Update and render itself, as well as maintain pathfinding information. We’ll also need to develop a simple class to represent our unit, which will allow it to This method is much faster, particularly on maps that have more Instead, we’ll use aĭifferent method, which uses a series of depth-first searches to calculate the connected sets of We’ll also revisit the function that calculates which portions of the map are connected,Īs the original method in Part 1 was horribly inefficient on some maps. Modify our QuadTree, so that the leaf nodes are tagged with the MapTile that their bounding boxes Was hit, rather than just the bounding box center. We’ll need to slightly rework our mouse picking code to return the tile in our map that Now we’re going to put all of the pieces togetherĪnd get a working example to showcase this pathfinding work. Last time, we discussed the implementation of our A* pathfinding algorithm, as well as someĬommonly used heuristics for A*. If (unitDefinitions.size = 'lg') else if ((distanceFromEnd >= 100) & (unit.Watch the intrepid red blob wind its way through the mountain slopes! Var findPathMatrixNodeSize = matrixNodeSize All of this happens very quickly between animation frames.Īt one point in the development of Strike Tactics, I utilized this same technique for pathfinding. If yes, it will wait, check again, and generate a new path if it is still occupied. It asks “i s the square in front of me occupied?” If no, it will continue along the path. A helper function detects when a path is no longer “accurate”. If you clicked your marine to go across the map, and a building gets placed in the middle of the map while the marine was en route, the original path calculated can no longer be considered accurate (because it was generated before the building was placed). And the older those results are, the less efficient they will be. Because the grid (remember the starcraft map is just 1 big grid) which marks the walkable and unwalkable areas is constantly changing, so also are the results of the pathfinding algorithm. The path is literally re-calculated each time you click, so technically a unit is finding the most efficient path at the point of time closest to the click. This behavior has given rise to spam-clicking. If the path is still unoccupied after a certain time increment, a new path is generated from the algorithm and the unit walks around the square that was unwalkable.Īnother circumstance in which the path is re-calculated is when a new move command is issued while the unit is en route. If the answer is “yes,” the unit waits a fraction of a second, and checks again. Each time it travels to a new square, it asks “ is the next square along the path occupied?” If the answer is “no,” the unit keeps moving along the path. The unit then moves along the path, but it only goes 1 square at a time, one set of coordinates at a time. When a unit is issued a move command, the parameters of that command (the current location and destination in the grid) are run through the pathfinding algorithm which spits out an array of path coordinates. Most units, the smaller units (like marines and zerglings) occupy a single square while the larger units (such as dragoons and ultralisks) occupy multiple squares. Imagine a Starcraft map as one big grid which is divided into hundreds of little squares.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |