imagelib.c

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/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
// imagelib.c

#include "cmdlib.h"
#include "imagelib.h"


int fgetLittleShort (FILE *f)
{
    byte    b1, b2;

    b1 = fgetc(f);
    b2 = fgetc(f);

    return (short)(b1 + b2*256);
}

int fgetLittleLong (FILE *f)
{
    byte    b1, b2, b3, b4;

    b1 = fgetc(f);
    b2 = fgetc(f);
    b3 = fgetc(f);
    b4 = fgetc(f);

    return b1 + (b2<<8) + (b3<<16) + (b4<<24);
}



/*
============================================================================

                        LBM STUFF

============================================================================
*/


typedef unsigned char   UBYTE;
//conflicts with windows typedef short          WORD;
typedef unsigned short  UWORD;
typedef long            LONG;

typedef enum
{
    ms_none,
    ms_mask,
    ms_transcolor,
    ms_lasso
} mask_t;

typedef enum
{
    cm_none,
    cm_rle1
} compress_t;

typedef struct
{
    UWORD       w,h;
    short       x,y;
    UBYTE       nPlanes;
    UBYTE       masking;
    UBYTE       compression;
    UBYTE       pad1;
    UWORD       transparentColor;
    UBYTE       xAspect,yAspect;
    short       pageWidth,pageHeight;
} bmhd_t;

extern  bmhd_t  bmhd;                       // will be in native byte order



#define FORMID ('F'+('O'<<8)+((int)'R'<<16)+((int)'M'<<24))
#define ILBMID ('I'+('L'<<8)+((int)'B'<<16)+((int)'M'<<24))
#define PBMID  ('P'+('B'<<8)+((int)'M'<<16)+((int)' '<<24))
#define BMHDID ('B'+('M'<<8)+((int)'H'<<16)+((int)'D'<<24))
#define BODYID ('B'+('O'<<8)+((int)'D'<<16)+((int)'Y'<<24))
#define CMAPID ('C'+('M'<<8)+((int)'A'<<16)+((int)'P'<<24))


bmhd_t  bmhd;

int    Align (int l)
{
    if (l&1)
        return l+1;
    return l;
}



/*
================
LBMRLEdecompress

Source must be evenly aligned!
================
*/
byte  *LBMRLEDecompress (byte *source,byte *unpacked, int bpwidth)
{
    int     count;
    byte    b,rept;

    count = 0;

    do
    {
        rept = *source++;

        if (rept > 0x80)
        {
            rept = (rept^0xff)+2;
            b = *source++;
            memset(unpacked,b,rept);
            unpacked += rept;
        }
        else if (rept < 0x80)
        {
            rept++;
            memcpy(unpacked,source,rept);
            unpacked += rept;
            source += rept;
        }
        else
            rept = 0;               // rept of 0x80 is NOP

        count += rept;

    } while (count<bpwidth);

    if (count>bpwidth)
        Error ("Decompression exceeded width!\n");


    return source;
}


/*
=================
LoadLBM
=================
*/
void LoadLBM (const char *filename, byte **picture, byte **palette)
{
    byte    *LBMbuffer, *picbuffer, *cmapbuffer;
    int             y;
    byte    *LBM_P, *LBMEND_P;
    byte    *pic_p;
    byte    *body_p;

    int    formtype,formlength;
    int    chunktype,chunklength;

// qiet compiler warnings
    picbuffer = NULL;
    cmapbuffer = NULL;

//
// load the LBM
//
    LoadFile (filename, (void **)&LBMbuffer);

//
// parse the LBM header
//
    LBM_P = LBMbuffer;
    if ( *(int *)LBMbuffer != LittleLong(FORMID) )
       Error ("No FORM ID at start of file!\n");

    LBM_P += 4;
    formlength = BigLong( *(int *)LBM_P );
    LBM_P += 4;
    LBMEND_P = LBM_P + Align(formlength);

    formtype = LittleLong(*(int *)LBM_P);

    if (formtype != ILBMID && formtype != PBMID)
        Error ("Unrecognized form type: %c%c%c%c\n", formtype&0xff
        ,(formtype>>8)&0xff,(formtype>>16)&0xff,(formtype>>24)&0xff);

    LBM_P += 4;

