Files
FlaxEngine/Source/Engine/AI/BehaviorTreeNode.h
2023-08-17 21:24:19 +02:00

89 lines
3.1 KiB
C++

// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.
#pragma once
#include "Engine/Scripting/SerializableScriptingObject.h"
#include "BehaviorTypes.h"
/// <summary>
/// Base class for Behavior Tree nodes.
/// </summary>
API_CLASS(Abstract) class FLAXENGINE_API BehaviorTreeNode : public SerializableScriptingObject
{
DECLARE_SCRIPTING_TYPE_WITH_CONSTRUCTOR_IMPL(BehaviorTreeNode, SerializableScriptingObject);
friend class BehaviorTreeGraph;
friend class BehaviorKnowledge;
protected:
// Raw memory byte offset from the start of the behavior memory block.
API_FIELD(ReadOnly) int32 _memoryOffset = 0;
// Execution index of the node within tree.
API_FIELD(ReadOnly) int32 _executionIndex = -1;
public:
/// <summary>
/// Node user name (eg. Follow Enemy, or Pick up Weapon).
/// </summary>
API_FIELD() String Name;
/// <summary>
/// Initializes node state. Called after whole tree is loaded and nodes hierarchy is setup.
/// </summary>
/// <param name="tree">Node owner asset.</param>
API_FUNCTION() virtual void Init(BehaviorTree* tree)
{
}
/// <summary>
/// Gets the node instance state size. A chunk of the valid memory is passed via InitState to setup that memory chunk (one per-behavior).
/// </summary>
API_FUNCTION() virtual int32 GetStateSize() const
{
return 0;
}
/// <summary>
/// Initializes node instance state. Called when starting logic simulation for a given behavior.
/// </summary>
/// <param name="behavior">Behavior to simulate.</param>
/// <param name="memory">Pointer to pre-allocated memory for this node to use (call constructor of the state container).</param>
API_FUNCTION() virtual void InitState(Behavior* behavior, void* memory)
{
}
/// <summary>
/// Cleanups node instance state. Called when stopping logic simulation for a given behavior.
/// </summary>
/// <param name="behavior">Behavior to simulate.</param>
/// <param name="memory">Pointer to pre-allocated memory for this node to use (call destructor of the state container).</param>
API_FUNCTION() virtual void ReleaseState(Behavior* behavior, void* memory)
{
}
/// <summary>
/// Updates node logic.
/// </summary>
/// <param name="context">Behavior update context data.</param>
/// <returns>Operation result enum.</returns>
API_FUNCTION() virtual BehaviorUpdateResult Update(BehaviorUpdateContext context)
{
return BehaviorUpdateResult::Success;
}
// Helper utility to update node with state creation/cleanup depending on node relevancy.
BehaviorUpdateResult InvokeUpdate(const BehaviorUpdateContext& context);
// [SerializableScriptingObject]
void Serialize(SerializeStream& stream, const void* otherObj) override;
void Deserialize(DeserializeStream& stream, ISerializeModifier* modifier) override;
public:
// Returns the typed node state at the given memory address.
template<typename T>
T* GetState(void* memory) const
{
ASSERT((int32)sizeof(T) <= GetStateSize());
return reinterpret_cast<T*>((byte*)memory + _memoryOffset);
}
};