UE4 读取本地图片

参考链接:https://answers.unrealengine.com/questions/235086/texture-2d-shows-wrong-colors-from-jpeg-on-html5-p.html

我这里，不能将图片全放工程之中，需要在外部在加载图片资源，再来使用

1.通过本地图片路径，获取图片，并将其数据转为uint类型的数组

 #pragma region 通过本地图片转换成UTexture2D
 UTexture2D* AMyProjectGameMode::GetLocalTexture(const FString &_TexPath)
 {
     UTexture2D* OutTex=NULL;
     IImageWrapperModule& imageWrapperModule = FModuleManager::LoadModuleChecked(FName("ImageWrapper"));
     IImageWrapperPtr imageWrapper = imageWrapperModule.CreateImageWrapper(EImageFormat::PNG);

     TArray OutArray;
     if(FFileHelper::LoadFileToArray(OutArray, *_TexPath))
     {
         if (imageWrapper.IsValid()&&
             imageWrapper->SetCompressed(OutArray.GetData(), OutArray.Num()))
         {
             const TArray* uncompressedRGBA = NULL;
             if (imageWrapper->GetRaw(ERGBFormat::RGBA, 8, uncompressedRGBA))
             {
                 const TArray uncompressedFColor=uint8ToFColor(*uncompressedRGBA);
                 OutTex=TextureFromImage(
                     imageWrapper->GetWidth(),
                     imageWrapper->GetHeight(),
                     uncompressedFColor,
                     true);
             }
         }
     }
     return OutTex;
 }
 #pragma endregion

2.将uint8数组转为颜色数组

 #pragma region 将uint8数组转为颜色数组
 TArray AMyProjectGameMode::uint8ToFColor(const TArray origin)
 {
     TArray uncompressedFColor;
     uint8 auxOrigin;
     FColor auxDst;

     for (int i = 0; i < origin.Num(); i++) {
         auxOrigin = origin[i];
         auxDst.R = auxOrigin;
         i++;
         auxOrigin = origin[i];
         auxDst.G = auxOrigin;
         i++;
         auxOrigin = origin[i];
         auxDst.B = auxOrigin;
         i++;
         auxOrigin = origin[i];
         auxDst.A = auxOrigin;
         uncompressedFColor.Add(auxDst);
     }

     return  uncompressedFColor;

 }
 #pragma endregion

3.将颜色数组赋值给Texture

 #pragma region 将颜色数组赋值给Texture
 UTexture2D* AMyProjectGameMode::TextureFromImage(const int32 SrcWidth, const int32 SrcHeight, const TArray &SrcData, const bool UseAlpha)
 {

     // 创建Texture2D纹理
     UTexture2D* MyScreenshot = UTexture2D::CreateTransient(SrcWidth, SrcHeight, PF_B8G8R8A8);

     // 锁住他的数据，以便修改
     uint8* MipData = static_cast(MyScreenshot->PlatformData->Mips[0].BulkData.Lock(LOCK_READ_WRITE));

     // 创建纹理数据
     uint8* DestPtr = NULL;
     const FColor* SrcPtr = NULL;
     for (int32 y = 0; y
     {
         DestPtr = &MipData[(SrcHeight - 1 - y) * SrcWidth * sizeof(FColor)];
         SrcPtr = const_cast(&SrcData[(SrcHeight - 1 - y) * SrcWidth]);
         for (int32 x = 0; x
         {
             *DestPtr++ = SrcPtr->B;
             *DestPtr++ = SrcPtr->G;
             *DestPtr++ = SrcPtr->R;
             if (UseAlpha)
             {
                 *DestPtr++ = SrcPtr->A;
             }
             else
             {
                 *DestPtr++ = 0xFF;
             }
             SrcPtr++;
         }
     }

     // 解锁纹理
     MyScreenshot->PlatformData->Mips[0].BulkData.Unlock();
     MyScreenshot->UpdateResource();

     return MyScreenshot;
 }
 #pragma endregion

4.我这里建图片路径放在工程的相对路径下，调用GetLocalTexture函数，获取Texture2D

 void AMyProjectGameMode::BeginPlay()
 {
     const FString _FilePath = FPaths::GameDir() + "video_logo.png";
     _UITex = GetLocalTexture(_FilePath);
 }

5.注意别忘了，需要添加两个头文件

 #include "Runtime/ImageWrapper/Public/Interfaces/IImageWrapper.h"
 #include "Runtime/ImageWrapper/Public/Interfaces/IImageWrapperModule.h"

6.运行截图，我这里将获取的图片放在了UI界面上

7.我在读取jpg格式的图片的时候，颜色明显不对，读png的格式的时候，就完全正常，还未去寻找原因

本文转自：http://blog.csdn.net/qq992817263/article/details/52704475