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

Wolfenstein: Enemy Territory GPL Source Code
Copyright (C) 1999-2010 id Software LLC, a ZeniMax Media company. 

This file is part of the Wolfenstein: Enemy Territory GPL Source Code (“Wolf ET Source Code”).  

Wolf ET 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 3 of the License, or
(at your option) any later version.

Wolf ET 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 Wolf ET Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Wolf: ET Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Wolf ET Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

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

#include "tr_local.h"



/*
=================
R_CullGenericSurface - ydnar
based on R_CullTriSurf()
this culls the basic subset of all triangle/mesh map drawsurfaces
=================
*/

#if 0

#define SPHERE_CULL

#ifdef SPHERE_CULL

/*static qboolean	R_CullGenericSurface( srfGeneric_t *surface )
{
	int     cull;


	// allow disabling of foliage
	if( surface->surfaceType == SF_FOLIAGE && !r_drawfoliage->integer )
		return qtrue;

	// allow disabling of foliage
	if( surface->surfaceType == SF_GRID && r_nocurves->integer )
		return qtrue;

	// try sphere cull
	if( tr.currentEntityNum != ENTITYNUM_WORLD )
		cull = R_CullLocalPointAndRadius( surface->origin, surface->radius );
	else
		cull = R_CullPointAndRadius( surface->origin, surface->radius );
	if( cull == CULL_OUT )
		return qtrue;

	// it's ok
	return qfalse;
}*/

#else

static qboolean R_CullTriSurf( srfTriangles_t *cv ) {
	int boxCull;

	boxCull = R_CullLocalBox( cv->bounds );

	if ( boxCull == CULL_OUT ) {
		return qtrue;
	}
	return qfalse;
}


/*
=================
R_CullGrid

Returns true if the grid is completely culled away.
Also sets the clipped hint bit in tess
=================
*/
static qboolean R_CullGrid( srfGridMesh_t *cv ) {
	int boxCull;
	int sphereCull;

	if ( r_nocurves->integer ) {
		return qtrue;
	}

	if ( tr.currentEntityNum != ENTITYNUM_WORLD ) {
		sphereCull = R_CullLocalPointAndRadius( cv->localOrigin, cv->meshRadius );
	} else {
		sphereCull = R_CullPointAndRadius( cv->localOrigin, cv->meshRadius );
	}
	boxCull = CULL_OUT;

	// check for trivial reject
	if ( sphereCull == CULL_OUT ) {
		tr.pc.c_sphere_cull_patch_out++;
		return qtrue;
	}
	// check bounding box if necessary
	else if ( sphereCull == CULL_CLIP ) {
		tr.pc.c_sphere_cull_patch_clip++;

		boxCull = R_CullLocalBox( cv->meshBounds );

		if ( boxCull == CULL_OUT ) {
			tr.pc.c_box_cull_patch_out++;
			return qtrue;
		} else if ( boxCull == CULL_IN )   {
			tr.pc.c_box_cull_patch_in++;
		} else
		{
			tr.pc.c_box_cull_patch_clip++;
		}
	} else
	{
		tr.pc.c_sphere_cull_patch_in++;
	}

	return qfalse;
}

#endif

#endif // 0

/*
================
R_CullSurface

Tries to back face cull surfaces before they are lighted or
added to the sorting list.

This will also allow mirrors on both sides of a model without recursion.
================
*/
static qboolean R_CullSurface( surfaceType_t *surface, shader_t *shader, int *frontFace ) {
	srfGeneric_t    *gen;
	int cull;
	float d;


	// force to non-front facing
	*frontFace = 0;

	// allow culling to be disabled
	if ( r_nocull->integer ) {
		return qfalse;
	}

	// ydnar: made surface culling generic, inline with q3map2 surface classification
	switch ( *surface )
	{
	case SF_FACE:
	case SF_TRIANGLES:
		break;
	case SF_GRID:
		if ( r_nocurves->integer ) {
			return qtrue;
		}
		break;
	case SF_FOLIAGE:
		if ( !r_drawfoliage->value ) {
			return qtrue;
		}
		break;

	default:
		return qtrue;
	}

	// get generic surface
	gen = (srfGeneric_t*) surface;

