Пример #1
0
        private void ComputeRawPath()
        {
            int nodesSearchedThisUpdate = 0;

            // Keep searching until we either find the end
            // or we're not allowed to search anymore
            while (!m_nodeHeap.Empty() &&
                   m_totalNodesSearched < MAX_TOTAL_NODES_SEARCHED_ALLOWED &&
                   (m_maxNodesSearchedPerUpdate == 0 || (m_maxNodesSearchedPerUpdate > 0 && nodesSearchedThisUpdate < m_maxNodesSearchedPerUpdate)))
            {
                PathNode currentNode = m_nodeHeap.Top();

                // Keep track of how many nodes total we have visited so far
                m_totalNodesSearched++;

                // Keep track of how many nodes were searched this update
                nodesSearchedThisUpdate++;

                // Make sure we haven't hit the destination
                if (currentNode.NavCellIndex != m_endNavRef.NavCellIndex)
                {
                    // Remove the current node from the heap now that we're investigating it
                    m_nodeHeap.Pop();

                    // Add the current nav-cell to the closed set
                    // (since we just visited it and don't want to visit it again)
                    currentNode.MarkAsInClosedSet();

                    // See which neighbor, if any, looks best at this moment to search from
                    for (NavCellNeighborIterator iterator = new NavCellNeighborIterator(m_navMesh, currentNode.NavCellIndex);
                         iterator.Valid(); iterator.Next())
                    {
                        // See if we already have a search node for the neighbor nav-cell
                        uint     neighborNavCellIndex = iterator.NeighborNavCellIndex;
                        PathNode neighborNode         = null;
                        bool     hasNeighbor          = m_navCellToNodeMap.TryGetValue(neighborNavCellIndex, out neighborNode);

                        // Skip this neighbor if we already put it in the closed set
                        if (!hasNeighbor || !neighborNode.InClosedSet)
                        {
                            // Compute G(x): The path cost from the start to this neighbor
                            float netTraversalCostToNeighbor = currentNode.Cost +
                                                               ComputeTraversalCost(currentNode.NavCellIndex, neighborNavCellIndex);

                            // Add this neighbor into consideration if:
                            // A) We haven't seen it before (i.e. not in the open set)
                            // B) We have seen it before, but the net traversal cost to the neighbor
                            //    from the start through the current node is cheaper than some previous
                            //    traversal to the neighbor.
                            if (neighborNode == null || netTraversalCostToNeighbor < neighborNode.Cost)
                            {
                                // Compute F(x)= G(x) + H(x): The past cost to the neighbor plus the estimated distance to the end
                                Point3d neighborCenter = m_navMesh.ComputeNavCellCenter(neighborNavCellIndex);
                                float   netTraversalPlusHeuristicCost =
                                    netTraversalCostToNeighbor +
                                    ComputeHeuristicCostEstimate(neighborCenter, m_endPosition);

                                // Make sure to add the neighbor to the open set if not already added
                                if (neighborNode == null)
                                {
                                    neighborNode =
                                        new PathNode(
                                            (int)m_nextPathNodeID,
                                            currentNode,
                                            neighborNavCellIndex,
                                            netTraversalCostToNeighbor,
                                            netTraversalPlusHeuristicCost);
                                    m_nextPathNodeID++;

                                    m_navCellToNodeMap[neighborNavCellIndex] = neighborNode;
                                }
                                else
                                {
                                    neighborNode.ParentNode = currentNode;
                                    neighborNode.Cost       = netTraversalCostToNeighbor;
                                    neighborNode.Total      = netTraversalPlusHeuristicCost;
                                }

                                // Add the neighbor into the heap for future consideration
                                m_nodeHeap.Push(neighborNode);
                            }
                        }
                    }
                }
                else
                {
                    // Stop searching and compute the raw path from the search nodes
                    m_state = eState.finalize_raw_path;
                    break;
                }
            }

            // Sanity check to make sure we never get in an infinite loop
            if (m_nodeHeap.Empty())
            {
                m_resultCode = eResult.failed_raw_path_search;
                m_state      = eState.complete;
            }
            else if (m_totalNodesSearched >= MAX_TOTAL_NODES_SEARCHED_ALLOWED)
            {
                //Debug.log("PathComputer: Ran out of search node!", Debug.RED);
                m_resultCode = eResult.failed_raw_path_search;
                m_state      = eState.complete;
            }
        }
Пример #2
0
        private void ComputeRawPath()
        {
            int nodesSearchedThisUpdate = 0;

