gtkradiant/tools/quake3/q3map2/light_trace.c

/*
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 LIGHT_TRACE_C



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


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



#define Vector2Copy( a, b )		((b)[ 0 ] = (a)[ 0 ], (b)[ 1 ] = (a)[ 1 ])
#define Vector4Copy( a, b )		((b)[ 0 ] = (a)[ 0 ], (b)[ 1 ] = (a)[ 1 ], (b)[ 2 ] = (a)[ 2 ], (b)[ 3 ] = (a)[ 3 ])

#define MAX_NODE_ITEMS			5
#define MAX_NODE_TRIANGLES		5
#define MAX_TRACE_DEPTH			32
#define MIN_NODE_SIZE			32.0f

#define GROW_TRACE_INFOS		32768		//%	4096
#define GROW_TRACE_WINDINGS		65536		//%	32768
#define GROW_TRACE_TRIANGLES	131072		//%	32768
#define GROW_TRACE_NODES		16384		//%	16384
#define GROW_NODE_ITEMS			16			//%	256

#define MAX_TW_VERTS			12

#define	TRACE_ON_EPSILON		0.1f

#define TRACE_LEAF				-1
#define TRACE_LEAF_SOLID		-2

typedef struct traceVert_s
{
	vec3_t						xyz;
	float						st[ 2 ];
}
traceVert_t;

typedef struct traceInfo_s
{
	shaderInfo_t				*si;
	int							surfaceNum, castShadows, padding;
}
traceInfo_t;

typedef struct traceWinding_s
{
	vec4_t						plane;
	int							infoNum, numVerts;
	traceVert_t					v[ MAX_TW_VERTS ];
}
traceWinding_t;

typedef struct traceTriangle_s
{
	vec3_t						edge1, edge2;
	int							infoNum, padding;
	traceVert_t					v[ 3 ];
}
traceTriangle_t;

typedef struct traceNode_s
{
	int							type;
	vec4_t						plane;
	vec3_t						mins, maxs;
	int							children[ 2 ];
	int							numItems, maxItems;
	int							*items;
}
traceNode_t;


int								noDrawContentFlags, noDrawSurfaceFlags, noDrawCompileFlags;

int								numTraceInfos = 0, maxTraceInfos = 0, firstTraceInfo = 0;
traceInfo_t						*traceInfos = NULL;

int								numTraceWindings = 0, maxTraceWindings = 0, deadWinding = -1;
traceWinding_t					*traceWindings = NULL;

int								numTraceTriangles = 0, maxTraceTriangles = 0, deadTriangle = -1;
traceTriangle_t					*traceTriangles = NULL;

int								headNodeNum = 0, skyboxNodeNum = 0, maxTraceDepth = 0, numTraceLeafNodes = 0;
int								numTraceNodes = 0, maxTraceNodes = 0;
traceNode_t						*traceNodes = NULL;



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

allocation and list management

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

/*
AddTraceInfo() - ydnar
adds a trace info structure to the pool
*/

static int AddTraceInfo( traceInfo_t *ti )
{
	int		num;
	void	*temp;
	
	
	/* find an existing info */
	for( num = firstTraceInfo; num < numTraceInfos; num++ )
	{
		if( traceInfos[ num ].si == ti->si &&
			traceInfos[ num ].surfaceNum == ti->surfaceNum &&
			traceInfos[ num ].castShadows == ti->castShadows )
			return num;
	}
	
	/* enough space? */
	if( numTraceInfos >= maxTraceInfos )
	{
		/* allocate more room */
		maxTraceInfos += GROW_TRACE_INFOS;
		temp = safe_malloc( maxTraceInfos * sizeof( *traceInfos ) );
		if( traceInfos != NULL )
		{
			memcpy( temp, traceInfos, numTraceInfos * sizeof( *traceInfos ) );
			free( traceInfos );
		}
		traceInfos = (traceInfo_t*) temp;
	}
	
	/* add the info */
	memcpy( &traceInfos[ num ], ti, sizeof( *traceInfos ) );
	if( num == numTraceInfos )
		numTraceInfos++;
	
	/* return the ti number */
	return num;
}



/*
AllocTraceNode() - ydnar
allocates a new trace node
*/

static int AllocTraceNode( void )
{
	traceNode_t	*temp;
	
	
	/* enough space? */
	if( numTraceNodes >= maxTraceNodes )
	{
		/* reallocate more room */
		maxTraceNodes += GROW_TRACE_NODES;
		temp = safe_malloc( maxTraceNodes * sizeof( traceNode_t ) );
		if( traceNodes != NULL )
		{
			memcpy( temp, traceNodes, numTraceNodes * sizeof( traceNode_t ) );
			free( traceNodes );
		}
		traceNodes = temp;
	}
	
	/* add the node */
	memset( &traceNodes[ numTraceNodes ], 0, sizeof( traceNode_t ) );
	traceNodes[ numTraceNodes ].type = TRACE_LEAF;
	ClearBounds( traceNodes[ numTraceNodes ].mins, traceNodes[ numTraceNodes ].maxs );
	numTraceNodes++;
	
	/* return the count */
	return (numTraceNodes - 1);
}



/*
AddTraceWinding() - ydnar
adds a winding to the raytracing pool
*/

static int AddTraceWinding( traceWinding_t *tw )
{
	int		num;
	void	*temp;
	
	
	/* check for a dead winding */
	if( deadWinding >= 0 && deadWinding < numTraceWindings )
		num = deadWinding;
	else
	{
		/* put winding at the end of the list */
		num = numTraceWindings;
		
		/* enough space? */
		if( numTraceWindings >= maxTraceWindings )
		{
			/* allocate more room */
			maxTraceWindings += GROW_TRACE_WINDINGS;
			temp = safe_malloc( maxTraceWindings * sizeof( *traceWindings ) );
			if( traceWindings != NULL )
			{
				memcpy( temp, traceWindings, numTraceWindings * sizeof( *traceWindings ) );
				free( traceWindings );
			}
			traceWindings = (traceWinding_t*) temp;
		}
	}
	
	/* add the winding */
	memcpy( &traceWindings[ num ], tw, sizeof( *traceWindings ) );
	if( num == numTraceWindings )
		numTraceWindings++;
	deadWinding = -1;
	
	/* return the winding number */
	return num;
}



/*
AddTraceTriangle() - ydnar
adds a triangle to the raytracing pool
*/

static int AddTraceTriangle( traceTriangle_t *tt )
{
	int		num;
	void	*temp;
	
	
	/* check for a dead triangle */
	if( deadTriangle >= 0 && deadTriangle < numTraceTriangles )
		num = deadTriangle;
	else
	{
		/* put triangle at the end of the list */
		num = numTraceTriangles;
		
		/* enough space? */
		if( numTraceTriangles >= maxTraceTriangles )
		{
			/* allocate more room */
			maxTraceTriangles += GROW_TRACE_TRIANGLES;
			temp = safe_malloc( maxTraceTriangles * sizeof( *traceTriangles ) );
			if( traceTriangles != NULL )
			{
				memcpy( temp, traceTriangles, numTraceTriangles * sizeof( *traceTriangles ) );
				free( traceTriangles );
			}
			traceTriangles = (traceTriangle_t*) temp;
		}
	}
	