//
// parse chunks
//

    while (LBM_P < LBMEND_P)
    {
        chunktype = LBM_P[0] + (LBM_P[1]<<8) + (LBM_P[2]<<16) + (LBM_P[3]<<24);
        LBM_P += 4;
        chunklength = LBM_P[3] + (LBM_P[2]<<8) + (LBM_P[1]<<16) + (LBM_P[0]<<24);
        LBM_P += 4;

        switch ( chunktype )
        {
        case BMHDID:
            memcpy (&bmhd,LBM_P,sizeof(bmhd));
            bmhd.w = BigShort(bmhd.w);
            bmhd.h = BigShort(bmhd.h);
            bmhd.x = BigShort(bmhd.x);
            bmhd.y = BigShort(bmhd.y);
            bmhd.pageWidth = BigShort(bmhd.pageWidth);
            bmhd.pageHeight = BigShort(bmhd.pageHeight);
            break;

        case CMAPID:
            cmapbuffer = malloc (768);
            memset (cmapbuffer, 0, 768);
            memcpy (cmapbuffer, LBM_P, chunklength);
            break;

        case BODYID:
            body_p = LBM_P;

            pic_p = picbuffer = malloc (bmhd.w*bmhd.h);
            if (formtype == PBMID)
            {
            //
            // unpack PBM
            //
                for (y=0 ; y<bmhd.h ; y++, pic_p += bmhd.w)
                {
                    if (bmhd.compression == cm_rle1)
                        body_p = LBMRLEDecompress ((byte *)body_p
                        , pic_p , bmhd.w);
                    else if (bmhd.compression == cm_none)
                    {
                        memcpy (pic_p,body_p,bmhd.w);
                        body_p += Align(bmhd.w);
                    }
                }

            }
            else
            {
            //
            // unpack ILBM
            //
                Error ("%s is an interlaced LBM, not packed", filename);
            }
            break;
        }

        LBM_P += Align(chunklength);
    }

    free (LBMbuffer);

    *picture = picbuffer;

    if (palette)
        *palette = cmapbuffer;
}


/*
============================================================================

                            WRITE LBM

============================================================================
*/

/*
==============
WriteLBMfile
==============
*/
void WriteLBMfile (const char *filename, byte *data,
                   int width, int height, byte *palette)
{
    byte    *lbm, *lbmptr;
    int    *formlength, *bmhdlength, *cmaplength, *bodylength;
    int    length;
    bmhd_t  basebmhd;

    lbm = lbmptr = malloc (width*height+1000);

//
// start FORM
//
    *lbmptr++ = 'F';
    *lbmptr++ = 'O';
    *lbmptr++ = 'R';
    *lbmptr++ = 'M';

    formlength = (int*)lbmptr;
    lbmptr+=4;                      // leave space for length

    *lbmptr++ = 'P';
    *lbmptr++ = 'B';
    *lbmptr++ = 'M';
    *lbmptr++ = ' ';

//
// write BMHD
//
    *lbmptr++ = 'B';
    *lbmptr++ = 'M';
    *lbmptr++ = 'H';
    *lbmptr++ = 'D';

    bmhdlength = (int *)lbmptr;
    lbmptr+=4;                      // leave space for length

    memset (&basebmhd,0,sizeof(basebmhd));
    basebmhd.w = BigShort((short)width);
    basebmhd.h = BigShort((short)height);
    basebmhd.nPlanes = BigShort(8);
    basebmhd.xAspect = BigShort(5);
    basebmhd.yAspect = BigShort(6);
    basebmhd.pageWidth = BigShort((short)width);
    basebmhd.pageHeight = BigShort((short)height);

    memcpy (lbmptr,&basebmhd,sizeof(basebmhd));
    lbmptr += sizeof(basebmhd);

    length = lbmptr-(byte *)bmhdlength-4;
    *bmhdlength = BigLong(length);
    if (length&1)
        *lbmptr++ = 0;          // pad chunk to even offset

//
// write CMAP
//
    *lbmptr++ = 'C';
    *lbmptr++ = 'M';
    *lbmptr++ = 'A';
    *lbmptr++ = 'P';

    cmaplength = (int *)lbmptr;
    lbmptr+=4;                      // leave space for length

    memcpy (lbmptr,palette,768);
    lbmptr += 768;

    length = lbmptr-(byte *)cmaplength-4;
    *cmaplength = BigLong(length);
    if (length&1)
        *lbmptr++ = 0;          // pad chunk to even offset

