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/* sputoppm.c - read an uncompressed Spectrum file and produce a portable pixmap
**
** Copyright (C) 1991 by Steve Belczyk and Jef Poskanzer
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation. This software is provided "as is" without express or
** implied warranty.
*/
#include "ppm.h"
#define ROWS 200
#define COLS 320
#define MAXVAL 7
static pixel pal[ROWS][48]; /* Spectrum palettes, three per row */
static short screen[ROWS*COLS/4]; /* simulates the Atari's video RAM */
int
main( argc, argv )
int argc;
char* argv[];
{
FILE* ifp;
int i, j;
pixel* pixelrow;
register pixel* pP;
int row, col;
ppm_init( &argc, argv );
/* Check args. */
if ( argc > 2 )
pm_usage( "[spufile]" );
if ( argc == 2 )
ifp = pm_openr( argv[1] );
else
ifp = stdin;
/* Read the SPU file */
/* Read the screen data. */
for ( i = 0; i < ROWS*COLS/4; ++i )
(void) pm_readbigshort( ifp, &screen[i] );
/* Clear the first palette line. */
for ( j = 0; j < 48; ++j )
PPM_ASSIGN( pal[0][j], 0, 0, 0 );
/* Read the palettes. */
for ( i = 1; i < ROWS; ++i )
for ( j = 0; j < 48; ++j )
{
short k;
(void) pm_readbigshort( ifp, &k );
PPM_ASSIGN( pal[i][j],
( k & 0x700 ) >> 8,
( k & 0x070 ) >> 4,
( k & 0x007 ) );
}
pm_close( ifp );
/* Ok, get set for writing PPM. */
ppm_writeppminit( stdout, COLS, ROWS, (pixval) MAXVAL, 0 );
pixelrow = ppm_allocrow( COLS );
/* Now do the conversion. */
for ( row = 0; row < ROWS; ++row )
{
for ( col = 0, pP = pixelrow; col < COLS; ++col, ++pP )
{
int c, ind, b, plane, x1;
/* Compute pixel value. */
ind = 80 * row + ( ( col >> 4 ) << 2 );
b = 0x8000 >> (col & 0xf);
c = 0;
for ( plane = 0; plane < 4; ++plane )
if ( b & screen[ind+plane] )
c |= (1 << plane);
/* Compute palette index. */
x1 = 10 * c;
if ( c & 1 )
x1 -= 5;
else
++x1;
if ( ( col >= x1 ) && ( col < ( x1 + 160 ) ) )
c += 16;
if ( col >= ( x1 + 160 ) )
c += 32;
/* Store the proper color. */
*pP = pal[row][c];
}
ppm_writeppmrow( stdout, pixelrow, COLS, (pixval) MAXVAL, 0 );
}
pm_close( stdout );
exit( 0 );
}
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