Paradise.BT 0.6.1

Paradise.BT

Paradise.BT is a pure .NET behavior tree runtime with struct-based nodes, an EntitiesBT-style blackboard API, and optional binary serialization through Paradise.BLOB.

Install

dotnet add package Paradise.BT

Features

• Pure .NET runtime with no Unity or ECS dependency.
• Targets netstandard2.1 and net10.0.
• Built-in sequence, selector, parallel, repeat, repeat-forever, inverter, succeeder, delay, success, failure, running, delegate action, and delegate condition nodes.
• Immutable compiled trees plus reusable BehaviorTreeInstance runtime state.
• Custom node authoring via unmanaged struct types that implement INodeData.
• Serialization and deserialization support through Paradise.BLOB.

Quick start

using Paradise.BT;

public struct HasTargetData
{
    public bool Value;
}

public struct ShotsFiredData
{
    public int Value;
}

var blackboard = new Blackboard();
blackboard.SetData(new HasTargetData { Value = true });
blackboard.SetData(new ShotsFiredData());

var tree = BehaviorTreeBuilder.Build(
    BehaviorNodes.Selector(
        BehaviorNodes.Sequence(
            BehaviorNodes.Condition(static bb => bb.GetData<HasTargetData>().Value),
            BehaviorNodes.Repeat(
                3,
                BehaviorNodes.Sequence(
                    BehaviorNodes.Delay(0.5f),
                    BehaviorNodes.Action(static bb =>
                    {
                        ref ShotsFiredData shots = ref bb.GetDataRef<ShotsFiredData>();
                        shots.Value++;
                        return NodeState.Success;
                    })))),
        BehaviorNodes.Action(static _ => NodeState.Success)));

BehaviorTreeInstance instance = tree.CreateInstance(blackboard);

NodeState firstTick = instance.Tick(0.25f);
NodeState secondTick = instance.Tick(0.25f);

Custom nodes

Implement INodeData on a struct and decorate it with GuidAttribute so it can participate in serialization.

using Paradise.BT;
using System.Runtime.InteropServices;

[Guid("7D4E31B3-0D57-4211-9C1F-91EAB87734E5")]
public struct CounterNode : INodeData
{
    public int Count;

    public NodeState Tick<TNodeBlob, TBlackboard>(int index, ref TNodeBlob blob, ref TBlackboard bb)
        where TNodeBlob : struct, INodeBlob
        where TBlackboard : struct, IBlackboard
    {
        Count++;
        return Count >= 3 ? NodeState.Success : NodeState.Running;
    }
}

var tree = BehaviorTreeBuilder.Build(
    BehaviorNodes.Node(new CounterNode()));

If a node needs reset side effects in addition to restoring its default struct data, also implement ICustomResetAction.

Serialization

Compiled trees can be turned into binary blobs and loaded back later.

using Paradise.BT;

using var blob = tree.Serialize();
BehaviorTree roundTripped = BehaviorTreeBlobSerializer.Deserialize(blob);

Custom unmanaged nodes must be registered before deserialization.

var registry = new BehaviorTreeSerializationRegistry()
    .Register<CounterNode>();

BehaviorTree roundTripped = BehaviorTreeBlobSerializer.Deserialize(blob, registry);

Notes

• BehaviorTreeInstance.Tick(deltaTime) stores the supplied delta time in the blackboard, which is how nodes such as BehaviorNodes.Delay(...) advance.
• Delegate-backed nodes are runtime-only and cannot be serialized because they capture managed references.
• The Blackboard type also supports object and keyed-value storage helpers for app-level data setup.