ref: bea7b7bf8ccbc2bc41906517079e76fcfb31cb5a
dir: /code/qcommon/cm_polylib.c/
/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
This file is part of Quake III Arena source code.
Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
===========================================================================
*/
// this is only used for visualization tools in cm_ debug functions
#include "cm_local.h"
// counters are only bumped when running single threaded,
// because they are an awefull coherence problem
int c_active_windings;
int c_peak_windings;
int c_winding_allocs;
int c_winding_points;
void pw(winding_t *w)
{
int i;
for (i=0 ; i<w->numpoints ; i++)
printf ("(%5.1f, %5.1f, %5.1f)\n",w->p[i][0], w->p[i][1],w->p[i][2]);
}
/*
=============
AllocWinding
=============
*/
winding_t *AllocWinding (int points)
{
winding_t *w;
int s;
c_winding_allocs++;
c_winding_points += points;
c_active_windings++;
if (c_active_windings > c_peak_windings)
c_peak_windings = c_active_windings;
s = sizeof(vec_t)*3*points + sizeof(int);
w = Z_Malloc (s);
Com_Memset (w, 0, s);
return w;
}
void FreeWinding (winding_t *w)
{
if (*(unsigned *)w == 0xdeaddead)
Com_Error (ERR_FATAL, "FreeWinding: freed a freed winding");
*(unsigned *)w = 0xdeaddead;
c_active_windings--;
Z_Free (w);
}
/*
============
RemoveColinearPoints
============
*/
int c_removed;
void RemoveColinearPoints (winding_t *w)
{
int i, j, k;
vec3_t v1, v2;
int nump;
vec3_t p[MAX_POINTS_ON_WINDING];
nump = 0;
for (i=0 ; i<w->numpoints ; i++)
{
j = (i+1)%w->numpoints;
k = (i+w->numpoints-1)%w->numpoints;
VectorSubtract (w->p[j], w->p[i], v1);
VectorSubtract (w->p[i], w->p[k], v2);
VectorNormalize2(v1,v1);
VectorNormalize2(v2,v2);
if (DotProduct(v1, v2) < 0.999)
{
VectorCopy (w->p[i], p[nump]);
nump++;
}
}
if (nump == w->numpoints)
return;
c_removed += w->numpoints - nump;
w->numpoints = nump;
Com_Memcpy (w->p, p, nump*sizeof(p[0]));
}
/*
============
WindingPlane
============
*/
void WindingPlane (winding_t *w, vec3_t normal, vec_t *dist)
{
vec3_t v1, v2;
VectorSubtract (w->p[1], w->p[0], v1);
VectorSubtract (w->p[2], w->p[0], v2);
CrossProduct (v2, v1, normal);
VectorNormalize2(normal, normal);
*dist = DotProduct (w->p[0], normal);
}
/*
=============
WindingArea
=============
*/
vec_t WindingArea (winding_t *w)
{
int i;
vec3_t d1, d2, cross;
vec_t total;
total = 0;
for (i=2 ; i<w->numpoints ; i++)
{
VectorSubtract (w->p[i-1], w->p[0], d1);
VectorSubtract (w->p[i], w->p[0], d2);
CrossProduct (d1, d2, cross);
total += 0.5 * VectorLength ( cross );
}
return total;
}
/*
=============
WindingBounds
=============
*/
void WindingBounds (winding_t *w, vec3_t mins, vec3_t maxs)
{
vec_t v;
int i,j;
mins[0] = mins[1] = mins[2] = MAX_MAP_BOUNDS;
maxs[0] = maxs[1] = maxs[2] = -MAX_MAP_BOUNDS;
for (i=0 ; i<w->numpoints ; i++)
{
for (j=0 ; j<3 ; j++)
{
v = w->p[i][j];
if (v < mins[j])
mins[j] = v;
if (v > maxs[j])
maxs[j] = v;
}
}
}
/*
=============
WindingCenter
=============
*/
void WindingCenter (winding_t *w, vec3_t center)
{
int i;
float scale;
VectorCopy (vec3_origin, center);
for (i=0 ; i<w->numpoints ; i++)
VectorAdd (w->p[i], center, center);
scale = 1.0/w->numpoints;
VectorScale (center, scale, center);
}
/*
=================
BaseWindingForPlane
=================
*/
