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<IImageWrapperModule>(FName("ImageWrapper"));
IImageWrapperPtr imageWrapper = imageWrapperModule.CreateImageWrapper(EImageFormat::PNG); TArray<uint8> OutArray;
if(FFileHelper::LoadFileToArray(OutArray, *_TexPath))
{
if (imageWrapper.IsValid()&&
imageWrapper->SetCompressed(OutArray.GetData(), OutArray.Num()))
{
const TArray<uint8>* uncompressedRGBA = NULL;
if (imageWrapper->GetRaw(ERGBFormat::RGBA, 8, uncompressedRGBA))
{
const TArray<FColor> 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<FColor> AMyProjectGameMode::uint8ToFColor(const TArray<uint8> origin)
{
TArray<FColor> 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<FColor> &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<uint8*>(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<SrcHeight; y++)
{
DestPtr = &MipData[(SrcHeight - 1 - y) * SrcWidth * sizeof(FColor)];
SrcPtr = const_cast<FColor*>(&SrcData[(SrcHeight - 1 - y) * SrcWidth]);
for (int32 x = 0; x<SrcWidth; 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

UE4 读取本地图片

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

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