293 lines
8.4 KiB
C++
293 lines
8.4 KiB
C++
// Copyright 2026 (c) Jupiter. All Rights Reserved.
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#include "CameraCaptureSubSystem.h"
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#include "CameraCaptureActor.h"
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#include "Components/SceneCaptureComponent2D.h"
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#include "Camera/CameraComponent.h"
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#include "EngineUtils.h"
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#include "Engine/World.h"
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#include "Engine/TextureRenderTarget2D.h"
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#include "IImageWrapper.h"
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#include "IImageWrapperModule.h"
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#include "HAL/PlatformFilemanager.h"
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#include "Misc/Paths.h"
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#include "Misc/FileHelper.h"
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#include "Modules/ModuleManager.h"
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#include "Async/Async.h"
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void UCameraCaptureSubSystem::Initialize(FSubsystemCollectionBase& Collection)
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{
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Super::Initialize(Collection);
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OutPutDirectoryPath = FPaths::Combine(FPaths::ProjectSavedDir(), TEXT("CameraCapture"));
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}
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void UCameraCaptureSubSystem::Deinitialize()
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{
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Super::Deinitialize();
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}
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void UCameraCaptureSubSystem::OnWorldBeginPlay(UWorld& InWorld)
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{
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Super::OnWorldBeginPlay(InWorld);
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for (TActorIterator<ACameraCaptureActor> It(GetWorld()); It; ++It)
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{
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ACameraCaptureActor* CameraCaptureActor = Cast<ACameraCaptureActor>(*It);
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if (CameraCaptureActor)
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{
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AllCaptureCameras.Emplace(CameraCaptureActor);
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}
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}
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if (AllCaptureCameras.Num() != CAMERA_WIDTH_NUMS * CAMERA_HEIGHTH_NUMS)
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{
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return;
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}
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}
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static void FlipVertical(TArray<FColor>& Pixels, int32 W, int32 H)
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{
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for (int32 Row = 0; Row < H / 2; ++Row)
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{
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const int32 A = Row * W;
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const int32 B = (H - 1 - Row) * W;
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for (int32 Col = 0; Col < W; ++Col)
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{
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Swap(Pixels[A + Col], Pixels[B + Col]);
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}
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}
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}
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void UCameraCaptureSubSystem::Tick(float DeltaTime)
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{
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CaptureViewToImageTick();
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}
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TStatId UCameraCaptureSubSystem::GetStatId() const
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{
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RETURN_QUICK_DECLARE_CYCLE_STAT(UCameraCaptureSubSystem, STATGROUP_Tickables);
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}
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void UCameraCaptureSubSystem::CaptureViewToImageTick()
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{
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if (AllCaptureCameras.IsEmpty())
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{
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return;
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}
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// 已经有一批在等 GPU 回读，就先尝试取回
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if (bReadbackInFlight)
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{
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TryResolveCaptureViewAtlas();
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return;
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}
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// 没有在飞行中的回读，就启动新的一批
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BeginCaptureViewToAtlas();
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}
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void UCameraCaptureSubSystem::BeginCaptureViewToAtlas()
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{
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const int32 AtlasW = ViewWidth * AtlasGridX;
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const int32 AtlasH = ViewHeight * AtlasGridY;
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PendingAtlasCapture = MakeUnique<FPendingAtlasCapture>();
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PendingAtlasCapture->FrameId = (int64)GFrameCounter;
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PendingAtlasCapture->AtlasW = AtlasW;
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PendingAtlasCapture->AtlasH = AtlasH;
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const int32 MaxTiles = AtlasGridX * AtlasGridY;
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const int32 CameraCount = FMath::Min(AllCaptureCameras.Num(), MaxTiles);
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PendingAtlasCapture->Items.Reserve(CameraCount);
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for (int32 CameraIndex = 0; CameraIndex < CameraCount; ++CameraIndex)
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{
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if (!AllCaptureCameras[CameraIndex].IsValid())
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{
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continue;
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}
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ACameraCaptureActor* CaptureActor = AllCaptureCameras[CameraIndex].Get();
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if (!CaptureActor)
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{
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continue;
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}
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// 先让这台 SceneCapture 更新一次 RT
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CaptureActor->CaptureNow(); // 你自己封装一个函数，内部调用 ViewCapture->CaptureScene()
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UTextureRenderTarget2D* RenderTarget = CaptureActor->GetViewRT();
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if (!RenderTarget)
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{
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continue;
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}
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FTextureRenderTargetResource* RTRes = RenderTarget->GameThread_GetRenderTargetResource();
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if (!RTRes)
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{
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continue;
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}
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FRHITexture* SourceTexture = RTRes->GetRenderTargetTexture();
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if (!SourceTexture)
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{
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continue;
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}
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FCameraReadbackItem Item;
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Item.CameraIndex = CameraIndex;
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Item.Width = ViewWidth;
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Item.Height = ViewHeight;
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Item.Readback = MakeUnique<FRHIGPUTextureReadback>(
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FName(*FString::Printf(TEXT("CameraReadback_%d"), CameraIndex))
