/*  Copyright (C) 1996-1997  Id Software, Inc.

    This program 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.

    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, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

    See file, 'COPYING', for details.
*/

// region.h

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "QF/sys.h"

#include "bsp5.h"

/*

input
-----
vertexes
edges
faces

output
------
smaller set of vertexes
smaller set of edges
regions
? triangulated regions
face to region mapping numbers

*/

#define	MAX_EDGES_IN_REGION	32

int         firstedge;

vec3_t      region_mins, region_maxs;

void
AddPointToRegion (vec3_t p)
{
	int         i;

	for (i = 0; i < 3; i++) {
		if (p[i] < region_mins[i])
			region_mins[i] = p[i];
		if (p[i] > region_maxs[i])
			region_maxs[i] = p[i];
	}
}

void
ClearRegionSize (void)
{
	region_mins[0] = region_mins[1] = region_mins[2] = 9999;
	region_maxs[0] = region_maxs[1] = region_maxs[2] = -9999;
}

void
AddFaceToRegionSize (face_t * f)
{
	int         i;

	for (i = 0; i < f->numpoints; i++)
		AddPointToRegion (f->pts[i]);
}

/*
==============
CanJoinFaces
==============
*/
qboolean
CanJoinFaces (face_t * f, face_t * f2)
{
	vec3_t      oldmins, oldmaxs;
	int         i;

	if (f2->planenum != f->planenum
		|| f2->planeside != f->planeside || f2->texturenum != f->texturenum)
		return false;
	if (f2->outputnumber != -1)
		return false;
	if (f2->contents[0] != f->contents[0]) {	// does this ever happen?
												// theyy shouldn't share.
		printf ("CanJoinFaces: edge with different contents");
		return false;
	}
// check size constraints
	if (!(bsp->texinfo[f->texturenum].flags & TEX_SPECIAL)) {
		VectorCopy (region_mins, oldmins);
		VectorCopy (region_maxs, oldmaxs);
		AddFaceToRegionSize (f2);
		for (i = 0; i < 3; i++) {
			if (region_maxs[i] - region_mins[i] > 240) {
				VectorCopy (oldmins, region_mins);
				VectorCopy (oldmaxs, region_maxs);
				return false;
			}
		}
	} else {
		if (bsp->numsurfedges - firstedge + f2->numpoints > MAX_EDGES_IN_REGION)
			return false;				// a huge water or sky polygon
	}

// check edge count constraints
	return true;
}


/*
==============
RecursiveGrowRegion
==============
*/
void
RecursiveGrowRegion (dface_t *r, face_t * f)
{
	int         e;
	face_t     *f2;
	int         i;

	if (f->outputnumber == bsp->numfaces)
		return;

	if (f->outputnumber != -1)
		Sys_Error ("RecursiveGrowRegion: region collision");
	f->outputnumber = bsp->numfaces;

// add edges    
	for (i = 0; i < f->numpoints; i++) {
		e = f->edges[i];
		if (!edgefaces[abs (e)][0])
			continue;					// edge has allready been removed
		if (e > 0)
			f2 = edgefaces[e][1];
		else
			f2 = edgefaces[-e][0];
		if (f2 && f2->outputnumber == bsp->numfaces) {
			edgefaces[abs (e)][0] = NULL;
			edgefaces[abs (e)][1] = NULL;
			continue;					// allready merged
		}
		if (f2 && CanJoinFaces (f, f2)) {	// remove the edge and merge the
											// faces
			edgefaces[abs (e)][0] = NULL;
			edgefaces[abs (e)][1] = NULL;
			RecursiveGrowRegion (r, f2);
		} else {
			// emit a surfedge
			if (bsp->numsurfedges == MAX_MAP_SURFEDGES)
				Sys_Error ("numsurfedges == MAX_MAP_SURFEDGES");
			bsp->surfedges[bsp->numsurfedges] = e;
			bsp->numsurfedges++;
		}
	}