	// plane cull
	if ( gen->plane.type != PLANE_NON_PLANAR && r_facePlaneCull->integer ) {
		d = DotProduct( tr.orientation.viewOrigin, gen->plane.normal ) - gen->plane.dist;
		if ( d > 0.0f ) {
			*frontFace = 1;
		}

		// don't cull exactly on the plane, because there are levels of rounding
		// through the BSP, ICD, and hardware that may cause pixel gaps if an
		// epsilon isn't allowed here
		if ( shader->cullType == CT_FRONT_SIDED ) {
			if ( d < -8.0f ) {
				tr.pc.c_plane_cull_out++;
				return qtrue;
			}
		} else if ( shader->cullType == CT_BACK_SIDED )    {
			if ( d > 8.0f ) {
				tr.pc.c_plane_cull_out++;
				return qtrue;
			}
		}

		tr.pc.c_plane_cull_in++;
	}

	{
		// try sphere cull
		if ( tr.currentEntityNum != ENTITYNUM_WORLD ) {
			cull = R_CullLocalPointAndRadius( gen->origin, gen->radius );
		} else {
			cull = R_CullPointAndRadius( gen->origin, gen->radius );
		}
		if ( cull == CULL_OUT ) {
			tr.pc.c_sphere_cull_out++;
			return qtrue;
		}

		tr.pc.c_sphere_cull_in++;
	}

	// must be visible
	return qfalse;
}

#if 0
static int R_DlightFace( srfSurfaceFace_t *face, int dlightBits ) {
	float d;
	int i;
	dlight_t    *dl;


	// ydnar: quick hack, need to rewrite for generic surfaces
	return dlightBits;

	for ( i = 0 ; i < tr.refdef.num_dlights ; i++ ) {
		if ( !( dlightBits & ( 1 << i ) ) ) {
			continue;
		}
		dl = &tr.refdef.dlights[i];
		d = DotProduct( dl->origin, face->plane.normal ) - face->plane.dist;
		if ( d < -dl->radius || d > dl->radius ) {
			// dlight doesn't reach the plane
			dlightBits &= ~( 1 << i );
		}
	}

	if ( !dlightBits ) {
		tr.pc.c_dlightSurfacesCulled++;
	}

	face->dlightBits[ tr.smpFrame ] = dlightBits;
	return dlightBits;
}

/*static int R_DlightGrid( srfGridMesh_t *grid, int dlightBits ) {
	int			i;
	dlight_t	*dl;

	for ( i = 0 ; i < tr.refdef.num_dlights ; i++ ) {
		if ( ! ( dlightBits & ( 1 << i ) ) ) {
			continue;
		}
		dl = &tr.refdef.dlights[i];
		if ( dl->origin[0] - dl->radius > grid->bounds[1][0]
			|| dl->origin[0] + dl->radius < grid->bounds[0][0]
			|| dl->origin[1] - dl->radius > grid->bounds[1][1]
			|| dl->origin[1] + dl->radius < grid->bounds[0][1]
			|| dl->origin[2] - dl->radius > grid->bounds[1][2]
			|| dl->origin[2] + dl->radius < grid->bounds[0][2] ) {
			// dlight doesn't reach the bounds
			dlightBits &= ~( 1 << i );
		}
	}

	if ( !dlightBits ) {
		tr.pc.c_dlightSurfacesCulled++;
	}

	grid->dlightBits[ tr.smpFrame ] = dlightBits;
	return dlightBits;
}*/


// ydnar: fixed this function (can be used for trisurfs and foliage)

static int R_DlightTrisurf( srfTriangles_t *srf, int dlightBits )

#if 0
{
	// FIXME: more dlight culling to trisurfs...
	surf->dlightBits[ tr.smpFrame ] = dlightBits;
	return dlightBits;
}
#else
{
	int i;
	dlight_t    *dl;
	vec3_t origin, delta;
	float radius2, dist2;


