/* -------------------------------------------------------------------------------

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

----------------------------------------------------------------------------------

This code has been altered significantly from its original form, to support
several games based on the Quake III Arena engine, in the form of "Q3Map2."

------------------------------------------------------------------------------- */



/* marker */
#define BRUSH_C



/* dependencies */
#include "q3map2.h"



/* -------------------------------------------------------------------------------

functions

------------------------------------------------------------------------------- */

/*
AllocSideRef() - ydnar
allocates and assigns a brush side reference
*/

sideRef_t      *AllocSideRef(side_t * side, sideRef_t * next)
{
	sideRef_t      *sideRef;


	/* dummy check */
	if(side == NULL)
		return next;

	/* allocate and return */
	sideRef = safe_malloc(sizeof(*sideRef));
	sideRef->side = side;
	sideRef->next = next;
	return sideRef;
}



/*
CountBrushList()
counts the number of brushes in a brush linked list
*/

int CountBrushList(brush_t * brushes)
{
	int             c = 0;


	/* count brushes */
	for(; brushes != NULL; brushes = brushes->next)
		c++;
	return c;
}



/*
AllocBrush()
allocates a new brush
*/

brush_t        *AllocBrush(int numSides)
{
	brush_t        *bb;
	size_t          c;


	/* allocate and clear */
	if(numSides <= 0)
		Error("AllocBrush called with numsides = %d", numSides);
	c = (size_t) & (((brush_t *) 0)->sides[numSides]);
	bb = safe_malloc(c);
	memset(bb, 0, c);
	if(numthreads == 1)
		numActiveBrushes++;

	/* return it */
	return bb;
}



/*
FreeBrush()
frees a single brush and all sides/windings
*/

void FreeBrush(brush_t * b)
{
	int             i;


	/* error check */
	if(*((unsigned int *)b) == 0xFEFEFEFE)
	{
		Sys_FPrintf(SYS_VRB, "WARNING: Attempt to free an already freed brush!\n");
		return;
	}

	/* free brush sides */
	for(i = 0; i < b->numsides; i++)
		if(b->sides[i].winding != NULL)
			FreeWinding(b->sides[i].winding);

	/* ydnar: overwrite it */
	memset(b, 0xFE, (size_t) & (((brush_t *) 0)->sides[b->numsides]));
	*((unsigned int *)b) = 0xFEFEFEFE;

	/* free it */
	free(b);
	if(numthreads == 1)
		numActiveBrushes--;
}



/*
FreeBrushList()
frees a linked list of brushes
*/

void FreeBrushList(brush_t * brushes)
{
	brush_t        *next;


	/* walk brush list */
	for(; brushes != NULL; brushes = next)
	{
		next = brushes->next;
		FreeBrush(brushes);
	}
}



/*
CopyBrush()
duplicates the brush, sides, and windings
*/

brush_t        *CopyBrush(brush_t * brush)
{
	brush_t        *newBrush;
	size_t          size;
	int             i;


	/* copy brush */
	size = (size_t) & (((brush_t *) 0)->sides[brush->numsides]);
	newBrush = AllocBrush(brush->numsides);
	memcpy(newBrush, brush, size);

	/* ydnar: nuke linked list */
	newBrush->next = NULL;

	/* copy sides */
	for(i = 0; i < brush->numsides; i++)
	{
		if(brush->sides[i].winding != NULL)
			newBrush->sides[i].winding = CopyWinding(brush->sides[i].winding);
	}

	/* return it */
	return newBrush;
}




/*
BoundBrush()
sets the mins/maxs based on the windings
returns false if the brush doesn't enclose a valid volume
*/

qboolean BoundBrush(brush_t * brush)
{
	int             i, j;
	winding_t      *w;


	ClearBounds(brush->mins, brush->maxs);
	for(i = 0; i < brush->numsides; i++)
	{
		w = brush->sides[i].winding;
		if(w == NULL)
			continue;
		for(j = 0; j < w->numpoints; j++)
			AddPointToBounds(w->p[j], brush->mins, brush->maxs);
	}

	for(i = 0; i < 3; i++)
	{
		if(brush->mins[i] < MIN_WORLD_COORD || brush->maxs[i] > MAX_WORLD_COORD || brush->mins[i] >= brush->maxs[i])
			return qfalse;
	}

	return qtrue;
}




/*
SnapWeldVector() - ydnar
welds two vec3_ts into a third, taking into account nearest-to-integer
instead of averaging
*/

#define SNAP_EPSILON	0.01

void SnapWeldVector(vec3_t a, vec3_t b, vec3_t out)
{
	int             i;
	vec_t           ai, bi, outi;


