/*
===========================================================================
Copyright (C) 1997-2006 Id Software, Inc.

This file is part of Quake 2 Tools source code.

Quake 2 Tools 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 2 Tools 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 Quake 2 Tools source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "qbsp.h"

/*

tag all brushes with original contents
brushes may contain multiple contents
there will be no brush overlap after csg phase




each side has a count of the other sides it splits

the best split will be the one that minimizes the total split counts
of all remaining sides

precalc side on plane table

evaluate split side
{
cost = 0
for all sides
	for all sides
		get 
		if side splits side and splitside is on same child
			cost++;
}


  */

void SplitBrush2 (bspbrush_t *brush, int planenum,
	bspbrush_t **front, bspbrush_t **back)
{
	SplitBrush (brush, planenum, front, back);
#if 0
	if (*front && (*front)->sides[(*front)->numsides-1].texinfo == -1)
		(*front)->sides[(*front)->numsides-1].texinfo = (*front)->sides[0].texinfo;	// not -1
	if (*back && (*back)->sides[(*back)->numsides-1].texinfo == -1)
		(*back)->sides[(*back)->numsides-1].texinfo = (*back)->sides[0].texinfo;	// not -1
#endif
}

/*
===============
SubtractBrush

Returns a list of brushes that remain after B is subtracted from A.
May by empty if A is contained inside B.

The originals are undisturbed.
===============
*/
bspbrush_t *SubtractBrush (bspbrush_t *a, bspbrush_t *b)
{	// a - b = out (list)
	int		i;
	bspbrush_t	*front, *back;
	bspbrush_t	*out, *in;

	in = a;
	out = NULL;
	for (i=0 ; i<b->numsides && in ; i++)
	{
		SplitBrush2 (in, b->sides[i].planenum, &front, &back);
		if (in != a)
			FreeBrush (in);
		if (front)
		{	// add to list
			front->next = out;
			out = front;
		}
		in = back;
	}
	if (in)
		FreeBrush (in);
	else
	{	// didn't really intersect
		FreeBrushList (out);
		return a;
	}
	return out;
}

/*
===============
IntersectBrush

Returns a single brush made up by the intersection of the
two provided brushes, or NULL if they are disjoint.

The originals are undisturbed.
===============
*/
bspbrush_t *IntersectBrush (bspbrush_t *a, bspbrush_t *b)
{
	int		i;
	bspbrush_t	*front, *back;
	bspbrush_t	*in;

	in = a;
	for (i=0 ; i<b->numsides && in ; i++)
	{
		SplitBrush2 (in, b->sides[i].planenum, &front, &back);
		if (in != a)
			FreeBrush (in);
		if (front)
			FreeBrush (front);
		in = back;
	}

	if (in == a)
		return NULL;

	in->next = NULL;
	return in;
}


/*
===============
BrushesDisjoint

Returns true if the two brushes definately do not intersect.
There will be false negatives for some non-axial combinations.
===============
*/
qboolean BrushesDisjoint (bspbrush_t *a, bspbrush_t *b)
{
	int		i, j;

	// check bounding boxes
	for (i=0 ; i<3 ; i++)
		if (a->mins[i] >= b->maxs[i]
		|| a->maxs[i] <= b->mins[i])
			return true;	// bounding boxes don't overlap

	// check for opposing planes
	for (i=0 ; i<a->numsides ; i++)
	{
		for (j=0 ; j<b->numsides ; j++)
		{
			if (a->sides[i].planenum ==
			(b->sides[j].planenum^1) )
				return true;	// opposite planes, so not touching
		}
	}

	return false;	// might intersect
}

/*
===============
IntersectionContents

Returns a content word for the intersection of two brushes.
Some combinations will generate a combination (water + clip),
but most will be the stronger of the two contents.
===============
*/
int	IntersectionContents (int c1, int c2)
{
	int		out;

	out = c1 | c2;

	if (out & CONTENTS_SOLID)
		out = CONTENTS_SOLID;

	return out;
}


int		minplanenums[3];
int		maxplanenums[3];

/*
===============
ClipBrushToBox

Any planes shared with the box edge will be set to no texinfo
===============
*/
bspbrush_t	*ClipBrushToBox (bspbrush_t *brush, vec3_t clipmins, vec3_t clipmaxs)
{
	int		i, j;
	bspbrush_t	*front,	*back;
	int		p;

	for (j=0 ; j<2 ; j++)
	{
		if (brush->maxs[j] > clipmaxs[j])
		{
			SplitBrush (brush, maxplanenums[j], &front, &back);
			if (front)
				FreeBrush (front);
			brush = back;
			if (!brush)
				return NULL;
		}
		if (brush->mins[j] < clipmins[j])
		{
			SplitBrush (brush, minplanenums[j], &front, &back);
			if (back)
				FreeBrush (back);
			brush = front;
			if (!brush)
				return NULL;
		}
	}

