koobas.hobune.stream
Specific 2D movement using Dijkstras Algorithm...
Hi,
I'm playing around with a top down 2D game and i've reached a point where I need to implement some kind of pathfinding. I followed a great tutorial for Dijkstra's Algorithm and i've got my character moving, but not exactly the way I'd like.
Here's my characters movement code: PirateAI.
The way it works is while most of the nodes on my ship are empty game objects, some of them are clickable, visible objects. Clicking on one of the visible nodes assigns its gameObject to the target variable in the above script and the selected character moves towards it. This is working. However three things are happening that i'd like to change/stop.
First of all the character is able to move diagonally. Is there a way to discourage diagonal movement so the character only moves vertically and horizontally?
Second, the character stops a short distance from the target node instead of directly on top of it. Is there a way to make sure my character stops at the nodes exact position?
Finally when the character stops moving I'm getting the following error over and over: "InvalidOperationException: Operation is not valid due to the current state of the object" Its saying its happening on line 7 of the above linked code.
Anyone have any ideas?
The other scripts used are here: DijkstrasAlgorthim, CurrentNode, Node
Just looking at the code fragment you reference, I can suggest a couple of things to look into. Could InvalidOperationException and the stopping short of the goal be due to you calling Pop() on an empty stack?
As for diagonal movement, you may be able to fix the problem by only allowing 'y' movement if 'x' movement is done:
if ($$anonymous$$athf.Approximatel(transform.position.x, goalPosition.x) {
// all the 'y' translation code goes here
}
Not looking, but Dykstra's (and any graph distance algorithm) uses a weight function. Somewhere in the code it's probably checking how far new squares are. Toss in something like "if x and y are both different, distance=99999" and it won't try to go diagonal.
Pirate is red, target is green. How do you want the pirate to walk? And what is your tilesize?
For blue, check if x-Distance or y-Distance is shorter and walk that first and then the other axis. If you use a Coroutine, you don't need to keep track of what you decided between frames.
For yellow alternate the axes if there is still some distance left on the axis.
For red, walk the longer axis till both axis are the same, then same as yellow
Let me know if you need more help
Yellow and red are flipped (red is alternate axis)
But this won't search for a path (which is what Djikstra's does, or A*.) It there was a long wall between green and red, this wouldn't know to walk around it, and which way was shorter.
He already has waypoints from Djikstra's. He just doesn't want his pirate to walk diagonally, which can be solved like above. If he additionally runs into obstacles depends on how far these waypoints are from each other and how his map looks.
