UE4生成二维码

1.首先到网上找个二维码的库，按照以前的文章导出第三方静态库

2. .h

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

#pragma once

#include "GameFramework/Actor.h"
#include "QRcode.generated.h"

UCLASS()
class TTTTT_API AQRcode : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AQRcode();

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

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;
	UFUNCTION(BlueprintCallable, Category = "My|MyActor")
		FString SetQECode(FString name = "Hello");

	
};

.cpp

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

#include "TTTTT.h"
#include "QRcode.h"
#include "qrencode.h"
#include <string>
#include <fstream>
using namespace std;

#define QRCODE_TEXT					"http://www.ultramundum.org/index.htm";		// Text to encode into QRCode
#define OUT_FILE					"E:/test.bmp"								// Output file name
#define OUT_FILE_PIXEL_PRESCALER	8											// Prescaler (number of pixels in bmp file for each QRCode pixel, on each dimension)

#define PIXEL_COLOR_R				0											// Color of bmp pixels
#define PIXEL_COLOR_G				0
#define PIXEL_COLOR_B				0

// BMP defines

typedef unsigned short	WORD;
typedef unsigned long	DWORD;
typedef signed long		LONG;

#define BI_RGB			0L

#pragma pack(push, 2) //2字节对齐，不然会出问题

typedef struct
{
	WORD    bfType;
	DWORD   bfSize;
	WORD    bfReserved1;
	WORD    bfReserved2;
	DWORD   bfOffBits;
} BITMAPFILEHEADER;

typedef struct
{
	DWORD      biSize;
	LONG       biWidth;
	LONG       biHeight;
	WORD       biPlanes;
	WORD       biBitCount;
	DWORD      biCompression;
	DWORD      biSizeImage;
	LONG       biXPelsPerMeter;
	LONG       biYPelsPerMeter;
	DWORD      biClrUsed;
	DWORD      biClrImportant;
} BITMAPINFOHEADER;

#pragma pack(pop)
//	-------------------------------------------------------



// Sets default values
AQRcode::AQRcode()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned
void AQRcode::BeginPlay()
{
	Super::BeginPlay();
	
}

 //Called every frame
void AQRcode::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

FString AQRcode::SetQECode(FString name)
{
		FString SavePath = FPaths::GameDir() + "Content/test.bmp";
		std::string MyStdString(TCHAR_TO_UTF8(*name));
		std::string MyStdPath(TCHAR_TO_UTF8(*SavePath));
		const char*			szSourceSring = MyStdString.c_str();    //QRCODE_TEXT
		const char*		szSavePathSring = MyStdPath.c_str();
		unsigned int	unWidth, x, y, l, n, unWidthAdjusted, unDataBytes;
		unsigned char*	pRGBData, *pSourceData, *pDestData;
		QRcode*			pQRC;
		FILE*			f;



		// Compute QRCode
		pQRC = QRcode_encodeString(szSourceSring, 0, QR_ECLEVEL_H, QR_MODE_8, 1);
		if (pQRC)
		{
			unWidth = pQRC->width; // 矩阵的维数
			unWidthAdjusted = unWidth * OUT_FILE_PIXEL_PRESCALER * 3; //每一个维度占的像素的个数（8），每个像素3个字节
			if (unWidthAdjusted % 4)
				unWidthAdjusted = (unWidthAdjusted / 4 + 1) * 4;
			unDataBytes = unWidthAdjusted * unWidth * OUT_FILE_PIXEL_PRESCALER;

			// Allocate pixels buffer
			pRGBData = (unsigned char*)malloc(unDataBytes);
			if (!pRGBData)
			{
				printf("Out of memory");
				exit(-1);
			}

			// Preset to white

			memset(pRGBData, 0xff, unDataBytes);


			// Prepare bmp headers

			BITMAPFILEHEADER kFileHeader;
			kFileHeader.bfType = 0x4d42;  // "BM"
			kFileHeader.bfSize = sizeof(BITMAPFILEHEADER) +
				sizeof(BITMAPINFOHEADER) +
				unDataBytes;
			kFileHeader.bfReserved1 = 0;
			kFileHeader.bfReserved2 = 0;
			kFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) +
				sizeof(BITMAPINFOHEADER);

			BITMAPINFOHEADER kInfoHeader;
			kInfoHeader.biSize = sizeof(BITMAPINFOHEADER);
			kInfoHeader.biWidth = unWidth * OUT_FILE_PIXEL_PRESCALER;
			kInfoHeader.biHeight = -((int)unWidth * OUT_FILE_PIXEL_PRESCALER); //负数可以控制图像上下颠倒
			kInfoHeader.biPlanes = 1;
			kInfoHeader.biBitCount = 24;
			kInfoHeader.biCompression = BI_RGB;
			kInfoHeader.biSizeImage = 0;
			kInfoHeader.biXPelsPerMeter = 0;
			kInfoHeader.biYPelsPerMeter = 0;
			kInfoHeader.biClrUsed = 0;
			kInfoHeader.biClrImportant = 0;


			// Convert QrCode bits to bmp pixels

			pSourceData = pQRC->data;
			for (y = 0; y < unWidth; y++)
			{
				pDestData = pRGBData + unWidthAdjusted * y * OUT_FILE_PIXEL_PRESCALER;
				for (x = 0; x < unWidth; x++)
				{
					if (*pSourceData & 1)
					{
						for (l = 0; l < OUT_FILE_PIXEL_PRESCALER; l++)
						{
							for (n = 0; n < OUT_FILE_PIXEL_PRESCALER; n++)
							{
								*(pDestData + n * 3 + unWidthAdjusted * l) = PIXEL_COLOR_B;
								*(pDestData + 1 + n * 3 + unWidthAdjusted * l) = PIXEL_COLOR_G;
								*(pDestData + 2 + n * 3 + unWidthAdjusted * l) = PIXEL_COLOR_R;
							}
						}
					}
					pDestData += 3 * OUT_FILE_PIXEL_PRESCALER;
					pSourceData++;
				}
			}


			// Output the bmp file

			if (!(fopen_s(&f, szSavePathSring, "wb")))
			{
				fwrite(&kFileHeader, sizeof(BITMAPFILEHEADER), 1, f);
				fwrite(&kInfoHeader, sizeof(BITMAPINFOHEADER), 1, f);
				fwrite(pRGBData, sizeof(unsigned char), unDataBytes, f);

				fclose(f);
			}
			else
			{
				GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Yellow, TEXT("QR Unable to open file!"));
			}

			// Free data

			free(pRGBData);
			QRcode_free(pQRC);
			return SavePath;
		}
		else
		{
			GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Yellow, TEXT("QR NULL returned!"));
			return SavePath;
		}
}

3.
参考：

http://blog.youkuaiyun.com/liyuanbhu/article/details/44647139
http://blog.youkuaiyun.com/sunnyloves/article/details/53053487
http://blog.youkuaiyun.com/jameskun77/article/details/53518113