winding_t *BaseWindingForPlane (vec3_t normal, vec_t dist)
{
int i, x;
vec_t max, v;
vec3_t org, vright, vup;
winding_t *w;
// find the major axis
max = -MAX_MAP_BOUNDS;
x = -1;
for (i=0 ; i<3; i++)
{
v = fabs(normal[i]);
if (v > max)
{
x = i;
max = v;
}
}
if (x==-1)
Com_Error (ERR_DROP, "BaseWindingForPlane: no axis found");
VectorCopy (vec3_origin, vup);
switch (x)
{
case 0:
case 1:
vup[2] = 1;
break;
case 2:
vup[0] = 1;
break;
}
v = DotProduct (vup, normal);
VectorMA (vup, -v, normal, vup);
VectorNormalize2(vup, vup);
VectorScale (normal, dist, org);
CrossProduct (vup, normal, vright);
VectorScale (vup, MAX_MAP_BOUNDS, vup);
VectorScale (vright, MAX_MAP_BOUNDS, vright);
// project a really big axis aligned box onto the plane
w = AllocWinding (4);
VectorSubtract (org, vright, w->p[0]);
VectorAdd (w->p[0], vup, w->p[0]);
VectorAdd (org, vright, w->p[1]);
VectorAdd (w->p[1], vup, w->p[1]);
VectorAdd (org, vright, w->p[2]);
VectorSubtract (w->p[2], vup, w->p[2]);
VectorSubtract (org, vright, w->p[3]);
VectorSubtract (w->p[3], vup, w->p[3]);
w->numpoints = 4;
return w;
}
/*
==================
CopyWinding
==================
*/
winding_t *CopyWinding (winding_t *w)
{
intptr size;
winding_t *c;
c = AllocWinding (w->numpoints);
size = (intptr)((winding_t *)0)->p[w->numpoints];
Com_Memcpy (c, w, size);
return c;
}
/*
==================
ReverseWinding
==================
*/
winding_t *ReverseWinding (winding_t *w)
{
int i;
winding_t *c;
c = AllocWinding (w->numpoints);
for (i=0 ; i<w->numpoints ; i++)
{
VectorCopy (w->p[w->numpoints-1-i], c->p[i]);
}
c->numpoints = w->numpoints;
return c;
}
/*
=============
ClipWindingEpsilon
=============
*/
void ClipWindingEpsilon (winding_t *in, vec3_t normal, vec_t dist,
vec_t epsilon, winding_t **front, winding_t **back)
{
vec_t dists[MAX_POINTS_ON_WINDING+4];
int sides[MAX_POINTS_ON_WINDING+4];
int counts[3];
static vec_t dot; // VC 4.2 optimizer bug if not static
int i, j;
vec_t *p1, *p2;
vec3_t mid;
winding_t *f, *b;
int maxpts;
counts[0] = counts[1] = counts[2] = 0;
// determine sides for each point
for (i=0 ; i<in->numpoints ; i++)
{
dot = DotProduct (in->p[i], normal);
dot -= dist;
dists[i] = dot;
if (dot > epsilon)
sides[i] = SIDE_FRONT;
else if (dot < -epsilon)
sides[i] = SIDE_BACK;
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
dists[i] = dists[0];
*front = *back = NULL;
if (!counts[0])
{
*back = CopyWinding (in);
return;
}
if (!counts[1])
{
*front = CopyWinding (in);
return;
}
maxpts = in->numpoints+4; // cant use counts[0]+2 because
// of fp grouping errors
*front = f = AllocWinding (maxpts);
*back = b = AllocWinding (maxpts);
for (i=0 ; i<in->numpoints ; i++)
{
p1 = in->p[i];
if (sides[i] == SIDE_ON)
{
VectorCopy (p1, f->p[f->numpoints]);
f->numpoints++;
VectorCopy (p1, b->p[b->numpoints]);
b->numpoints++;
continue;
}
if (sides[i] == SIDE_FRONT)
{
VectorCopy (p1, f->p[f->numpoints]);
f->numpoints++;
}
if (sides[i] == SIDE_BACK)
{
VectorCopy (p1, b->p[b->numpoints]);
b->numpoints++;
}
if (sides[i+1] == SIDE_ON || sides[i+1] == sides[i])
continue;
// generate a split point
p2 = in->p[(i+1)%in->numpoints];
dot = dists[i] / (dists[i]-dists[i+1]);
for (j=0 ; j<3 ; j++)
{ // avoid round off error when possible
if (normal[j] == 1)
mid[j] = dist;
else if (normal[j] == -1)