	/* find vectors for two edges sharing the first vert */
	VectorSubtract( tt->v[ 1 ].xyz, tt->v[ 0 ].xyz, tt->edge1 );
	VectorSubtract( tt->v[ 2 ].xyz, tt->v[ 0 ].xyz, tt->edge2 );
	
	/* add the triangle */
	memcpy( &traceTriangles[ num ], tt, sizeof( *traceTriangles ) );
	if( num == numTraceTriangles )
		numTraceTriangles++;
	deadTriangle = -1;
	
	/* return the triangle number */
	return num;
}



/*
AddItemToTraceNode() - ydnar
adds an item reference (winding or triangle) to a trace node
*/

static int AddItemToTraceNode( traceNode_t *node, int num )
{
	void			*temp;
	
	
	/* dummy check */
	if( num < 0 )
		return -1;
	
	/* enough space? */
	if( node->numItems >= node->maxItems )
	{
		/* allocate more room */
		if( node == traceNodes )
			node->maxItems *= 2;
		else
			node->maxItems += GROW_NODE_ITEMS;
		temp = safe_malloc( node->maxItems * sizeof( *node->items ) );
		if( node->items != NULL )
		{
			memcpy( temp, node->items, node->numItems * sizeof( *node->items ) );
			free( node->items );
		}
		node->items = (int*) temp;
	}
	
	/* add the poly */
	node->items[ node->numItems ] = num;
	node->numItems++;
	
	/* return the count */
	return (node->numItems - 1);
}




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

trace node setup

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

/*
SetupTraceNodes_r() - ydnar
recursively create the initial trace node structure from the bsp tree
*/

static int SetupTraceNodes_r( int bspNodeNum )
{
	int				i, nodeNum, bspLeafNum;
	bspPlane_t		*plane;
	bspNode_t 		*bspNode;
	
	
	/* get bsp node and plane */
	bspNode = &bspNodes[ bspNodeNum ];
	plane = &bspPlanes[ bspNode->planeNum ];
	
	/* allocate a new trace node */
	nodeNum = AllocTraceNode();
	
	/* setup trace node */
	traceNodes[ nodeNum ].type = PlaneTypeForNormal( plane->normal );
	VectorCopy( plane->normal, traceNodes[ nodeNum ].plane );
	traceNodes[ nodeNum ].plane[ 3 ] = plane->dist;
	
	/* setup children */
	for( i = 0; i < 2; i++ )
	{
		/* leafnode */
		if( bspNode->children[ i ] < 0 )
		{
			bspLeafNum = -bspNode->children[ i ] - 1;
			
			#if 0
			/* solid leaf */
			if( bspLeafs[ bspLeafNum ].cluster == -1 )
				traceNodes[ nodeNum ].children[ i ] = -1;
			
			/* passable leaf */
			else
				traceNodes[ nodeNum ].children[ i ] = AllocTraceNode();
			#endif
			
			/* new code */
			traceNodes[ nodeNum ].children[ i ] = AllocTraceNode();
			if( bspLeafs[ bspLeafNum ].cluster == -1 )
				traceNodes[ traceNodes[ nodeNum ].children[ i ] ].type = TRACE_LEAF_SOLID;
		}
		
		/* normal node */
		else
			traceNodes[ nodeNum ].children[ i ] = SetupTraceNodes_r( bspNode->children[ i ] );
	}
	
	/* return node number */
	return nodeNum;
}



/*
ClipTraceWinding() - ydnar
clips a trace winding against a plane into one or two parts
*/

#define TW_ON_EPSILON	0.25f

void ClipTraceWinding( traceWinding_t *tw, vec4_t plane, traceWinding_t *front, traceWinding_t *back )
{
	int				i, j, k;
	int				sides[ MAX_TW_VERTS ], counts[ 3 ] = { 0, 0, 0 };
	float			dists[ MAX_TW_VERTS ];
	float			frac;
	traceVert_t		*a, *b, mid;
	
	
	/* clear front and back */
	front->numVerts = 0;
	back->numVerts = 0;
	
	/* classify points */
	for( i = 0; i < tw->numVerts; i++ )
	{
		dists[ i ] = DotProduct( tw->v[ i ].xyz, plane ) - plane[ 3 ];
		if( dists[ i ] < -TW_ON_EPSILON )
			sides[ i ] = SIDE_BACK;
		else if( dists[ i ] > TW_ON_EPSILON )
			sides[ i ] = SIDE_FRONT;
		else
			sides[ i ] = SIDE_ON;
		counts[ sides[ i ] ]++;
	}
	
	/* entirely on front? */
	if( counts[ SIDE_BACK ] == 0 )
		memcpy( front, tw, sizeof( *front ) );
	
	/* entirely on back? */
	else if( counts[ SIDE_FRONT ] == 0 )
		memcpy( back, tw, sizeof( *back ) );
	
	/* straddles the plane */
	else
	{
		/* setup front and back */
		memcpy( front, tw, sizeof( *front ) );
		front->numVerts = 0;
		memcpy( back, tw, sizeof( *back ) ); 
		back->numVerts = 0;
		
		/* split the winding */
		for( i = 0; i < tw->numVerts; i++ )
		{
			/* radix */
			j = (i + 1) % tw->numVerts;
			
			/* get verts */
			a = &tw->v[ i ];
			b = &tw->v[ j ];
			
			/* handle points on the splitting plane */
			switch( sides[ i ] )
			{
				case SIDE_FRONT:
					if( front->numVerts >= MAX_TW_VERTS )
						Error( "MAX_TW_VERTS (%d) exceeded", MAX_TW_VERTS );
					front->v[ front->numVerts++ ] = *a;
					break;
				
				case SIDE_BACK:
					if( back->numVerts >= MAX_TW_VERTS )
						Error( "MAX_TW_VERTS (%d) exceeded", MAX_TW_VERTS );
					back->v[ back->numVerts++ ] = *a;
					break;
				
				case SIDE_ON:
					if( front->numVerts >= MAX_TW_VERTS || back->numVerts >= MAX_TW_VERTS )
						Error( "MAX_TW_VERTS (%d) exceeded", MAX_TW_VERTS );
					front->v[ front->numVerts++ ] = *a;
					back->v[ back->numVerts++ ] = *a;
					continue;
			}
			
			/* check next point to see if we need to split the edge */
			if( sides[ j ] == SIDE_ON || sides[ j ] == sides[ i ] )
				continue;
			
			/* check limit */
			if( front->numVerts >= MAX_TW_VERTS || back->numVerts >= MAX_TW_VERTS )
				Error( "MAX_TW_VERTS (%d) exceeded", MAX_TW_VERTS );
			
			/* generate a split point */
			frac = dists[ i ] / (dists[ i ] - dists[ j ]);
			for( k = 0; k < 3; k++ )
			{
				/* minimize fp precision errors */
				if( plane[ k ] == 1.0f )
					mid.xyz[ k ] = plane[ 3 ];
				else if( plane[ k ] == -1.0f )
					mid.xyz[ k ] = -plane[ 3 ];
				else
					mid.xyz[ k ] = a->xyz[ k ] + frac * (b->xyz[ k ] - a->xyz[ k ]);
				
