/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena 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 III Arena 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 III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
#include "cm_local.h"


/*
==================
CM_PointLeafnum_r

==================
*/
static int CM_PointLeafnum_r( const vec3_t p, int num ) {
	float		d;
	cNode_t		*node;
	cplane_t	*plane;

	while (num >= 0)
	{
		node = cm.nodes + num;
		plane = node->plane;
		
		if (plane->type < 3)
			d = p[plane->type] - plane->dist;
		else
			d = DotProduct (plane->normal, p) - plane->dist;
		if (d < 0)
			num = node->children[1];
		else
			num = node->children[0];
	}

	c_pointcontents++;		// optimize counter

	return -1 - num;
}

int CM_PointLeafnum( const vec3_t p ) {
	if ( !cm.numNodes ) {	// map not loaded
		return 0;
	}
	return CM_PointLeafnum_r (p, 0);
}


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

LEAF LISTING

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


void CM_StoreLeafs( leafList_t *ll, int nodenum ) {
	int		leafNum;

	leafNum = -1 - nodenum;

	// store the lastLeaf even if the list is overflowed
	if ( cm.leafs[ leafNum ].cluster != -1 ) {
		ll->lastLeaf = leafNum;
	}

	if ( ll->count >= ll->maxcount) {
		ll->overflowed = qtrue;
		return;
	}
	ll->list[ ll->count++ ] = leafNum;
}

void CM_StoreBrushes( leafList_t *ll, int nodenum ) {
	int			i, k;
	int			leafnum;
	int			brushnum;
	cLeaf_t		*leaf;
	cbrush_t	*b;

	leafnum = -1 - nodenum;

	leaf = &cm.leafs[leafnum];

	for ( k = 0 ; k < leaf->numLeafBrushes ; k++ ) {
		brushnum = cm.leafbrushes[leaf->firstLeafBrush+k];
		b = &cm.brushes[brushnum];
		if ( b->checkcount == cm.checkcount ) {
			continue;	// already checked this brush in another leaf
		}
		b->checkcount = cm.checkcount;
		for ( i = 0 ; i < 3 ; i++ ) {
			if ( b->bounds[0][i] >= ll->bounds[1][i] || b->bounds[1][i] <= ll->bounds[0][i] ) {
				break;
			}
		}
		if ( i != 3 ) {
			continue;
		}
		if ( ll->count >= ll->maxcount) {
			ll->overflowed = qtrue;
			return;
		}
		((cbrush_t **)ll->list)[ ll->count++ ] = b;
	}
#if 0
	// store patches?
	for ( k = 0 ; k < leaf->numLeafSurfaces ; k++ ) {
		patch = cm.surfaces[ cm.leafsurfaces[ leaf->firstleafsurface + k ] ];
		if ( !patch ) {
			continue;
		}
	}
#endif
}

/*
=============
CM_BoxLeafnums

Fills in a list of all the leafs touched
=============
*/
void CM_BoxLeafnums_r( leafList_t *ll, int nodenum ) {
	cplane_t	*plane;
	cNode_t		*node;
	int			s;

	while (1) {
		if (nodenum < 0) {
			ll->storeLeafs( ll, nodenum );
			return;
		}
	
		node = &cm.nodes[nodenum];
		plane = node->plane;
		s = BoxOnPlaneSide( ll->bounds[0], ll->bounds[1], plane );
		if (s == 1) {
			nodenum = node->children[0];
		} else if (s == 2) {
			nodenum = node->children[1];
		} else {
			// go down both
			CM_BoxLeafnums_r( ll, node->children[0] );
			nodenum = node->children[1];
		}

	}
}

/*
==================
CM_BoxLeafnums
==================
*/
int	CM_BoxLeafnums( const vec3_t mins, const vec3_t maxs, int *list, int listsize, int *lastLeaf) {
	leafList_t	ll;

	cm.checkcount++;

	VectorCopy( mins, ll.bounds[0] );
	VectorCopy( maxs, ll.bounds[1] );
	ll.count = 0;
	ll.maxcount = listsize;
	ll.list = list;
	ll.storeLeafs = CM_StoreLeafs;
	ll.lastLeaf = 0;
	ll.overflowed = qfalse;

	CM_BoxLeafnums_r( &ll, 0 );