mid[j] = -dist;
else
mid[j] = p1[j] + dot*(p2[j]-p1[j]);
}
VectorCopy (mid, f->p[f->numpoints]);
f->numpoints++;
VectorCopy (mid, b->p[b->numpoints]);
b->numpoints++;
}
if (f->numpoints > maxpts || b->numpoints > maxpts)
Com_Error (ERR_DROP, "ClipWinding: points exceeded estimate");
if (f->numpoints > MAX_POINTS_ON_WINDING || b->numpoints > MAX_POINTS_ON_WINDING)
Com_Error (ERR_DROP, "ClipWinding: MAX_POINTS_ON_WINDING");
}
/*
=============
ChopWindingInPlace
=============
*/
void ChopWindingInPlace (winding_t **inout, vec3_t normal, vec_t dist, vec_t epsilon)
{
winding_t *in;
vec_t dists[MAX_POINTS_ON_WINDING+4];
int sides[MAX_POINTS_ON_WINDING+4];
int counts[3];
static vec_t dot; // VC 4.2 optimizer bug if not static
int i, j;
vec_t *p1, *p2;
vec3_t mid;
winding_t *f;
int maxpts;
in = *inout;
counts[0] = counts[1] = counts[2] = 0;
// determine sides for each point
for (i=0 ; i<in->numpoints ; i++)
{
dot = DotProduct (in->p[i], normal);
dot -= dist;
dists[i] = dot;
if (dot > epsilon)
sides[i] = SIDE_FRONT;
else if (dot < -epsilon)
sides[i] = SIDE_BACK;
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
dists[i] = dists[0];
if (!counts[0])
{
FreeWinding (in);
*inout = NULL;
return;
}
if (!counts[1])
return; // inout stays the same
maxpts = in->numpoints+4; // cant use counts[0]+2 because
// of fp grouping errors
f = AllocWinding (maxpts);
for (i=0 ; i<in->numpoints ; i++)
{
p1 = in->p[i];
if (sides[i] == SIDE_ON)
{
VectorCopy (p1, f->p[f->numpoints]);
f->numpoints++;
continue;
}
if (sides[i] == SIDE_FRONT)
{
VectorCopy (p1, f->p[f->numpoints]);
f->numpoints++;
}
if (sides[i+1] == SIDE_ON || sides[i+1] == sides[i])
continue;
// generate a split point
p2 = in->p[(i+1)%in->numpoints];
dot = dists[i] / (dists[i]-dists[i+1]);
for (j=0 ; j<3 ; j++)
{ // avoid round off error when possible
if (normal[j] == 1)
mid[j] = dist;
else if (normal[j] == -1)
mid[j] = -dist;
else
mid[j] = p1[j] + dot*(p2[j]-p1[j]);
}
VectorCopy (mid, f->p[f->numpoints]);
f->numpoints++;
}
if (f->numpoints > maxpts)
Com_Error (ERR_DROP, "ClipWinding: points exceeded estimate");
if (f->numpoints > MAX_POINTS_ON_WINDING)
Com_Error (ERR_DROP, "ClipWinding: MAX_POINTS_ON_WINDING");
FreeWinding (in);
*inout = f;
}
/*
=================
ChopWinding
Returns the fragment of in that is on the front side
of the cliping plane. The original is freed.
=================
*/
winding_t *ChopWinding (winding_t *in, vec3_t normal, vec_t dist)
{
winding_t *f, *b;
ClipWindingEpsilon (in, normal, dist, ON_EPSILON, &f, &b);
FreeWinding (in);
if (b)
FreeWinding (b);
return f;
}
/*
=================
CheckWinding
=================
*/
void CheckWinding (winding_t *w)
{
int i, j;
vec_t *p1, *p2;
vec_t d, edgedist;
vec3_t dir, edgenormal, facenormal;
vec_t area;
vec_t facedist;
if (w->numpoints < 3)
Com_Error (ERR_DROP, "CheckWinding: %i points",w->numpoints);
area = WindingArea(w);
if (area < 1)
Com_Error (ERR_DROP, "CheckWinding: %f area", area);
WindingPlane (w, facenormal, &facedist);
for (i=0 ; i<w->numpoints ; i++)
{
p1 = w->p[i];
for (j=0 ; j<3 ; j++)
if (p1[j] > MAX_MAP_BOUNDS || p1[j] < -MAX_MAP_BOUNDS)
Com_Error (ERR_DROP, "CheckFace: BUGUS_RANGE: %f",p1[j]);
j = i+1 == w->numpoints ? 0 : i+1;
// check the point is on the face plane