				/* set texture coordinates */
				if( k > 1 )
					continue;
				mid.st[ 0 ] = a->st[ 0 ] + frac * (b->st[ 0 ] - a->st[ 0 ]);
				mid.st[ 1 ] = a->st[ 1 ] + frac * (b->st[ 1 ] - a->st[ 1 ]);
			}
			
			/* copy midpoint to front and back polygons */
			front->v[ front->numVerts++ ] = mid;
			back->v[ back->numVerts++ ] = mid;
		}
	}
}



/*
FilterPointToTraceNodes_r() - ydnar
debugging tool
*/

static int FilterPointToTraceNodes_r( vec3_t pt, int nodeNum )
{
	float			dot;
	traceNode_t		*node;
	
	
	if( nodeNum < 0 || nodeNum >= numTraceNodes )
		return -1;
	
	node = &traceNodes[ nodeNum ];
	
	if( node->type >= 0 )
	{
		dot = DotProduct( pt, node->plane ) - node->plane[ 3 ];
		if( dot > -0.001f )
			FilterPointToTraceNodes_r( pt, node->children[ 0 ] );
		if( dot < 0.001f )
			FilterPointToTraceNodes_r( pt, node->children[ 1 ] );
		return -1;
	}
	
	Sys_Printf( "%d ", nodeNum );
	
	return nodeNum;
}



/*
FilterTraceWindingIntoNodes_r() - ydnar
filters a trace winding into the raytracing tree
*/

static void FilterTraceWindingIntoNodes_r( traceWinding_t *tw, int nodeNum )
{
	int				num;
	vec4_t			plane1, plane2, reverse;
	traceNode_t		*node;
	traceWinding_t	front, back;
	
	
	/* don't filter if passed a bogus node (solid, etc) */
	if( nodeNum < 0 || nodeNum >= numTraceNodes )
		return;
	
	/* get node */
	node = &traceNodes[ nodeNum ];
	
	/* is this a decision node? */
	if( node->type >= 0 )
	{	
		/* create winding plane if necessary, filtering out bogus windings as well */
		if( nodeNum == headNodeNum )
		{
			if( !PlaneFromPoints( tw->plane, tw->v[ 0 ].xyz, tw->v[ 1 ].xyz, tw->v[ 2 ].xyz ) )
				return;
		}
	
		/* validate the node */
		if( node->children[ 0 ] == 0 || node->children[ 1 ] == 0 )
			Error( "Invalid tracenode: %d", nodeNum );
		
		/* get node plane */
		Vector4Copy( node->plane, plane1 );
		
		/* get winding plane */
		Vector4Copy( tw->plane, plane2 );
		
		/* invert surface plane */
		VectorSubtract( vec3_origin, plane2, reverse );
		reverse[ 3 ] = -plane2[ 3 ];
		
		/* front only */
		if( DotProduct( plane1, plane2 ) > 0.999f && fabs( plane1[ 3 ] - plane2[ 3 ] ) < 0.001f )
		{
			FilterTraceWindingIntoNodes_r( tw, node->children[ 0 ] );
			return;
		}
		
		/* back only */
		if( DotProduct( plane1, reverse ) > 0.999f && fabs( plane1[ 3 ] - reverse[ 3 ] ) < 0.001f )
		{
			FilterTraceWindingIntoNodes_r( tw, node->children[ 1 ] );
			return;
		}
		
		/* clip the winding by node plane */
		ClipTraceWinding( tw, plane1, &front, &back );
		
		/* filter by node plane */
		if( front.numVerts >= 3 )
			FilterTraceWindingIntoNodes_r( &front, node->children[ 0 ] );
		if( back.numVerts >= 3 )
			FilterTraceWindingIntoNodes_r( &back, node->children[ 1 ] );
		
		/* return to caller */
		return;
	}
	
	/* add winding to leaf node */
	num = AddTraceWinding( tw );
	AddItemToTraceNode( node, num );
}



/*
SubdivideTraceNode_r() - ydnar
recursively subdivides a tracing node until it meets certain size and complexity criteria
*/

static void SubdivideTraceNode_r( int nodeNum, int depth )
{
	int				i, j, count, num, frontNum, backNum, type;
	vec3_t			size;
	float			dist;
	double			average[ 3 ];
	traceNode_t		*node, *frontNode, *backNode;
	traceWinding_t	*tw, front, back;
	
	
	/* dummy check */
	if( nodeNum < 0 || nodeNum >= numTraceNodes )
		return;
	
	/* get node */
	node = &traceNodes[ nodeNum ];
	
	/* runaway recursion check */
	if( depth >= MAX_TRACE_DEPTH )
	{
		//%	Sys_Printf( "Depth: (%d items)\n", node->numItems );
		numTraceLeafNodes++;
		return;
	}
	depth++;
	
	/* is this a decision node? */
	if( node->type >= 0 )
	{
		/* subdivide children */
		frontNum = node->children[ 0 ];
		backNum = node->children[ 1 ];
		SubdivideTraceNode_r( frontNum, depth );
		SubdivideTraceNode_r( backNum, depth );
		return;
	}
	
	/* bound the node */
	ClearBounds( node->mins, node->maxs );
	VectorClear( average );
	count = 0;
	for( i = 0; i < node->numItems; i++ )
	{
		/* get winding */
		tw = &traceWindings[ node->items[ i ] ];
		
		/* walk its verts */
		for( j = 0; j < tw->numVerts; j++ )
		{
			AddPointToBounds( tw->v[ j ].xyz, node->mins, node->maxs );
			average[ 0 ] += tw->v[ j ].xyz[ 0 ];
			average[ 1 ] += tw->v[ j ].xyz[ 1 ];
			average[ 2 ] += tw->v[ j ].xyz[ 2 ];
			count++;
		}
	}
	
	/* check triangle limit */
	//%	if( node->numItems <= MAX_NODE_ITEMS )
	if( (count - (node->numItems * 2)) < MAX_NODE_TRIANGLES )
	{
		//%	Sys_Printf( "Limit: (%d triangles)\n", (count - (node->numItems * 2)) );
		numTraceLeafNodes++;
		return;
	}
	
	/* the largest dimension of the bounding box will be the split axis */
	VectorSubtract( node->maxs, node->mins, size );
	if( size[ 0 ] >= size[ 1 ] && size[ 0 ] >= size[ 2 ] )
		type = PLANE_X;
	else if( size[ 1 ] >= size[ 0 ] && size[ 1 ] >= size[ 2 ] )
		type = PLANE_Y;
	else
		type = PLANE_Z;
	
	/* don't split small nodes */
	if( size[ type ] <= MIN_NODE_SIZE )
	{
		//%	Sys_Printf( "Limit: %f %f %f (%d items)\n", size[ 0 ], size[ 1 ], size[ 2 ], node->numItems );
		numTraceLeafNodes++;
		return;
	}
	
