Simple BMP image Reading

BMP full Name Bitmap (bitmap), is the standard image file format in Windows, can be read into a BMP image as a texture.

here is the bitmap load Class I am currently using. First is the header file:

#define Swapcolor (A, a) {         (a) ^= (b);             (b) ^= (a);             (a) ^= (b);     Class Bmploader {private:        unsigned char* header;//file header        unsigned int datapos;//read position        unsigned int width, height;//picture width height        unsigned int imagesize;//picture content size public:        unsigned char * data;//picture content RGB        bmploader ();        ~bmploader ();        void Bfree ();        int getwidth ();        int getheight ();        BOOL LoadBitmap (const char* fileName);};

Swapcolor is used to exchange color values, because the BMP storage color order is BGR, to turn it into RGB
This is followed by a specific implementation:

Bmploader::bmploader () {        header=new unsigned char[54];} Bmploader::~bmploader () {        bfree ();        delete[] data;} void Bmploader::bfree () {        delete[] header;}

constructors and destructors with a file header size of 54 bytes

followed by the main method of reading the image, filename is the image name (with path)

BOOL Bmploader::loadbitmap (const char* fileName) {file * file = fopen (FileName, "RB");                if (!file) {printf ("Image could not being opened");        return false;            } if (header, 1, fread, file)!=54) {//Header not 54 bytes read failed printf ("Not a correct BMP file");        return false;            } if (header[0]!= ' B ' | | header[1]!= ' M ') {//header at the beginning of the file is not BM Read failed printf ("Not a correct BMP file");        return false; } datapos = * (int*) & (header[0x0a]);//Read position location at file header 0x0A imageSize = * (int*) & (header[0x22]);//picture content is large Small data location at file header 0x22 width = * (int*) & (header[0x12]);//Picture width data position at file header 0x12 height = * (int*) & (Heade R[0X16]);//Picture height data position at file header 0x16 if (imagesize==0) imagesize=width*height*3;//picture content data = Total pixel number x3 (simplicity uses a width height of 2 N-size picture, regardless of 4-byte alignment) if (datapos==0) datapos=54;//file header is read at 54 bytes at data = new unsigned char [imag Esize];//data put Pixel information frEAD (data,1,imagesize,file);//Read pixel fclose (file);  for (int i= 0;i< (int) imagesize;i+=3) Swapcolor (data[i],data[i+2]);//BGR becomes RGB return true;}

get picture width and height:

int Bmploader::getwidth () {        return width;} int Bmploader::getheight () {        return height;}

call LoadBitmap to load the image data, data is the image of the pixels.
Note that this class can only be used to read 24-bit BMP bitmaps, and the width and height of the graph is 2 of the n-th square.

reference:  http://www.opengl-tutorial.org/beginners-tutorials/tutorial-5-a-textured-cube/

Simple BMP image Reading