www.pudn.com > opengl_pick_sample.rar > bmpreader.cpp

//	bmpreader.cpp 
// 
 
#include "stdafx.h" 
#include "dibsect.h" 
 
/* 
 * Dib Header Marker - used in writing DIBs to files 
 */ 
#define DIB_HEADER_MARKER   ((WORD) ('M' << 8) | 'B') 
int ReadDIBFile(const char * filename, DIBSection& dib); 
 
int ReadBMPFile(const char * filename, DIBSection& dib) 
{ 
	int result = ReadDIBFile(filename,dib); 
	return result; 
} 
 
int ReadDIBFile(const char * filename, DIBSection& dib) 
{ 
	int result = 0; 
 
	BITMAPFILEHEADER bmfHeader; 
	BITMAPINFO bmInfo; 
	DWORD dwBitsSize; 
 
	/* 
	** get length of DIB in bytes for use when reading 
	*/ 
 
	FILE * fp = fopen(filename,"rb"); 
	if (fp) 
	{ 
		fseek(fp,0l,SEEK_END); 
		dwBitsSize = ftell(fp); 
		fseek(fp,0l,SEEK_SET); 
 
		unsigned long bmfHeaderSize = sizeof(bmfHeader); 
 
		if (fread(&bmfHeader,sizeof(unsigned char),bmfHeaderSize,fp) == bmfHeaderSize) 
		{ 
			//if (bmfHeader.bfType != DIB_HEADER_MARKER) 
			//	return result; 
		} 
 
		unsigned long bmInfoSize = sizeof(BITMAPINFOHEADER); 
 
		if (fread(&bmInfo,sizeof(unsigned char),bmInfoSize,fp) == bmInfoSize) 
		{ 
		} 
		else 
		{ 
			return result; 
		} 
 
		if (bmInfo.bmiHeader.biBitCount != 24) 
		{ 
			return result; 
		} 
 
		int nColors = bmInfo.bmiHeader.biClrUsed ? bmInfo.bmiHeader.biClrUsed :  
						1 << bmInfo.bmiHeader.biBitCount; 
 
		int w = bmInfo.bmiHeader.biWidth; 
		int h = bmInfo.bmiHeader.biHeight; 
		int bitcount = bmInfo.bmiHeader.biBitCount; 
 
		dib.Create(w,h,bitcount); 
 
		if (dib.IsCreated()) 
		{ 
			unsigned long total_width = dib.GetTotalWidth(); 
 
			DWORD remainder = dwBitsSize - bmfHeaderSize - bmInfo.bmiHeader.biSize; 
 
			unsigned char * bits = new unsigned char[remainder]; 
			if (!bits) 
			{ 
				  // outta memory 
				return result; 
			} 
 
			memset(bits,0,(size_t)remainder); 
			unsigned long bytes_read = fread(bits,sizeof(unsigned char),remainder,fp); 
 
			if (bytes_read == remainder) 
			{ 
				result++; 
 
				if (nColors <= 256) 
				{ 
				} 
 
				unsigned char * dst = (unsigned char *)dib.GetBits(); 
				unsigned long dst_offset; 
				unsigned long src_offset; 
 
				for (int row=0;row