	/* dummy check */
	if(a == NULL || b == NULL || out == NULL)
		return;

	/* do each element */
	for(i = 0; i < 3; i++)
	{
		/* round to integer */
		ai = rint(a[i]);
		bi = rint(a[i]);

		/* prefer exact integer */
		if(ai == a[i])
			out[i] = a[i];
		else if(bi == b[i])
			out[i] = b[i];

		/* use nearest */
		else if(fabs(ai - a[i]) < fabs(bi < b[i]))
			out[i] = a[i];
		else
			out[i] = b[i];

		/* snap */
		outi = rint(out[i]);
		if(fabs(outi - out[i]) <= SNAP_EPSILON)
			out[i] = outi;
	}
}



/*
FixWinding() - ydnar
removes degenerate edges from a winding
returns qtrue if the winding is valid
*/

#define DEGENERATE_EPSILON	0.1

qboolean FixWinding(winding_t * w)
{
	qboolean        valid = qtrue;
	int             i, j, k;
	vec3_t          vec;
	float           dist;


	/* dummy check */
	if(!w)
		return qfalse;

	/* check all verts */
	for(i = 0; i < w->numpoints; i++)
	{
		/* don't remove points if winding is a triangle */
		if(w->numpoints == 3)
			return valid;

		/* get second point index */
		j = (i + 1) % w->numpoints;

		/* degenerate edge? */
		VectorSubtract(w->p[i], w->p[j], vec);
		dist = VectorLength(vec);
		if(dist < DEGENERATE_EPSILON)
		{
			valid = qfalse;
			//Sys_FPrintf( SYS_VRB, "WARNING: Degenerate winding edge found, fixing...\n" );

			/* create an average point (ydnar 2002-01-26: using nearest-integer weld preference) */
			SnapWeldVector(w->p[i], w->p[j], vec);
			VectorCopy(vec, w->p[i]);
			//VectorAdd( w->p[ i ], w->p[ j ], vec );
			//VectorScale( vec, 0.5, w->p[ i ] );

			/* move the remaining verts */
			for(k = i + 2; k < w->numpoints; k++)
			{
				VectorCopy(w->p[k], w->p[k - 1]);
			}
			w->numpoints--;
		}
	}

	/* one last check and return */
	if(w->numpoints < 3)
		valid = qfalse;
	return valid;
}







/*
CreateBrushWindings()
makes basewindigs for sides and mins/maxs for the brush
returns false if the brush doesn't enclose a valid volume
*/

qboolean CreateBrushWindings(brush_t * brush)
{
	int             i, j;

#if Q3MAP2_EXPERIMENTAL_HIGH_PRECISION_MATH_FIXES
	winding_accu_t *w;
#else
	winding_t      *w;
#endif
	side_t         *side;
	plane_t        *plane;


	/* walk the list of brush sides */
	for(i = 0; i < brush->numsides; i++)
	{
		/* get side and plane */
		side = &brush->sides[i];
		plane = &mapplanes[side->planenum];

		/* make huge winding */
#if Q3MAP2_EXPERIMENTAL_HIGH_PRECISION_MATH_FIXES
		w = BaseWindingForPlaneAccu(plane->normal, plane->dist);
#else
		w = BaseWindingForPlane(plane->normal, plane->dist);
#endif

		/* walk the list of brush sides */
		for(j = 0; j < brush->numsides && w != NULL; j++)
		{
			if(i == j)
				continue;
			if(brush->sides[j].planenum == (brush->sides[i].planenum ^ 1))
				continue;		/* back side clipaway */
			if(brush->sides[j].bevel)
				continue;
			plane = &mapplanes[brush->sides[j].planenum ^ 1];
#if Q3MAP2_EXPERIMENTAL_HIGH_PRECISION_MATH_FIXES
			ChopWindingInPlaceAccu(&w, plane->normal, plane->dist, 0);
#else
			ChopWindingInPlace(&w, plane->normal, plane->dist, 0);	// CLIP_EPSILON );
#endif

			/* ydnar: fix broken windings that would generate trifans */
#if Q3MAP2_EXPERIMENTAL_HIGH_PRECISION_MATH_FIXES
			// I think it's better to FixWindingAccu() once after we chop with all planes
			// so that error isn't multiplied.  There is nothing natural about welding
			// the points unless they are the final endpoints.  ChopWindingInPlaceAccu()
			// is able to handle all kinds of degenerate windings.
#else
			FixWinding(w);
#endif
		}