	*lastLeaf = ll.lastLeaf;
	return ll.count;
}

/*
==================
CM_BoxBrushes
==================
*/
int CM_BoxBrushes( const vec3_t mins, const vec3_t maxs, cbrush_t **list, int listsize ) {
	leafList_t	ll;

	cm.checkcount++;

	VectorCopy( mins, ll.bounds[0] );
	VectorCopy( maxs, ll.bounds[1] );
	ll.count = 0;
	ll.maxcount = listsize;
	ll.list = (void *)list;
	ll.storeLeafs = CM_StoreBrushes;
	ll.lastLeaf = 0;
	ll.overflowed = qfalse;
	
	CM_BoxLeafnums_r( &ll, 0 );

	return ll.count;
}


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


/*
==================
CM_PointContents

==================
*/
int CM_PointContents( const vec3_t p, clipHandle_t model ) {
	int			leafnum;
	int			i, k;
	int			brushnum;
	cLeaf_t		*leaf;
	cbrush_t	*b;
	int			contents;
	float		d;
	cmodel_t	*clipm;

	if (!cm.numNodes) {	// map not loaded
		return 0;
	}

	if ( model ) {
		clipm = CM_ClipHandleToModel( model );
		leaf = &clipm->leaf;
	} else {
		leafnum = CM_PointLeafnum_r (p, 0);
		leaf = &cm.leafs[leafnum];
	}

	contents = 0;
	for (k=0 ; k<leaf->numLeafBrushes ; k++) {
		brushnum = cm.leafbrushes[leaf->firstLeafBrush+k];
		b = &cm.brushes[brushnum];

		if ( !CM_BoundsIntersectPoint( b->bounds[0], b->bounds[1], p ) ) {
			continue;
		}

		// see if the point is in the brush
		for ( i = 0 ; i < b->numsides ; i++ ) {
			d = DotProduct( p, b->sides[i].plane->normal );
// FIXME test for Cash
//			if ( d >= b->sides[i].plane->dist ) {
			if ( d > b->sides[i].plane->dist ) {
				break;
			}
		}

		if ( i == b->numsides ) {
			contents |= b->contents;
		}
	}

	return contents;
}

/*
==================
CM_TransformedPointContents

Handles offsetting and rotation of the end points for moving and
rotating entities
==================
*/
int	CM_TransformedPointContents( const vec3_t p, clipHandle_t model, const vec3_t origin, const vec3_t angles) {
	vec3_t		p_l;
	vec3_t		temp;
	vec3_t		forward, right, up;

	// subtract origin offset
	VectorSubtract (p, origin, p_l);

	// rotate start and end into the models frame of reference
	if ( model != BOX_MODEL_HANDLE && 
	(angles[0] || angles[1] || angles[2]) )
	{
		AngleVectors (angles, forward, right, up);

		VectorCopy (p_l, temp);
		p_l[0] = DotProduct (temp, forward);
		p_l[1] = -DotProduct (temp, right);
		p_l[2] = DotProduct (temp, up);
	}

	return CM_PointContents( p_l, model );
}



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

PVS

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

byte	*CM_ClusterPVS (int cluster) {
	if (cluster < 0 || cluster >= cm.numClusters || !cm.visibility ) {
		return cm.novis;
	}

	return cm.visibility + cluster * cm.clusterBytes;
}



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

AREAPORTALS

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

static void CM_FloodArea_r( int areaNum, int floodnum) {
	int		i;
	cArea_t *area;
	int		*con;

	area = &cm.areas[ areaNum ];

	if ( area->floodvalid == cm.floodvalid ) {
		if (area->floodnum == floodnum)
			return;
		Com_Error (ERR_DROP, "FloodArea_r: reflooded");
	}

	area->floodnum = floodnum;
	area->floodvalid = cm.floodvalid;
	con = cm.areaPortals + areaNum * cm.numAreas;
	for ( i=0 ; i < cm.numAreas  ; i++ ) {
		if ( con[i] > 0 ) {
			CM_FloodArea_r( i, floodnum );
		}
	}
}

/*
====================
CM_FloodAreaConnections

====================
*/
void	CM_FloodAreaConnections( void ) {
	int		i;
	cArea_t	*area;
	int		floodnum;

	// all current floods are now invalid
	cm.floodvalid++;
	floodnum = 0;

	for (i = 0 ; i < cm.numAreas ; i++) {
		area = &cm.areas[i];
		if (area->floodvalid == cm.floodvalid) {
			continue;		// already flooded into
		}
		floodnum++;
		CM_FloodArea_r (i, floodnum);
	}

