Hello Pathfinders,
So I am looking remove / disable / set unwalkable some nodes on my grid graph.
I am using this code, but not getting any results:
// Loop through tile objects and trim path
for (int level = 0; level < tileObjects.GetLength(0); level++)
{
for (int row = 0; row < tileObjects.GetLength(1); row++)
{
for (int column = 0; column < tileObjects.GetLength(2); column++)
{
TileProp tile = tileObjects[level, row, column].GetComponent<TileProp>();
// If tile should be avoided
if (tile.AvoidPathfinding())
{
GridNode node = activePath.GetNearest(tile.transform.position).node as GridNode;
node.Walkable = false;
}
}
}
}
Is there something I am missing?
Hi
Iām not sure why that wouldnāt work. It should work.
It does miss a few steps however. I recommend that you take a look at the āUsing direct access to graph dataā section on this page: https://arongranberg.com/astar/documentation/dev_4_1_6_17dee0ac/graph-updates.php#direct
It has some example code which is very similar to what you want to do.
1 Like
Using this code from your documentation doesnāt actually compile?
AstarPath.active.AddWorkItem(new AstarWorkItem(ctx => {
var node = AstarPath.active.GetNearest(transform.position).node;
node.Walkable = false;
ctx.QueueFloodFill();
}));
As is I get this errror:
Error CS0246 The type or namespace name 'AstarWorkItem' could not be found (are you missing a using directive or an assembly reference?) remote
If I correct the struct reference to : AstarPath.AstarWorkItem I get this error:
Error CS1643 Not all code paths return a value in lambda expression of type 'Func<bool, bool>' remote C:\Users\tomdo\Documents\Work\Unity\Remote\remote\Assets\Scripts\Generation\Map.cs 171 Active
if I add a āreturn trueā I get this error:
Error CS1061 'bool' does not contain a definition for 'QueueWorkItemFloodFill' and no extension method 'QueueWorkItemFloodFill' accepting a first argument of type 'bool' could be found (are you missing a using directive or an assembly reference?) remote
Is this the correct way the AddWorkItem? Commenting out the ctx.QueueFloodFill() results in the function not working, as before.
Hi
Which version are you using?
That code should work in all versions above 3.7.4 I think.
I am on version 3.8.10.
It looks like it ctx needs to be a IWorkItemContext type, but I have no idea how to set it to that type?
I would have thought it would infer that from it not returning anything, but you can try
AstarPath.active.AddWorkItem(new AstarWorkItem((IWorkItemContext ctx) => {
var node = AstarPath.active.GetNearest(transform.position).node;
node.Walkable = false;
ctx.QueueFloodFill();
}));
That doesnāt compile as well. Also, I canāt find any reference to IWorkItemContext or WorkItemContext in the your plugin at all.
I donāt merge the examples scenes when I import, would that be the problem?
Aah. I see. Version 3.7.4 that I mentioned earlier was a beta version, not a public release.
The IWorkItemContext doesnāt exist in a non-beta version until 4.x.
I think this code will work in your version:
AstarPath.active.AddWorkItem(new AstarPath.AstarWorkItem(force => {
var node = AstarPath.active.GetNearest(transform.position).node;
node.Walkable = false;
AstarPath.active.QueueWorkItemFloodFill();
return true;
}));
That still doesnāt appear to work.
Iām printing out a debug log for each node I am disabling and the node is coming back as disabled, but the graph debug mesh isnāt showing the node as disabled.
Perhaps its just the debug gizmos that arenāt being updated and the data is correct? Either that, or the graph update / flood fill isnāt being properly called.
Thatās odd. The debug gizmos should always be up to date. Are you doing any other graph updates at the same time?
I was doing a scan afterwards, yeah, as I originally thought I needed to do with to update the graphs.
Commenting that out seems to fix the problem. 
Actually, sorry, I am now getting some errors.
NullReferenceException: Object reference not set to an instance of an object
Map+<TrimPathfinding>c__AnonStorey1.<>m__0 (Boolean force) (at Assets/Scripts/Generation/Map.cs:164)
AstarPath.ProcessWorkItems (Boolean force) (at Assets/Addons/AstarPathfindingProject/Core/AstarPath.cs:1052)
Am I trying to disable nodes that I have already disabled?
That errors comes from your code so Iām not completely sure, but I would guess that the GetNearest call returns that it didnāt find any node at all (so ānodeā will be null).
The range of the GetNearest call is limited by A* Inspector -> Settings -> Max Nearest Node Distance. Are you sure you are querying for nodes on the graph and that the graph has been scanned earlier (otherwise the graph will not contain any nodes)?
The graph has only just been created, I am trying to instantly trim any nodes that arenāt needed.
Is there a process I need to do after creating a graph to make sure it is ready to set the nodes as not walkable?
Did you create it from code? Newly created graphs are not scanned when they are created, you will need to call AstarPath.active.Scan() to make sure you have something to start from.
If I do that then the node.Walkable = false stops working.
Scan the graph before you run that code.
I am scanning before I run that code, it still seems to affect the walkable flag.
That said, time.timeScale = 0 at this point. Would that be a problem?
You arenāt scanning the graph for every node you try to make unwalkable by any chance?
The time scale shouldnāt be a problem.
Well, Iāve running that example code for each tile that I want to remove, yeah.
Do I need to move the floodfill to outside the loop of setting the unwalkable tiles?
