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      1 //
      2 // Book:      OpenGL(R) ES 2.0 Programming Guide
      3 // Authors:   Aaftab Munshi, Dan Ginsburg, Dave Shreiner
      4 // ISBN-10:   0321502795
      5 // ISBN-13:   9780321502797
      6 // Publisher: Addison-Wesley Professional
      7 // URLs:      http://safari.informit.com/9780321563835
      8 //            http://www.opengles-book.com
      9 //
     10 
     11 // esUtil_TGA.c
     12 //
     13 //    This file contains the Win32 implementation of a TGA image loader
     14 
     15 #include <windows.h>
     16 #include <stdio.h>
     17 #include <stdlib.h>
     18 
     19 ///
     20 //  Macros
     21 //
     22 #define INVERTED_BIT            (1 << 5)
     23 
     24 ///
     25 //  Types
     26 //
     27 #pragma pack(push,x1)                            // Byte alignment (8-bit)
     28 #pragma pack(1)
     29 
     30 typedef struct
     31 {
     32    unsigned char  IdSize,
     33                   MapType,
     34                   ImageType;
     35    unsigned short PaletteStart,
     36                   PaletteSize;
     37    unsigned char  PaletteEntryDepth;
     38    unsigned short X,
     39                   Y,
     40                   Width,
     41                   Height;
     42    unsigned char  ColorDepth,
     43                   Descriptor;
     44 
     45 } TGA_HEADER;
     46 
     47 #pragma pack(pop,x1)
     48 
     49 ////////////////////////////////////////////////////////////////////////////////////
     50 //
     51 //  Private Functions
     52 //
     53 
     54 ////////////////////////////////////////////////////////////////////////////////////
     55 //
     56 //  Public Functions
     57 //
     58 //
     59 
     60 
     61 ///
     62 //  WinTGALoad()
     63 //
     64 int WinTGALoad( const char *fileName, char **buffer, int *width, int *height )
     65 {
     66    FILE        *fp;
     67    TGA_HEADER   Header;
     68 
     69    if ( fopen_s ( &fp, fileName, "rb" ) != 0 )
     70    {
     71       return FALSE;
     72    }
     73 
     74    if ( fp == NULL )
     75    {
     76       return FALSE;
     77    }
     78 
     79    fread ( &Header, sizeof(TGA_HEADER), 1, fp );
     80 
     81    *width = Header.Width;
     82    *height = Header.Height;
     83 
     84    if ( Header.ColorDepth == 24 )
     85    {
     86       RGBTRIPLE *Buffer24;
     87 
     88       Buffer24= (RGBTRIPLE*)malloc(sizeof(RGBTRIPLE) * (*width) * (*height));
     89 
     90       if(Buffer24)
     91       {
     92          int i=0;
     93          int x,
     94              y;
     95 
     96          fread(Buffer24, sizeof(RGBTRIPLE), (*width) * (*height), fp);
     97 
     98          *buffer= (LPSTR) malloc(3 * (*width) * (*height));
     99 
    100          for ( y = 0; y < *height; y++ )
    101             for( x = 0; x < *width; x++ )
    102             {
    103                int Index= y * (*width) + x;
    104 
    105                if(!(Header.Descriptor & INVERTED_BIT))
    106                   Index= ((*height) - 1 - y) * (*width) + x;
    107 
    108                (*buffer)[(i * 3)]=      Buffer24[Index].rgbtRed;
    109                (*buffer)[(i * 3) + 1]=  Buffer24[Index].rgbtGreen;
    110                (*buffer)[(i * 3) + 2]=  Buffer24[Index].rgbtBlue;
    111 
    112                i++;
    113             }
    114 
    115          fclose(fp);
    116          free(Buffer24);
    117          return(TRUE);
    118       }
    119    }
    120 
    121    return(FALSE);
    122 }
    123