	VectorCopy( srf->origin, origin );
	radius2 = srf->radius * srf->radius;

	for ( i = 0; i < tr.refdef.num_dlights; i++ )
	{
		if ( !( dlightBits & ( 1 << i ) ) ) {
			continue;
		}

		dl = &tr.refdef.dlights[ i ];

		VectorSubtract( dl->origin, srf->origin, delta );
		dist2 = DotProduct( delta, delta ) - ( dl->radius * dl->radius );
		if ( dist2 > radius2 ) {
			dlightBits &= ~( 1 << i );
		}
	}

	// Com_Printf( "Surf: 0x%08X dlightBits: 0x%08X\n", srf, dlightBits );

	if ( !dlightBits ) {
		tr.pc.c_dlightSurfacesCulled++;
	}

	srf->dlightBits[ tr.smpFrame ] = dlightBits;
	return dlightBits;
}
#endif
#endif // 0

/*
====================
R_DlightSurface

The given surface is going to be drawn, and it touches a leaf
that is touched by one or more dlights, so try to throw out
more dlights if possible.
====================
*/

#if 0

static int R_DlightSurface( msurface_t *surf, int dlightBits ) {
	if ( *surf->data == SF_FACE ) {
		dlightBits = R_DlightFace( (srfSurfaceFace_t *)surf->data, dlightBits );
	} else if ( *surf->data == SF_GRID ) {
		dlightBits = R_DlightGrid( (srfGridMesh_t *)surf->data, dlightBits );
	} else if ( *surf->data == SF_TRIANGLES || *surf->data == SF_FOLIAGE ) {    // ydnar
		dlightBits = R_DlightTrisurf( (srfTriangles_t *)surf->data, dlightBits );
	} else {
		dlightBits = 0;
	}

	if ( dlightBits ) {
		tr.pc.c_dlightSurfaces++;
	}

	return dlightBits;
}

#else

// ydnar: made this use generic surface

static int R_DlightSurface( msurface_t *surface, int dlightBits ) {
	int i;
	vec3_t origin;
	float radius;
	srfGeneric_t    *gen;


	// get generic surface
	gen = (srfGeneric_t*) surface->data;

	// ydnar: made surface dlighting generic, inline with q3map2 surface classification
	switch ( (surfaceType_t) *surface->data )
	{
	case SF_FACE:
	case SF_TRIANGLES:
	case SF_GRID:
	case SF_FOLIAGE:
		break;

	default:
		gen->dlightBits[ tr.smpFrame ] = 0;
		return 0;
	}

	// debug code
	//%	gen->dlightBits[ tr.smpFrame ] = dlightBits;
	//%	return dlightBits;

	// try to cull out dlights
	for ( i = 0; i < tr.refdef.num_dlights; i++ )
	{
		if ( !( dlightBits & ( 1 << i ) ) ) {
			continue;
		}

		// junior dlights don't affect world surfaces
		if ( tr.refdef.dlights[ i ].flags & REF_JUNIOR_DLIGHT ) {
			dlightBits &= ~( 1 << i );
			continue;
		}

		// lightning dlights affect all surfaces
		if ( tr.refdef.dlights[ i ].flags & REF_DIRECTED_DLIGHT ) {
			continue;
		}

		// test surface bounding sphere against dlight bounding sphere
		VectorCopy( tr.refdef.dlights[ i ].transformed, origin );
		radius = tr.refdef.dlights[ i ].radius;

		if ( ( gen->origin[ 0 ] + gen->radius ) < ( origin[ 0 ] - radius ) ||
			 ( gen->origin[ 0 ] - gen->radius ) > ( origin[ 0 ] + radius ) ||
			 ( gen->origin[ 1 ] + gen->radius ) < ( origin[ 1 ] - radius ) ||
			 ( gen->origin[ 1 ] - gen->radius ) > ( origin[ 1 ] + radius ) ||
			 ( gen->origin[ 2 ] + gen->radius ) < ( origin[ 2 ] - radius ) ||
			 ( gen->origin[ 2 ] - gen->radius ) > ( origin[ 2 ] + radius ) ) {
			dlightBits &= ~( 1 << i );
		}
	}