}

/*
====================
CM_AdjustAreaPortalState

====================
*/
void	CM_AdjustAreaPortalState( int area1, int area2, qboolean open ) {
	if ( area1 < 0 || area2 < 0 ) {
		return;
	}

	if ( area1 >= cm.numAreas || area2 >= cm.numAreas ) {
		Com_Error (ERR_DROP, "CM_ChangeAreaPortalState: bad area number");
	}

	if ( open ) {
		cm.areaPortals[ area1 * cm.numAreas + area2 ]++;
		cm.areaPortals[ area2 * cm.numAreas + area1 ]++;
	} else {
		cm.areaPortals[ area1 * cm.numAreas + area2 ]--;
		cm.areaPortals[ area2 * cm.numAreas + area1 ]--;
		if ( cm.areaPortals[ area2 * cm.numAreas + area1 ] < 0 ) {
			Com_Error (ERR_DROP, "CM_AdjustAreaPortalState: negative reference count");
		}
	}

	CM_FloodAreaConnections ();
}

/*
====================
CM_AreasConnected

====================
*/
qboolean	CM_AreasConnected( int area1, int area2 ) {
#ifndef BSPC
	if ( cm_noAreas->integer ) {
		return qtrue;
	}
#endif

	if ( area1 < 0 || area2 < 0 ) {
		return qfalse;
	}

	if (area1 >= cm.numAreas || area2 >= cm.numAreas) {
		Com_Error (ERR_DROP, "area >= cm.numAreas");
	}

	if (cm.areas[area1].floodnum == cm.areas[area2].floodnum) {
		return qtrue;
	}
	return qfalse;
}


/*
=================
CM_WriteAreaBits

Writes a bit vector of all the areas
that are in the same flood as the area parameter
Returns the number of bytes needed to hold all the bits.

The bits are OR'd in, so you can CM_WriteAreaBits from multiple
viewpoints and get the union of all visible areas.

This is used to cull non-visible entities from snapshots
=================
*/
int CM_WriteAreaBits (byte *buffer, int area)
{
	int		i;
	int		floodnum;
	int		bytes;

	bytes = (cm.numAreas+7)>>3;

#ifndef BSPC
	if (cm_noAreas->integer || area == -1)
#else
	if (area == -1)
#endif
	{	// for debugging, send everything
		Com_Memset (buffer, 255, bytes);
	}
	else
	{
		floodnum = cm.areas[area].floodnum;
		for (i=0 ; i<cm.numAreas ; i++)
		{
			if (cm.areas[i].floodnum == floodnum)
				buffer[i>>3] |= 1<<(i&7);
		}
	}

	return bytes;
}


#define BOUNDS_CLIP_EPSILON 0.25f // assume single precision and slightly increase to compensate potential SIMD precision loss in 64-bit environment

/*
====================
CM_BoundsIntersect
====================
*/
qboolean CM_BoundsIntersect( const vec3_t mins, const vec3_t maxs, const vec3_t mins2, const vec3_t maxs2 )
{
	if (maxs[0] < mins2[0] - BOUNDS_CLIP_EPSILON ||
		maxs[1] < mins2[1] - BOUNDS_CLIP_EPSILON ||
		maxs[2] < mins2[2] - BOUNDS_CLIP_EPSILON ||
		mins[0] > maxs2[0] + BOUNDS_CLIP_EPSILON ||
		mins[1] > maxs2[1] + BOUNDS_CLIP_EPSILON ||
		mins[2] > maxs2[2] + BOUNDS_CLIP_EPSILON)
	{
		return qfalse;
	}

	return qtrue;
}


/*
====================
CM_BoundsIntersectPoint
====================
*/
qboolean CM_BoundsIntersectPoint( const vec3_t mins, const vec3_t maxs, const vec3_t point )
{
	if (maxs[0] < point[0] - BOUNDS_CLIP_EPSILON ||
		maxs[1] < point[1] - BOUNDS_CLIP_EPSILON ||
		maxs[2] < point[2] - BOUNDS_CLIP_EPSILON ||
		mins[0] > point[0] + BOUNDS_CLIP_EPSILON ||
		mins[1] > point[1] + BOUNDS_CLIP_EPSILON ||
		mins[2] > point[2] + BOUNDS_CLIP_EPSILON)
	{
		return qfalse;
	}

	return qtrue;
}