d = DotProduct (p1, facenormal) - facedist;
if (d < -ON_EPSILON || d > ON_EPSILON)
Com_Error (ERR_DROP, "CheckWinding: point off plane");
// check the edge isnt degenerate
p2 = w->p[j];
VectorSubtract (p2, p1, dir);
if (VectorLength (dir) < ON_EPSILON)
Com_Error (ERR_DROP, "CheckWinding: degenerate edge");
CrossProduct (facenormal, dir, edgenormal);
VectorNormalize2 (edgenormal, edgenormal);
edgedist = DotProduct (p1, edgenormal);
edgedist += ON_EPSILON;
// all other points must be on front side
for (j=0 ; j<w->numpoints ; j++)
{
if (j == i)
continue;
d = DotProduct (w->p[j], edgenormal);
if (d > edgedist)
Com_Error (ERR_DROP, "CheckWinding: non-convex");
}
}
}
/*
============
WindingOnPlaneSide
============
*/
int WindingOnPlaneSide (winding_t *w, vec3_t normal, vec_t dist)
{
qboolean front, back;
int i;
vec_t d;
front = qfalse;
back = qfalse;
for (i=0 ; i<w->numpoints ; i++)
{
d = DotProduct (w->p[i], normal) - dist;
if (d < -ON_EPSILON)
{
if (front)
return SIDE_CROSS;
back = qtrue;
continue;
}
if (d > ON_EPSILON)
{
if (back)
return SIDE_CROSS;
front = qtrue;
continue;
}
}
if (back)
return SIDE_BACK;
if (front)
return SIDE_FRONT;
return SIDE_ON;
}
/*
=================
AddWindingToConvexHull
Both w and *hull are on the same plane
=================
*/
#define MAX_HULL_POINTS 128
void AddWindingToConvexHull( winding_t *w, winding_t **hull, vec3_t normal ) {
int i, j, k;
float *p, *copy;
vec3_t dir;
float d;
int numHullPoints, numNew;
vec3_t hullPoints[MAX_HULL_POINTS];
vec3_t newHullPoints[MAX_HULL_POINTS];
vec3_t hullDirs[MAX_HULL_POINTS];
qboolean hullSide[MAX_HULL_POINTS];
qboolean outside;
if ( !*hull ) {
*hull = CopyWinding( w );
return;
}
numHullPoints = (*hull)->numpoints;
Com_Memcpy( hullPoints, (*hull)->p, numHullPoints * sizeof(vec3_t) );
for ( i = 0 ; i < w->numpoints ; i++ ) {
p = w->p[i];
// calculate hull side vectors
for ( j = 0 ; j < numHullPoints ; j++ ) {
k = ( j + 1 ) % numHullPoints;
VectorSubtract( hullPoints[k], hullPoints[j], dir );
VectorNormalize2( dir, dir );
CrossProduct( normal, dir, hullDirs[j] );
}
outside = qfalse;
for ( j = 0 ; j < numHullPoints ; j++ ) {
VectorSubtract( p, hullPoints[j], dir );
d = DotProduct( dir, hullDirs[j] );
if ( d >= ON_EPSILON ) {
outside = qtrue;
}
if ( d >= -ON_EPSILON ) {
hullSide[j] = qtrue;
} else {
hullSide[j] = qfalse;
}
}
// if the point is effectively inside, do nothing
if ( !outside ) {
continue;
}
// find the back side to front side transition
for ( j = 0 ; j < numHullPoints ; j++ ) {
if ( !hullSide[ j % numHullPoints ] && hullSide[ (j + 1) % numHullPoints ] ) {
break;
}
}
if ( j == numHullPoints ) {
continue;
}
// insert the point here
VectorCopy( p, newHullPoints[0] );
numNew = 1;
// copy over all points that aren't double fronts
j = (j+1)%numHullPoints;
for ( k = 0 ; k < numHullPoints ; k++ ) {
if ( hullSide[ (j+k) % numHullPoints ] && hullSide[ (j+k+1) % numHullPoints ] ) {
continue;
}
copy = hullPoints[ (j+k+1) % numHullPoints ];
VectorCopy( copy, newHullPoints[numNew] );
numNew++;
}
numHullPoints = numNew;
Com_Memcpy( hullPoints, newHullPoints, numHullPoints * sizeof(vec3_t) );
}
FreeWinding( *hull );
w = AllocWinding( numHullPoints );
w->numpoints = numHullPoints;
*hull = w;
Com_Memcpy( w->p, hullPoints, numHullPoints * sizeof(vec3_t) );
}