//
// write BODY
//
    *lbmptr++ = 'B';
    *lbmptr++ = 'O';
    *lbmptr++ = 'D';
    *lbmptr++ = 'Y';

    bodylength = (int *)lbmptr;
    lbmptr+=4;                      // leave space for length

    memcpy (lbmptr,data,width*height);
    lbmptr += width*height;

    length = lbmptr-(byte *)bodylength-4;
    *bodylength = BigLong(length);
    if (length&1)
        *lbmptr++ = 0;          // pad chunk to even offset

//
// done
//
    length = lbmptr-(byte *)formlength-4;
    *formlength = BigLong(length);
    if (length&1)
        *lbmptr++ = 0;          // pad chunk to even offset

//
// write output file
//
    SaveFile (filename, lbm, lbmptr-lbm);
    free (lbm);
}


/*
============================================================================

LOAD PCX

============================================================================
*/

typedef struct
{
    char    manufacturer;
    char    version;
    char    encoding;
    char    bits_per_pixel;
    unsigned short  xmin,ymin,xmax,ymax;
    unsigned short  hres,vres;
    unsigned char   palette[48];
    char    reserved;
    char    color_planes;
    unsigned short  bytes_per_line;
    unsigned short  palette_type;
    char    filler[58];
    unsigned char   data;           // unbounded
} pcx_t;


/*
==============
LoadPCX
==============
*/
void LoadPCX (const char *filename, byte **pic, byte **palette, int *width, int *height)
{
    byte    *raw;
    pcx_t   *pcx;
    int     x, y;
    int     len;
    int     dataByte, runLength;
    byte    *out, *pix;

    //
    // load the file
    //
    len = LoadFile (filename, (void **)&raw);

    //
    // parse the PCX file
    //
    pcx = (pcx_t *)raw;
    raw = &pcx->data;

    pcx->xmin = LittleShort(pcx->xmin);
    pcx->ymin = LittleShort(pcx->ymin);
    pcx->xmax = LittleShort(pcx->xmax);
    pcx->ymax = LittleShort(pcx->ymax);
    pcx->hres = LittleShort(pcx->hres);
    pcx->vres = LittleShort(pcx->vres);
    pcx->bytes_per_line = LittleShort(pcx->bytes_per_line);
    pcx->palette_type = LittleShort(pcx->palette_type);

    if (pcx->manufacturer != 0x0a
        || pcx->version != 5
        || pcx->encoding != 1
        || pcx->bits_per_pixel != 8
        || pcx->xmax >= 640
        || pcx->ymax >= 480)
        Error ("Bad pcx file %s", filename);
    
    if (palette)
    {
        *palette = malloc(768);
        memcpy (*palette, (byte *)pcx + len - 768, 768);
    }

    if (width)
        *width = pcx->xmax+1;
    if (height)
        *height = pcx->ymax+1;

    if (!pic)
        return;

    out = malloc ( (pcx->ymax+1) * (pcx->xmax+1) );
    if (!out)
        Error ("Skin_Cache: couldn't allocate");

    *pic = out;

    pix = out;

    for (y=0 ; y<=pcx->ymax ; y++, pix += pcx->xmax+1)
    {
        for (x=0 ; x<=pcx->xmax ; )
        {
            dataByte = *raw++;

            if((dataByte & 0xC0) == 0xC0)
            {
                runLength = dataByte & 0x3F;
                dataByte = *raw++;
            }
            else
                runLength = 1;

            // FIXME: this shouldn't happen, but it does.  Are we decoding the file wrong?
            // Truncate runLength so we don't overrun the end of the buffer
            if ( ( y == pcx->ymax ) && ( x + runLength > pcx->xmax + 1 ) ) {
                runLength = pcx->xmax - x + 1;
            }

            while(runLength-- > 0)
                pix[x++] = dataByte;
        }

    }

    if ( raw - (byte *)pcx > len)
        Error ("PCX file %s was malformed", filename);

    free (pcx);
}

/* 
============== 
WritePCXfile 
============== 
*/ 
void WritePCXfile (const char *filename, byte *data, 
                   int width, int height, byte *palette) 
{
    int     i, j, length;
    pcx_t   *pcx;
    byte        *pack;
      
    pcx = malloc (width*height*2+1000);
    memset (pcx, 0, sizeof(*pcx));

