ptrude/: added (overly, this far) simple extruder
This commit is contained in:
Werner Almesberger
parent
3dcd5cc9aa
commit
c202eda676
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@ -13,7 +13,7 @@
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SHELL = /bin/bash
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MAIN = ptrude
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OBJS = $(MAIN).o path.o
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OBJS = $(MAIN).o path.o extrude.o
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CFLAGS = -Wall -g -Wshadow -Wmissing-prototypes \
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-Wmissing-declarations -Wno-format-zero-length
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@ -0,0 +1,123 @@
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/*
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* extrude.c - Perform the extrusion
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*
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* Written 2011 by Werner Almesberger
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* Copyright 2011 by Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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/*
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* Known bugs:
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*
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* - negative x coordinates in shape produce overlapping faces
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* - the rounding is only accurate for x = 0. For x > 0, we need to add
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* more points. Tricky.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#include "path.h"
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#include "extrude.h"
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#define alloc_tn(t, n) ((t *) malloc(sizeof(t)*(n)))
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static void slice(double x, double y, double nx, double ny,
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const struct path *shape, struct point *p)
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{
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const struct vertex *v;
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for (v = shape->vertices; v; v = v->next) {
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p->x = x+nx*v->x;
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p->y = y+ny*v->x;
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p->z = v->y;
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p++;
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}
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}
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static void mesh(const struct point *a, const struct point *b, int n,
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void (*face)(void *data, struct point a, struct point b, struct point c),
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void *data)
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{
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int i;
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for (i = 0; i != n-1; i++) {
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face(data, a[i], b[i], a[i+1]);
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face(data, a[i+1], b[i], b[i+1]);
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}
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}
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void extrude(const struct path *path, const struct path *shape,
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void (*face)(void *data, struct point a, struct point b, struct point c),
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void *data)
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{
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const struct vertex *v; /* current vertex (for iteration) */
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const struct vertex *a, *b, *c; /* previous, current, next vertex */
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struct point *prev, *this; /* previous and current slice */
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double nx, ny; /* 2D normals */
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double f; /* factor for normalization */
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double tx, ty; /* temporary 2D normals */
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int n = 0; /* number of vertices in shape */
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if (!path->vertices || !path->vertices->next || !shape->vertices)
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return;
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for (v = shape->vertices; v; v = v->next)
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n++;
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prev = alloc_tn(struct point, n);
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this = alloc_tn(struct point, n);
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a = path->vertices;
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b = a->next;
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nx = b->y-a->y;
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ny = a->x-b->x;
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f = hypot(nx, ny);
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slice(a->x, a->y, nx/f, ny/f, shape, prev);
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for (v = path->vertices->next; v->next; v = v->next) {
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b = v;
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c = v->next;
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tx = b->y-a->y;
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ty = a->x-b->x;
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f = hypot(tx, ty);
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nx = tx/f;
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ny = ty/f;
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tx = c->y-b->y;
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ty = b->x-c->x;
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f = hypot(tx, ty);
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nx += tx/f;
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ny += ty/f;
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slice(b->x, b->y, nx/2, ny/2, shape, this);
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mesh(prev, this, n, face, data);
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memcpy(prev, this, sizeof(*prev)*n);
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a = v;
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}
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nx = v->y-a->y;
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ny = a->x-v->x;
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f = hypot(nx, ny);
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slice(v->x, v->y, nx/f, ny/f, shape, this);
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mesh(prev, this, n, face, data);
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/* @@@ To do: close shape and close top and bottom */
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free(prev);
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free(this);
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}
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@ -0,0 +1,65 @@
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#FIG 3.2 Produced by xfig version 3.2.5b
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Landscape
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Center
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Metric
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A4
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100.00
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Single
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-2
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1200 2
