/* * doSearch method will run the A* search till a goal is found, or a node is in another agent closed list, or the * nodes expanded is equal to the nodesToExpand variable * Parameter: (int)nodesToExpand is the number of nodes that the search can expand * (AIAgentAStarSearchList) secondSearchClosedList is the closed list from the other agent * Return: (int) * 0 if nothing was found * 1 if the goal for this search agent was found * 2 if a node on the second agent's closed list was found */ public int doSearch(int nodesToExpand, AIAgentAStarSearchList secondSearchClosedList) { int nodesExpandedCount = 0; while (openList.isEmpty() == false && nodesExpandedCount < nodesToExpand) //goes until nothing is left on the open list meaning a path could not be found { currentNode = openList.popNode(); //take the first(Best) polygon off the openList queueSize--; nodesVisited++; if (currentNode == null) { return(0); } closedList.enqueue(currentNode); //add currentNode to the closedList if (isBackwards == true) { if (currentNode.getPolygon().getHasAgent() == true) { finalSolutionStart = currentNode; return(1); } } else { if (currentNode.getPolygon().getHasGoal() == true) //checks to see if the currentNode has the goal inside its polygon { finalSolutionStart = currentNode; return(1); } } if (secondSearchClosedList.isNodeOnList(currentNode.getPolygon()) == true) { finalSolutionStart = currentNode; return(2); } for (int count = 0; count < currentNode.getPolygon().getNeighborsHeld(); count++) //adds all the neighbors that are not on the closed list to the open list { if (closedList.isNodeOnList(polygonArray[currentNode.getPolygon().getNeighborAt(count)]) == false) { gCost = (currentNode.getPolygon().getCenterVector() - polygonArray[currentNode.getPolygon().getNeighborAt(count)].getCenterVector()).magnitude + currentNode.getGFromStartingNode(); if (openList.isNodeOnList(polygonArray[currentNode.getPolygon().getNeighborAt(count)]) == false) { openList.addNode(polygonArray[currentNode.getPolygon().getNeighborAt(count)], currentNode, gCost); queueSize++; } else if (openList.getNodeOnList(polygonArray[currentNode.getPolygon().getNeighborAt(count)]).compareToG(gCost) > 0f) //updates the a Nodes information if the new GCost (cost from start to node) is less then what was previously in it { openList.updateNode(openList.getNodeOnList(polygonArray[currentNode.getPolygon().getNeighborAt(count)]), currentNode, gCost); queueSize++; } } } if (openList.getSize() > maxQueueSize) { maxQueueSize = openList.getSize(); } nodesExpandedCount++; } return(0); }
/* updateNode updates the parent of a node and the gFromStartingNodeCost of a node * Parameter: (AIAgentAStarSearchNode) nodeToUpdate is the node to be updated * (AIAgentAStarSearchNode) newParentNode is the new parent of the node to be updated * (float) newCost is the new gFromStartingNodeCost of the node to be updated * Return: none */ public void updateNode(AIAgentAStarSearchNode nodeToUpdate, AIAgentAStarSearchNode newParentNode, float newCost) { AIPolygon temp = nodeToUpdate.getPolygon(); deleteNodeOfId(nodeToUpdate.getPolygon().getID()); addNode(temp, newParentNode, newCost); }
/* deleteNodeOfId deletes the node from the list that is holding a polygon with a certain id * Parameter: (int) idToDelete is the id of the polygon being held by the node to be deleted * Return: none */ public void deleteNodeOfId(int idToDelete) { AIAgentAStarSearchNode tempFront = frontOfList; if (frontOfList != null) { if (doesIDMatch(frontOfList.getPolygon().getID(), idToDelete) == true) { frontOfList = frontOfList.getNextNode(); numberOfNodesHeld--; return; } AIAgentAStarSearchNode tempback = tempFront.getNextNode(); while ((tempback.getNextNode() != null) && (doesIDMatch(tempback.getPolygon().getID(), idToDelete) == false)) { tempFront = tempback; tempback = tempFront.getNextNode(); } if (doesIDMatch(tempback.getPolygon().getID(), idToDelete) == true) { tempFront.setNextNode(tempback.getNextNode()); } } numberOfNodesHeld--; }