    pcx->manufacturer = 0x0a;   // PCX id
    pcx->version = 5;           // 256 color
    pcx->encoding = 1;      // uncompressed
    pcx->bits_per_pixel = 8;        // 256 color
    pcx->xmin = 0;
    pcx->ymin = 0;
    pcx->xmax = LittleShort((short)(width-1));
    pcx->ymax = LittleShort((short)(height-1));
    pcx->hres = LittleShort((short)width);
    pcx->vres = LittleShort((short)height);
    pcx->color_planes = 1;      // chunky image
    pcx->bytes_per_line = LittleShort((short)width);
    pcx->palette_type = LittleShort(1);     // not a grey scale

    // pack the image
    pack = &pcx->data;
    
    for (i=0 ; i<height ; i++)
    {
        for (j=0 ; j<width ; j++)
        {
            if ( (*data & 0xc0) != 0xc0)
                *pack++ = *data++;
            else
            {
                *pack++ = 0xc1;
                *pack++ = *data++;
            }
        }
    }
            
    // write the palette
    *pack++ = 0x0c; // palette ID byte
    for (i=0 ; i<768 ; i++)
        *pack++ = *palette++;
        
// write output file 
    length = pack - (byte *)pcx;
    SaveFile (filename, pcx, length);

    free (pcx);
} 
 
/*
============================================================================

LOAD BMP

============================================================================
*/


/*

// we can't just use these structures, because
// compiler structure alignment will not be portable
// on this unaligned stuff

typedef struct tagBITMAPFILEHEADER { // bmfh 
        WORD    bfType;             // BM
        DWORD   bfSize; 
        WORD    bfReserved1; 
        WORD    bfReserved2; 
        DWORD   bfOffBits; 
} BITMAPFILEHEADER; 
 
typedef struct tagBITMAPINFOHEADER{ // bmih 
   DWORD  biSize; 
   LONG   biWidth; 
   LONG   biHeight; 
   WORD   biPlanes; 
   WORD   biBitCount 
   DWORD  biCompression; 
   DWORD  biSizeImage; 
   LONG   biXPelsPerMeter; 
   LONG   biYPelsPerMeter; 
   DWORD  biClrUsed; 
   DWORD  biClrImportant; 
} BITMAPINFOHEADER; 
 
typedef struct tagBITMAPINFO { // bmi 
   BITMAPINFOHEADER bmiHeader; 
   RGBQUAD          bmiColors[1]; 
} BITMAPINFO; 

typedef struct tagBITMAPCOREHEADER { // bmch 
        DWORD   bcSize; 
        WORD    bcWidth; 
        WORD    bcHeight; 
        WORD    bcPlanes; 
        WORD    bcBitCount; 
} BITMAPCOREHEADER; 
 
typedef struct _BITMAPCOREINFO {    // bmci 
        BITMAPCOREHEADER  bmciHeader; 
        RGBTRIPLE         bmciColors[1]; 
} BITMAPCOREINFO; 
 
*/

/*
==============
LoadBMP
==============
*/
void LoadBMP (const char *filename, byte **pic, byte **palette, int *width, int *height)
{
    byte    *out;
    FILE    *fin;
    int     i;
    int     bfSize; 
    int     bfOffBits; 
    int     structSize;
    int     bcWidth; 
    int     bcHeight; 
    int     bcPlanes; 
    int     bcBitCount; 
    byte    bcPalette[1024];
    qboolean    flipped;

    fin = fopen (filename, "rb");
    if (!fin) {
        Error ("Couldn't read %s", filename);
    }

    i = fgetLittleShort (fin);
    if (i != 'B' + ('M'<<8) ) {
        Error ("%s is not a bmp file", filename);
    }

    bfSize = fgetLittleLong (fin);
    fgetLittleShort(fin);
    fgetLittleShort(fin);
    bfOffBits = fgetLittleLong (fin);

