虚幻4动态加载PNG给Texture2D

本教程适用于4.17以前的版本，4.18以上不兼容

头文件：

#include "ImageWrapper.h"

/*载入PNG贴图*/

UFUNCTION(BlueprintCallable, Category = "GameSetting")

UTexture2D* GetPngFromPath(const FString& FullFilePath, bool& IsValid, int32& Width, int32& Height);

/*载入贴图*/

UTexture2D* GetTexture2DFromPath(const FString& FullFilePath, EImageFormat::Type ImageFormat, bool& IsValid, int32& Width, int32& Height);

源文件：

UTexture2D* AAKGameGameModeBase::GetPngFromPath(const FString& FullFilePath, bool& IsValid, int32& Width, int32& Height)

{

return GetTexture2DFromPath(FullFilePath, EImageFormat::Type::PNG,IsValid,Width,Height);

}

UTexture2D* AAKGameGameModeBase::GetTexture2DFromPath(const FString& FullFilePath, EImageFormat::Type ImageFormat, bool& IsValid, int32& Width, int32& Height)

{

IsValid = false;

UTexture2D* LoadedT2D = NULL;

IImageWrapperModule& ImageWrapperModule = FModuleManager::LoadModuleChecked<IImageWrapperModule>(FName("ImageWrapper"));

IImageWrapperPtr ImageWrapper = ImageWrapperModule.CreateImageWrapper(ImageFormat);

// 从指定路径的文件加载

TArray<uint8> RawFileData;

if (!FFileHelper::LoadFileToArray(RawFileData, *FullFilePath)) return NULL;

// 新建Texture2D

bool valid = ImageWrapper.IsValid();

bool setCompressed = ImageWrapper->SetCompressed(RawFileData.GetData(), RawFileData.Num());

if (valid && setCompressed)

{

const TArray<uint8>* UncompressedBGRA = NULL;

if (ImageWrapper->GetRaw(ERGBFormat::BGRA, 8, UncompressedBGRA))

{

LoadedT2D = UTexture2D::CreateTransient(ImageWrapper->GetWidth(), ImageWrapper->GetHeight(), PF_B8G8R8A8);

// 检查是否存在

if (!LoadedT2D) return NULL;

// 设置出参

Width = ImageWrapper->GetWidth();

Height = ImageWrapper->GetHeight();

// 复制图像内容

void* TextureData = LoadedT2D->PlatformData->Mips[0].BulkData.Lock(LOCK_READ_WRITE);

FMemory::Memcpy(TextureData, UncompressedBGRA->GetData(), UncompressedBGRA->Num());

LoadedT2D->PlatformData->Mips[0].BulkData.Unlock();

// 更新图像

LoadedT2D->UpdateResource();

// 成功

IsValid = true;

return LoadedT2D;

}

}

// 失败

IsValid = false;

return NULL;

}

这个官方的教程也可以尝试下，比较复杂

https://wiki.unrealengine.com/Asynchronous_Image_Loading_from_Disk