            // Keep searching until we either find the end
            // or we're not allowed to search anymore
            while (!m_nodeHeap.Empty() &&
                    m_totalNodesSearched < MAX_TOTAL_NODES_SEARCHED_ALLOWED &&
                    (m_maxNodesSearchedPerUpdate == 0 || (m_maxNodesSearchedPerUpdate > 0 && nodesSearchedThisUpdate < m_maxNodesSearchedPerUpdate)))
            {
                PathNode currentNode = m_nodeHeap.Top();

                // Keep track of how many nodes total we have visited so far
                m_totalNodesSearched++;

                // Keep track of how many nodes were searched this update
                nodesSearchedThisUpdate++;

                // Make sure we haven't hit the destination
                if (currentNode.NavCellIndex != m_endNavRef.NavCellIndex)
                {
                    // Remove the current node from the heap now that we're investigating it
                    m_nodeHeap.Pop();

                    // Add the current nav-cell to the closed set
                    // (since we just visited it and don't want to visit it again)
                    currentNode.MarkAsInClosedSet();

                    // See which neighbor, if any, looks best at this moment to search from
                    for (NavCellNeighborIterator iterator = new NavCellNeighborIterator(m_navMesh, currentNode.NavCellIndex);
                        iterator.Valid(); iterator.Next())
                    {
                        // See if we already have a search node for the neighbor nav-cell
                        uint neighborNavCellIndex = iterator.NeighborNavCellIndex;
                        PathNode neighborNode = null;
                        bool hasNeighbor = m_navCellToNodeMap.TryGetValue(neighborNavCellIndex, out neighborNode);

                        // Skip this neighbor if we already put it in the closed set
                        if (!hasNeighbor || !neighborNode.InClosedSet)
                        {
                            // Compute G(x): The path cost from the start to this neighbor
                            float netTraversalCostToNeighbor = currentNode.Cost +
                                ComputeTraversalCost(currentNode.NavCellIndex, neighborNavCellIndex);

                            // Add this neighbor into consideration if:
                            // A) We haven't seen it before (i.e. not in the open set)
                            // B) We have seen it before, but the net traversal cost to the neighbor
                            //    from the start through the current node is cheaper than some previous
                            //    traversal to the neighbor.
                            if (neighborNode == null || netTraversalCostToNeighbor < neighborNode.Cost)
                            {
                                // Compute F(x)= G(x) + H(x): The past cost to the neighbor plus the estimated distance to the end
                                Point3d neighborCenter = m_navMesh.ComputeNavCellCenter(neighborNavCellIndex);
                                float netTraversalPlusHeuristicCost =
                                    netTraversalCostToNeighbor +
                                    ComputeHeuristicCostEstimate(neighborCenter, m_endPosition);

                                // Make sure to add the neighbor to the open set if not already added
                                if (neighborNode == null)
                                {
                                    neighborNode =
                                        new PathNode(
                                            (int)m_nextPathNodeID,
                                            currentNode,
                                            neighborNavCellIndex,
                                            netTraversalCostToNeighbor,
                                            netTraversalPlusHeuristicCost);
                                    m_nextPathNodeID++;

                                    m_navCellToNodeMap[neighborNavCellIndex] = neighborNode;
                                }
                                else
                                {
                                    neighborNode.ParentNode = currentNode;
                                    neighborNode.Cost = netTraversalCostToNeighbor;
                                    neighborNode.Total = netTraversalPlusHeuristicCost;
                                }

                                // Add the neighbor into the heap for future consideration
                                m_nodeHeap.Push(neighborNode);
                            }
                        }
                    }
                }
                else
                {
                    // Stop searching and compute the raw path from the search nodes
                    m_state = eState.finalize_raw_path;
                    break;
                }
            }

            // Sanity check to make sure we never get in an infinite loop
            if (m_nodeHeap.Empty())
            {
                m_resultCode = eResult.failed_raw_path_search;
                m_state = eState.complete;
            }
            else if (m_totalNodesSearched >= MAX_TOTAL_NODES_SEARCHED_ALLOWED)
            {
                //Debug.log("PathComputer: Ran out of search node!", Debug.RED);
                m_resultCode = eResult.failed_raw_path_search;
                m_state = eState.complete;
            }
        }