    // the size will tell us if it is a
    // bitmapinfo or a bitmapcore
    structSize = fgetLittleLong (fin);
    if (structSize == 40) {
        // bitmapinfo
        bcWidth = fgetLittleLong(fin); 
        bcHeight= fgetLittleLong(fin); 
        bcPlanes = fgetLittleShort(fin); 
        bcBitCount = fgetLittleShort(fin); 

        fseek (fin, 24, SEEK_CUR);

        if (palette) {
            fread (bcPalette, 1, 1024, fin);
            *palette = malloc(768);

            for (i = 0 ; i < 256 ; i++) {
                (*palette)[i * 3 + 0] = bcPalette[i * 4 + 2];
                (*palette)[i * 3 + 1] = bcPalette[i * 4 + 1];
                (*palette)[i * 3 + 2] = bcPalette[i * 4 + 0];
            }
        }
    } else if (structSize == 12) {
        // bitmapcore
        bcWidth = fgetLittleShort(fin); 
        bcHeight= fgetLittleShort(fin); 
        bcPlanes = fgetLittleShort(fin); 
        bcBitCount = fgetLittleShort(fin); 

        if (palette) {
            fread (bcPalette, 1, 768, fin);
            *palette = malloc(768);

            for (i = 0 ; i < 256 ; i++) {
                (*palette)[i * 3 + 0] = bcPalette[i * 3 + 2];
                (*palette)[i * 3 + 1] = bcPalette[i * 3 + 1];
                (*palette)[i * 3 + 2] = bcPalette[i * 3 + 0];
            }
        }
    } else {
        Error ("%s had strange struct size", filename);
    }
    
    if (bcPlanes != 1) {
        Error ("%s was not a single plane image", filename);
    }

    if (bcBitCount != 8) {
        Error ("%s was not an 8 bit image", filename);
    }

    if (bcHeight < 0) {
        bcHeight = -bcHeight;
        flipped = qtrue;
    } else {
        flipped = qfalse;
    }

    if (width)
        *width = bcWidth;
    if (height)
        *height = bcHeight;

    if (!pic) {
        fclose (fin);
        return;
    }

    out = malloc ( bcWidth * bcHeight );
    *pic = out;
    fseek (fin, bfOffBits, SEEK_SET);

    if (flipped) {
        for (i = 0 ; i < bcHeight ; i++) {
            fread (out + bcWidth * (bcHeight - 1 - i), 1, bcWidth, fin);
        }
    } else {
        fread (out, 1, bcWidth*bcHeight, fin);
    }

    fclose (fin);
}


/*
============================================================================

LOAD IMAGE

============================================================================
*/

/*
==============
Load256Image

Will load either an lbm or pcx, depending on extension.
Any of the return pointers can be NULL if you don't want them.
==============
*/
void Load256Image (const char *name, byte **pixels, byte **palette,
                   int *width, int *height)
{
    char    ext[128];

    ExtractFileExtension (name, ext);
    if (!Q_stricmp (ext, "lbm"))
    {
        LoadLBM (name, pixels, palette);
        if (width)
            *width = bmhd.w;
        if (height)
            *height = bmhd.h;
    }
    else if (!Q_stricmp (ext, "pcx"))
    {
        LoadPCX (name, pixels, palette, width, height);
    }
    else if (!Q_stricmp (ext, "bmp"))
    {
        LoadBMP (name, pixels, palette, width, height);
    }
    else
        Error ("%s doesn't have a known image extension", name);
}


/*
==============
Save256Image

Will save either an lbm or pcx, depending on extension.
==============
*/
void Save256Image (const char *name, byte *pixels, byte *palette,
                   int width, int height)
{
    char    ext[128];

    ExtractFileExtension (name, ext);
    if (!Q_stricmp (ext, "lbm"))
    {
        WriteLBMfile (name, pixels, width, height, palette);
    }
    else if (!Q_stricmp (ext, "pcx"))
    {
        WritePCXfile (name, pixels, width, height, palette);
    }
    else
        Error ("%s doesn't have a known image extension", name);
}




/*
============================================================================

TARGA IMAGE

============================================================================
*/

typedef struct _TargaHeader {
    unsigned char   id_length, colormap_type, image_type;
    unsigned short  colormap_index, colormap_length;
    unsigned char   colormap_size;
    unsigned short  x_origin, y_origin, width, height;
    unsigned char   pixel_size, attributes;
} TargaHeader;

/*
=============
LoadTGABuffer
=============
*/
void LoadTGABuffer ( byte *buffer, byte **pic, int *width, int *height)
{
    int     columns, rows, numPixels;
    byte    *pixbuf;
    int     row, column;
    byte    *buf_p;
    TargaHeader targa_header;
    byte        *targa_rgba;

