331 lines
6.8 KiB
C
331 lines
6.8 KiB
C
/*
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Copyright (C) 1996-1997 Id Software, Inc.
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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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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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See file, 'COPYING', for details.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifdef HAVE_STRING_H
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# include <string.h>
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#endif
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif
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#if defined(_WIN32) && defined(HAVE_MALLOC_H)
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#include <malloc.h>
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#endif
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#include <stdlib.h>
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#include "qfalloca.h"
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#include "QF/sys.h"
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#include "QF/winding.h"
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#define BOGUS (18000.0)
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/** \addtogroup qfbsp_winding
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*/
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//@{
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int c_activewindings, c_peakwindings;
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winding_t *
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BaseWindingForPlane (const plane_t *p)
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{
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int i, x;
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vec_t max, v;
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vec3_t org, vright, vup;
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winding_t *w;
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// find the major axis
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max = -BOGUS;
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x = -1;
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for (i = 0; i < 3; i++) {
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v = fabs (p->normal[i]);
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if (v > max) {
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x = i;
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max = v;
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}
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}
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if (x == -1)
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Sys_Error ("BaseWindingForPlane: no axis found");
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VectorZero (vup);
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switch (x) {
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case 0:
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case 1:
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vup[2] = 1;
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break;
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case 2:
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vup[0] = 1;
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break;
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}
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v = DotProduct (vup, p->normal);
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VectorMultSub (vup, v, p->normal, vup);
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_VectorNormalize (vup);
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VectorScale (p->normal, p->dist, org);
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CrossProduct (vup, p->normal, vright);
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VectorScale (vup, BOGUS, vup);
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VectorScale (vright, BOGUS, vright);
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// project a really big axis aligned box onto the plane
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w = NewWinding (4);
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VectorSubtract (org, vright, w->points[0]);
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VectorAdd (w->points[0], vup, w->points[0]);
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VectorAdd (org, vright, w->points[1]);
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VectorAdd (w->points[1], vup, w->points[1]);
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VectorAdd (org, vright, w->points[2]);
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VectorSubtract (w->points[2], vup, w->points[2]);
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VectorSubtract (org, vright, w->points[3]);
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VectorSubtract (w->points[3], vup, w->points[3]);
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w->numpoints = 4;
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return w;
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}
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winding_t *
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CopyWinding (const winding_t *w)
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{
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size_t size;
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winding_t *c;
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size = (size_t) (uintptr_t) &((winding_t *) 0)->points[w->numpoints];
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c = malloc (size);
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memcpy (c, w, size);
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return c;
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}
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winding_t *
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CopyWindingReverse (const winding_t *w)
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{
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int i;
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size_t size;
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winding_t *c;
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size = (size_t) (uintptr_t) &((winding_t *) 0)->points[w->numpoints];
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c = malloc (size);
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c->numpoints = w->numpoints;
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for (i = 0; i < w->numpoints; i++) {
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// add points backwards
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VectorCopy (w->points[w->numpoints - 1 - i], c->points[i]);
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}
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return c;
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}
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winding_t *
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WindingVectors (const winding_t *w, int unit)
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{
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int i;
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size_t size;
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winding_t *c;
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size = (size_t) (uintptr_t) &((winding_t *) 0)->points[w->numpoints];
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c = malloc (size);
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c->numpoints = w->numpoints;
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for (i = 0; i < w->numpoints; i++) {
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VectorSubtract (w->points[(i + 1) % w->numpoints], w->points[i],
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c->points[i]);
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if (unit)
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VectorNormalize (c->points[i]);
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}
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return c;
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}
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winding_t *
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ClipWinding (winding_t *in, plane_t *split, qboolean keepon)
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{
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int maxpts, i, j;
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int *sides;
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int counts[3];
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vec_t dot;
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vec_t *dists;
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vec_t *p1, *p2;
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vec3_t mid;
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winding_t *neww;
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counts[0] = counts[1] = counts[2] = 0;
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// +1 for duplicating the first point
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sides = alloca ((in->numpoints + 1) * sizeof (int));
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dists = alloca ((in->numpoints + 1) * sizeof (vec_t));