}

void
PrintDface (int f)
{										// for debugging
	dface_t    *df;
	dedge_t    *e;
	int         i, n;

	df = &bsp->faces[f];
	for (i = 0; i < df->numedges; i++) {
		n = bsp->surfedges[df->firstedge + i];
		e = &bsp->edges[abs (n)];
		if (n < 0)
			printf ("%5i  =  %5i : %5i\n", n, e->v[1], e->v[0]);
		else
			printf ("%5i  =  %5i : %5i\n", n, e->v[0], e->v[1]);
	}
}

void
FindVertexUse (int v)
{										// for debugging
	int         i, j, n;
	dface_t    *df;
	dedge_t    *e;

	for (i = firstmodelface; i < bsp->numfaces; i++) {
		df = &bsp->faces[i];
		for (j = 0; j < df->numedges; j++) {
			n = bsp->surfedges[df->firstedge + j];
			e = &bsp->edges[abs (n)];
			if (e->v[0] == v || e->v[1] == v) {
				printf ("on face %i\n", i);
				break;
			}
		}
	}
}

void
FindEdgeUse (int v)
{										// for debugging
	int         i, j, n;
	dface_t    *df;

	for (i = firstmodelface; i < bsp->numfaces; i++) {
		df = &bsp->faces[i];
		for (j = 0; j < df->numedges; j++) {
			n = bsp->surfedges[df->firstedge + j];
			if (n == v || -n == v) {
				printf ("on face %i\n", i);
				break;
			}
		}
	}
}

/*
================
HealEdges

Extends e1 so that it goes all the way to e2, and removes all references
to e2
================
*/
int         edgemapping[MAX_MAP_EDGES];
void
HealEdges (int e1, int e2)
{
	int         i, j, n, saved;
	dface_t    *df;
	dedge_t    *ed, *ed2;
	vec3_t      v1, v2;
	dface_t    *found[2];
	int         foundj[2];

	return;
	e1 = edgemapping[e1];
	e2 = edgemapping[e2];

// extend e1 to e2
	ed = &bsp->edges[e1];
	ed2 = &bsp->edges[e2];
	VectorSubtract (bsp->vertexes[ed->v[1]].point,
					bsp->vertexes[ed->v[0]].point, v1);
	VectorNormalize (v1);

	if (ed->v[0] == ed2->v[0])
		ed->v[0] = ed2->v[1];
	else if (ed->v[0] == ed2->v[1])
		ed->v[0] = ed2->v[0];
	else if (ed->v[1] == ed2->v[0])
		ed->v[1] = ed2->v[1];
	else if (ed->v[1] == ed2->v[1])
		ed->v[1] = ed2->v[0];
	else
		Sys_Error ("HealEdges: edges don't meet");

	VectorSubtract (bsp->vertexes[ed->v[1]].point,
					bsp->vertexes[ed->v[0]].point, v2);
	VectorNormalize (v2);

	if (!VectorCompare (v1, v2))
		Sys_Error ("HealEdges: edges not colinear");

	edgemapping[e2] = e1;
	saved = 0;

// remove all uses of e2
	for (i = firstmodelface; i < bsp->numfaces; i++) {
		df = &bsp->faces[i];
		for (j = 0; j < df->numedges; j++) {
			n = bsp->surfedges[df->firstedge + j];
			if (n == e2 || n == -e2) {
				found[saved] = df;
				foundj[saved] = j;
				saved++;
				break;
			}
		}
	}

	if (saved != 2)
		printf ("WARNING: didn't find both faces for a saved edge\n");
	else {
		for (i = 0; i < 2; i++) {		// remove this edge
			df = found[i];
			j = foundj[i];
			for (j++; j < df->numedges; j++)
				bsp->surfedges[df->firstedge + j - 1] =
					bsp->surfedges[df->firstedge + j];
			bsp->surfedges[df->firstedge + j - 1] = 0;
			df->numedges--;
		}


		edgefaces[e2][0] = edgefaces[e2][1] = NULL;
	}
}

typedef struct {
	int         numedges;
	int         edges[2];
} checkpoint_t;

checkpoint_t checkpoints[MAX_MAP_VERTS];

/*
==============
RemoveColinearEdges
==============
*/
void
RemoveColinearEdges (void)
{
	int         i, j, v;
	int         c0, c1, c2, c3;
	checkpoint_t *cp;

// no edges remapped yet
	for (i = 0; i < bsp->numedges; i++)
		edgemapping[i] = i;