    *pic = NULL;

    buf_p = buffer;

    targa_header.id_length = *buf_p++;
    targa_header.colormap_type = *buf_p++;
    targa_header.image_type = *buf_p++;
    
    targa_header.colormap_index = LittleShort ( *(short *)buf_p );
    buf_p += 2;
    targa_header.colormap_length = LittleShort ( *(short *)buf_p );
    buf_p += 2;
    targa_header.colormap_size = *buf_p++;
    targa_header.x_origin = LittleShort ( *(short *)buf_p );
    buf_p += 2;
    targa_header.y_origin = LittleShort ( *(short *)buf_p );
    buf_p += 2;
    targa_header.width = LittleShort ( *(short *)buf_p );
    buf_p += 2;
    targa_header.height = LittleShort ( *(short *)buf_p );
    buf_p += 2;
    targa_header.pixel_size = *buf_p++;
    targa_header.attributes = *buf_p++;

    if (targa_header.image_type!=2 
        && targa_header.image_type!=10
        && targa_header.image_type != 3 ) 
    {
        Error("LoadTGA: Only type 2 (RGB), 3 (gray), and 10 (RGB) TGA images supported\n");
    }

    if ( targa_header.colormap_type != 0 )
    {
        Error("LoadTGA: colormaps not supported\n" );
    }

    if ( ( targa_header.pixel_size != 32 && targa_header.pixel_size != 24 ) && targa_header.image_type != 3 )
    {
        Error("LoadTGA: Only 32 or 24 bit images supported (no colormaps)\n");
    }

    columns = targa_header.width;
    rows = targa_header.height;
    numPixels = columns * rows;

    if (width)
        *width = columns;
    if (height)
        *height = rows;

    targa_rgba = malloc (numPixels*4);
    *pic = targa_rgba;

    if (targa_header.id_length != 0)
        buf_p += targa_header.id_length;  // skip TARGA image comment
    
    if ( targa_header.image_type==2 || targa_header.image_type == 3 )
    { 
        // Uncompressed RGB or gray scale image
        for(row=rows-1; row>=0; row--) 
        {
            pixbuf = targa_rgba + row*columns*4;
            for(column=0; column<columns; column++) 
            {
                unsigned char red,green,blue,alphabyte;
                switch (targa_header.pixel_size) 
                {
                    
                case 8:
                    blue = *buf_p++;
                    green = blue;
                    red = blue;
                    *pixbuf++ = red;
                    *pixbuf++ = green;
                    *pixbuf++ = blue;
                    *pixbuf++ = 255;
                    break;

                case 24:
                    blue = *buf_p++;
                    green = *buf_p++;
                    red = *buf_p++;
                    *pixbuf++ = red;
                    *pixbuf++ = green;
                    *pixbuf++ = blue;
                    *pixbuf++ = 255;
                    break;
                case 32:
                    blue = *buf_p++;
                    green = *buf_p++;
                    red = *buf_p++;
                    alphabyte = *buf_p++;
                    *pixbuf++ = red;
                    *pixbuf++ = green;
                    *pixbuf++ = blue;
                    *pixbuf++ = alphabyte;
                    break;
                default:
                    //Error("LoadTGA: illegal pixel_size '%d' in file '%s'\n", targa_header.pixel_size, name );
                    break;
                }
            }
        }
    }
    else if (targa_header.image_type==10) {   // Runlength encoded RGB images
        unsigned char red,green,blue,alphabyte,packetHeader,packetSize,j;

        red = 0;
        green = 0;
        blue = 0;
        alphabyte = 0xff;

        for(row=rows-1; row>=0; row--) {
            pixbuf = targa_rgba + row*columns*4;
            for(column=0; column<columns; ) {
                packetHeader= *buf_p++;
                packetSize = 1 + (packetHeader & 0x7f);
                if (packetHeader & 0x80) {        // run-length packet
                    switch (targa_header.pixel_size) {
                        case 24:
                                blue = *buf_p++;
                                green = *buf_p++;
                                red = *buf_p++;
                                alphabyte = 255;
                                break;
                        case 32:
                                blue = *buf_p++;
                                green = *buf_p++;
                                red = *buf_p++;
                                alphabyte = *buf_p++;
                                break;
                        default:
                            //Error("LoadTGA: illegal pixel_size '%d' in file '%s'\n", targa_header.pixel_size, name );
                            break;
                    }
    