	/* set max trace depth */
	if( depth > maxTraceDepth )
		maxTraceDepth = depth;
	
	/* snap the average */
	dist = floor( average[ type ] / count );
	
	/* dummy check it */
	if( dist <= node->mins[ type ] || dist >= node->maxs[ type ] )
		dist = floor( 0.5f * (node->mins[ type ] + node->maxs[ type ]) );
	
	/* allocate child nodes */
	frontNum = AllocTraceNode();
	backNum = AllocTraceNode();
	
	/* reset pointers */
	node = &traceNodes[ nodeNum ];
	frontNode = &traceNodes[ frontNum ];
	backNode = &traceNodes[ backNum ];
	
	/* attach children */
	node->type = type;
	node->plane[ type ] = 1.0f;
	node->plane[ 3 ] = dist;
	node->children[ 0 ] = frontNum;
	node->children[ 1 ] = backNum;
	
	/* setup front node */
	frontNode->maxItems = (node->maxItems >> 1);
	frontNode->items = safe_malloc( frontNode->maxItems * sizeof( *frontNode->items ) );
	
	/* setup back node */
	backNode->maxItems = (node->maxItems >> 1);
	backNode->items = safe_malloc( backNode->maxItems * sizeof( *backNode->items ) );
	
	/* filter windings into child nodes */
	for( i = 0; i < node->numItems; i++ )
	{
		/* get winding */
		tw = &traceWindings[ node->items[ i ] ];
		
		/* clip the winding by the new split plane */
		ClipTraceWinding( tw, node->plane, &front, &back );
		
		/* kill the existing winding */
		if( front.numVerts >= 3 || back.numVerts >= 3 )
			deadWinding = node->items[ i ];
		
		/* add front winding */
		if( front.numVerts >= 3 )
		{
			num = AddTraceWinding( &front );
			AddItemToTraceNode( frontNode, num );
		}
		
		/* add back winding */
		if( back.numVerts >= 3 )
		{
			num = AddTraceWinding( &back );
			AddItemToTraceNode( backNode, num );
		}
	}
	
	/* free original node winding list */
	node->numItems = 0;
	node->maxItems = 0;
	free( node->items );
	node->items = NULL;
	
	/* check children */
	if( frontNode->numItems <= 0 )
	{
		frontNode->maxItems = 0;
		free( frontNode->items );
		frontNode->items = NULL;
	}
	
	if( backNode->numItems <= 0 )
	{
		backNode->maxItems = 0;
		free( backNode->items );
		backNode->items = NULL;
	}
	
	/* subdivide children */
	SubdivideTraceNode_r( frontNum, depth );
	SubdivideTraceNode_r( backNum, depth );
}



/*
TriangulateTraceNode_r()
optimizes the tracing data by changing trace windings into triangles
*/

static int TriangulateTraceNode_r( int nodeNum )
{
	int				i, j, num, frontNum, backNum, numWindings, *windings;
	traceNode_t		*node;
	traceWinding_t	*tw;
	traceTriangle_t	tt;
	
	
	/* dummy check */
	if( nodeNum < 0 || nodeNum >= numTraceNodes )
		return 0;
	
	/* get node */
	node = &traceNodes[ nodeNum ];
	
	/* is this a decision node? */
	if( node->type >= 0 )
	{
		/* triangulate children */
		frontNum = node->children[ 0 ];
		backNum = node->children[ 1 ];
		node->numItems = TriangulateTraceNode_r( frontNum );
		node->numItems += TriangulateTraceNode_r( backNum );
		return node->numItems;
	}
	
	/* empty node? */
	if( node->numItems == 0 )
	{
		node->maxItems = 0;
		if( node->items != NULL )
			free( node->items );
		return node->numItems;
	}
	
	/* store off winding data */
	numWindings = node->numItems;
	windings = node->items;
	
	/* clear it */
	node->numItems = 0;
	node->maxItems = numWindings * 2;
	node->items = safe_malloc( node->maxItems * sizeof( tt ) );
	
	/* walk winding list */
	for( i = 0; i < numWindings; i++ )
	{
		/* get winding */
		tw = &traceWindings[ windings[ i ] ];
		
		/* initial setup */
		tt.infoNum = tw->infoNum;
		tt.v[ 0 ] = tw->v[ 0 ];
		
		/* walk vertex list */
		for( j = 1; j + 1 < tw->numVerts; j++ )
		{
			/* set verts */
			tt.v[ 1 ] = tw->v[ j ];
			tt.v[ 2 ] = tw->v[ j + 1 ];
			
			/* find vectors for two edges sharing the first vert */
			VectorSubtract( tt.v[ 1 ].xyz, tt.v[ 0 ].xyz, tt.edge1 );
			VectorSubtract( tt.v[ 2 ].xyz, tt.v[ 0 ].xyz, tt.edge2 );
			
			/* add it to the node */
			num = AddTraceTriangle( &tt );
			AddItemToTraceNode( node, num );
		}
	}
	
	/* free windings */
	if( windings != NULL )
		free( windings );
	
	/* return item count */
	return node->numItems;
}



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

shadow casting item setup (triangles, patches, entities)

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

/*
PopulateWithBSPModel() - ydnar
filters a bsp model's surfaces into the raytracing tree
*/

static void PopulateWithBSPModel( bspModel_t *model, m4x4_t transform )
{
	int					i, j, x, y, pw[ 5 ], r, nodeNum;
	bspDrawSurface_t	*ds;
	surfaceInfo_t		*info;
	bspDrawVert_t		*verts;
	int					*indexes;
	mesh_t				srcMesh, *mesh, *subdivided;
	traceInfo_t			ti;
	traceWinding_t		tw;
	
	
	/* dummy check */
	if( model == NULL || transform == NULL )
		return;
	
	/* walk the list of surfaces in this model and fill out the info structs */
	for( i = 0; i < model->numBSPSurfaces; i++ )
	{
		/* get surface and info */
		ds = &bspDrawSurfaces[ model->firstBSPSurface + i ];
		info = &surfaceInfos[ model->firstBSPSurface + i ];
		if( info->si == NULL )
			continue;
		
		/* no shadows */
		if( !info->castShadows )
			continue;
		
		/* patchshadows? */
		if( ds->surfaceType == MST_PATCH && patchShadows == qfalse )
			continue;
		
		/* some surfaces in the bsp might have been tagged as nodraw, with a bogus shader */
		if( (bspShaders[ ds->shaderNum ].contentFlags & noDrawContentFlags) || 
			(bspShaders[ ds->shaderNum ].surfaceFlags & noDrawSurfaceFlags) )
			continue;
		
		/* translucent surfaces that are neither alphashadow or lightfilter don't cast shadows */
		if( (info->si->compileFlags & C_NODRAW) )
			continue;
		if( (info->si->compileFlags & C_TRANSLUCENT) &&
			!(info->si->compileFlags & C_ALPHASHADOW) && 
			!(info->si->compileFlags & C_LIGHTFILTER) )
			continue;
		
		/* setup trace info */
		ti.si = info->si;
		ti.castShadows = info->castShadows;
		ti.surfaceNum = model->firstBSPBrush + i;
		
