Generated texture is always created as vertical lines

[3dRaven]

Your code works. Not sure where the problem is. Maybe something is happening during the saving of the asset?

Example code I made based on it

ImageFunctionLibrary.cpp

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


#include "ImageFunctionLibrary.h"

UTexture2D* UImageFunctionLibrary::GeneratePerlin(int32 textureWidth, int32 textureHeight)
{		
	UTexture2D* NewTexture = UTexture2D::CreateTransient(textureWidth, textureHeight);
	FTexturePlatformData* PlatformData = NewTexture->GetPlatformData();
	FTexture2DMipMap* MipMap = &PlatformData->Mips[0];
	MipMap->BulkData.Lock(LOCK_READ_WRITE);
	uint8* RawImageData = (uint8*)MipMap->BulkData.Realloc(textureWidth * textureHeight * 4);

	int32 numPixels = textureWidth * textureHeight;
	for (int32 x = 0; x < numPixels; x++)
	{
		FColor RandomColor = FColor::MakeRandomColor();

		RawImageData[4 * x] = RandomColor.B;
		RawImageData[4 * x + 1] = RandomColor.G;
		RawImageData[4 * x + 2] = RandomColor.R;
		RawImageData[4 * x + 3] = 255;
	}

	MipMap->BulkData.Unlock();
	NewTexture->UpdateResource();

	return NewTexture;
}

.h

#pragma once

#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "Engine/Texture2D.h"
#include "ImageFunctionLibrary.generated.h"

/**
 * 
 */
UCLASS()
class YOUR_API UImageFunctionLibrary : public UBlueprintFunctionLibrary
{
	GENERATED_BODY()
	
	UFUNCTION(BlueprintCallable)
	static UTexture2D* GeneratePerlin(int32 textureWidth = 512, int32 textureHeight = 512);

};

Editor widget

Generation in engine

Double check if your UV map of the target mesh is not throwing off your results.