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// determine sides for each point
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for (i = 0; i < in->numpoints; i++) {
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dot = DotProduct (in->points[i], split->normal);
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dot -= split->dist;
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dists[i] = dot;
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if (dot > ON_EPSILON)
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sides[i] = SIDE_FRONT;
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else if (dot < -ON_EPSILON)
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sides[i] = SIDE_BACK;
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else {
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sides[i] = SIDE_ON;
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}
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counts[sides[i]]++;
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}
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// duplicate the first point
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sides[i] = sides[0];
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dists[i] = dists[0];
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if (keepon && !counts[SIDE_FRONT] && !counts[SIDE_BACK])
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return in;
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if (!counts[SIDE_FRONT]) {
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FreeWinding (in);
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return NULL;
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}
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if (!counts[SIDE_BACK])
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return in;
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for (maxpts = 0, i = 0; i < in->numpoints; i++) {
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if (!(sides[i] & 1))
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maxpts++;
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if ((sides[i] ^ 1) == sides[i + 1])
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maxpts++;
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}
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neww = NewWinding (maxpts);
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for (i = 0; i < in->numpoints; i++) {
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p1 = in->points[i];
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if (sides[i] == SIDE_ON) {
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if (neww->numpoints == maxpts)
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Sys_Error ("ClipWinding: points exceeded estimate");
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VectorCopy (p1, neww->points[neww->numpoints]);
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neww->numpoints++;
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continue;
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}
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if (sides[i] == SIDE_FRONT) {
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if (neww->numpoints == maxpts)
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Sys_Error ("ClipWinding: points exceeded estimate");
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VectorCopy (p1, neww->points[neww->numpoints]);
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neww->numpoints++;
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}
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if (sides[i + 1] == SIDE_ON || sides[i + 1] == sides[i])
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continue;
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if (neww->numpoints == maxpts)
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Sys_Error ("ClipWinding: points exceeded estimate");
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// generate a split point
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p2 = in->points[(i + 1) % in->numpoints];
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dot = dists[i] / (dists[i] - dists[i + 1]);
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for (j = 0; j < 3; j++) { // avoid round off error when possible
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if (split->normal[j] == 1)
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mid[j] = split->dist;
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else if (split->normal[j] == -1)
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mid[j] = -split->dist;
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else
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mid[j] = p1[j] + dot * (p2[j] - p1[j]);
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}
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VectorCopy (mid, neww->points[neww->numpoints]);
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neww->numpoints++;
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}
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// free the original winding
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FreeWinding (in);
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return neww;
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}
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void
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DivideWinding (winding_t *in, plane_t *split, winding_t **front,
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winding_t **back)
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{
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int i;
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int counts[3];
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plane_t plane;
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vec_t dot;
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winding_t *tmp;
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counts[0] = counts[1] = counts[2] = 0;
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// determine sides for each point
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for (i = 0; i < in->numpoints; i++) {
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dot = DotProduct (in->points[i], split->normal) - split->dist;
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if (dot > ON_EPSILON)
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counts[SIDE_FRONT]++;
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else if (dot < -ON_EPSILON)
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counts[SIDE_BACK]++;
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}
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*front = *back = NULL;
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if (!counts[SIDE_FRONT]) {
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*back = in;
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return;
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}
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if (!counts[SIDE_BACK]) {
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*front = in;
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return;
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}
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tmp = CopyWinding (in);
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*front = ClipWinding (tmp, split, 0);
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plane.dist = -split->dist;
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VectorNegate (split->normal, plane.normal);
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tmp = CopyWinding (in);
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*back = ClipWinding (tmp, &plane, 0);
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}
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winding_t *
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NewWinding (int points)
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{
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size_t size;
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winding_t *w;
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if (points < 3)
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Sys_Error ("NewWinding: %i points", points);
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c_activewindings++;
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if (c_activewindings > c_peakwindings)
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c_peakwindings = c_activewindings;
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size = (size_t) (uintptr_t) &((winding_t *) 0)->points[points];
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w = malloc (size);
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memset (w, 0, size);
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return w;
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}
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void
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FreeWinding (winding_t *w)
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{
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c_activewindings--;
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free (w);
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}
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//@}
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