ST_VJ_PingPongBuffer.h

// Copyright (c) 2025 Aaron Trotter (ShaderTech). All Rights Reserved.
 
#pragma once
#include "RenderGraphUtils.h"
#include "RenderGraphBuilder.h"
#include "GlobalShader.h"
#include "RenderGraphResources.h"
#include "ST_VJ_ComputeFunctionLibrary.h"

struct FST_VJ_PingPongBuffer
{
    TRefCountPtr<FRDGPooledBuffer> ReadPooled = nullptr;

    TRefCountPtr<FRDGPooledBuffer> WritePooled = nullptr;

    FRDGBufferRef ReadScopedRef = nullptr;

    FRDGBufferRef WriteScopedRef = nullptr;

    FRDGBufferSRVRef ReadScopedSRV = nullptr;

    FRDGBufferUAVRef WriteScopedUAV = nullptr;

    FST_VJ_PingPongBuffer()
    {
        ReadPooled = nullptr;
        WritePooled = nullptr;
        ReadScopedRef = nullptr;
        WriteScopedRef = nullptr;
        ReadScopedSRV = nullptr;
        WriteScopedUAV = nullptr;
    }

    void PingPong(FRDGBuilder& GraphBuilder)
    {
        Swap(ReadScopedRef, WriteScopedRef);
 
        ReadScopedSRV = GraphBuilder.CreateSRV(ReadScopedRef);
        WriteScopedUAV = GraphBuilder.CreateUAV(WriteScopedRef);
    }

    void RegisterRW(FRDGBuilder& GraphBuilder, FString readName, FString writeName)
    {
        UST_VJ_ComputeFunctionLibrary::RegisterSRV(GraphBuilder, ReadPooled, readName, ReadScopedRef, ReadScopedSRV);
        UST_VJ_ComputeFunctionLibrary::RegisterUAV(GraphBuilder, WritePooled, writeName, WriteScopedRef, WriteScopedUAV);
    }

    void RegisterR(FRDGBuilder& GraphBuilder, FString readName)
    {
        UST_VJ_ComputeFunctionLibrary::RegisterSRV(GraphBuilder, ReadPooled, readName, ReadScopedRef, ReadScopedSRV);
    }

    void RegisterW(FRDGBuilder& GraphBuilder, FString writeName)
    {
        UST_VJ_ComputeFunctionLibrary::RegisterUAV(GraphBuilder, WritePooled, writeName, WriteScopedRef, WriteScopedUAV);
    }

    ~FST_VJ_PingPongBuffer()
    {
        ReleaseData();
    }

    void ReleaseData()
    {
        if (ReadPooled.IsValid())
        {
            ReadPooled.SafeRelease();
        }
 
        if (WritePooled.IsValid())
        {
            WritePooled.SafeRelease();
        }
 
        ReadScopedRef = nullptr;
        WriteScopedRef = nullptr;
        ReadScopedSRV = nullptr;
        WriteScopedUAV = nullptr;
    }
};