/* enqueue adds a node to the front of this list * Parameter: (AIAgentAStarSearchNode) nodeToAdd is the node to be added to the front of the list * Return: none */ public void enqueue(AIAgentAStarSearchNode nodeToAdd) { AIAgentAStarSearchNode newNode = new AIAgentAStarSearchNode(nodeToAdd.getPolygon(), nodeToAdd.getParentNode(), nodeToAdd.getGFromStartingNode(), goalPosition); newNode.setNextNode(frontOfList); frontOfList = newNode; }
/* getNodeOnList returns node from list that contains a specified polygon * Parameter: (AIPolygon) polygonToCheck is the polygon being held by the node to be returned * Return: (AIAgentAStarSearchNode) * node on list that is holding polygonToCheck */ public AIAgentAStarSearchNode getNodeOnList(AIPolygon polygonToCheck) { AIAgentAStarSearchNode tempFront = frontOfList; if (tempFront == null) { return(null); } if (doesIDMatch(polygonToCheck.getID(), tempFront.getPolygon().getID()) == true) { return(tempFront); } AIAgentAStarSearchNode tempBack = tempFront.getNextNode(); while ((tempBack != null) && (tempBack.getNextNode() != null) && (doesIDMatch(polygonToCheck.getID(), tempBack.getPolygon().getID()) == false)) { tempFront = tempBack; tempBack = tempFront.getNextNode(); } if (tempBack == null) { return(null); } if (doesIDMatch(polygonToCheck.getID(), tempBack.getPolygon().getID()) == true) { return(tempBack); } return(null); }
/* * addFinalsolutionPolygonsPostOrder method is a recusive method that will look at the parent of each node passed in until * the node passed in is null, then it will add each Node's polygon to the finalSolutionArray in pre order * from start until end * Parameter: (AIAgentAStarSearchNode)currentNode is the node that needs to be checked and then have its parent passed * (ref int)counter is the current count of polygons in the FinalSolution array used to access the next index * Return: none */ void addFinalSolutionPolygonsPreOrder(AIAgentAStarSearchNode currentNode, ref int counter) { if (currentNode != null) { finalSolutionArray [counter] = currentNode.getPolygon(); counter++; addFinalSolutionPolygonsPreOrder(currentNode.getParentNode(), ref counter); } }
//used for debugging void printSolutionRecusively(AIAgentAStarSearchNode currentNode) { if (currentNode != null) { printSolutionRecusively(currentNode.getParentNode()); Debug.Log(Time.realtimeSinceStartup + " id = " + currentNode.getPolygon().getID()); polygonFinalCount++; } }
/* * addFinalsolutionPolygons method is a recusive method that will look at the parent of each node passed in until * the node passed in is null, then it will add each Node's polygon to the finalSolutionArray in order * from start until end * Parameter: (AIAgentAStarSearchNode)currentNode is the node that needs to be checked and then have its parent passed * (ref int)counter is the current count of polygons in the FinalSolution array used to access the next index * Return: none */ void addFinalSolutionPolygons(AIAgentAStarSearchNode currentNode, ref int counter) { if (currentNode != null) { addFinalSolutionPolygons(currentNode.getParentNode(), ref counter); finalSolutionArray [counter] = currentNode.getPolygon(); if (counter != 0) { finalPathCost += (finalSolutionArray[counter].getCenterVector() - finalSolutionArray[counter - 1].getCenterVector()).magnitude; } counter++; } }
/* popNode removes and returns the node at the front of the list (node with lowest fToatlCost value) * Parameter: none * Return: (AIAgentAStarSearchNode) * node that was removed from the front of this list */ public AIAgentAStarSearchNode popNode() { if (numberOfNodesHeld == 0) { return(null); } AIAgentAStarSearchNode tempNode = heap [0]; indicesArray [tempNode.getPolygon().getID()] = -1; numberOfNodesHeld--; heap [0] = heap [numberOfNodesHeld]; indicesArray [heap [0].getPolygon().getID()] = 0; if (numberOfNodesHeld > 0) { shiftDown(0); } return(tempNode); }
/* * getFinalPathStart method will return the starting polygon of the final solution * Parameter: none * Return: (AIPolygon) * the starting polygon of the final solution */ public AIPolygon getFinalPathStart() { return(finalSolutionStart.getPolygon()); }