                    for(j=0;j<packetSize;j++) {
                        *pixbuf++=red;
                        *pixbuf++=green;
                        *pixbuf++=blue;
                        *pixbuf++=alphabyte;
                        column++;
                        if (column==columns) { // run spans across rows
                            column=0;
                            if (row>0)
                                row--;
                            else
                                goto breakOut;
                            pixbuf = targa_rgba + row*columns*4;
                        }
                    }
                }
                else {                            // non run-length packet
                    for(j=0;j<packetSize;j++) {
                        switch (targa_header.pixel_size) {
                            case 24:
                                    blue = *buf_p++;
                                    green = *buf_p++;
                                    red = *buf_p++;
                                    *pixbuf++ = red;
                                    *pixbuf++ = green;
                                    *pixbuf++ = blue;
                                    *pixbuf++ = 255;
                                    break;
                            case 32:
                                    blue = *buf_p++;
                                    green = *buf_p++;
                                    red = *buf_p++;
                                    alphabyte = *buf_p++;
                                    *pixbuf++ = red;
                                    *pixbuf++ = green;
                                    *pixbuf++ = blue;
                                    *pixbuf++ = alphabyte;
                                    break;
                            default:
                                //Sys_Printf("LoadTGA: illegal pixel_size '%d' in file '%s'\n", targa_header.pixel_size, name );
                                break;
                        }
                        column++;
                        if (column==columns) { // pixel packet run spans across rows
                            column=0;
                            if (row>0)
                                row--;
                            else
                                goto breakOut;
                            pixbuf = targa_rgba + row*columns*4;
                        }                       
                    }
                }
            }
            breakOut:;
        }
    }

    //free(buffer);
}



/*
=============
LoadTGA
=============
*/
void LoadTGA (const char *name, byte **pixels, int *width, int *height)
{
    byte            *buffer;
  int nLen;
    //
    // load the file
    //
    nLen = LoadFile ( ( char * ) name, (void **)&buffer);
    if (nLen == -1) 
  {
        Error ("Couldn't read %s", name);
  }

  LoadTGABuffer(buffer, pixels, width, height);

}


/*
================
WriteTGA
================
*/
void WriteTGA (const char *filename, byte *data, int width, int height) {
    byte    *buffer;
    int     i;
    int     c;
    FILE    *f;

    buffer = malloc(width*height*4 + 18);
    memset (buffer, 0, 18);
    buffer[2] = 2;      // uncompressed type
    buffer[12] = width&255;
    buffer[13] = width>>8;
    buffer[14] = height&255;
    buffer[15] = height>>8;
    buffer[16] = 32;    // pixel size

    // swap rgb to bgr
    c = 18 + width * height * 4;
    for (i=18 ; i<c ; i+=4)
    {
        buffer[i] = data[i-18+2];       // blue
        buffer[i+1] = data[i-18+1];     // green
        buffer[i+2] = data[i-18+0];     // red
        buffer[i+3] = data[i-18+3];     // alpha
    }

    f = fopen (filename, "wb");
    fwrite (buffer, 1, c, f);
    fclose (f);

    free (buffer);
}

/*
============================================================================

LOAD32BITIMAGE

============================================================================
*/

/*
==============
Load32BitImage

Any of the return pointers can be NULL if you don't want them.
==============
*/
void Load32BitImage (const char *name, unsigned **pixels,  int *width, int *height)
{
    char    ext[128];
    byte    *palette;
    byte    *pixels8;
    byte    *pixels32;
    int     size;
    int     i;
    int     v;

    ExtractFileExtension (name, ext);
    if (!Q_stricmp (ext, "tga")) {
        LoadTGA (name, (byte **)pixels, width, height);
    } else {
        Load256Image (name, &pixels8, &palette, width, height);
        if (!pixels) {
            return;
        }
        size = *width * *height;
        pixels32 = malloc(size * 4);
        *pixels = (unsigned *)pixels32;
        for (i = 0 ; i < size ; i++) {
            v = pixels8[i];
            pixels32[i*4 + 0] = palette[ v * 3 + 0 ];
            pixels32[i*4 + 1] = palette[ v * 3 + 1 ];
            pixels32[i*4 + 2] = palette[ v * 3 + 2 ];
            pixels32[i*4 + 3] = 0xff;
        }
    }
}

---