/*
=============
R_PlaneForSurface
=============
*/
void R_PlaneForSurface (surfaceType_t *surfType, cplane_t *plane) {
	srfTriangles_t  *tri;
	srfPoly_t		*poly;
	drawVert_t    *v1, *v2, *v3;
	vec4_t			plane4;

	if (!surfType) {
		Com_Memset (plane, 0, sizeof(*plane));
		plane->normal[0] = 1;
		return;
	}
	switch (*surfType) {
	case SF_TRIANGLES:
		tri = (srfTriangles_t *)surfType;
		v1 = tri->verts + tri->indexes[0];
		v2 = tri->verts + tri->indexes[1];
		v3 = tri->verts + tri->indexes[2];
		PlaneFromPoints( plane4, v1->xyz, v2->xyz, v3->xyz );
		VectorCopy( plane4, plane->normal );
		plane->dist = plane4[3];
		return;
	case SF_POLY:
		poly = (srfPoly_t *)surfType;
		PlaneFromPoints( plane4, poly->verts[0].xyz, poly->verts[1].xyz, poly->verts[2].xyz );
		VectorCopy( plane4, plane->normal ); 
		plane->dist = plane4[3];
		return;
	default:
		Com_Memset (plane, 0, sizeof(*plane));
		plane->normal[0] = 1;		
		return;
	}
}

qboolean CM_GenerateFacetFor4Points( cFacet_t *f, drawVert_t *a, drawVert_t *b, drawVert_t *c, drawVert_t *d ) {
	float	dist;
	int		i;
	vec4_t	plane;

	// if we can't generate a valid plane for the points, ignore the facet
	if ( !PlaneFromPoints( f->surface, a->xyz, b->xyz, c->xyz ) ) {
		f->numBoundaries = 0;
		return qfalse;
	}

	// if the fourth point is also on the plane, we can make a quad facet
	dist = DotProduct( d->xyz, f->surface ) - f->surface[3];
	if ( fabs( dist ) > PLANAR_EPSILON ) {
		f->numBoundaries = 0;
		return qfalse;
	}

	// make boundaries
	f->numBoundaries = 4;

	CM_GenerateBoundaryForPoints( f->boundaries[0], f->surface, a->xyz, b->xyz );
	CM_GenerateBoundaryForPoints( f->boundaries[1], f->surface, b->xyz, c->xyz );
	CM_GenerateBoundaryForPoints( f->boundaries[2], f->surface, c->xyz, d->xyz );
	CM_GenerateBoundaryForPoints( f->boundaries[3], f->surface, d->xyz, a->xyz );

	VectorCopy( a->xyz, f->points[0] );
	VectorCopy( b->xyz, f->points[1] );
	VectorCopy( c->xyz, f->points[2] );
	VectorCopy( d->xyz, f->points[3] );

	for (i = 1; i < 4; i++)
	{
		if ( !PlaneFromPoints( plane, f->points[i], f->points[(i+1) % 4], f->points[(i+2) % 4]) ) {
			f->numBoundaries = 0;
			return qfalse;
		}

		if (DotProduct(f->surface, plane) < 0.9) {
			f->numBoundaries = 0;
			return qfalse;
		}
	}

	TextureMatrixFromPoints( f, a, b, c );

	return qtrue;
}

void R_PlaneForSurface (surfaceType_t *surfType, cplane_t *plane) {
	srfTriangles_t	*tri;
	srfPoly_t		*poly;
	drawVert_t		*v1, *v2, *v3;
	vector4			plane4;

	if (!surfType) {
		memset (plane, 0, sizeof(*plane));
		plane->normal.x = 1;
		return;
	}
	switch (*surfType) {
	case SF_FACE:
		*plane = ((srfSurfaceFace_t *)surfType)->plane;
		return;
	case SF_TRIANGLES:
		tri = (srfTriangles_t *)surfType;
		v1 = tri->verts + tri->indexes[0];
		v2 = tri->verts + tri->indexes[1];
		v3 = tri->verts + tri->indexes[2];
		PlaneFromPoints( &plane4, &v1->xyz, &v2->xyz, &v3->xyz );
		VectorCopy( (vector3 *)&plane4, &plane->normal ); 
		plane->dist = plane4.w;
		return;
	case SF_POLY:
		poly = (srfPoly_t *)surfType;
		PlaneFromPoints( &plane4, &poly->verts[0].xyz, &poly->verts[1].xyz, &poly->verts[2].xyz );
		VectorCopy( (vector3 *)&plane4, &plane->normal ); 
		plane->dist = plane4.w;
		return;
	default:
		memset (plane, 0, sizeof(*plane));
		plane->normal.x = 1;
		return;
	}
}

/*
=====================
CM_GenerateFacetFor3Points
=====================
*/
qboolean CM_GenerateFacetFor3Points( cFacet_t *f, drawVert_t *a, drawVert_t *b, drawVert_t *c ) {
	// if we can't generate a valid plane for the points, ignore the facet
	if ( !PlaneFromPoints( f->surface, a->xyz, b->xyz, c->xyz ) ) {
		f->numBoundaries = 0;
		return qfalse;
	}

	// make boundaries
	f->numBoundaries = 3;