		/* setup trace winding */
		memset( &tw, 0, sizeof( tw ) );
		tw.infoNum = AddTraceInfo( &ti );
		tw.numVerts = 3;
		
		/* choose which node (normal or skybox) */
		if( info->parentSurfaceNum >= 0 )
			nodeNum = skyboxNodeNum;
		else
			nodeNum = headNodeNum;
		
		/* switch on type */
		switch( ds->surfaceType )
		{
			/* handle patches */
			case MST_PATCH:
				/* subdivide the surface */
				srcMesh.width = ds->patchWidth;
				srcMesh.height = ds->patchHeight;
				srcMesh.verts = &bspDrawVerts[ ds->firstVert ];
				//%	subdivided = SubdivideMesh( srcMesh, 8, 512 );
				subdivided = SubdivideMesh2( srcMesh, info->patchIterations );
				
				/* fit it to the curve and remove colinear verts on rows/columns */
				PutMeshOnCurve( *subdivided );
				mesh = RemoveLinearMeshColumnsRows( subdivided );
				FreeMesh( subdivided );
				
				/* set verts */
				verts = mesh->verts;
				
				/* subdivide each quad to place the models */
				for( y = 0; y < (mesh->height - 1); y++ )
				{
					for( x = 0; x < (mesh->width - 1); x++ )
					{
						/* set indexes */
						pw[ 0 ] = x + (y * mesh->width);
						pw[ 1 ] = x + ((y + 1) * mesh->width);
						pw[ 2 ] = x + 1 + ((y + 1) * mesh->width);
						pw[ 3 ] = x + 1 + (y * mesh->width);
						pw[ 4 ] = x + (y * mesh->width);	/* same as pw[ 0 ] */
						
						/* set radix */
						r = (x + y) & 1;
						
						/* make first triangle */
						VectorCopy( verts[ pw[ r + 0 ] ].xyz, tw.v[ 0 ].xyz );
						Vector2Copy( verts[ pw[ r + 0 ] ].st, tw.v[ 0 ].st );
						VectorCopy( verts[ pw[ r + 1 ] ].xyz, tw.v[ 1 ].xyz );
						Vector2Copy( verts[ pw[ r + 1 ] ].st, tw.v[ 1 ].st );
						VectorCopy( verts[ pw[ r + 2 ] ].xyz, tw.v[ 2 ].xyz );
						Vector2Copy( verts[ pw[ r + 2 ] ].st, tw.v[ 2 ].st );
						m4x4_transform_point( transform, tw.v[ 0 ].xyz );
						m4x4_transform_point( transform, tw.v[ 1 ].xyz );
						m4x4_transform_point( transform, tw.v[ 2 ].xyz );
						FilterTraceWindingIntoNodes_r( &tw, nodeNum );
						
						/* make second triangle */
						VectorCopy( verts[ pw[ r + 0 ] ].xyz, tw.v[ 0 ].xyz );
						Vector2Copy( verts[ pw[ r + 0 ] ].st, tw.v[ 0 ].st );
						VectorCopy( verts[ pw[ r + 2 ] ].xyz, tw.v[ 1 ].xyz );
						Vector2Copy( verts[ pw[ r + 2 ] ].st, tw.v[ 1 ].st );
						VectorCopy( verts[ pw[ r + 3 ] ].xyz, tw.v[ 2 ].xyz );
						Vector2Copy( verts[ pw[ r + 3 ] ].st, tw.v[ 2 ].st );
						m4x4_transform_point( transform, tw.v[ 0 ].xyz );
						m4x4_transform_point( transform, tw.v[ 1 ].xyz );
						m4x4_transform_point( transform, tw.v[ 2 ].xyz );
						FilterTraceWindingIntoNodes_r( &tw, nodeNum );
					}
				}
				
				/* free the subdivided mesh */
				FreeMesh( mesh );
				break;
			
			/* handle triangle surfaces */
			case MST_TRIANGLE_SOUP:
			case MST_PLANAR:
				/* set verts and indexes */
				verts = &bspDrawVerts[ ds->firstVert ];
				indexes = &bspDrawIndexes[ ds->firstIndex ];
				
				/* walk the triangle list */
				for( j = 0; j < ds->numIndexes; j += 3 )
				{
					VectorCopy( verts[ indexes[ j ] ].xyz, tw.v[ 0 ].xyz );
					Vector2Copy( verts[ indexes[ j ] ].st, tw.v[ 0 ].st );
					VectorCopy( verts[ indexes[ j + 1 ] ].xyz, tw.v[ 1 ].xyz );
					Vector2Copy( verts[ indexes[ j + 1 ] ].st, tw.v[ 1 ].st );
					VectorCopy( verts[ indexes[ j + 2 ] ].xyz, tw.v[ 2 ].xyz );
					Vector2Copy( verts[ indexes[ j + 2 ] ].st, tw.v[ 2 ].st );
					m4x4_transform_point( transform, tw.v[ 0 ].xyz );
					m4x4_transform_point( transform, tw.v[ 1 ].xyz );
					m4x4_transform_point( transform, tw.v[ 2 ].xyz );
					FilterTraceWindingIntoNodes_r( &tw, nodeNum );
				}
				break;
			
			/* other surface types do not cast shadows */
			default:
				break;
		}
	}
}



/*
PopulateWithPicoModel() - ydnar
filters a picomodel's surfaces into the raytracing tree
*/

static void PopulateWithPicoModel( int castShadows, picoModel_t *model, m4x4_t transform )
{
	int					i, j, k, numSurfaces, numIndexes;
	picoSurface_t		*surface;
	picoShader_t		*shader;
	picoVec_t			*xyz, *st;
	picoIndex_t			*indexes;
	traceInfo_t			ti;
	traceWinding_t		tw;
	
	
	/* dummy check */
	if( model == NULL || transform == NULL )
		return;
	
	/* get info */
	numSurfaces = PicoGetModelNumSurfaces( model );
	
	/* walk the list of surfaces in this model and fill out the info structs */
	for( i = 0; i < numSurfaces; i++ )
	{
		/* get surface */
		surface = PicoGetModelSurface( model, i );
		if( surface == NULL )
			continue;
		
		/* only handle triangle surfaces initially (fixme: support patches) */
		if( PicoGetSurfaceType( surface ) != PICO_TRIANGLES )
			continue;
		
		/* get shader (fixme: support shader remapping) */
		shader = PicoGetSurfaceShader( surface );
		if( shader == NULL )
			continue;
		ti.si = ShaderInfoForShader( PicoGetShaderName( shader ) );
		if( ti.si == NULL )
			continue;
		
		/* translucent surfaces that are neither alphashadow or lightfilter don't cast shadows */
		if( (ti.si->compileFlags & C_NODRAW) )
			continue;
		if( (ti.si->compileFlags & C_TRANSLUCENT) &&
			!(ti.si->compileFlags & C_ALPHASHADOW) && 
			!(ti.si->compileFlags & C_LIGHTFILTER) )
			continue;
		