		/* set side winding */
#if Q3MAP2_EXPERIMENTAL_HIGH_PRECISION_MATH_FIXES
		if(w != NULL)
		{
			FixWindingAccu(w);
			if(w->numpoints < 3)
			{
				FreeWindingAccu(w);
				w = NULL;
			}
		}
		side->winding = (w ? CopyWindingAccuToRegular(w) : NULL);
		if(w)
			FreeWindingAccu(w);
#else
		side->winding = w;
#endif
	}

	/* find brush bounds */
	return BoundBrush(brush);
}




/*
==================
BrushFromBounds

Creates a new axial brush
==================
*/
brush_t        *BrushFromBounds(vec3_t mins, vec3_t maxs)
{
	brush_t        *b;
	int             i;
	vec3_t          normal;
	vec_t           dist;

	b = AllocBrush(6);
	b->numsides = 6;
	for(i = 0; i < 3; i++)
	{
		VectorClear(normal);
		normal[i] = 1;
		dist = maxs[i];
		b->sides[i].planenum = FindFloatPlane(normal, dist, 1, (vec3_t *) & maxs);

		normal[i] = -1;
		dist = -mins[i];
		b->sides[3 + i].planenum = FindFloatPlane(normal, dist, 1, (vec3_t *) & mins);
	}

	CreateBrushWindings(b);

	return b;
}

/*
==================
BrushVolume

==================
*/
vec_t BrushVolume(brush_t * brush)
{
	int             i;
	winding_t      *w;
	vec3_t          corner;
	vec_t           d, area, volume;
	plane_t        *plane;

	if(!brush)
		return 0;

	// grab the first valid point as the corner

	w = NULL;
	for(i = 0; i < brush->numsides; i++)
	{
		w = brush->sides[i].winding;
		if(w)
			break;
	}
	if(!w)
		return 0;
	VectorCopy(w->p[0], corner);

	// make tetrahedrons to all other faces

	volume = 0;
	for(; i < brush->numsides; i++)
	{
		w = brush->sides[i].winding;
		if(!w)
			continue;
		plane = &mapplanes[brush->sides[i].planenum];
		d = -(DotProduct(corner, plane->normal) - plane->dist);
		area = WindingArea(w);
		volume += d * area;
	}

	volume /= 3;
	return volume;
}



/*
WriteBSPBrushMap()
writes a map with the split bsp brushes
*/

void WriteBSPBrushMap(char *name, brush_t * list)
{
	FILE           *f;
	side_t         *s;
	int             i;
	winding_t      *w;


	/* note it */
	Sys_Printf("Writing %s\n", name);

	/* open the map file */
	f = fopen(name, "wb");
	if(f == NULL)
		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++)
		{
			// TODO: See if we can use a smaller winding to prevent resolution loss.
			// Is WriteBSPBrushMap() used only to decompile maps?
			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, "notexture 0 0 0 1 1\n");
			FreeWinding(w);
		}
		fprintf(f, "}\n");
	}
	fprintf(f, "}\n");

	fclose(f);

}



/*
FilterBrushIntoTree_r()
adds brush reference to any intersecting bsp leafnode
*/

int FilterBrushIntoTree_r(brush_t * b, node_t * node)
{
	brush_t        *front, *back;
	int             c;


	/* dummy check */
	if(b == NULL)
		return 0;

	/* add it to the leaf list */
	if(node->planenum == PLANENUM_LEAF)
	{
		/* something somewhere is hammering brushlist */
		b->next = node->brushlist;
		node->brushlist = b;

		/* classify the leaf by the structural brush */
		if(!b->detail)
		{
			if(b->opaque)
			{
				node->opaque = qtrue;
				node->areaportal = qfalse;
			}
			else if(b->compileFlags & C_AREAPORTAL)
			{
				if(!node->opaque)
					node->areaportal = qtrue;
			}
		}

		return 1;
	}

	/* split it by the node plane */
	c = b->numsides;
	SplitBrush(b, node->planenum, &front, &back);
	FreeBrush(b);

	c = 0;
	c += FilterBrushIntoTree_r(front, node->children[0]);
	c += FilterBrushIntoTree_r(back, node->children[1]);

	return c;
}



/*
FilterDetailBrushesIntoTree
fragment all the detail brushes into the structural leafs
*/

void FilterDetailBrushesIntoTree(entity_t * e, tree_t * tree)
{
	brush_t        *b, *newb;
	int             r;
	int             c_unique, c_clusters;
	int             i;


	/* note it */
	Sys_FPrintf(SYS_VRB, "--- FilterDetailBrushesIntoTree ---\n");

