UE4 从 C++ 创建纹理

Posted 2023-03-25

【中文标题】UE4 从 C++ 创建纹理

【英文标题】：UE4 create texture from C++

【发布时间】：2021-12-17 20:35:36

【问题描述】：

我想将游戏中的相机视图转换为永久纹理。 为此，我设法将渲染目标转换为 Texture2d。 现在，如果我将此 Texture2D 保存在纹理数组中，所有纹理都是相同的，因为它们都引用相同的指针，我很难解决这个问题。我假设我必须创建一个新的纹理对象，但是...我还没有设法...

我希望你能帮助我。

这是我的代码和相应的蓝图。

ScreenShotToTexture.h

#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "ScreenShotToTexture.generated.h"


UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class MYPROJECT_API UScreenShotToTexture : public UActorComponent

    GENERATED_BODY()

public: 
    // Sets default values for this component's properties
    UScreenShotToTexture();

protected:
    // Called when the game starts
    virtual void BeginPlay() override;    

public: 
    // Called every frame
    virtual void TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction) override;

public:
    UPROPERTY(EditAnywhere)
    UTextureRenderTarget2D* RenderTarget;

    UPROPERTY(EditAnywhere)
    UTexture2D* Picture;

    UFUNCTION(BlueprintCallable) //so visible in BluePrints
    UTexture2D* TakePic();
;

ScrenShotToTexture.cpp

// Fill out your copyright notice in the Description page of Project Settings.


#include "ScreenShotToTexture.h"
#include "Engine/TextureRenderTarget2D.h"
#include "Components/SceneCaptureComponent2D.h"
#include "UObject/ObjectMacros.h"

// Sets default values for this component's properties
UScreenShotToTexture::UScreenShotToTexture()

    // Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
    // off to improve performance if you don't need them.
    PrimaryComponentTick.bCanEverTick = true;

    // ...



// Called when the game starts
void UScreenShotToTexture::BeginPlay()

    Super::BeginPlay();

    // ...
    



// Called every frame
void UScreenShotToTexture::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)

    Super::TickComponent(DeltaTime, TickType, ThisTickFunction);

    // ...


UTexture2D* UScreenShotToTexture::TakePic()

    if(RenderTarget == nullptr)
    
        UE_LOG(LogTemp, Error, TEXT("No RenderTarget set."));
        return nullptr;
    

    Picture = RenderTarget->ConstructTexture2D(this,"Test", EObjectFlags::RF_NoFlags, CTF_Default) ;

    return Picture;

【参考方案1】：

在这里找到答案： https://answers.unrealengine.com/questions/193827/how-to-get-texture-pixels-using-utexturerendertarg.html

void UScreenShotToTexture::CreateTexture()
    UTextureRenderTarget2D* TextureRenderTarget;
     // Creates Texture2D to store TextureRenderTarget content
     UTexture2D *Texture = UTexture2D::CreateTransient(TextureRenderTarget->SizeX, TextureRenderTarget->SizeY, PF_B8G8R8A8);
     #if WITH_EDITORONLY_DATA
     Texture->MipGenSettings = TMGS_NoMipmaps;
     #endif
     Texture->SRGB = TextureRenderTarget->SRGB;
     
     // Read the pixels from the RenderTarget and store them in a FColor array
     TArray<FColor> SurfData;
     FRenderTarget *RenderTarget = TextureRenderTarget->GameThread_GetRenderTargetResource();
     RenderTarget->ReadPixels(SurfData);
     
     // Lock and copies the data between the textures
     void* TextureData = Texture->PlatformData->Mips[0].BulkData.Lock(LOCK_READ_WRITE);
     const int32 TextureDataSize = SurfData.Num() * 4;
     FMemory::Memcpy(TextureData, SurfData.GetData(), TextureDataSize);
     Texture->PlatformData->Mips[0].BulkData.Unlock();
     // Apply Texture changes to GPU memory
     Texture->UpdateResource();