(Runtime graph) Need to execute 2 time for parameter to get set?

[jejelite]

(Runtime graph) Need to execute 2 time for parameter to get set?

[alelievr]

Hello,

Can you send the error stacktrace you have in the console?

[jejelite]

The error is a missing reference in this case it will happen in "HasLessHealthThenX" but i could change the first node evaluated and i would have the same result.

Error StackTrace :

System.NullReferenceException: Object reference not set to an instance of an object at FracLib.NodeGraph.TreeBehavior.HasLessHealthThenX.Evaluate () [0x00008] in C:\Users\JEJELITE\Documents\GitHub\ObsoletePrototype\ObsoleteProto\Assets\_Test_TreeBehavior\HasLessHealthThenX.cs:21 at FracLib.NodeGraph.TreeBehavior.SequenceNode.Evaluate () [0x0001a] in C:\Users\JEJELITE\Documents\GitHub\ObsoletePrototype\ObsoleteProto\Assets\FracLib\NodeGraph\TreeBehavior\Nodes\Composite\SequenceNode.cs:19 at FracLib.NodeGraph.TreeBehavior.SelectorNode.Evaluate () [0x00018] in C:\Users\JEJELITE\Documents\GitHub\ObsoletePrototype\ObsoleteProto\Assets\FracLib\NodeGraph\TreeBehavior\Nodes\Composite\SelectorNode.cs:18 at FracLib.NodeGraph.TreeBehavior.StartNode.Evaluate () [0x00018] in C:\Users\JEJELITE\Documents\GitHub\ObsoletePrototype\ObsoleteProto\Assets\FracLib\NodeGraph\TreeBehavior\Nodes\StartNode.cs:26 at FracLib.NodeGraph.TreeBehavior.StartNode.Process () [0x00001] in C:\Users\JEJELITE\Documents\GitHub\ObsoletePrototype\ObsoleteProto\Assets\FracLib\NodeGraph\TreeBehavior\Nodes\StartNode.cs:19 at GraphProcessor.BaseNode.<OnProcess>b__52_0 () [0x00000] in C:\Users\JEJELITE\Documents\GitHub\ObsoletePrototype\ObsoleteProto\Library\PackageCache\[email protected]\Runtime\Elements\BaseNode.cs:356 at GraphProcessor.ExceptionToLog.Call (System.Action a) [0x00002] in C:\Users\JEJELITE\Documents\GitHub\ObsoletePrototype\ObsoleteProto\Library\PackageCache\[email protected]\Runtime\Utils\ExceptionToLog.cs:14 UnityEngine.Debug:LogError(Object) GraphProcessor.ExceptionToLog:Call(Action) (at Library/PackageCache/[email protected]/Runtime/Utils/ExceptionToLog.cs:19) GraphProcessor.BaseNode:OnProcess() (at Library/PackageCache/[email protected]/Runtime/Elements/BaseNode.cs:356) GraphProcessor.ProcessGraphProcessor:Run() (at Library/PackageCache/[email protected]/Runtime/Processing/ProcessGraphProcessor.cs:39) Testing:Execute() (at Assets/_Test_TreeBehavior/Testing.cs:38) System.Reflection.MethodBase:Invoke(Object, Object[]) Sirenix.OdinInspector.Editor.Drawers.DefaultMethodDrawer:InvokeButton() (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Drawers/Misc Drawers/DefaultMethodDrawer.cs:388) Sirenix.OdinInspector.Editor.Drawers.DefaultMethodDrawer:DrawNormalButton() (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Drawers/Misc Drawers/DefaultMethodDrawer.cs:237) Sirenix.OdinInspector.Editor.Drawers.DefaultMethodDrawer:DrawPropertyLayout(GUIContent) (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Drawers/Misc Drawers/DefaultMethodDrawer.cs:149) Sirenix.OdinInspector.Editor.OdinDrawer:DrawProperty(GUIContent) (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Drawers/OdinDrawer.cs:176) Sirenix.OdinInspector.Editor.InspectorProperty:Draw(GUIContent) (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Core/InspectorProperty.cs:602) Sirenix.OdinInspector.Editor.InspectorUtilities:DrawPropertiesInTree(PropertyTree) (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Misc/InspectorUtilities.cs:418) Sirenix.OdinInspector.Editor.PropertyTree:Draw(Boolean) (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Core/PropertyTree.cs:308) Sirenix.OdinInspector.Editor.OdinEditor:DrawTree() (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Drawers/OdinEditor.cs:93) Sirenix.OdinInspector.Editor.OdinEditor:DrawOdinInspector() (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Drawers/OdinEditor.cs:215) Sirenix.OdinInspector.Editor.OdinEditor:OnInspectorGUI() (at X:/Repositories/sirenix-development/Sirenix Solution/Sirenix.OdinInspector.Editor/Drawers/OdinEditor.cs:85) UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