		/* setup trace info */
		ti.castShadows = castShadows;
		ti.surfaceNum = -1;
		
		/* setup trace winding */
		memset( &tw, 0, sizeof( tw ) );
		tw.infoNum = AddTraceInfo( &ti );
		tw.numVerts = 3;
		
		/* get info */
		numIndexes = PicoGetSurfaceNumIndexes( surface );
		indexes = PicoGetSurfaceIndexes( surface, 0 );
		
		/* walk the triangle list */
		for( j = 0; j < numIndexes; j += 3, indexes += 3 )
		{
			for( k = 0; k < 3; k++ )
			{
				xyz = PicoGetSurfaceXYZ( surface, indexes[ k ] );
				st = PicoGetSurfaceST( surface, 0, indexes[ k ] );
				VectorCopy( xyz, tw.v[ k ].xyz );
				Vector2Copy( st, tw.v[ k ].st );
				m4x4_transform_point( transform, tw.v[ k ].xyz );
			}
			FilterTraceWindingIntoNodes_r( &tw, headNodeNum );
		}
	}
}



/*
PopulateTraceNodes() - ydnar
fills the raytracing tree with world and entity occluders
*/

static void PopulateTraceNodes( void )
{
	int				i, m, frame, castShadows;
	float			temp;
	entity_t		*e;
	const char		*value;
	picoModel_t		*model;
	vec3_t			origin, scale, angles;
	m4x4_t			transform;

	
	/* add worldspawn triangles */
	m4x4_identity( transform );
	PopulateWithBSPModel( &bspModels[ 0 ], transform );
	
	/* walk each entity list */
	for( i = 1; i < numEntities; i++ )
	{
		/* get entity */
		e = &entities[ i ];
		
		/* get shadow flags */
		castShadows = ENTITY_CAST_SHADOWS;
		GetEntityShadowFlags( e, NULL, &castShadows, NULL );
		
		/* early out? */
		if( !castShadows )
			continue;
		
		/* get entity origin */
		GetVectorForKey( e, "origin", origin );
		
		/* get scale */
		scale[ 0 ] = scale[ 1 ] = scale[ 2 ] = 1.0f;
		temp = FloatForKey( e, "modelscale" );
		if( temp != 0.0f )
			scale[ 0 ] = scale[ 1 ] = scale[ 2 ] = temp;
		value = ValueForKey( e, "modelscale_vec" );
		if( value[ 0 ] != '\0' )
			sscanf( value, "%f %f %f", &scale[ 0 ], &scale[ 1 ], &scale[ 2 ] );
		
		/* get "angle" (yaw) or "angles" (pitch yaw roll) */
		angles[ 0 ] = angles[ 1 ] = angles[ 2 ] = 0.0f;
		angles[ 2 ] = FloatForKey( e, "angle" );
		value = ValueForKey( e, "angles" );
		if( value[ 0 ] != '\0' )
			sscanf( value, "%f %f %f", &angles[ 1 ], &angles[ 2 ], &angles[ 0 ] );
		
		/* set transform matrix (thanks spog) */
		m4x4_identity( transform );
		m4x4_pivoted_transform_by_vec3( transform, origin, angles, eXYZ, scale, vec3_origin );
		
		/* hack: Stable-1_2 and trunk have differing row/column major matrix order
		   this transpose is necessary with Stable-1_2
		   uncomment the following line with old m4x4_t (non 1.3/spog_branch) code */
		//%	m4x4_transpose( transform );
		
		/* get model */
		value = ValueForKey( e, "model" );
		
		/* switch on model type */
		switch( value[ 0 ] )
		{
			/* no model */
			case '\0':
				break;
			
			/* bsp model */
			case '*':
				m = atoi( &value[ 1 ] );
				if( m <= 0 || m >= numBSPModels )
					continue;
				PopulateWithBSPModel( &bspModels[ m ], transform );
				break;
			
			/* external model */
			default:
				frame = IntForKey( e, "_frame" );
				model = LoadModel( (char*) value, frame );
				if( model == NULL )
					continue;
				PopulateWithPicoModel( castShadows, model, transform );
				continue;
		}
		
		/* get model2 */
		value = ValueForKey( e, "model2" );
		
		/* switch on model type */
		switch( value[ 0 ] )
		{
			/* no model */
			case '\0':
				break;
			
			/* bsp model */
			case '*':
				m = atoi( &value[ 1 ] );
				if( m <= 0 || m >= numBSPModels )
					continue;
				PopulateWithBSPModel( &bspModels[ m ], transform );
				break;
			
			/* external model */
			default:
				frame = IntForKey( e, "_frame2" );
				model = LoadModel( (char*) value, frame );
				if( model == NULL )
					continue;
				PopulateWithPicoModel( castShadows, model, transform );
				continue;
		}
	}
}




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

trace initialization

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

/*
SetupTraceNodes() - ydnar
creates a balanced bsp with axis-aligned splits for efficient raytracing
*/

void SetupTraceNodes( void )
{
	/* note it */
	Sys_FPrintf( SYS_VRB, "--- SetupTraceNodes ---\n" );
	
	/* find nodraw bit */
	noDrawContentFlags = noDrawSurfaceFlags = noDrawCompileFlags = 0;
	ApplySurfaceParm( "nodraw", &noDrawContentFlags, &noDrawSurfaceFlags, &noDrawCompileFlags );
	
	/* create the baseline raytracing tree from the bsp tree */
	headNodeNum = SetupTraceNodes_r( 0 );
	
	/* create outside node for skybox surfaces */
	skyboxNodeNum = AllocTraceNode();
	
	/* populate the tree with triangles from the world and shadow casting entities */
	PopulateTraceNodes();
	
	/* create the raytracing bsp */
	if( loMem == qfalse )
	{
		SubdivideTraceNode_r( headNodeNum, 0 );
		SubdivideTraceNode_r( skyboxNodeNum, 0 );
	}
	
	/* create triangles from the trace windings */
	TriangulateTraceNode_r( headNodeNum );
	TriangulateTraceNode_r( skyboxNodeNum );
	
	/* emit some stats */
	//%	Sys_FPrintf( SYS_VRB, "%9d original triangles\n", numOriginalTriangles );
	Sys_FPrintf( SYS_VRB, "%9d trace windings (%.2fMB)\n", numTraceWindings, (float) (numTraceWindings * sizeof( *traceWindings )) / (1024.0f * 1024.0f) );
	Sys_FPrintf( SYS_VRB, "%9d trace triangles (%.2fMB)\n", numTraceTriangles, (float) (numTraceTriangles * sizeof( *traceTriangles )) / (1024.0f * 1024.0f) );
	Sys_FPrintf( SYS_VRB, "%9d trace nodes (%.2fMB)\n", numTraceNodes, (float) (numTraceNodes * sizeof( *traceNodes )) / (1024.0f * 1024.0f) );
	Sys_FPrintf( SYS_VRB, "%9d leaf nodes (%.2fMB)\n", numTraceLeafNodes, (float) (numTraceLeafNodes * sizeof( *traceNodes )) / (1024.0f * 1024.0f) );
	//%	Sys_FPrintf( SYS_VRB, "%9d average triangles per leaf node\n", numTraceTriangles / numTraceLeafNodes );
	Sys_FPrintf( SYS_VRB, "%9d average windings per leaf node\n", numTraceWindings / (numTraceLeafNodes + 1) );
	Sys_FPrintf( SYS_VRB, "%9d max trace depth\n", maxTraceDepth );
	