	// remove any colinear faces

	for (i=0 ; i<brush->numsides ; i++)
	{
		p = brush->sides[i].planenum & ~1;
		if (p == maxplanenums[0] || p == maxplanenums[1] 
			|| p == minplanenums[0] || p == minplanenums[1])
		{
			brush->sides[i].texinfo = TEXINFO_NODE;
			brush->sides[i].visible = false;
		}
	}
	return brush;
}

/*
===============
MakeBspBrushList 
===============
*/
bspbrush_t *MakeBspBrushList (int startbrush, int endbrush,
		vec3_t clipmins, vec3_t clipmaxs)
{
	mapbrush_t	*mb;
	bspbrush_t	*brushlist, *newbrush;
	int			i, j;
	int			c_faces;
	int			c_brushes;
	int			numsides;
	int			vis;
	vec3_t		normal;
	float		dist;

	for (i=0 ; i<2 ; i++)
	{
		VectorClear (normal);
		normal[i] = 1;
		dist = clipmaxs[i];
		maxplanenums[i] = FindFloatPlane (normal, dist);
		dist = clipmins[i];
		minplanenums[i] = FindFloatPlane (normal, dist);
	}

	brushlist = NULL;
	c_faces = 0;
	c_brushes = 0;

	for (i=startbrush ; i<endbrush ; i++)
	{
		mb = &mapbrushes[i];

		numsides = mb->numsides;
		if (!numsides)
			continue;
		// make sure the brush has at least one face showing
		vis = 0;
		for (j=0 ; j<numsides ; j++)
			if (mb->original_sides[j].visible && mb->original_sides[j].winding)
				vis++;
#if 0
		if (!vis)
			continue;	// no faces at all
#endif
		// if the brush is outside the clip area, skip it
		for (j=0 ; j<3 ; j++)
			if (mb->mins[j] >= clipmaxs[j]
			|| mb->maxs[j] <= clipmins[j])
			break;
		if (j != 3)
			continue;

		//
		// make a copy of the brush
		//
		newbrush = AllocBrush (mb->numsides);
		newbrush->original = mb;
		newbrush->numsides = mb->numsides;
		memcpy (newbrush->sides, mb->original_sides, numsides*sizeof(side_t));
		for (j=0 ; j<numsides ; j++)
		{
			if (newbrush->sides[j].winding)
				newbrush->sides[j].winding = CopyWinding (newbrush->sides[j].winding);
			if (newbrush->sides[j].surf & SURF_HINT)
				newbrush->sides[j].visible = true;	// hints are always visible
		}
		VectorCopy (mb->mins, newbrush->mins);
		VectorCopy (mb->maxs, newbrush->maxs);

		//
		// carve off anything outside the clip box
		//
		newbrush = ClipBrushToBox (newbrush, clipmins, clipmaxs);
		if (!newbrush)
			continue;

		c_faces += vis;
		c_brushes++;

		newbrush->next = brushlist;
		brushlist = newbrush;
	}

	return brushlist;
}

/*
===============
AddBspBrushListToTail
===============
*/
bspbrush_t *AddBrushListToTail (bspbrush_t *list, bspbrush_t *tail)
{
	bspbrush_t	*walk, *next;

	for (walk=list ; walk ; walk=next)
	{	// add to end of list
		next = walk->next;
		walk->next = NULL;
		tail->next = walk;
		tail = walk;
	}

	return tail;
}

/*
===========
CullList

Builds a new list that doesn't hold the given brush
===========
*/
bspbrush_t *CullList (bspbrush_t *list, bspbrush_t *skip1)
{
	bspbrush_t	*newlist;
	bspbrush_t	*next;

	newlist = NULL;

	for ( ; list ; list = next)
	{
		next = list->next;
		if (list == skip1)
		{
			FreeBrush (list);
			continue;
		}
		list->next = newlist;
		newlist = list;
	}
	return newlist;
}


/*
==================
WriteBrushMap
==================
*/
void WriteBrushMap (char *name, bspbrush_t *list)
{
	FILE	*f;
	side_t	*s;
	int		i;
	winding_t	*w;

	printf ("writing %s\n", name);
	f = fopen (name, "wb");
	if (!f)
		Error ("Can't write %s\b", name);

	fprintf (f, "{\n\"classname\" \"worldspawn\"\n");

	for ( ; list ; list=list->next )
	{
		fprintf (f, "{\n");
		for (i=0,s=list->sides ; i<list->numsides ; i++,s++)
		{
			w = BaseWindingForPlane (mapplanes[s->planenum].normal, mapplanes[s->planenum].dist);

			fprintf (f,"( %i %i %i ) ", (int)w->p[0][0], (int)w->p[0][1], (int)w->p[0][2]);
			fprintf (f,"( %i %i %i ) ", (int)w->p[1][0], (int)w->p[1][1], (int)w->p[1][2]);
			fprintf (f,"( %i %i %i ) ", (int)w->p[2][0], (int)w->p[2][1], (int)w->p[2][2]);

			fprintf (f, "%s 0 0 0 1 1\n", texinfo[s->texinfo].texture);
			FreeWinding (w);
		}
		fprintf (f, "}\n");
	}
	fprintf (f, "}\n");

	fclose (f);