	// Com_Printf( "Surf: 0x%08X dlightBits: 0x%08X\n", srf, dlightBits );

	// set counters
	if ( dlightBits == 0 ) {
		tr.pc.c_dlightSurfacesCulled++;
	} else {
		tr.pc.c_dlightSurfaces++;
	}

	// set surface dlight bits and return
	gen->dlightBits[ tr.smpFrame ] = dlightBits;
	return dlightBits;
}

#endif



/*
======================
R_AddWorldSurface
======================
*/
static void R_AddWorldSurface( msurface_t *surf, shader_t *shader, int dlightMap, int decalBits ) {
	int i, frontFace;


	if ( surf->viewCount == tr.viewCount ) {
		return;     // already in this view

	}
	surf->viewCount = tr.viewCount;
	// FIXME: bmodel fog?

	// try to cull before dlighting or adding
	if ( R_CullSurface( surf->data, shader, &frontFace ) ) {
		return;
	}

	// check for dlighting
	if ( dlightMap ) {
		dlightMap = R_DlightSurface( surf, dlightMap );
		dlightMap = ( dlightMap != 0 );
	}

	// add decals
	if ( decalBits ) {
		// ydnar: project any decals
		for ( i = 0; i < tr.refdef.numDecalProjectors; i++ )
		{
			if ( decalBits & ( 1 << i ) ) {
				R_ProjectDecalOntoSurface( &tr.refdef.decalProjectors[ i ], surf, tr.currentBModel );
			}
		}
	}

	R_AddDrawSurf( surf->data, shader, surf->fogIndex, frontFace, dlightMap );
}

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

	BRUSH MODELS

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

//----(SA) added

/*
=================
R_BmodelFogNum

See if a sprite is inside a fog volume
Return positive with /any part/ of the brush falling within a fog volume
=================
*/

// ydnar: the original implementation of this function is a bit flaky...
int R_BmodelFogNum( trRefEntity_t *re, bmodel_t *bmodel )

#if 1

{
	int i, j;
	fog_t           *fog;

	for ( i = 1; i < tr.world->numfogs; i++ )
	{
		fog = &tr.world->fogs[ i ];
		for ( j = 0; j < 3; j++ )
		{
			if ( re->e.origin[ j ] + bmodel->bounds[ 0 ][ j ] >= fog->bounds[ 1 ][ j ] ) {
				break;
			}
			if ( re->e.origin[ j ] + bmodel->bounds[ 1 ][ j ] <= fog->bounds[ 0 ][ j ] ) {
				break;
			}
		}
		if ( j == 3 ) {
			return i;
		}
	}

	return 0;
}

#else

{
	int i, j;
	fog_t           *fog;

	for ( i = 1 ; i < tr.world->numfogs ; i++ ) {
		fog = &tr.world->fogs[i];
		for ( j = 0 ; j < 3 ; j++ ) {
			if ( re->e.origin[j] + bmodel->bounds[0][j] > fog->bounds[1][j] ) {
				break;
			}
			if ( re->e.origin[j] + bmodel->bounds[0][j] < fog->bounds[0][j] ) {
				break;
			}
		}
		if ( j == 3 ) {
			return i;
		}
		for ( j = 0 ; j < 3 ; j++ ) {
			if ( re->e.origin[j] + bmodel->bounds[1][j] > fog->bounds[1][j] ) {
				break;
			}
			if ( bmodel->bounds[1][j] < fog->bounds[0][j] ) {
				break;
			}
		}
		if ( j == 3 ) {
			return i;
		}
	}