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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2925 7200 4050 8325
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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2925 5400 4275 7200
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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2025 4500 4275 5400
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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3420 4500 6930 4050
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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6075 3150 8325 2025
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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4275 5400 6975 5850
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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6975 5850 8100 4950
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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4275 7200 6750 6975
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2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 0 0 2
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6975 4050 8280 3825
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2 1 0 3 1 7 50 -1 -1 0.000 0 0 -1 1 0 4
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1 1 3.00 90.00 120.00
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2700 8325 2925 7200 2925 5400 2025 4500
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2 1 0 2 1 7 50 -1 -1 0.000 0 0 7 0 0 4
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4050 8325 4275 7200 4275 5400 3375 4500
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2 1 0 2 1 7 50 -1 -1 0.000 0 0 7 0 0 4
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6750 6975 6975 5850 6975 4050 6075 3150
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2 1 0 2 1 7 50 -1 -1 0.000 0 0 7 0 0 4
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8100 4950 8325 3825 8325 2025 7425 1125
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2 1 0 2 4 7 50 -1 -1 0.000 0 0 7 0 0 4
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2025 4500 3375 4500 6075 3150 7425 1125
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2 1 0 2 4 7 50 -1 -1 0.000 0 0 7 0 0 4
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2925 5400 4275 5400 6975 4050 8325 2025
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2 1 0 3 4 7 50 -1 -1 0.000 0 0 -1 1 0 4
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1 1 3.00 90.00 120.00
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2925 7200 4275 7200 6975 5850 8325 3825
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2 1 0 2 4 7 50 -1 -1 0.000 0 0 7 0 0 4
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2709 8343 4059 8343 6759 6993 8109 4968
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2 1 0 2 4 7 52 -1 -1 0.000 0 0 -1 0 0 2
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3195 6975 3015 7155
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2 1 0 2 1 7 52 -1 -1 0.000 0 0 -1 0 0 2
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2520 7200 2790 7200
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2 1 0 2 1 7 52 -1 -1 0.000 0 0 -1 0 0 2
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2250 8505 2565 8370
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3 2 0 2 0 7 50 -1 -1 0.000 0 1 0 3
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0 0 2.00 90.00 120.00
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4680 6705 5580 6075 4545 5805
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0.000 -1.000 0.000
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3 2 0 2 0 7 50 -1 -1 0.000 0 1 0 3
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0 0 2.00 90.00 120.00
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5265 5265 6570 5445 6705 4545
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0.000 -1.000 0.000
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4 2 1 50 -1 18 18 0.0000 4 270 870 2835 6480 Shape\001
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4 1 4 50 -1 18 18 0.0000 4 210 615 3690 7515 Path\001
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4 1 4 50 -1 19 15 0.0000 4 240 375 3330 6930 tag\001
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4 1 1 50 -1 19 15 0.0000 4 240 375 2295 7245 tag\001
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4 1 1 50 -1 14 15 0.0000 4 135 750 1845 8640 start\001
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4 1 1 50 -1 18 12 0.0000 4 195 1365 2205 8865 (or unique tag)\001
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@ -17,6 +17,7 @@
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#include <math.h>
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#include "path.h"
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#include "extrude.h"
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#include "ptrude.h"
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@ -50,6 +51,29 @@ static void close_file(FILE *file)
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}
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static void do_face(void *data, struct point a, struct point b, struct point c)
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{
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FILE *file = data;
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fprintf(file, "facet normal 0 0 0\n");
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fprintf(file, " outer loop\n");
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fprintf(file, " vertex %f %f %f\n", a.x, a.y, a.z);
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fprintf(file, " vertex %f %f %f\n", b.x, b.y, b.z);
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fprintf(file, " vertex %f %f %f\n", c.x, c.y, c.z);
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fprintf(file, " endloop\nendfacet\n");
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}
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static void do_extrude(const struct path *path, const struct path *shape)
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{
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FILE *file = stdout;
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fprintf(file, "solid ptrude\n");
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extrude(path, shape, do_face, file);
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fprintf(file, "endsolid ptrude\n");
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}
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static void usage(const char *name)
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{
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fprintf(stderr,
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*/
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path = round_path(path, r, sqrt(d));
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shape = round_path(shape, r, sqrt(d));
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/* ... now all that's missing is the extrusion :-) */
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do_extrude(path, shape);
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} else {
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shape = round_path(shape, r, d);
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save_path(stdout, shape);
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@ -0,0 +1,10 @@
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# test path
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-100 0
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100 0
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200 100
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200 200
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100 300
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0 300
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-100 200
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-100 100
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0 100
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