NiagaraDataInterfaceSTReactiveBoids.h

// Copyright (c) 2025 Aaron Trotter (ShaderTech). All Rights Reserved.
 
#pragma once
 
#include "NiagaraCommon.h"
#include "NiagaraShared.h"
#include "NiagaraDataInterface.h"
#include "RenderGraphFwd.h"
#include "RenderGraphResources.h"
#include "NiagaraDataInterfaceSTReactiveBoids.generated.h"
 
struct FNiagaraDataInterfaceGeneratedFunction;
struct FNiagaraFunctionSignature;

UCLASS(EditInlineNew, Category = "ShaderTech|AudioVisualisation", meta = (DisplayName = "ST Reactive Boids Query"))
class ST_AUDIOVISUALISATION_API UNiagaraDataInterfaceSTReactiveBoids : public UNiagaraDataInterface
{
    GENERATED_UCLASS_BODY()
 
    
    BEGIN_SHADER_PARAMETER_STRUCT(FShaderParameters, )
        SHADER_PARAMETER_RDG_BUFFER_SRV(StructuredBuffer<FST_VJ_BoidItem>, boidsIn)
        SHADER_PARAMETER(int32, numBoids)
    END_SHADER_PARAMETER_STRUCT()
 
private:
    int32 numBoids = 0;
    TRefCountPtr<FRDGPooledBuffer> ReadPooled = nullptr;
 
public:
    void SetData(int32 _numBoids, TRefCountPtr<FRDGPooledBuffer> _ReadPooled)
    {
        numBoids = _numBoids;
        ReadPooled = _ReadPooled;
    }
 
    // UObject Interface
    virtual void PostInitProperties() override;
    // UObject Interface End
 
    // UNiagaraDataInterface Interface
    virtual void GetFunctions(TArray<FNiagaraFunctionSignature>& OutFunctions)override;

    virtual bool CanExecuteOnTarget(ENiagaraSimTarget Target) const override { return Target == ENiagaraSimTarget::GPUComputeSim; }

    virtual void BuildShaderParameters(FNiagaraShaderParametersBuilder& ShaderParametersBuilder) const override;

    virtual void SetShaderParameters(const FNiagaraDataInterfaceSetShaderParametersContext& Context) const override;
 
#if WITH_EDITORONLY_DATA
    virtual bool AppendCompileHash(FNiagaraCompileHashVisitor* InVisitor) const override;

    virtual bool GetFunctionHLSL(const FNiagaraDataInterfaceGPUParamInfo& ParamInfo, const FNiagaraDataInterfaceGeneratedFunction& FunctionInfo, int FunctionInstanceIndex, FString& OutHLSL) override;

    virtual void GetParameterDefinitionHLSL(const FNiagaraDataInterfaceGPUParamInfo& ParamInfo, FString& OutHLSL) override;
#endif

    virtual bool HasPreSimulateTick() const override { return true; }

    virtual bool PerInstanceTick(void* PerInstanceData, FNiagaraSystemInstance* SystemInstance, float DeltaSeconds) override;

    virtual int32 PerInstanceDataSize() const override;

    virtual bool InitPerInstanceData(void* PerInstanceData, FNiagaraSystemInstance* SystemInstance) override;

    virtual void DestroyPerInstanceData(void* PerInstanceData, FNiagaraSystemInstance* SystemInstance) override;
    // UNiagaraDataInterface Interface
};

struct FNDISTReactiveBoidsInstanceData_GameThread
{
    TRefCountPtr<FRDGPooledBuffer> ReadPooled = nullptr;
    int32 numBoids = 0;

    ~FNDISTReactiveBoidsInstanceData_GameThread()
    {
        ReleaseData();
    }

    void ReleaseData()
    {
        numBoids = 0;
        ReadPooled.SafeRelease();
    }
};

struct FNDISTReactiveBoidsInstanceData_RenderThread
{
    TRefCountPtr<FRDGPooledBuffer> ReadPooled = nullptr;
    FRDGBufferRef ReadScopedRef = nullptr;
    FRDGBufferSRVRef ReadScopedSRV = nullptr;
    int32 numBoids = 0;

    ~FNDISTReactiveBoidsInstanceData_RenderThread()
    {
        ReleaseData();
    }

    void UpdateData(FNDISTReactiveBoidsInstanceData_GameThread& InstanceData_GT)
    {
        ReleaseData();
        ReadPooled = InstanceData_GT.ReadPooled;
        numBoids = InstanceData_GT.numBoids;
    }

    void ReleaseData()
    {
        numBoids = 0;
        ReadPooled.SafeRelease();
    }
};

struct FNDISTReactiveBoidsProxy : public FNiagaraDataInterfaceProxy
{
    virtual void ConsumePerInstanceDataFromGameThread(void* PerInstanceData, const FNiagaraSystemInstanceID& Instance) override {}

    virtual int32 PerInstanceDataPassedToRenderThreadSize() const override { return 0; }

    TMap<FNiagaraSystemInstanceID, FNDISTReactiveBoidsInstanceData_RenderThread> SystemInstancesToProxyData_RT;
};