	return 0;
}

#endif

//----(SA) done



/*
=================
R_AddBrushModelSurfaces
=================
*/
void R_AddBrushModelSurfaces( trRefEntity_t *ent ) {
	int i, clip, fognum, decalBits;
	vec3_t mins, maxs;
	model_t             *pModel;
	bmodel_t            *bmodel;
	int savedNumDecalProjectors, numLocalProjectors;
	decalProjector_t    *savedDecalProjectors, localProjectors[ MAX_DECAL_PROJECTORS ];


	pModel = R_GetModelByHandle( ent->e.hModel );

	bmodel = pModel->model.bmodel;

	clip = R_CullLocalBox( bmodel->bounds );
	if ( clip == CULL_OUT ) {
		return;
	}

	// ydnar: set current brush model to world
	tr.currentBModel = bmodel;

	// ydnar: set model state for decals and dynamic fog
	VectorCopy( ent->e.origin, bmodel->orientation[ tr.smpFrame ].origin );
	VectorCopy( ent->e.axis[ 0 ], bmodel->orientation[ tr.smpFrame ].axis[ 0 ] );
	VectorCopy( ent->e.axis[ 1 ], bmodel->orientation[ tr.smpFrame ].axis[ 1 ] );
	VectorCopy( ent->e.axis[ 2 ], bmodel->orientation[ tr.smpFrame ].axis[ 2 ] );
	bmodel->visible[ tr.smpFrame ] = qtrue;
	bmodel->entityNum[ tr.smpFrame ] = tr.currentEntityNum;

	R_DlightBmodel( bmodel );

	// determine if in fog
	fognum = R_BmodelFogNum( ent, bmodel );

	// ydnar: project any decals
	decalBits = 0;
	numLocalProjectors = 0;
	for ( i = 0; i < tr.refdef.numDecalProjectors; i++ )
	{
		// early out
		if ( tr.refdef.decalProjectors[ i ].shader == NULL ) {
			continue;
		}

		// transform entity bbox (fixme: rotated entities have invalid bounding boxes)
		VectorAdd( bmodel->bounds[ 0 ], tr.orientation.origin, mins );
		VectorAdd( bmodel->bounds[ 1 ], tr.orientation.origin, maxs );

		// set bit
		if ( R_TestDecalBoundingBox( &tr.refdef.decalProjectors[ i ], mins, maxs ) ) {
			R_TransformDecalProjector( &tr.refdef.decalProjectors[ i ], tr.orientation.axis, tr.orientation.origin, &localProjectors[ numLocalProjectors ] );
			numLocalProjectors++;
			decalBits <<= 1;
			decalBits |= 1;
		}
	}

	// ydnar: save old decal projectors
	savedNumDecalProjectors = tr.refdef.numDecalProjectors;
	savedDecalProjectors = tr.refdef.decalProjectors;

	// set local decal projectors
	tr.refdef.numDecalProjectors = numLocalProjectors;
	tr.refdef.decalProjectors = localProjectors;

	// add model surfaces
	for ( i = 0; i < bmodel->numSurfaces; i++ )
	{
		( bmodel->firstSurface + i )->fogIndex = fognum;
		// Arnout: custom shader support for brushmodels
		if ( ent->e.customShader ) {
			R_AddWorldSurface( bmodel->firstSurface + i, R_GetShaderByHandle( ent->e.customShader ), tr.currentEntity->needDlights, decalBits );
		} else {
			R_AddWorldSurface( bmodel->firstSurface + i, ( ( msurface_t * )( bmodel->firstSurface + i ) )->shader, tr.currentEntity->needDlights, decalBits );
		}
	}

	// ydnar: restore old decal projectors
	tr.refdef.numDecalProjectors = savedNumDecalProjectors;
	tr.refdef.decalProjectors = savedDecalProjectors;

	// ydnar: add decal surfaces
	R_AddDecalSurfaces( bmodel );

	// ydnar: clear current brush model
	tr.currentBModel = NULL;
}


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

	WORLD MODEL

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


/*
R_AddLeafSurfaces() - ydnar
adds a leaf's drawsurfaces
*/

static void R_AddLeafSurfaces( mnode_t *node, int dlightBits, int decalBits ) {
	int c;
	msurface_t  *surf, **mark;