	/* free trace windings */
	free( traceWindings );
	numTraceWindings = 0;
	maxTraceWindings = 0;
	deadWinding = -1;
	
	/* debug code: write out trace triangles to an alias obj file */
	#if 0
	{
		int				i, j;
		FILE			*file;
		char			filename[ 1024 ];
		traceWinding_t	*tw;
		
		
		/* open the file */
		strcpy( filename, source );
		StripExtension( filename );
		strcat( filename, ".lin" );
		Sys_Printf( "Opening light trace file %s...\n", filename );
		file = fopen( filename, "w" );
		if( file == NULL )
			Error( "Error opening %s for writing", filename );
		
		/* walk node list */
		for( i = 0; i < numTraceWindings; i++ )
		{
			tw = &traceWindings[ i ];
			for( j = 0; j < tw->numVerts + 1; j++ )
				fprintf( file, "%f %f %f\n",
					tw->v[ j % tw->numVerts ].xyz[ 0 ], tw->v[ j % tw->numVerts ].xyz[ 1 ], tw->v[ j % tw->numVerts ].xyz[ 2 ] );
		}
		
		/* close it */
		fclose( file );
	}
	#endif
}



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

raytracer

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

/*
TraceTriangle()
based on code written by william 'spog' joseph
based on code originally written by tomas moller and ben trumbore, journal of graphics tools, 2(1):21-28, 1997
*/

#define BARY_EPSILON			0.01f
#define ASLF_EPSILON			0.0001f	/* so to not get double shadows */
#define COPLANAR_EPSILON		0.25f	//%	0.000001f
#define NEAR_SHADOW_EPSILON		1.5f	//%	1.25f
#define SELF_SHADOW_EPSILON		0.5f

qboolean TraceTriangle( traceInfo_t *ti, traceTriangle_t *tt, trace_t *trace )
{
	int				i;
	float			tvec[ 3 ], pvec[ 3 ], qvec[ 3 ];
	float			det, invDet, depth;
	float			u, v, w, s, t;
	int				is, it;
	byte			*pixel;
	float			shadow;
	shaderInfo_t	*si;
	
	
	/* don't double-trace against sky */
	si = ti->si;
	if( trace->compileFlags & si->compileFlags & C_SKY )
		return qfalse;
	
	/* receive shadows from worldspawn group only */
	if( trace->recvShadows == 1 )
	{
		if( ti->castShadows != 1 )
			return qfalse;
	}
	
	/* receive shadows from same group and worldspawn group */
	else if( trace->recvShadows > 1 )
	{
		if( ti->castShadows != 1 && abs( ti->castShadows ) != abs( trace->recvShadows ) )
			return qfalse;
		//%	Sys_Printf( "%d:%d ", tt->castShadows, trace->recvShadows );
	}
	
	/* receive shadows from the same group only (< 0) */
	else
	{
		if( abs( ti->castShadows ) != abs( trace->recvShadows ) )
			return qfalse;
	}
	
	/* begin calculating determinant - also used to calculate u parameter */
	CrossProduct( trace->direction, tt->edge2, pvec );
	
	/* if determinant is near zero, trace lies in plane of triangle */
	det = DotProduct( tt->edge1, pvec );
	
	/* the non-culling branch */
	if( det > -COPLANAR_EPSILON && det < COPLANAR_EPSILON )
		return qfalse;
	invDet = 1.0f / det;
	
	/* calculate distance from first vertex to ray origin */
	VectorSubtract( trace->origin, tt->v[ 0 ].xyz, tvec );
	
	/* calculate u parameter and test bounds */
	u = DotProduct( tvec, pvec ) * invDet;
	if( u < -BARY_EPSILON || u > (1.0f + BARY_EPSILON) )
		return qfalse;
	
	/* prepare to test v parameter */
	CrossProduct( tvec, tt->edge1, qvec );
	
	/* calculate v parameter and test bounds */
	v = DotProduct( trace->direction, qvec ) * invDet;
	if( v < -BARY_EPSILON || (u + v) > (1.0f + BARY_EPSILON) )
		return qfalse;
	
	/* calculate t (depth) */
	depth = DotProduct( tt->edge2, qvec ) * invDet;
	//%	if( depth <= SELF_SHADOW_EPSILON || depth >= (trace->dist - SELF_SHADOW_EPSILON) )
	//%		return qfalse;
	if( depth <= trace->inhibitRadius || depth >= trace->distance )
		return qfalse;
	
	/* if hitpoint is really close to trace origin (sample point), then check for self-shadowing */
	if( depth <= SELF_SHADOW_EPSILON )
	{
		/* don't self-shadow */
		for( i = 0; i < trace->numSurfaces; i++ )
		{
			if( ti->surfaceNum == trace->surfaces[ i ] )
				return qfalse;
		}
	}
	
	/* stack compile flags */
	trace->compileFlags |= si->compileFlags;
	
	/* don't trace against sky */
	if( si->compileFlags & C_SKY )
		return qfalse;
	
	/* most surfaces are completely opaque */
	if( !(si->compileFlags & (C_ALPHASHADOW | C_LIGHTFILTER)) ||
		si->lightImage == NULL || si->lightImage->pixels == NULL )
	{
		VectorClear( trace->color );
		trace->opaque = qtrue;
		return qtrue;
	}
	
	/* try to avoid double shadows near triangle seams */
	if( u < -ASLF_EPSILON || u > (1.0f + ASLF_EPSILON) ||
		v < -ASLF_EPSILON || (u + v) > (1.0f + ASLF_EPSILON) )
		return qfalse;
	
	/* calculate w parameter */
	w = 1.0f - (u + v);
	
	/* calculate st from uvw (barycentric) coordinates */
	s = w * tt->v[ 0 ].st[ 0 ] + u * tt->v[ 1 ].st[ 0 ] + v * tt->v[ 2 ].st[ 0 ];
	t = w * tt->v[ 0 ].st[ 1 ] + u * tt->v[ 1 ].st[ 1 ] + v * tt->v[ 2 ].st[ 1 ];
	s = s - floor( s );
	t = t - floor( t );
	is = s * si->lightImage->width;
	it = t * si->lightImage->height;
	
	/* get pixel */
	pixel = si->lightImage->pixels + 4 * (it * si->lightImage->width + is);
	
	/* ydnar: color filter */
	if( si->compileFlags & C_LIGHTFILTER )
	{
		/* filter by texture color */
		trace->color[ 0 ] *= ((1.0f / 255.0f) * pixel[ 0 ]);
		trace->color[ 1 ] *= ((1.0f / 255.0f) * pixel[ 1 ]);
		trace->color[ 2 ] *= ((1.0f / 255.0f) * pixel[ 2 ]);
	}
	
