jkxr/Projects/Android/jni/OpenJK/code/qcommon/cm_polylib.cpp

/*
===========================================================================
Copyright (C) 1999 - 2005, Id Software, Inc.
Copyright (C) 2000 - 2013, Raven Software, Inc.
Copyright (C) 2001 - 2013, Activision, Inc.
Copyright (C) 2013 - 2015, OpenJK contributors

This file is part of the OpenJK source code.

OpenJK is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License version 2 as
published by the Free Software Foundation.

This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
===========================================================================
*/

// 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 = (winding_t *) Z_Malloc (s,TAG_BSP, qtrue);//TAG_WINDING);
//	memset (w, 0, s);	// qtrue above does this
	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);
}

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

	mins[0] = mins[1] = mins[2] =  WORLD_SIZE;	// 99999;	// WORLD_SIZE instead of MAX_WORLD_COORD so that...
	maxs[0] = maxs[1] = maxs[2] = -WORLD_SIZE;	//-99999;	// ... it's guaranteed to be outide of legal

	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;
		}
	}
}

/*
=================
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_t	size;
	winding_t	*c;

	c = AllocWinding (w->numpoints);
	size = (intptr_t)((winding_t *)0)->p[w->numpoints];
	memcpy (c, w, size);
	return c;
}

/*
=============
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;
}