gtkradiant/tools/quake2/common/polylib.c

/*
   Copyright (C) 1999-2007 id Software, Inc. and contributors.
   For a list of contributors, see the accompanying CONTRIBUTORS file.

   This file is part of GtkRadiant.

   GtkRadiant 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.

   GtkRadiant 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 GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "cmdlib.h"
#include "inout.h"
#include "mathlib.h"
#include "polylib.h"


extern int numthreads;

// 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;

#define BOGUS_RANGE 8192

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;

	if ( numthreads == 1 ) {
		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 = malloc( s );
	memset( w, 0, s );
	return w;
}

void FreeWinding( winding_t *w ){
	if ( *(unsigned *)w == 0xdeaddead ) {
		Error( "FreeWinding: freed a freed winding" );
	}
	*(unsigned *)w = 0xdeaddead;

	if ( numthreads == 1 ) {
		c_active_windings--;
	}
	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 );
		VectorNormalize( v1,v1 );
		VectorNormalize( v2,v2 );
		if ( DotProduct( v1, v2 ) < 0.999 ) {
			VectorCopy( w->p[i], p[nump] );
			nump++;
		}
	}

	if ( nump == w->numpoints ) {
		return;
	}

	if ( numthreads == 1 ) {
		c_removed += w->numpoints - nump;
	}
	w->numpoints = nump;
	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 );
	VectorNormalize( 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;
}

void    WindingBounds( winding_t *w, vec3_t mins, vec3_t maxs ){
	vec_t v;
	int i,j;

	mins[0] = mins[1] = mins[2] = 99999;
	maxs[0] = maxs[1] = maxs[2] = -99999;

	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 = -BOGUS_RANGE;
	x = -1;
	for ( i = 0 ; i < 3; i++ )
	{
		v = fabs( normal[i] );
		if ( v > max ) {
			x = i;
			max = v;
		}
	}
	if ( x == -1 ) {
		Error( "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 );
	VectorNormalize( vup, vup );

	VectorScale( normal, dist, org );

	CrossProduct( vup, normal, vright );

	VectorScale( vup, 8192, vup );
	VectorScale( vright, 8192, 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 ){
	int size;
	winding_t   *c;

	c = AllocWinding( w->numpoints );
	size = (int)( (winding_t *)0 )->p[w->numpoints];
	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 ) {
		Error( "ClipWinding: points exceeded estimate" );
	}
	if ( f->numpoints > MAX_POINTS_ON_WINDING || b->numpoints > MAX_POINTS_ON_WINDING ) {
		Error( "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 ) {
		Error( "ClipWinding: points exceeded estimate" );
	}
	if ( f->numpoints > MAX_POINTS_ON_WINDING ) {
		Error( "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 ) {
		Error( "CheckWinding: %i points",w->numpoints );
	}

	area = WindingArea( w );
	if ( area < 1 ) {
		Error( "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] > BOGUS_RANGE || p1[j] < -BOGUS_RANGE ) {
				Error( "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 ) {
			Error( "CheckWinding: point off plane" );
		}

		// check the edge isnt degenerate
		p2 = w->p[j];
		VectorSubtract( p2, p1, dir );

		if ( VectorLength( dir ) < ON_EPSILON ) {
			Error( "CheckWinding: degenerate edge" );
		}

		CrossProduct( facenormal, dir, edgenormal );
		VectorNormalize( 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 ) {
				Error( "CheckWinding: non-convex" );
			}
		}
	}
}


/*
   ============
   WindingOnPlaneSide
   ============
 */
int     WindingOnPlaneSide( winding_t *w, vec3_t normal, vec_t dist ){
	qboolean front, back;
	int i;
	vec_t d;

	front = false;
	back = false;
	for ( i = 0 ; i < w->numpoints ; i++ )
	{
		d = DotProduct( w->p[i], normal ) - dist;
		if ( d < -ON_EPSILON ) {
			if ( front ) {
				return SIDE_CROSS;
			}
			back = true;
			continue;
		}
		if ( d > ON_EPSILON ) {
			if ( back ) {
				return SIDE_CROSS;
			}
			front = true;
			continue;
		}
	}

	if ( back ) {
		return SIDE_BACK;
	}
	if ( front ) {
		return SIDE_FRONT;
	}
	return SIDE_ON;
}