	/* walk the list of brushes */
	c_unique = 0;
	c_clusters = 0;
	for(b = e->brushes; b; b = b->next)
	{
		if(!b->detail)
			continue;
		c_unique++;
		newb = CopyBrush(b);
		r = FilterBrushIntoTree_r(newb, tree->headnode);
		c_clusters += r;

		/* mark all sides as visible so drawsurfs are created */
		if(r)
		{
			for(i = 0; i < b->numsides; i++)
			{
				if(b->sides[i].winding)
					b->sides[i].visible = qtrue;
			}
		}
	}

	/* emit some statistics */
	Sys_FPrintf(SYS_VRB, "%9d detail brushes\n", c_unique);
	Sys_FPrintf(SYS_VRB, "%9d cluster references\n", c_clusters);
}

/*
=====================
FilterStructuralBrushesIntoTree

Mark the leafs as opaque and areaportals
=====================
*/
void FilterStructuralBrushesIntoTree(entity_t * e, tree_t * tree)
{
	brush_t        *b, *newb;
	int             r;
	int             c_unique, c_clusters;
	int             i;

	Sys_FPrintf(SYS_VRB, "--- FilterStructuralBrushesIntoTree ---\n");

	c_unique = 0;
	c_clusters = 0;
	for(b = e->brushes; b; b = b->next)
	{
		if(b->detail)
		{
			continue;
		}
		c_unique++;
		newb = CopyBrush(b);
		r = FilterBrushIntoTree_r(newb, tree->headnode);
		c_clusters += r;

		// mark all sides as visible so drawsurfs are created
		if(r)
		{
			for(i = 0; i < b->numsides; i++)
			{
				if(b->sides[i].winding)
				{
					b->sides[i].visible = qtrue;
				}
			}
		}
	}

	/* emit some statistics */
	Sys_FPrintf(SYS_VRB, "%9d structural brushes\n", c_unique);
	Sys_FPrintf(SYS_VRB, "%9d cluster references\n", c_clusters);
}



/*
================
AllocTree
================
*/
tree_t         *AllocTree(void)
{
	tree_t         *tree;

	tree = safe_malloc(sizeof(*tree));
	memset(tree, 0, sizeof(*tree));
	ClearBounds(tree->mins, tree->maxs);

	return tree;
}

/*
================
AllocNode
================
*/
node_t         *AllocNode(void)
{
	node_t         *node;

	node = safe_malloc(sizeof(*node));
	memset(node, 0, sizeof(*node));

	return node;
}


/*
================
WindingIsTiny

Returns true if the winding would be crunched out of
existence by the vertex snapping.
================
*/
#define	EDGE_LENGTH	0.2
qboolean WindingIsTiny(winding_t * w)
{
/*
	if (WindingArea (w) < 1)
		return qtrue;
	return qfalse;
*/
	int             i, j;
	vec_t           len;
	vec3_t          delta;
	int             edges;

	edges = 0;
	for(i = 0; i < w->numpoints; i++)
	{
		j = i == w->numpoints - 1 ? 0 : i + 1;
		VectorSubtract(w->p[j], w->p[i], delta);
		len = VectorLength(delta);
		if(len > EDGE_LENGTH)
		{
			if(++edges == 3)
				return qfalse;
		}
	}
	return qtrue;
}

/*
================
WindingIsHuge

Returns true if the winding still has one of the points
from basewinding for plane
================
*/
qboolean WindingIsHuge(winding_t * w)
{
	int             i, j;

	for(i = 0; i < w->numpoints; i++)
	{
		for(j = 0; j < 3; j++)
			if(w->p[i][j] <= MIN_WORLD_COORD || w->p[i][j] >= MAX_WORLD_COORD)
				return qtrue;
	}
	return qfalse;
}

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

/*
==================
BrushMostlyOnSide

==================
*/
int BrushMostlyOnSide(brush_t * brush, plane_t * plane)
{
	int             i, j;
	winding_t      *w;
	vec_t           d, max;
	int             side;

	max = 0;
	side = PSIDE_FRONT;
	for(i = 0; i < brush->numsides; i++)
	{
		w = brush->sides[i].winding;
		if(!w)
			continue;
		for(j = 0; j < w->numpoints; j++)
		{
			d = DotProduct(w->p[j], plane->normal) - plane->dist;
			if(d > max)
			{
				max = d;
				side = PSIDE_FRONT;
			}
			if(-d > max)
			{
				max = -d;
				side = PSIDE_BACK;
			}
		}
	}
	return side;
}



