UE4 读取本地图片

一时失言乱红尘 2022-07-14 02:07 518阅读 0赞

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

**\[cpp\]** [view plain][] [copy][view plain]

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1.  \#pragma region 通过本地图片转换成UTexture2D
2.  UTexture2D\* AMyProjectGameMode::GetLocalTexture(**const** FString &\_TexPath) 
3.  \{ 
4.   UTexture2D\* OutTex=NULL; 
5.   IImageWrapperModule& imageWrapperModule = FModuleManager::LoadModuleChecked<IImageWrapperModule>(FName("ImageWrapper")); 
6.   IImageWrapperPtr imageWrapper = imageWrapperModule.CreateImageWrapper(EImageFormat::PNG); 
7.  
8.   TArray<uint8> OutArray; 
9.  **if**(FFileHelper::LoadFileToArray(OutArray, \*\_TexPath)) 
10.  \{ 
11. **if** (imageWrapper.IsValid()&& 
12.  imageWrapper->SetCompressed(OutArray.GetData(), OutArray.Num())) 
13.  \{ 
14. **const** TArray<uint8>\* uncompressedRGBA = NULL; 
15. **if** (imageWrapper->GetRaw(ERGBFormat::RGBA, 8, uncompressedRGBA)) 
16.  \{ 
17. **const** TArray<FColor> uncompressedFColor=uint8ToFColor(\*uncompressedRGBA); 
18.  OutTex=TextureFromImage( 
19.  imageWrapper->GetWidth(), 
20.  imageWrapper->GetHeight(), 
21.  uncompressedFColor, 
22. **true**); 
23.  \} 
24.  \} 
25.  \} 
26. **return** OutTex; 
27. \} 
28. \#pragma endregion

2.将uint8数组转为颜色数组

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1.  \#pragma region 将uint8数组转为颜色数组
2.  TArray<FColor> AMyProjectGameMode::uint8ToFColor(**const** TArray<uint8> origin) 
3.  \{ 
4.   TArray<FColor> uncompressedFColor; 
5.   uint8 auxOrigin; 
6.   FColor auxDst; 
7.  
8.  **for** (**int** i = 0; i < origin.Num(); i++) \{ 
9.   auxOrigin = origin\[i\]; 
10.  auxDst.R = auxOrigin; 
11.  i++; 
12.  auxOrigin = origin\[i\]; 
13.  auxDst.G = auxOrigin; 
14.  i++; 
15.  auxOrigin = origin\[i\]; 
16.  auxDst.B = auxOrigin; 
17.  i++; 
18.  auxOrigin = origin\[i\]; 
19.  auxDst.A = auxOrigin; 
20.  uncompressedFColor.Add(auxDst); 
21.  \} 
22. 
23. **return** uncompressedFColor; 
24. 
25. \} 
26. \#pragma endregion

3.将颜色数组赋值给Texture

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1.  \#pragma region 将颜色数组赋值给Texture
2.  UTexture2D\* AMyProjectGameMode::TextureFromImage(**const** int32 SrcWidth, **const** int32 SrcHeight, **const** TArray<FColor> &SrcData, **const****bool** UseAlpha) 
3.  \{ 
4.  
5.  // 创建Texture2D纹理
6.   UTexture2D\* MyScreenshot = UTexture2D::CreateTransient(SrcWidth, SrcHeight, PF\_B8G8R8A8); 
7.  
8.  // 锁住他的数据，以便修改
9.   uint8\* MipData = **static\_cast**<uint8\*>(MyScreenshot->PlatformData->Mips\[0\].BulkData.Lock(LOCK\_READ\_WRITE)); 
10. 
11. // 创建纹理数据
12.  uint8\* DestPtr = NULL; 
13. **const** FColor\* SrcPtr = NULL; 
14. **for** (int32 y = 0; y<SrcHeight; y++) 
15.  \{ 
16.  DestPtr = &MipData\[(SrcHeight - 1 - y) \* SrcWidth \* **sizeof**(FColor)\]; 
17.  SrcPtr = **const\_cast**<FColor\*>(&SrcData\[(SrcHeight - 1 - y) \* SrcWidth\]); 
18. **for** (int32 x = 0; x<SrcWidth; x++) 
19.  \{ 
20.  \*DestPtr++ = SrcPtr->B; 
21.  \*DestPtr++ = SrcPtr->G; 
22.  \*DestPtr++ = SrcPtr->R; 
23. **if** (UseAlpha) 
24.  \{ 
25.  \*DestPtr++ = SrcPtr->A; 
26.  \} 
27. **else**
28.  \{ 
29.  \*DestPtr++ = 0xFF; 
30.  \} 
31.  SrcPtr++; 
32.  \} 
33.  \} 
34. 
35. // 解锁纹理
36.  MyScreenshot->PlatformData->Mips\[0\].BulkData.Unlock(); 
37.  MyScreenshot->UpdateResource(); 
38. 
39. **return** MyScreenshot; 
40. \} 
41. \#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

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1.  **void** AMyProjectGameMode::BeginPlay() 
2.  \{ 
3.  **const** FString \_FilePath = FPaths::GameDir() + "video\_logo.png"; 
4.   \_UITex = GetLocalTexture(\_FilePath); 
5.  \}

5.注意别忘了，需要添加两个头文件

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1.  \#include "Runtime/ImageWrapper/Public/Interfaces/IImageWrapper.h"
2.  \#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

![Center][]

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

[https_answers.unrealengine.com_questions_235086_texture-2d-shows-wrong-colors-from-jpeg-on-html5-p.html]: https://answers.unrealengine.com/questions/235086/texture-2d-shows-wrong-colors-from-jpeg-on-html5-p.html
[view plain]: http://blog.csdn.net/qq992817263/article/details/52704475#
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