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/* sputoppm.c - read an uncompressed Spectrum file and produce a PPM
**
** 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
typedef struct {
pixel pal[ROWS][48]; /* Spectrum palettes, three per row */
} Pal;
static void
readPalettes(FILE * const ifP,
Pal * const palP) {
unsigned int row;
/* Clear the first palette line. */
{
unsigned int j;
for (j = 0; j < 48; ++j)
PPM_ASSIGN(palP->pal[0][j], 0, 0, 0);
}
/* Read the palettes. */
for (row = 1; row < ROWS; ++row) {
unsigned int j;
for (j = 0; j < 48; ++j) {
short k;
pm_readbigshort(ifP, &k);
PPM_ASSIGN(palP->pal[row][j],
(k & 0x700) >> 8,
(k & 0x070) >> 4,
(k & 0x007) >> 0);
}
}
}
int
main(int argc, const char ** argv) {
FILE * ifP;
unsigned int i;
pixel * pixelrow;
unsigned int row;
Pal pal;
short screen[ROWS*COLS/4]; /* simulates the Atari's video RAM */
pm_proginit(&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)
pm_readbigshort(ifP, &screen[i]);
readPalettes(ifP, &pal);
pm_close(ifP);
/* Ok, get set for writing PPM. */
ppm_writeppminit(stdout, COLS, ROWS, MAXVAL, 0);
pixelrow = ppm_allocrow(COLS);
/* Now do the conversion. */
for (row = 0; row < ROWS; ++row) {
unsigned int col;
for (col = 0; col < COLS; ++col) {
/* Compute pixel value. */
unsigned int const ind = 80 * row + ((col >> 4) << 2);
unsigned int const b = 0x8000 >> (col & 0xf);
unsigned int c;
unsigned int plane;
unsigned int x1;
c = 0; /* initial value */
for (plane = 0; plane < 4; ++plane) {
if (b & screen[ind + plane])
c |= (1 << plane);
}
/* Compute palette index. */
x1 = 10 * c;
if ((c & 1) != 0)
x1 -= 5;
else
++x1;
if ((col >= x1 ) && (col < (x1 + 160)))
c += 16;
if (col >= (x1 + 160))
c += 32;
/* Set the proper color. */
pixelrow[col] = pal.pal[row][c];
}
ppm_writeppmrow(stdout, pixelrow, COLS, MAXVAL, 0);
}
ppm_freerow(pixelrow);
pm_close(stdout);
return 0;
}
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