Exemplo n.º 1
0
        public static bool TryGetPath(PathfindingGrid grid, int startX, int startY, int finishX, int finishY,
                                      int unitSize, long unitCapabilities, Allocator allocator, NativeList <int> resultPath)
        {
            //Requests Min
            var priorityQueue      = new PriorityQueue <CellSearchRecord>(HeapType.Min, allocator);
            var openSetSupportData = new NativeHashMap <int, OpenSetRecord>(20, allocator);

            var startCellIndex = PathfindingGrid.CalculateIndex(startX, startY, grid.Width);
            var endCellIndex   = PathfindingGrid.CalculateIndex(finishX, finishY, grid.Width);

            var endCell = new CellSearchRecord();

            endCell.Priority = AStarSearchHeuristic.DiagonalDistance(finishX, finishY, startX, startY);
            endCell.CellId   = endCellIndex;
            priorityQueue.Add(endCell);

            //Set distance passed
            openSetSupportData[endCellIndex] = new OpenSetRecord
            {
                DistancePassed = 0,
                ParentCell     = -1,
            };

            while (priorityQueue.Count > 0)
            {
                var currentCell      = priorityQueue.Remove();
                var currentCellIndex = currentCell.CellId;

                //Mark cell as expanded
                var currentCellData = openSetSupportData[currentCellIndex];
                currentCellData.Expanded             = Expanded.True;
                openSetSupportData[currentCellIndex] = currentCellData;

                //Reconstruct path
                var pathFound = currentCellIndex == startCellIndex;
                if (!pathFound)
                {
                    var endX = startX;
                    var endY = startY;
                    PathfindingGrid.CalculateCoordinates(currentCellIndex, grid.Width, out var x, out var y);
                    for (var i = 0; i < OFFSETS.Length; ++i)
                    {
                        var moveCost = Math.Abs(OFFSETS[i].x) == Math.Abs(OFFSETS[i].y) ?
                                       AStarConsts.DIAGONAL_MOVEMENT : AStarConsts.STRAIGHT_MOVEMENT;

                        ProcessNeighbour(x + OFFSETS[i].x, y + OFFSETS[i].y, unitSize, unitCapabilities,
                                         currentCellData.DistancePassed + moveCost,
                                         currentCellIndex,
                                         endX, endY, grid, openSetSupportData, priorityQueue);
                    }
                }
                else
                {
                    ReconstructPath(openSetSupportData, startCellIndex, endCellIndex, resultPath);

                    priorityQueue.Dispose();
                    openSetSupportData.Dispose();
                    return(true);
                }
            }


            priorityQueue.Dispose();
            openSetSupportData.Dispose();
            return(false);
        }
Exemplo n.º 2
0
        private static void ProcessNeighbour(
            int x, int y, int unitSize, long unitCapabilities,
            float distancePassed, int parenCellId,
            int finishX, int finishY,
            PathfindingGrid grid,
            NativeHashMap <int, OpenSetRecord> openSetSupportData,
            PriorityQueue <CellSearchRecord> priorityQueue)
        {
            //Ignore invalid cells
            if (x < 0 || y < 0)
            {
                return;
            }

            if (x >= grid.Width || y >= grid.Height)
            {
                return;
            }

            var neighbourCellIndex = PathfindingGrid.CalculateIndex(x, y, grid.Width);
            var isInOpenList       = openSetSupportData.TryGetValue(neighbourCellIndex, out var neighbourCell);

            if (!isInOpenList)
            {
                neighbourCell = openSetSupportData[neighbourCellIndex] = new OpenSetRecord();
                openSetSupportData[neighbourCellIndex] = neighbourCell;
            }
            else if (neighbourCell.Expanded == Expanded.True)
            {
                //Item is in Closed list, return
                return;
            }
            else if (distancePassed >= neighbourCell.DistancePassed)
            {
                //if it's already in priority queue and the distance has not improved, we are returning
                return;
            }

            //Item is not traversable, return
            if (!grid.IsPassable(x, y, unitCapabilities, unitSize))
            {
                return;
            }

            var cellRecord = new CellSearchRecord {
                Priority = 0, CellId = neighbourCellIndex
            };

            //We found a better route to this cell, so we need to remove it from Priority queue as later we are going to add it with better metrics
            if (isInOpenList && distancePassed < neighbourCell.DistancePassed)
            {
                priorityQueue.Remove(cellRecord);
            }

            float distanceToTarget = AStarSearchHeuristic.DiagonalDistance(x, y, finishX, finishY);

            neighbourCell.ParentCell               = parenCellId;
            neighbourCell.DistancePassed           = distancePassed;
            openSetSupportData[neighbourCellIndex] = neighbourCell;

            cellRecord.Priority = distanceToTarget + distancePassed;
            priorityQueue.Add(cellRecord);
        }