	// add to count
	tr.pc.c_leafs++;

	// add to z buffer bounds
	if ( node->mins[0] < tr.viewParms.visBounds[0][0] ) {
		tr.viewParms.visBounds[0][0] = node->mins[0];
	}
	if ( node->mins[1] < tr.viewParms.visBounds[0][1] ) {
		tr.viewParms.visBounds[0][1] = node->mins[1];
	}
	if ( node->mins[2] < tr.viewParms.visBounds[0][2] ) {
		tr.viewParms.visBounds[0][2] = node->mins[2];
	}

	if ( node->maxs[0] > tr.viewParms.visBounds[1][0] ) {
		tr.viewParms.visBounds[1][0] = node->maxs[0];
	}
	if ( node->maxs[1] > tr.viewParms.visBounds[1][1] ) {
		tr.viewParms.visBounds[1][1] = node->maxs[1];
	}
	if ( node->maxs[2] > tr.viewParms.visBounds[1][2] ) {
		tr.viewParms.visBounds[1][2] = node->maxs[2];
	}

	// add the individual surfaces
	mark = node->firstmarksurface;
	c = node->nummarksurfaces;
	while ( c-- ) {
		// the surface may have already been added if it
		// spans multiple leafs
		surf = *mark;
		R_AddWorldSurface( surf, surf->shader, dlightBits, decalBits );
		mark++;
	}
}


/*
================
R_RecursiveWorldNode
================
*/
static void R_RecursiveWorldNode( mnode_t *node, int planeBits, int dlightBits, int decalBits ) {
	int i, r;
	dlight_t    *dl;


	do
	{
		// if the node wasn't marked as potentially visible, exit
		if ( node->visframe != tr.visCount ) {
			return;
		}

		// if the bounding volume is outside the frustum, nothing
		// inside can be visible OPTIMIZE: don't do this all the way to leafs?

		if ( !r_nocull->integer ) {
			if ( planeBits & 1 ) {
				r = BoxOnPlaneSide( node->mins, node->maxs, &tr.viewParms.frustum[0] );
				if ( r == 2 ) {
					return;                     // culled
				}
				if ( r == 1 ) {
					planeBits &= ~1;            // all descendants will also be in front
				}
			}

			if ( planeBits & 2 ) {
				r = BoxOnPlaneSide( node->mins, node->maxs, &tr.viewParms.frustum[1] );
				if ( r == 2 ) {
					return;                     // culled
				}
				if ( r == 1 ) {
					planeBits &= ~2;            // all descendants will also be in front
				}
			}

			if ( planeBits & 4 ) {
				r = BoxOnPlaneSide( node->mins, node->maxs, &tr.viewParms.frustum[2] );
				if ( r == 2 ) {
					return;                     // culled
				}
				if ( r == 1 ) {
					planeBits &= ~4;            // all descendants will also be in front
				}
			}

			if ( planeBits & 8 ) {
				r = BoxOnPlaneSide( node->mins, node->maxs, &tr.viewParms.frustum[3] );
				if ( r == 2 ) {
					return;                     // culled
				}
				if ( r == 1 ) {
					planeBits &= ~8;            // all descendants will also be in front
				}
			}

			// ydnar: farplane culling
			if ( planeBits & 16 ) {
				r = BoxOnPlaneSide( node->mins, node->maxs, &tr.viewParms.frustum[4] );
				if ( r == 2 ) {
					return;                     // culled
				}
				if ( r == 1 ) {
					planeBits &= ~8;            // all descendants will also be in front
				}
			}

		}

		// ydnar: cull dlights
		if ( dlightBits ) {  //%	&& node->contents != -1 )
			for ( i = 0; i < tr.refdef.num_dlights; i++ )
			{
				if ( dlightBits & ( 1 << i ) ) {
					// directional dlights don't get culled
					if ( tr.refdef.dlights[ i ].flags & REF_DIRECTED_DLIGHT ) {
						continue;
					}

