www.pudn.com > Billiard.rar > LoadTGA.cpp

// LoadTGA.cpp: implementation of the CLoadTGA class. 
// 
////////////////////////////////////////////////////////////////////// 
 
#include "stdafx.h" 
#include "Billiard.h" 
#include "LoadTGA.h" 
 
#ifdef _DEBUG 
#undef THIS_FILE 
static char THIS_FILE[]=__FILE__; 
#define new DEBUG_NEW 
#endif 
 
////////////////////////////////////////////////////////////////////// 
// Construction/Destruction 
////////////////////////////////////////////////////////////////////// 
 
CLoadTGA::CLoadTGA() 
{ 
 
} 
 
CLoadTGA::~CLoadTGA() 
{ 
 
} 
 
//  下面函数的功能是将TGA文件中的数据读入到一个位图变量中 
unsigned char *CLoadTGA::LoadTGAFile( char * strFilename,	tTGAHeader_s *header) 
{ 
	short			BitsPerPixel; 
	unsigned char	*buffer; 
	int bitsize;		// 位图总的大小 
	unsigned char	*newbits; 
	unsigned char	*from, *to; 
	int		i, j, width; 
    FILE* file; 
    long dwWidth, dwHeight; 
 
    // 打开文件并读入文件头信息 
	file = fopen( strFilename, "rb"); 
    if( NULL == file ) 
        return NULL; 
 
    if ( fread( header, sizeof( tTGAHeader_s ), 1, file ) != 1 ) 
    { 
        fclose( file ); 
        return NULL; 
    } 
 
    // 获得图像数据的大小 
	dwWidth = (long)header->d_width; 
	dwHeight = (long)header->d_height; 
	BitsPerPixel = (short)header->d_pixel_size;          // 像素大小 
 
    // 创建一个装入图像数据的位图 
	bitsize = dwWidth * dwHeight * (BitsPerPixel/8); 
	if ((newbits = (unsigned char *)calloc(bitsize, 1)) == NULL) 
	{ 
        fclose( file ); 
        return NULL; 
	} 
 	buffer = (unsigned char *)malloc(dwWidth*dwHeight*(BitsPerPixel / 8)); 
    if ( fread( buffer, dwWidth*dwHeight*(BitsPerPixel / 8), 1, file ) != 1 ) 
	{ 
        fclose( file ); 
		free(buffer); 
		free(newbits); 
        return NULL; 
	} 
 
	width   = (BitsPerPixel / 8) * dwWidth; 
 
    for (i = 0; i < dwHeight; i ++) 
		for (j = 0, from = ((unsigned char *)buffer) + i * width, 
	        to = newbits + i * width; 
			j < dwWidth; 
			j ++, from += (BitsPerPixel / 8), to += (BitsPerPixel / 8)) 
        { 
				if (BitsPerPixel == 24) 
				{ 
					to[0] = from[2]; 
					to[1] = from[1]; 
					to[2] = from[0]; 
				} 
				else 
				{ 
					to[0] = from[2]; 
					to[1] = from[1]; 
					to[2] = from[0]; 
					to[3] = from[3]; 
				} 
        }; 
	free(buffer); 
    fclose( file ); 
 
    return newbits; 
}