	/* ydnar: alpha filter */
	if( si->compileFlags & C_ALPHASHADOW )
	{
		/* filter by inverse texture alpha */
		shadow = (1.0f / 255.0f) * (255 - pixel[ 3 ]);
		trace->color[ 0 ] *= shadow;
		trace->color[ 1 ] *= shadow;
		trace->color[ 2 ] *= shadow;
	}
	
	/* check filter for opaque */
	if( trace->color[ 0 ] <= 0.001f && trace->color[ 1 ] <= 0.001f && trace->color[ 2 ] <= 0.001f )
	{
		trace->opaque = qtrue;
		return qtrue;
	}
	
	/* continue tracing */
	return qfalse;
}



/*
TraceWinding() - ydnar
temporary hack
*/

qboolean TraceWinding( traceWinding_t *tw, trace_t *trace )
{
	int				i;
	traceTriangle_t	tt;
	
	
	/* initial setup */
	tt.infoNum = tw->infoNum;
	tt.v[ 0 ] = tw->v[ 0 ];
	
	/* walk vertex list */
	for( i = 1; i + 1 < tw->numVerts; i++ )
	{
		/* set verts */
		tt.v[ 1 ] = tw->v[ i ];
		tt.v[ 2 ] = tw->v[ i + 1 ];
		
		/* find vectors for two edges sharing the first vert */
		VectorSubtract( tt.v[ 1 ].xyz, tt.v[ 0 ].xyz, tt.edge1 );
		VectorSubtract( tt.v[ 2 ].xyz, tt.v[ 0 ].xyz, tt.edge2 );
		
		/* trace it */
		if( TraceTriangle( &traceInfos[ tt.infoNum ], &tt, trace ) )
			return qtrue;
	}
	
	/* done */
	return qfalse;
}




/*
TraceLine_r()
returns qtrue if something is hit and tracing can stop
*/

static qboolean TraceLine_r( int nodeNum, vec3_t origin, vec3_t end, trace_t *trace )
{
	traceNode_t		*node;
	int				side;
	float			front, back, frac;
	vec3_t			mid;
	qboolean		r;

	
	/* bogus node number means solid, end tracing unless testing all */
	if( nodeNum < 0 )
	{
		trace->passSolid = qtrue;
		return qtrue;
	}
	
	/* get node */
	node = &traceNodes[ nodeNum ];
	
	/* solid? */
	if( node->type == TRACE_LEAF_SOLID )
	{
		trace->passSolid = qtrue;
		return qtrue;
	}
	
	/* leafnode? */
	if( node->type < 0 )
	{
		/* note leaf and return */	
		if( node->numItems > 0 && trace->numTestNodes < MAX_TRACE_TEST_NODES )
			trace->testNodes[ trace->numTestNodes++ ] = nodeNum;
		return qfalse;
	}
	
	/* ydnar 2003-09-07: don't test branches of the bsp with nothing in them when testall is enabled */
	if( trace->testAll && node->numItems == 0 )
		return qfalse;
	
	/* classify beginning and end points */
	switch( node->type )
	{
		case PLANE_X:
			front = origin[ 0 ] - node->plane[ 3 ];
			back = end[ 0 ] - node->plane[ 3 ];
			break;
		
		case PLANE_Y:
			front = origin[ 1 ] - node->plane[ 3 ];
			back = end[ 1 ] - node->plane[ 3 ];
			break;
		
		case PLANE_Z:
			front = origin[ 2 ] - node->plane[ 3 ];
			back = end[ 2 ] - node->plane[ 3 ];
			break;
		
		default:
			front = DotProduct( origin, node->plane ) - node->plane[ 3 ];
			back = DotProduct( end, node->plane ) - node->plane[ 3 ];
			break;
	}
	
	/* entirely in front side? */
	if( front >= -TRACE_ON_EPSILON && back >= -TRACE_ON_EPSILON )
		return TraceLine_r( node->children[ 0 ], origin, end, trace );
	
	/* entirely on back side? */
	if( front < TRACE_ON_EPSILON && back < TRACE_ON_EPSILON )
		return TraceLine_r( node->children[ 1 ], origin, end, trace );
	
	/* select side */
	side = front < 0;
	
	/* calculate intercept point */
	frac = front / (front - back);
	mid[ 0 ] = origin[ 0 ] + (end[ 0 ] - origin[ 0 ]) * frac;
	mid[ 1 ] = origin[ 1 ] + (end[ 1 ] - origin[ 1 ]) * frac;
	mid[ 2 ] = origin[ 2 ] + (end[ 2 ] - origin[ 2 ]) * frac;
	
	/* fixme: check inhibit radius, then solid nodes and ignore */
	
	/* trace first side */
	r = TraceLine_r( node->children[ side ], origin, mid, trace );
	if( r )
		return r;
	
	/* trace other side */
	return TraceLine_r( node->children[ !side ], mid, end, trace );
}



/*
TraceLine() - ydnar
rewrote this function a bit :)
*/

void TraceLine( trace_t *trace )
{
	int				i, j;
	traceNode_t		*node;
	traceTriangle_t	*tt;
	traceInfo_t		*ti;
	
	
	/* setup output (note: this code assumes the input data is completely filled out) */
	trace->passSolid = qfalse;
	trace->opaque = qfalse;
	trace->compileFlags = 0;
	trace->numTestNodes = 0;
	
	/* early outs */
	if( !trace->recvShadows || !trace->testOcclusion || trace->distance <= 0.00001f )
		return;
	
	/* trace through nodes */
	TraceLine_r( headNodeNum, trace->origin, trace->end, trace );
	if( (trace->passSolid && !trace->testAll) )
	{
		trace->opaque = qtrue;
		return;
	}
	
	/* skip surfaces? */
	if( noSurfaces )
		return;
	
	/* testall means trace through sky */	
	if( trace->testAll && trace->numTestNodes < MAX_TRACE_TEST_NODES &&
		(trace->numSurfaces == 0 || surfaceInfos[ trace->surfaces[ 0 ] ].childSurfaceNum < 0) )
	{
		//%	trace->testNodes[ trace->numTestNodes++ ] = skyboxNodeNum;
		TraceLine_r( skyboxNodeNum, trace->origin, trace->end, trace );
	}
	
	/* walk node list */
	for( i = 0; i < trace->numTestNodes; i++ )
	{
		/* get node */
		node = &traceNodes[ trace->testNodes[ i ] ];
		
		/* walk node item list */
		for( j = 0; j < node->numItems; j++ )
		{
			tt = &traceTriangles[ node->items[ j ] ];
			ti = &traceInfos[ tt->infoNum ];
			if( TraceTriangle( ti, tt, trace ) )
				return;
			//%	if( TraceWinding( &traceWindings[ node->items[ j ] ], trace ) )
			//%		return;
		}
	}
}



/*
SetupTrace() - ydnar
sets up certain trace values
*/

float SetupTrace( trace_t *trace )
{
	VectorSubtract( trace->end, trace->origin, trace->displacement );
	trace->distance = VectorNormalize( trace->displacement, trace->direction );
	return trace->distance;
}