UE4 截图并保存（C++实现）

你可以使用以下代码实现在UE4中截取屏幕并保存为图片：

UTexture2D* UScreenshotFunctionLibrary::TakeScreenshot(UObject* WorldContextObject, int32 Width, int32 Height)
{
    // Get the player controller
    APlayerController* PlayerController = UGameplayStatics::GetPlayerController(WorldContextObject, 0);
    if (!PlayerController)
    {
        return nullptr;
    }

    // Take the screenshot
    FViewport* Viewport = GEngine->GameViewport->Viewport;
    TArray<FColor> Bitmap;
    bool bScreenshotSuccessful = Viewport->ReadPixels(Bitmap, FReadSurfaceDataFlags(), FIntRect(0, 0, Width, Height));
    if (!bScreenshotSuccessful)
    {
        return nullptr;
    }

    // Create the texture
    UTexture2D* Texture = UTexture2D::CreateTransient(Width, Height, PF_B8G8R8A8);
    Texture->AddToRoot(); // Make sure the texture isn't garbage collected
    Texture->UpdateResource();

    // Copy the bitmap data to the texture
    uint8* MipData = static_cast<uint8*>(Texture->PlatformData->Mips[0].BulkData.Lock(LOCK_READ_WRITE));
    for (int32 Y = 0; Y < Height; Y++)
    {
        for (int32 X = 0; X < Width; X++)
        {
            int32 Index = Y * Width + X;
            MipData[Index * 4 + 0] = Bitmap[Index].B;
            MipData[Index * 4 + 1] = Bitmap[Index].G;
            MipData[Index * 4 + 2] = Bitmap[Index].R;
            MipData[Index * 4 + 3] = Bitmap[Index].A;
        }
    }
    Texture->PlatformData->Mips[0].BulkData.Unlock();

    // Save the texture to a file
    FString Filename = FPaths::ProjectDir() / TEXT("Screenshots") / FDateTime::Now().ToString(TEXT("yyyy-MM-dd_HH-mm-ss")) + TEXT(".png");
    FFileHelper::SaveObjectAsPNG(Texture, *Filename);

    return Texture;
}

此代码通过读取屏幕像素并将其复制到一个临时纹理中，最后将纹理保存为 PNG 文件。你可以调用此函数来截取当前屏幕并保存为文件。

注意：你需要在项目设置中启用 "With Editor" 选项，以便在运行时允许截屏。