					// test dlight bounds against node surface bounds
					dl = &tr.refdef.dlights[ i ];
					if ( node->surfMins[ 0 ] >= ( dl->origin[ 0 ] + dl->radius ) || node->surfMaxs[ 0 ] <= ( dl->origin[ 0 ] - dl->radius ) ||
						 node->surfMins[ 1 ] >= ( dl->origin[ 1 ] + dl->radius ) || node->surfMaxs[ 1 ] <= ( dl->origin[ 1 ] - dl->radius ) ||
						 node->surfMins[ 2 ] >= ( dl->origin[ 2 ] + dl->radius ) || node->surfMaxs[ 2 ] <= ( dl->origin[ 2 ] - dl->radius ) ) {
						dlightBits &= ~( 1 << i );
					}
				}
			}
		}

		// ydnar: cull decals
		if ( decalBits ) {
			for ( i = 0; i < tr.refdef.numDecalProjectors; i++ )
			{
				if ( decalBits & ( 1 << i ) ) {
					// test decal bounds against node surface bounds
					if ( tr.refdef.decalProjectors[ i ].shader == NULL ||
						 !R_TestDecalBoundingBox( &tr.refdef.decalProjectors[ i ], node->surfMins, node->surfMaxs ) ) {
						decalBits &= ~( 1 << i );
					}
				}
			}
		}

		// handle leaf nodes
		if ( node->contents != -1 ) {
			break;
		}

		// recurse down the children, front side first
		R_RecursiveWorldNode( node->children[ 0 ], planeBits, dlightBits, decalBits );

		// tail recurse
		node = node->children[ 1 ];
	} while ( 1 );

	// short circuit
	if ( node->nummarksurfaces == 0 ) {
		return;
	}

	// ydnar: moved off to separate function
	R_AddLeafSurfaces( node, dlightBits, decalBits );
}


/*
===============
R_PointInLeaf
===============
*/
static mnode_t *R_PointInLeaf( const vec3_t p ) {
	mnode_t     *node;
	float d;
	cplane_t    *plane;

	if ( !tr.world ) {
		ri.Error( ERR_DROP, "R_PointInLeaf: bad model" );
	}

	node = tr.world->nodes;
	while ( 1 ) {
		if ( node->contents != -1 ) {
			break;
		}
		plane = node->plane;
		d = DotProduct( p,plane->normal ) - plane->dist;
		if ( d > 0 ) {
			node = node->children[0];
		} else {
			node = node->children[1];
		}
	}

	return node;
}

/*
==============
R_ClusterPVS
==============
*/
static const byte *R_ClusterPVS( int cluster ) {
	if ( !tr.world || !tr.world->vis || cluster < 0 || cluster >= tr.world->numClusters ) {
		return tr.world->novis;
	}

	return tr.world->vis + cluster * tr.world->clusterBytes;
}

/*
=================
R_inPVS
=================
*/
qboolean R_inPVS( const vec3_t p1, const vec3_t p2 ) {
	mnode_t *leaf;
	byte    *vis;

	leaf = R_PointInLeaf( p1 );
	vis = CM_ClusterPVS( leaf->cluster );
	leaf = R_PointInLeaf( p2 );

	if ( !( vis[leaf->cluster >> 3] & ( 1 << ( leaf->cluster & 7 ) ) ) ) {
		return qfalse;
	}
	return qtrue;
}


/*
===============
R_MarkLeaves

Mark the leaves and nodes that are in the PVS for the current
cluster
===============
*/
static void R_MarkLeaves( void ) {
	const byte  *vis;
	mnode_t *leaf, *parent;
	int i;
	int cluster;

	// lockpvs lets designers walk around to determine the
	// extent of the current pvs
	if ( r_lockpvs->integer ) {
		return;
	}

	// current viewcluster
	leaf = R_PointInLeaf( tr.viewParms.pvsOrigin );
	cluster = leaf->cluster;