}

/*
==================
BrushGE

Returns true if b1 is allowed to bite b2
==================
*/
qboolean BrushGE (bspbrush_t *b1, bspbrush_t *b2)
{
	// detail brushes never bite structural brushes
	if ( (b1->original->contents & CONTENTS_DETAIL) 
		&& !(b2->original->contents & CONTENTS_DETAIL) )
		return false;
	if (b1->original->contents & CONTENTS_SOLID)
		return true;
	return false;
}

/*
=================
ChopBrushes

Carves any intersecting solid brushes into the minimum number
of non-intersecting brushes. 
=================
*/
bspbrush_t *ChopBrushes (bspbrush_t *head)
{
	bspbrush_t	*b1, *b2, *next;
	bspbrush_t	*tail;
	bspbrush_t	*keep;
	bspbrush_t	*sub, *sub2;
	int			c1, c2;

	qprintf ("---- ChopBrushes ----\n");
	qprintf ("original brushes: %i\n", CountBrushList (head));

#if 0
	if (startbrush == 0)
		WriteBrushList ("before.gl", head, false);
#endif
	keep = NULL;

newlist:
	// find tail
	if (!head)
		return NULL;
	for (tail=head ; tail->next ; tail=tail->next)
	;

	for (b1=head ; b1 ; b1=next)
	{
		next = b1->next;
		for (b2=b1->next ; b2 ; b2 = b2->next)
		{
			if (BrushesDisjoint (b1, b2))
				continue;

			sub = NULL;
			sub2 = NULL;
			c1 = 999999;
			c2 = 999999;

			if ( BrushGE (b2, b1) )
			{
				sub = SubtractBrush (b1, b2);
				if (sub == b1)
					continue;		// didn't really intersect
				if (!sub)
				{	// b1 is swallowed by b2
					head = CullList (b1, b1);
					goto newlist;
				}
				c1 = CountBrushList (sub);
			}

			if ( BrushGE (b1, b2) )
			{
				sub2 = SubtractBrush (b2, b1);
				if (sub2 == b2)
					continue;		// didn't really intersect
				if (!sub2)
				{	// b2 is swallowed by b1
					FreeBrushList (sub);
					head = CullList (b1, b2);
					goto newlist;
				}
				c2 = CountBrushList (sub2);
			}

			if (!sub && !sub2)
				continue;		// neither one can bite

			// only accept if it didn't fragment
			// (commening this out allows full fragmentation)
			if (c1 > 1 && c2 > 1)
			{
				if (sub2)
					FreeBrushList (sub2);
				if (sub)
					FreeBrushList (sub);
				continue;
			}

			if (c1 < c2)
			{
				if (sub2)
					FreeBrushList (sub2);
				tail = AddBrushListToTail (sub, tail);
				head = CullList (b1, b1);
				goto newlist;
			}
			else
			{
				if (sub)
					FreeBrushList (sub);
				tail = AddBrushListToTail (sub2, tail);
				head = CullList (b1, b2);
				goto newlist;
			}
		}

		if (!b2)
		{	// b1 is no longer intersecting anything, so keep it
			b1->next = keep;
			keep = b1;
		}
	}

	qprintf ("output brushes: %i\n", CountBrushList (keep));
#if 0
	{
		WriteBrushList ("after.gl", keep, false);
		WriteBrushMap ("after.map", keep);
	}
#endif
	return keep;
}


/*
=================
InitialBrushList
=================
*/
bspbrush_t *InitialBrushList (bspbrush_t *list)
{
	bspbrush_t *b;
	bspbrush_t	*out, *newb;
	int			i;

	// only return brushes that have visible faces
	out = NULL;
	for (b=list ; b ; b=b->next)
	{
#if 0
		for (i=0 ; i<b->numsides ; i++)
			if (b->sides[i].visible)
				break;
		if (i == b->numsides)
			continue;
#endif
		newb = CopyBrush (b);
		newb->next = out;
		out = newb;

		// clear visible, so it must be set by MarkVisibleFaces_r
		// to be used in the optimized list
		for (i=0 ; i<b->numsides ; i++)
		{
			newb->sides[i].original = &b->sides[i];
//			newb->sides[i].visible = true;
			b->sides[i].visible = false;
		}
	}

	return out;
}

/*
=================
OptimizedBrushList
=================
*/
bspbrush_t *OptimizedBrushList (bspbrush_t *list)
{
	bspbrush_t *b;
	bspbrush_t	*out, *newb;
	int			i;

	// only return brushes that have visible faces
	out = NULL;
	for (b=list ; b ; b=b->next)
	{
		for (i=0 ; i<b->numsides ; i++)
			if (b->sides[i].visible)
				break;
		if (i == b->numsides)
			continue;
		newb = CopyBrush (b);
		newb->next = out;
		out = newb;
	}

//	WriteBrushList ("vis.gl", out, true);

	return out;
}
