reading a .bmp file in c++

Question

I\'m trying to load a bmp file for reusing it in opengl. I\'ve found some code via google on how to load a bmp file. I took this code and put in a class Bitmap in my project. Th

Answer 1

The header needs to be 2 byte aligned.

#pragma pack(2) // Add this

typedef struct
{
    unsigned short bfType;
    unsigned int   bfSize;
    unsigned short bfReserved1;
    unsigned short bfReserved2;
    unsigned int   bfOffBits;
} BITMAPFILEHEADER;

#pragma pack() // and this

Answer 2

BITMAPINFOHEADER :: You need to read first the biSize in order to know how large the info header is, you cannot rely on sizeof().

Check out this wiki article about the file format

Answer 3

How about letting your Windows OS load it for you with LoadImage.

HBITMAP hbm = LoadImage( NULL, path, 0, 0, LR_LOADFROMFILE|LR_CREATEDIBSECTION);

Use GetObject() to find further info like size, etc. and GetDIBits() if you want to get at the individual bits.