/*
SplitBrush()
generates two new brushes, leaving the original unchanged
*/

void SplitBrush(brush_t * brush, int planenum, brush_t ** front, brush_t ** back)
{
	brush_t        *b[2];
	int             i, j;
	winding_t      *w, *cw[2], *midwinding;
	plane_t        *plane, *plane2;
	side_t         *s, *cs;
	float           d, d_front, d_back;


	*front = NULL;
	*back = NULL;
	plane = &mapplanes[planenum];

	// check all points
	d_front = d_back = 0;
	for(i = 0; i < brush->numsides; i++)
	{
		w = brush->sides[i].winding;
		if(!w)
			continue;
		for(j = 0; j < w->numpoints; j++)
		{
			d = DotProduct(w->p[j], plane->normal) - plane->dist;
			if(d > 0 && d > d_front)
				d_front = d;
			if(d < 0 && d < d_back)
				d_back = d;
		}
	}

	if(d_front < 0.1)			// PLANESIDE_EPSILON)
	{							// only on back
		*back = CopyBrush(brush);
		return;
	}

	if(d_back > -0.1)			// PLANESIDE_EPSILON)
	{							// only on front
		*front = CopyBrush(brush);
		return;
	}

	// create a new winding from the split plane
	w = BaseWindingForPlane(plane->normal, plane->dist);
	for(i = 0; i < brush->numsides && w; i++)
	{
		plane2 = &mapplanes[brush->sides[i].planenum ^ 1];
		ChopWindingInPlace(&w, plane2->normal, plane2->dist, 0);	// PLANESIDE_EPSILON);
	}

	if(!w || WindingIsTiny(w))
	{							// the brush isn't really split
		int             side;

		side = BrushMostlyOnSide(brush, plane);
		if(side == PSIDE_FRONT)
			*front = CopyBrush(brush);
		if(side == PSIDE_BACK)
			*back = CopyBrush(brush);
		return;
	}

	if(WindingIsHuge(w))
		Sys_FPrintf(SYS_VRB, "WARNING: huge winding\n");

	midwinding = w;

	// split it for real

	for(i = 0; i < 2; i++)
	{
		b[i] = AllocBrush(brush->numsides + 1);
		memcpy(b[i], brush, sizeof(brush_t) - sizeof(brush->sides));
		b[i]->numsides = 0;
		b[i]->next = NULL;
		b[i]->original = brush->original;
	}

	// split all the current windings

	for(i = 0; i < brush->numsides; i++)
	{
		s = &brush->sides[i];
		w = s->winding;
		if(!w)
			continue;
		ClipWindingEpsilon(w, plane->normal, plane->dist, 0 /*PLANESIDE_EPSILON */ , &cw[0], &cw[1]);
		for(j = 0; j < 2; j++)
		{
			if(!cw[j])
				continue;
			cs = &b[j]->sides[b[j]->numsides];
			b[j]->numsides++;
			*cs = *s;
			cs->winding = cw[j];
		}
	}


	// see if we have valid polygons on both sides
	for(i = 0; i < 2; i++)
	{
		if(b[i]->numsides < 3 || !BoundBrush(b[i]))
		{
			if(b[i]->numsides >= 3)
				Sys_FPrintf(SYS_VRB, "bogus brush after clip\n");
			FreeBrush(b[i]);
			b[i] = NULL;
		}
	}

	if(!(b[0] && b[1]))
	{
		if(!b[0] && !b[1])
			Sys_FPrintf(SYS_VRB, "split removed brush\n");
		else
			Sys_FPrintf(SYS_VRB, "split not on both sides\n");
		if(b[0])
		{
			FreeBrush(b[0]);
			*front = CopyBrush(brush);
		}
		if(b[1])
		{
			FreeBrush(b[1]);
			*back = CopyBrush(brush);
		}
		return;
	}

	// add the midwinding to both sides
	for(i = 0; i < 2; i++)
	{
		cs = &b[i]->sides[b[i]->numsides];
		b[i]->numsides++;

		cs->planenum = planenum ^ i ^ 1;
		cs->shaderInfo = NULL;
		if(i == 0)
			cs->winding = CopyWinding(midwinding);
		else
			cs->winding = midwinding;
	}

	{
		vec_t           v1;
		int             i;


		for(i = 0; i < 2; i++)
		{
			v1 = BrushVolume(b[i]);
			if(v1 < 1.0)
			{
				FreeBrush(b[i]);
				b[i] = NULL;
				//          Sys_FPrintf (SYS_VRB,"tiny volume after clip\n");
			}
		}
	}

	*front = b[0];
	*back = b[1];
}