	// if the cluster is the same and the area visibility matrix
	// hasn't changed, we don't need to mark everything again

	// if r_showcluster was just turned on, remark everything
	if ( tr.viewCluster == cluster && !tr.refdef.areamaskModified
		 && !r_showcluster->modified ) {
		return;
	}

	if ( r_showcluster->modified || r_showcluster->integer ) {
		r_showcluster->modified = qfalse;
		if ( r_showcluster->integer ) {
			ri.Printf( PRINT_ALL, "cluster:%i  area:%i\n", cluster, leaf->area );
		}
	}

	tr.visCount++;
	tr.viewCluster = cluster;

	if ( r_novis->integer || tr.viewCluster == -1 ) {
		for ( i = 0 ; i < tr.world->numnodes ; i++ ) {
			if ( tr.world->nodes[i].contents != CONTENTS_SOLID ) {
				tr.world->nodes[i].visframe = tr.visCount;
			}
		}
		return;
	}

	vis = R_ClusterPVS( tr.viewCluster );

	for ( i = 0,leaf = tr.world->nodes ; i < tr.world->numnodes ; i++, leaf++ ) {
		cluster = leaf->cluster;
		if ( cluster < 0 || cluster >= tr.world->numClusters ) {
			continue;
		}

		// check general pvs
		if ( !( vis[cluster >> 3] & ( 1 << ( cluster & 7 ) ) ) ) {
			continue;
		}

		// check for door connection
		if ( ( tr.refdef.areamask[leaf->area >> 3] & ( 1 << ( leaf->area & 7 ) ) ) ) {
			continue;       // not visible
		}

		// ydnar: don't want to walk the entire bsp to add skybox surfaces
		if ( tr.refdef.rdflags & RDF_SKYBOXPORTAL ) {
			// this only happens once, as game/cgame know the origin of the skybox
			// this also means the skybox portal cannot move, as this list is calculated once and never again
			if ( tr.world->numSkyNodes < WORLD_MAX_SKY_NODES ) {
				tr.world->skyNodes[ tr.world->numSkyNodes++ ] = leaf;
			}
			R_AddLeafSurfaces( leaf, 0, 0 );
			continue;
		}

		parent = leaf;
		do {
			if ( parent->visframe == tr.visCount ) {
				break;
			}
			parent->visframe = tr.visCount;
			parent = parent->parent;
		} while ( parent );
	}
}


/*
=============
R_AddWorldSurfaces
=============
*/
void R_AddWorldSurfaces( void ) {
	if ( !r_drawworld->integer ) {
		return;
	}

	if ( tr.refdef.rdflags & RDF_NOWORLDMODEL ) {
		return;
	}

	tr.currentEntityNum = ENTITYNUM_WORLD;
	tr.shiftedEntityNum = tr.currentEntityNum << QSORT_ENTITYNUM_SHIFT;

	// ydnar: set current brush model to world
	tr.currentBModel = &tr.world->bmodels[ 0 ];

	// clear out the visible min/max
	ClearBounds( tr.viewParms.visBounds[0], tr.viewParms.visBounds[1] );

	// render sky or world?
	if ( tr.refdef.rdflags & RDF_SKYBOXPORTAL && tr.world->numSkyNodes > 0 ) {
		int i;
		mnode_t **node;

		for ( i = 0, node = tr.world->skyNodes; i < tr.world->numSkyNodes; i++, node++ )
			R_AddLeafSurfaces( *node, tr.refdef.dlightBits, 0 );    // no decals on skybox nodes
	} else
	{
		// determine which leaves are in the PVS / areamask
		R_MarkLeaves();

		// perform frustum culling and add all the potentially visible surfaces
		R_RecursiveWorldNode( tr.world->nodes, 255, tr.refdef.dlightBits, tr.refdef.decalBits );

		// ydnar: add decal surfaces
		R_AddDecalSurfaces( tr.world->bmodels );
	}

	// clear brush model
	tr.currentBModel = NULL;
}