCell.Hscore = h;                                                      // set the Cell's Hscore
                        adjacentCell.Gscore = tempGScore;                                             // set the Cell's Gscore
                        adjacentCell.Fscore = tempGScore + h;                                         // set the Cell's Fscore
                    }
                    if (!open.contains(adjacentCell))                                                 // if the adjacent Cell we just examined is not yet on the open list, add it
                    {
                        open.enqueue(adjacentCell);
                    }
                }
                iterations++;
            }

            // no valid path exists, so find the nearest path
            closed.RemoveAt(0);                                                                         // remove the start Cell from the closed List
            if (closed.Count > 0)                                                                       // if there are still Cells on the closed list
            {
                Cell nearestCell = closed[0];                                                           // find the closed Cell with the lowest Hscore;
                for (int i = 1; i < closed.Count; i++)                                                  // this should be the Cell closest to the desired destination,
                {                                                                                       // so return a path ending with that Cell.
                    if (closed[i].Hscore < nearestCell.Hscore)
                    {
                        nearestCell = closed[i];
                    }
                }
                return(reconstruct(nearestCell));
            }
            else
            {
                List <Cell> path = new List <Cell>();                                                   // otherwise, our only path was the start Cell (i.e. we are completely trapped);
                path.Add(endCell);                                                                      // so return a path with just that Cell.
                return(path);
            }
        }
Esempio n. 14
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        /*
         * helper functions
         */

        /// <summary>
        /// Puts all valid Cells adjacent to the given Cell in a PQueue and returns it
        /// </summary>
        /// <param name="map">The Map</param>
        /// <param name="closed">The closed list</param>
        /// <param name="currentCell">The current (center) Cell</param>
        /// <returns>A PQueue of all traversable adjacent Cells</returns>
        private static PQueue getAdjacentCells(Map map, PQueue open, List <Cell> closed, Cell currentCell)
        {
            int         x             = currentCell.Xcoord;
            int         y             = currentCell.Ycoord;
            List <Cell> immediate     = new List <Cell>();
            List <Cell> diagonal      = new List <Cell>();
            PQueue      adjacentCells = new PQueue();

            // grab all adjacent Cells (or null values) and store them here
            Cell[,] temp = map.getCells(x - 1, y - 1, 3, 3);

            // iterate over all adjacent Cells; add the ones that are open and in bounds to the appropriate List<Cell>
            for (int j = 0; j < 3; j++)
            {
                for (int i = 0; i < 3; i++)
                {
                    if (temp[i, j] != null && !closed.Contains(temp[i, j]))
                    {
                        // if the Cell is horizontally or vertically adjacent,
                        // add the Cell to the list of immediately adjacent Cells
                        if (Math.Abs(2 - i - j) == 1)
                        {
                            immediate.Add(temp[i, j]);
                        }

                        // otherwise, if the Cell is valid, add it to the list of diagonally adjacent Cells
                        else if (temp[i, j].isValid)
                        {
                            diagonal.Add(temp[i, j]);
                        }
                    }
                }
            }

            // iterate over all immediately adjacent Cells.  If they are valid, enqueue them;
            // otherwise, remove the neighboring diagonally adjacent Cells from the diagonal List
            for (int i = 0; i < immediate.Count(); i++)
            {
                if (!immediate[i].isValid)
                {
                    Cell one, two = null;
                    if (immediate[i].Xcoord == x)   // the Cell is vertically adjacent
                    {
                        one = map.getCell(x + 1, immediate[i].Ycoord);
                        two = map.getCell(x - 1, immediate[i].Ycoord);
                    }
                    else                            // the Cell is horizontally adjacent
                    {
                        one = map.getCell(immediate[i].Xcoord, y - 1);
                        two = map.getCell(immediate[i].Xcoord, y + 1);
                    }
                    if (one != null)
                    {
                        diagonal.Remove(one);
                    }
                    if (two != null)
                    {
                        diagonal.Remove(two);
                    }
                }
                else
                {
                    adjacentCells.enqueue(immediate[i]);
                }
            }

            // enqueue all remaining diagonally adjacent Cells
            for (int i = 0; i < diagonal.Count(); i++)
            {
                adjacentCells.enqueue(diagonal[i]);
            }

            // return the finished PQueue
            return(adjacentCells);
        }
 /// <summary>
 /// Copy constructor
 /// </summary>
 public PQueue(PQueue p)
 {
     for (int i = 0; i < p.pq.Count(); i++)
         pq.Add(p.pq[i]);
 }