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#ifndef lint |
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static const char RCSid[] = "$Id: genflake.c,v 1.1 2003/02/22 02:07:26 greg Exp $"; |
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#endif |
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/* |
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* genflake.c - program to make snowflakes |
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* |
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* 11/12/86 |
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* |
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* cc genflake.c primout.o mfio.o syscalls.o misc.o |
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*/ |
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|
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#include "meta.h" |
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|
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#include "random.h" |
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|
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#define FSIZE 6144 |
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#define FACT(a) (int)((a)*5321L/FSIZE) |
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#define CENTER 8192 |
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|
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char *progname; |
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|
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int branch = 6; /* number of branches */ |
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|
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main(argc, argv) |
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int argc; |
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char *argv[]; |
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{ |
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int i; |
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int seed = 0; |
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int nflakes = 1; |
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|
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progname = argv[0]; |
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for (i = 1; i < argc && argv[i][0] == '-'; i++) |
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switch (argv[i][1]) { |
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case 's': /* seed */ |
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seed = atoi(argv[++i]); |
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break; |
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case 'b': /* number of branches */ |
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branch = atoi(argv[++i]); |
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break; |
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case 'n': /* number of flakes */ |
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nflakes = atoi(argv[++i]); |
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break; |
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default: |
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fprintf(stderr, "%s: unknown option: %s\n", |
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progname, argv[i]); |
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exit(1); |
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} |
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while (seed-- > 0) |
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random(); |
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while (nflakes-- > 0) { |
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genflake(0, 0, 0, FSIZE, branch); |
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pglob(PEOP, 0200, NULL); |
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} |
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writeof(stdout); |
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exit(0); |
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} |
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|
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|
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genflake(x0, y0, x1, y1, nb) /* make a flake */ |
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int x0, y0, x1, y1; |
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int nb; |
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{ |
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int bx0, by0, bx1, by1; |
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int i; |
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|
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symvect(x0, y0, x1, y1); |
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for (i = 0; i < nb; i++) { |
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bx0 = random()%FSIZE; |
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by0 = y0 + (y1-y0)*(long)bx0/FSIZE; |
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bx0 = x0 + (x1-x0)*(long)bx0/FSIZE; |
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bx1 = FACT(y0-y1); |
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by1 = FACT(x1-x0); |
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if (random()&1) { |
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bx1 += (x1-x0)/2; |
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by1 += (y1-y0)/2; |
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} else { |
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bx1 -= (x1-x0)/2; |
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by1 -= (y1-y0)/2; |
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} |
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bx1 = bx0 + bx1*(i+1)/(2*nb); |
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by1 = by0 + by1*(i+1)/(2*nb); |
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genflake(bx0, by0, bx1, by1, i); |
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} |
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} |
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|
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|
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symvect(x0, y0, x1, y1) /* output with symmetry */ |
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int x0, y0, x1, y1; |
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{ |
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symvect2(x0, y0, x1, y1); |
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symvect2(x0, -y0, x1, -y1); |
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symvect2(-x0, y0, -x1, y1); |
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symvect2(-x0, -y0, -x1, -y1); |
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} |
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|
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|
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symvect2(x0, y0, x1, y1) |
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int x0, y0, x1, y1; |
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{ |
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int x0p, x1p, y0p, y1p; |
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|
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plseg(0, CENTER+x0, CENTER+y0, CENTER+x1, CENTER+y1); |
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plseg(0, CENTER+x0/2+FACT(-y0), CENTER+y0/2+FACT(x0), |
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CENTER+x1/2+FACT(-y1), CENTER+y1/2+FACT(x1)); |
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plseg(0, CENTER+x0/2+FACT(y0), CENTER+y0/2+FACT(-x0), |
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CENTER+x1/2+FACT(y1), CENTER+y1/2+FACT(-x1)); |
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} |
