/*
** Copyright (c) 1995, 3Dfx Interactive, Inc.
** All Rights Reserved.
**
** This is UNPUBLISHED PROPRIETARY SOURCE CODE of 3Dfx Interactive, Inc.;
** the contents of this file may not be disclosed to third parties, copied or
** duplicated in any form, in whole or in part, without the prior written
** permission of 3Dfx Interactive, Inc.
**
** RESTRICTED RIGHTS LEGEND:
** Use, duplication or disclosure by the Government is subject to restrictions
** as set forth in subdivision (c)(1)(ii) of the Rights in Technical Data
** and Computer Software clause at DFARS 252.227-7013, and/or in similar or
** successor clauses in the FAR, DOD or NASA FAR Supplement. Unpublished  -
** rights reserved under the Copyright Laws of the United States.
**
** $Revision: 3 $
** $Date: 12/19/96 12:02p $
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#include "texusint.h"

#define TX_3DF  0x100
#define TX_PPM  0x101
#define TX_BMP  0x102
#define TX_IFF  0x103
#define TX_PCX  0x104
#define TX_SBI  0x105
#define TX_RGT  0x106
#define TX_UNK  0x200   // TGA is unknown from cookie signature.

int 
_txReadHeader( FILE *stream, TxMip *info )
{
    FxU32       cookie;
    int         c;
        int             fformat;                // format of the image file.
        int             status;

    if ( stream == NULL ) {
                txError("Bad file handle.");
                return 0;
    }

    if ((c=getc( stream )) == EOF ) {
                txError("Unexpected end of file");
                return 0;
    }
        cookie = (c << 8);

    if ((c=getc( stream )) == EOF ) {
                txError("Unexpected end of file");
                return 0;
    }
        cookie |= c;

    switch( cookie )
    {
        case ('P' << 8) | '9':  fformat = TX_SBI; break;
        case ('P' << 8) | '6':  fformat = TX_PPM; break;
        case ('3' << 8) | 'd':  fformat = TX_3DF; break;
        case ('3' << 8) | 'D':  fformat = TX_3DF; break;
        case 0x01DA:            // byte swapped RGT file.
        case 0xDA01:            fformat = TX_RGT; break;
        default:                fformat = TX_UNK; break;
    }

    switch (fformat) {
    case TX_SBI: status = _txReadSBIHeader( stream, cookie, info ); break;
    case TX_RGT: status = _txReadRGTHeader( stream, cookie, info ); break;
    case TX_PPM: status = _txReadPPMHeader( stream, cookie, info ); break;
    case TX_3DF: status = _txRead3DFHeader( stream, cookie, info ); break;
    case TX_UNK: status = _txReadTGAHeader( stream, cookie, info ); break;
    }

        /* Not reached. */
        return (status) ? fformat : 0;
}

static FxBool 
_txReadData( FILE *stream, int fformat, TxMip *info )
{
        switch (fformat) {
    case TX_SBI:        return _txReadSBIData( stream, info );
    case TX_RGT:        return _txReadRGTData( stream, info );
    case TX_PPM:        return _txReadPPMData( stream, info );
    case TX_3DF:        return _txRead3DFData( stream, info );
        case TX_UNK:    return _txReadTGAData( stream, info );
    }

        /* Not reached. */
        return FXFALSE;
}


FxBool
txMipRead(TxMip *txMip, const char *filename, int prefFormat)
{
  FILE *file;
  FxBool retval;

  file = fopen(filename, "rb");
  if( file == NULL ) 
    {
      fprintf( stderr,"Error: can't open input file %s\n", filename );
      exit(2);
    }
  
  retval = txMipReadFromFP( txMip, filename, file, prefFormat );
  fclose(file);
  return retval;
}

FxBool
txMipReadFromFP(TxMip *txMip, const char *debug_filename, FILE *file, int prefFormat)
{
        int                     i, format;
        TxMip           txTrue;
        int                     w, h;

        if ((prefFormat != GR_TEXFMT_ARGB_8888) &&
            (prefFormat != GR_TEXFMT_ANY)) 
          {
            txPanic("txMipRead: bad preferred format.");
            return FXFALSE;
          }

        if ( (format = _txReadHeader( file, txMip )) == 0 ) {
                fprintf(stderr,"Error: reading info for %s, %s\n",
                        debug_filename, "");
                exit(2);
        }
        if( txVerbose )
          {
            fprintf(stderr,"Loading image file ");

            fprintf (stderr,"%s (%dw x %dh x %d Bpp x %d mips) .. ", debug_filename, 
                     txMip->width,txMip->height, GR_TEXFMT_SIZE(txMip->format), txMip->depth);
          }

        /*
         * Allocate memory requested in data[0]; 
         */

        w = txMip->width;
        h = txMip->height;
        txMip->data[0] = txMalloc(txMip->size);
        for (i=1; i< TX_MAX_LEVEL; i++) {
                if (i >= txMip->depth) {
                        txMip->data[i] = NULL;
                        continue;
                }
                txMip->data[i] = (FxU8*)txMip->data[i-1] + 
                        w * h * GR_TEXFMT_SIZE(txMip->format);
                if (w > 1) w >>= 1;
                if (h > 1) h >>= 1;
        }

        if( txVerbose ) {
	          fprintf( stderr, "mip-> format: %d width: %d height: %d depth: %d size: %d\n",
		txMip->format, txMip->width, txMip->height, txMip->depth,
		txMip->size );
	         fflush( stderr );
        }

        if ( _txReadData( file, format, txMip ) == FXFALSE ) {
                fprintf(stderr, "\nError: reading data for %s\n",debug_filename);
                exit(4);
        }

        if( txVerbose )
          fprintf(stderr," done.\n");
        if (prefFormat == GR_TEXFMT_ANY) return FXTRUE;

        /*
         * Now convert to ARGB8888 if requested.
         */
        txTrue.format = GR_TEXFMT_ARGB_8888;
        txTrue.width  = txMip->width;
        txTrue.height = txMip->height;
        txTrue.depth  = txMip->depth;
        if (txMipAlloc(&txTrue) == FXFALSE) return FXFALSE;

        /*
         * Dequantize from src to dest.
         */
        if( txVerbose )
          {
            fprintf(stderr, "Dequantizing Input from %s to argb8888.\n", 
                   Format_Name[txMip->format]);
          }
        txMipDequantize(&txTrue, txMip);

        /*
         * Free the original mipmap, and copy new mipmap into it.
         */
        txFree(txMip->data[0]);
        *txMip = txTrue;

        return FXTRUE;
}


FxBool _txReadSBIHeader( FILE *stream, FxU32 cookie, TxMip *info){ return FXFALSE;}
FxBool _txReadSBIData( FILE *stream, TxMip *info){ return FXFALSE;}