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);
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FRHIGPUTextureReadback* ReadbackPtr = Item.Readback.Get();
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const FResolveRect CopyRect(0, 0, ViewWidth, ViewHeight);
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ENQUEUE_RENDER_COMMAND(QueueCameraTextureReadback)(
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[ReadbackPtr, SourceTexture, CopyRect](FRHICommandListImmediate& RHICmdList)
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{
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if (ReadbackPtr && SourceTexture)
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{
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ReadbackPtr->EnqueueCopy(RHICmdList, SourceTexture, CopyRect);
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}
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});
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PendingAtlasCapture->Items.Add(MoveTemp(Item));
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}
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bReadbackInFlight = PendingAtlasCapture->Items.Num() > 0;
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}
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void UCameraCaptureSubSystem::TryResolveCaptureViewAtlas()
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{
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if (!bReadbackInFlight || !PendingAtlasCapture.IsValid())
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{
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return;
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}
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// 只要有一个还没准备好，就下一帧再来
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for (const FCameraReadbackItem& Item : PendingAtlasCapture->Items)
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{
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if (!Item.Readback.IsValid() || !Item.Readback->IsReady())
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{
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return;
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}
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}
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// 全部 ready，开始组装 atlas
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TArray<FColor> AtlasPixels;
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AtlasPixels.SetNumZeroed(PendingAtlasCapture->AtlasW * PendingAtlasCapture->AtlasH);
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for (const FCameraReadbackItem& Item : PendingAtlasCapture->Items)
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{
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if (!Item.Readback.IsValid())
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{
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continue;
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}
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int32 RowPitchInPixels = 0;
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int32 BufferHeight = 0;
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void* RawPtr = Item.Readback->Lock(RowPitchInPixels, &BufferHeight);
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if (!RawPtr)
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{
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Item.Readback->Unlock();
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continue;
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}
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// RawPtr 指向 GPU 读回后的 CPU 可访问数据
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const FColor* SrcPixels = static_cast<const FColor*>(RawPtr);
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// 先拷到一个连续的小图缓存里
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TArray<FColor> ViewPixels;
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ViewPixels.SetNumUninitialized(Item.Width * Item.Height);
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for (int32 Y = 0; Y < Item.Height; ++Y)
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{
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const FColor* SrcRow = SrcPixels + Y * RowPitchInPixels;
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FColor* DstRow = ViewPixels.GetData() + Y * Item.Width;
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FMemory::Memcpy(DstRow, SrcRow, sizeof(FColor) * Item.Width);
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}
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Item.Readback->Unlock();
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// 如果你最后导出的图上下颠倒，这里保留翻转
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FlipVertical(ViewPixels, Item.Width, Item.Height);
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const int32 GX = Item.CameraIndex % AtlasGridX;
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const int32 GY = Item.CameraIndex / AtlasGridX;
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const int32 DstX0 = GX * Item.Width;
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const int32 DstY0 = GY * Item.Height;
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for (int32 Y = 0; Y < Item.Height; ++Y)
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{
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const int32 AtlasY = DstY0 + Y;
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if (AtlasY < 0 || AtlasY >= PendingAtlasCapture->AtlasH)
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{
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continue;
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}
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const int32 SrcRowIndex = Y * Item.Width;
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const int32 DstRowIndex = AtlasY * PendingAtlasCapture->AtlasW;
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for (int32 X = 0; X < Item.Width; ++X)
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{
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const int32 AtlasX = DstX0 + X;
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if (AtlasX < 0 || AtlasX >= PendingAtlasCapture->AtlasW)
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{
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continue;
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}
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AtlasPixels[DstRowIndex + AtlasX] = ViewPixels[SrcRowIndex + X];
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}
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}
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}
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const int32 AtlasW = PendingAtlasCapture->AtlasW;
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const int32 AtlasH = PendingAtlasCapture->AtlasH;
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PendingAtlasCapture.Reset();
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bReadbackInFlight = false;
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AsyncWriteImageToDisk(MoveTemp(AtlasPixels), AtlasW, AtlasH);
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}
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void UCameraCaptureSubSystem::AsyncWriteImageToDisk(TArray<FColor> AtlasPixels, const int32 AtlasW, const int32 AtlasH)
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{
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const FString FullPath = FPaths::Combine( OutPutDirectoryPath, FString::Printf(TEXT("atlas_%010lld.png"), (int64)GFrameCounter) );
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auto EncodeAndWrite = [AtlasPixels = MoveTemp(AtlasPixels), AtlasW, AtlasH, FullPath]()
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{
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IImageWrapperModule& ImageWrapperModule =
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FModuleManager::LoadModuleChecked<IImageWrapperModule>(TEXT("ImageWrapper"));
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TSharedPtr<IImageWrapper> Wrapper = ImageWrapperModule.CreateImageWrapper(EImageFormat::PNG);
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if (!Wrapper.IsValid()) return;
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if (!Wrapper->SetRaw(AtlasPixels.GetData(), AtlasPixels.Num() * sizeof(FColor),
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AtlasW, AtlasH, ERGBFormat::BGRA, 8))
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{
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return;
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}
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const TArray64<uint8>& Compressed = Wrapper->GetCompressed();
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TArray<uint8> Bytes;
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Bytes.Append(Compressed.GetData(), (int32)Compressed.Num());
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FFileHelper::SaveArrayToFile(Bytes, *FullPath);
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};
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// 基础版默认异步写盘，避免卡
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Async(EAsyncExecution::ThreadPool, MoveTemp(EncodeAndWrite));
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}
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