在c++中读取.bmp文件

我正在尝试加载一个bmp文件，以便在opengl中重用它。我通过谷歌找到了一些关于如何加载bmp文件的代码。我把这段代码放在我的项目中的位图类中。该类还远未完成，但文件头的读取已经出错。在读取INFOHEADER和FILEHEADER的字节后，我的结构中没有正确的值。一些想法？

//
//  Bitmap.h
//
#ifndef LaserMaze_Bitmap_h
#define LaserMaze_Bitmap_h
typedef struct                       /**** BMP file header structure ****/
{
    unsigned short bfType;           /* Magic number for file */
    unsigned int   bfSize;           /* Size of file */
    unsigned short bfReserved1;      /* Reserved */
    unsigned short bfReserved2;      /* ... */
    unsigned int   bfOffBits;        /* Offset to bitmap data */
} BITMAPFILEHEADER;
#  define BF_TYPE 0x4D42             /* "MB" */
typedef struct                       /**** BMP file info structure ****/
{
    unsigned int   biSize;           /* Size of info header */
    int            biWidth;          /* Width of image */
    int            biHeight;         /* Height of image */
    unsigned short biPlanes;         /* Number of color planes */
    unsigned short biBitCount;       /* Number of bits per pixel */
    unsigned int   biCompression;    /* Type of compression to use */
    unsigned int   biSizeImage;      /* Size of image data */
    int            biXPelsPerMeter;  /* X pixels per meter */
    int            biYPelsPerMeter;  /* Y pixels per meter */
    unsigned int   biClrUsed;        /* Number of colors used */
    unsigned int   biClrImportant;   /* Number of important colors */
} BITMAPINFOHEADER;
/*
 * Constants for the biCompression field...
 */
#  define BI_RGB       0             /* No compression - straight BGR data */
#  define BI_RLE8      1             /* 8-bit run-length compression */
#  define BI_RLE4      2             /* 4-bit run-length compression */
#  define BI_BITFIELDS 3             /* RGB bitmap with RGB masks */
typedef struct                       /**** Colormap entry structure ****/
{
    unsigned char  rgbBlue;          /* Blue value */
    unsigned char  rgbGreen;         /* Green value */
    unsigned char  rgbRed;           /* Red value */
    unsigned char  rgbReserved;      /* Reserved */
} RGBQUAD;
class Bitmap {
public:
    Bitmap(const char* filename);
    ~Bitmap();
    RGBQUAD* pixels;
    BITMAPFILEHEADER fh;
    BITMAPINFOHEADER ih;
    private:
};
#endif

cpp

//  Bitmap.cpp
//
#include <iostream>
#include <stdio.h>
#include "Bitmap.h"
Bitmap::Bitmap(const char* filename) {
    FILE* file;
    file = fopen(filename, "rb");
    std::cout << sizeof(BITMAPFILEHEADER) << std::endl;
    if(file != NULL) { // file opened
        BITMAPFILEHEADER h;
        size_t x = fread(&h, sizeof(BITMAPFILEHEADER), 1, file); //reading the FILEHEADER
        std::cout << x;
        fread(&this->ih, sizeof(BITMAPINFOHEADER), 1, file);
        fclose(file);
    }
}