#include?“jpegtools.h“

void?DecodeJPG（jpeg_decompress_struct*?cinfo?JPGtexture?*pImageData）
{
????GLint?rowSpan;
????//讀取JPEG文件頭
????jpeg_read_header（cinfo?TRUE）;
????//?使用壓縮信息開始解壓縮
????jpeg_start_decompress（cinfo）;
????//?讀取圖像大小、像素數據
????rowSpan?=?cinfo->image_width?*?cinfo->num_components;
????pImageData->width???=?cinfo->image_width;
????pImageData->height???=?cinfo->image_height;
????//為pImageData->data分配內存
????pImageData->texels?=?new?GLubyte[rowSpan?*?pImageData->height];
????switch?（cinfo->num_components）
????{
????????case?1:
????????{
????????????????pImageData->internalFormat?=?1;
????????????????pImageData->format?=?GL_LUMINANCE;
????????????????break;
????????}
????????case?2:
????????{
????????????????pImageData->internalFormat?=?2;
????????????????pImageData->format?=?GL_LUMINANCE_ALPHA;
????????????????break;
????????}
????????case?3:
????????{
????????????????pImageData->internalFormat?=?3;
????????????????pImageData->format?=?GL_RGB;
????????????????break;
????????}
????????case?4:
????????{
????????????????pImageData->internalFormat?=?4;
????????????????pImageData->format?=?GL_RGBA;
????????????????break;
????????}
????????default:
????????????break;
????}
????//創建每一行數據的指針
????GLubyte?**?rowPtr?=?new?GLubyte?*[pImageData->height];
????for?（int?i?=?0;?i?height;?i++）
????????rowPtr[i]?=?&（pImageData->texels[（pImageData->height-1-i）*rowSpan]）;
????//讀取像素數據
????int?rowsRead?=?0;
????while?（cinfo->output_scanline?output_height）
????{
????????rowsRead+=jpeg_read_scanlines（cinfo&rowPtr[rowsRead]
??????????????????????????????????????cinfo->output_height-rowsRead）;
????}
????//?釋放臨時使用的指針
????delete?[]?rowPtr;
????//?解壓縮結束
????jpeg_finish_decompress（cinfo）;
}

JPGtexture?*ReadJPEGFromFile（const?char?*filename）
{
????struct?jpeg_decompress_struct?cinfo;
????JPGtexture?*pImageData?=?NULL;???????//存放JPEG數據
????FILE?*pFile;
????//打開文件
????if（（pFile?=?fopen（filename?“rb“））?==?NULL）
????{
????????fprintf?（stderr?“error:?couldn‘t?open?\“%s\“!\n“?filename）;
????????return?NULL;
????}
????//?定義一個錯誤句柄
????jpeg_error_mgr?jerr;
????//解壓縮信息對象指向錯誤句柄
????cinfo.err?=?jpeg_std_error（&jerr）;
????//?初始化解壓縮對象
????jpeg_create_decompress（&cinfo）;
????//指定數據源
????jpeg_stdio_src（&cinfo?pFile）;
????//分配內存，用于存放數據
????pImageData?=?（JPGtexture*）malloc（sizeof（JPGtexture））;
????//?進行解壓縮
????DecodeJPG（&cinfo?pImageData）;
????//?釋放內存
????jpeg_destroy_decompress（&cinfo）;
????fclose（pFile）;
????//?返回已經解壓縮后的數據
????return?pImageData;
}

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2018-04-14?13:16??JPEG_texture\
?????文件??????427514??2016-10-11?13:18??JPEG_texture\car.jpg
?????文件?????????287??2016-10-10?13:58??JPEG_texture\Identity.fp
?????文件?????????327??2016-10-10?13:57??JPEG_texture\Identity.vp
?????文件????????2756??2016-10-11?14:26??JPEG_texture\jpegtools.cpp
?????文件?????????444??2016-10-11?14:24??JPEG_texture\jpegtools.h
?????文件????????5386??2016-10-11?14:20??JPEG_texture\main.cpp
?????文件?????????307??2016-10-11?13:25??JPEG_texture\Rectangle.pro