// find vertexes that only have two edges
	memset (checkpoints, 0, sizeof (checkpoints));

	for (i = firstmodeledge; i < bsp->numedges; i++) {
		if (!edgefaces[i][0])
			continue;					// removed
		for (j = 0; j < 2; j++) {
			v = bsp->edges[i].v[j];
			cp = &checkpoints[v];
			if (cp->numedges < 2)
				cp->edges[cp->numedges] = i;
			cp->numedges++;
		}
	}

// if a vertex only has two edges and they are colinear, it can be removed
	c0 = c1 = c2 = c3 = 0;

	for (i = 0; i < bsp->numvertexes; i++) {
		cp = &checkpoints[i];
		switch (cp->numedges) {
			case 0:
				c0++;
				break;
			case 1:
				c1++;
				break;
			case 2:
				c2++;
				HealEdges (cp->edges[0], cp->edges[1]);
				break;
			default:
				c3++;
				break;
		}
	}

//  qprintf ("%5i c0\n", c0);
//  qprintf ("%5i c1\n", c1);
//  qprintf ("%5i c2\n", c2);
//  qprintf ("%5i c3+\n", c3);
	qprintf ("%5i deges removed by tjunction healing\n", c2);
}

/*
==============
CountRealNumbers
==============
*/
void
CountRealNumbers (void)
{
	int         i;
	int         c;

	qprintf ("%5i regions\n", bsp->numfaces - firstmodelface);

	c = 0;
	for (i = firstmodelface; i < bsp->numfaces; i++)
		c += bsp->faces[i].numedges;
	qprintf ("%5i real marksurfaces\n", c);

	c = 0;
	for (i = firstmodeledge; i < bsp->numedges; i++)
		if (edgefaces[i][0])
			c++;						// not removed

	qprintf ("%5i real edges\n", c);
}

//=============================================================================

/*
==============
GrowNodeRegion_r
==============
*/
void
GrowNodeRegion_r (node_t * node)
{
	dface_t    *r;
	face_t     *f;
	int         i;

	if (node->planenum == PLANENUM_LEAF)
		return;

	node->firstface = bsp->numfaces;

	for (f = node->faces; f; f = f->next) {
//      if (f->outputnumber != -1)
//          continue;   // allready grown into an earlier region

		// emit a region

		if (bsp->numfaces == MAX_MAP_FACES)
			Sys_Error ("MAX_MAP_FACES");
		f->outputnumber = bsp->numfaces;
		r = &bsp->faces[bsp->numfaces];

		r->planenum = node->outputplanenum;
		r->side = f->planeside;
		r->texinfo = f->texturenum;
		for (i = 0; i < MAXLIGHTMAPS; i++)
			r->styles[i] = 255;
		r->lightofs = -1;

		// add the face and mergable neighbors to it

#if 0
		ClearRegionSize ();
		AddFaceToRegionSize (f);
		RecursiveGrowRegion (r, f);
#endif
		r->firstedge = firstedge = bsp->numsurfedges;
		for (i = 0; i < f->numpoints; i++) {
			if (bsp->numsurfedges == MAX_MAP_SURFEDGES)
				Sys_Error ("numsurfedges == MAX_MAP_SURFEDGES");
			bsp->surfedges[bsp->numsurfedges] = f->edges[i];
			bsp->numsurfedges++;
		}

		r->numedges = bsp->numsurfedges - r->firstedge;

		bsp->numfaces++;
	}

	node->numfaces = bsp->numfaces - node->firstface;

	GrowNodeRegion_r (node->children[0]);
	GrowNodeRegion_r (node->children[1]);
}


/*
==============
GrowNodeRegions
==============
*/
void
GrowNodeRegions (node_t * headnode)
{
	qprintf ("---- GrowRegions ----\n");

	GrowNodeRegion_r (headnode);

//RemoveColinearEdges ();
	CountRealNumbers ();
}

/*
===============================================================================

Turn the faces on a plane into optimal non-convex regions
The edges may still be split later as a result of tjunctions

typedef struct
{
	vec3_t	dir;
	vec3_t	origin;
	vec3_t	p[2];
} 
for all faces
	for all edges
		for all edges so far
			if overlap
				split
				

===============================================================================
*/