[alelievr]

So, If I understand correctly the crash happens when you do

var p = graph.GetParameterValue("...");

in HasLessHealthThenX.cs:21 ?
Can you also check that the graph is not null? It's very unlikely but who knows

[jejelite]

The "Null reference" error occur when running the graph for the first time with "processor.Run()" , so no the error doesn't occur directly on the line "var p = graph.GetParameterValue("...");".

What is strange is that every parameters are set correctly if i run a second time the graph without changing anything.

Here is the code of the node in question (note that it happen on any node referencing a exposed parameter)

    [Input(name = "More Then", allowMultiple = false)]
    public int moreThen;
    [Input(name = "entity", allowMultiple = false), SerializeField]
    public RPGEntity entity;

    public override NodeState Evaluate()
    {
        nodeState = NodeState.RUNNING;

        if (entity.health < moreThen) //<-- ERROR HERE
            nodeState = NodeState.SUCCESS;
        else
            nodeState = NodeState.FAILURE;

        return nodeState;
    }

[alelievr]

Hum, it's weird I tried to repro with a simple scriptable object that I expose as a parameter and then I run the graph from a script but it works correctly.

Just as a sanity check: what happens if you connect a Debug.Log node to the parameter node "This Entity"? Is it null on the first run or have the correct value?

[jejelite]

The Debug.log reflect the same problem, the entity appear null on the first run, if i rerun the graph it's set correctly.

[alelievr]

Then maybe it's a compute order problem, can you check that the nodes are processed in the correct order? you can enable debug mode on the node to display the compute order:

If it's not that I really don't know. Maybe if you don't mind you can send me your project or a unity pacakge if it's not too big for a repro?

[jejelite]

Ok, sry for the delay i took a week off , the problem is not from the compute order. I just sent you a invite to a repo with a package containing the example and code we used for testing the api if you want to take a look.

Thanks for your help and patience.

[alelievr]

👍 I'll take a look

[alelievr]

So I took a look and there is indeed something in your code that breaks evaluation of the graph (from SequenceNode):

            bool anyChildRunning = false;
            foreach (TreeBehaviorNode node in GetChildren())
            {
==>            switch (node.Evaluate())
                {
                    case NodeState.FAILURE:
                        nodeState = NodeState.FAILURE;
                        return nodeState;

This switch line call the Evalute on a node that have not yet been evaluated, but this also means that this node was not ready to be executed. In this precise case, the parameter node hasn't been processed yet when we process the SequenceNode so it's value is not yet sent to the HasLessHealthThenX node.
This explains why on the first run, you don't have the correct value in your node (your code basically shortcuts the graph execution order and thus gives in incorrect results).

Note that doing this also doesn't work because you are using the ProcessGraphProcessor in your Testing.cs which will result in the execution of all the nodes in the graph, completely ignoring the logic you have in your conditional nodes.

I think the correct solution in this case is to modify the ProcessGraphProcessor or write a new one. You have an example of conditional processing in this repo here: https://github.com/alelievr/NodeGraphProcessor/blob/master/Assets/Examples/ConditionalGraph/ConditionalProcessor.cs#L83
It's probably more complicated than what you need but it should be a good example.

[jejelite]

Thanks for the answer! Will look into implementing a custom GraphProcessor for a ThreeBehavior logic. I was initially hoping to avoid that.That why i try what i did but i for some reason didn't think that the node would not be set properly because of that.

Thanks again