	CM_GenerateBoundaryForPoints( f->boundaries[0], f->surface, a->xyz, b->xyz );
	CM_GenerateBoundaryForPoints( f->boundaries[1], f->surface, b->xyz, c->xyz );
	CM_GenerateBoundaryForPoints( f->boundaries[2], f->surface, c->xyz, a->xyz );

	VectorCopy( a->xyz, f->points[0] );
	VectorCopy( b->xyz, f->points[1] );
	VectorCopy( c->xyz, f->points[2] );

	TextureMatrixFromPoints( f, a, b, c );

	return qtrue;
}

static void ProjectDecalOntoWinding( decalProjector_t *dp, mapDrawSurface_t *ds, winding_t *w )
{
	int		i, j;
	float		d, d2, alpha;
	winding_t		*front, *back;
	mapDrawSurface_t	*ds2;
	bspDrawVert_t	*dv;
	vec4_t		plane;
	
	/* dummy check */
	if( w->numpoints < 3 )
	{
		FreeWinding( w );
		return;
	}
	
	/* offset by entity origin */
	for( i = 0; i < w->numpoints; i++ )
		VectorAdd( w->p[ i ], entityOrigin, w->p[ i ] );
	
	/* make a plane from the winding */
	if( !PlaneFromPoints( plane, w->p[ 0 ], w->p[ 1 ], w->p[ 2 ] ) )
	{
		FreeWinding( w );
		return;
	}
	
	/* backface check */
	d = DotProduct( dp->planes[ 0 ], plane );
	if( d < -0.0001f )
	{
		FreeWinding( w );
		return;
	}
	
	/* walk list of planes */
	for( i = 0; i < dp->numPlanes; i++ )
	{
		/* chop winding by the plane */
		ClipWindingEpsilon( w, dp->planes[ i ], dp->planes[ i ][ 3 ], 0.0625f, &front, &back );
		FreeWinding( w );
		
		/* lose the front fragment */
		if( front != NULL )
			FreeWinding( front );
		
		/* if nothing left in back, then bail */
		if( back == NULL )
			return;
		
		/* reset winding */
		w = back;
	}
	
	/* nothing left? */
	if( w == NULL || w->numpoints < 3 )
		return;
	
	/* add to counts */
	numDecalSurfaces++;
	
	/* make a new surface */
	ds2 = AllocDrawSurface( SURFACE_DECAL );
	
	/* set it up */
	ds2->entityNum = ds->entityNum;
	ds2->castShadows = ds->castShadows;
	ds2->recvShadows = ds->recvShadows;
	ds2->shaderInfo = dp->si;
	ds2->fogNum = ds->fogNum;	/* why was this -1? */
	ds2->lightmapScale = ds->lightmapScale;
	ds2->numVerts = w->numpoints;
	ds2->verts = Malloc( ds2->numVerts * sizeof( *ds2->verts ) );
	Mem_Set( ds2->verts, 0, ds2->numVerts * sizeof( *ds2->verts ) );
	
	/* set vertexes */
	for( i = 0; i < ds2->numVerts; i++ )
	{
		/* get vertex */
		dv = &ds2->verts[ i ];
		
		/* set alpha */
		d = DotProduct( w->p[ i ], dp->planes[ 0 ] ) - dp->planes[ 0 ][ 3 ];
		d2 = DotProduct( w->p[ i ], dp->planes[ 1 ] ) - dp->planes[ 1 ][ 3 ];
		alpha = 255.0f * d2 / (d + d2);
		if( alpha > 255 )
			alpha = 255;
		else if( alpha < 0 )
			alpha = 0;
		
		/* set misc */
		VectorSubtract( w->p[ i ], entityOrigin, dv->xyz );
		VectorCopy( plane, dv->normal );
		dv->st[ 0 ] = DotProduct( dv->xyz, dp->texMat[ 0 ] ) + dp->texMat[ 0 ][ 3 ];
		dv->st[ 1 ] = DotProduct( dv->xyz, dp->texMat[ 1 ] ) + dp->texMat[ 1 ][ 3 ];
		
		/* set color */
		for( j = 0; j < MAX_LIGHTMAPS; j++ )
		{
			dv->color[ j ][ 0 ] = 255;
//.........这里部分代码省略.........

//.........这里部分代码省略.........
			GetToken(false);
			side->contents = atoi(token);
			GetToken(false);
			side->surf = td.flags = atoi(token);
			GetToken(false);
			td.value = atoi(token);
		} else {
			side->contents = CONTENTS_SOLID;
			side->surf = td.flags = 0;
			td.value = 0;
		}

		// resolve implicit surface and contents flags
		SetImpliedFlags(side, td.name);

		// translucent objects are automatically classified as detail
		if (side->surf & (SURF_ALPHA_TEST | SURF_BLEND_33 | SURF_BLEND_66))
			side->contents |= CONTENTS_DETAIL;
		if (side->contents & (CONTENTS_PLAYER_CLIP | CONTENTS_MONSTER_CLIP))
			side->contents |= CONTENTS_DETAIL;
		if (fulldetail)
			side->contents &= ~CONTENTS_DETAIL;
		if (!(side->contents & ((LAST_VISIBLE_CONTENTS - 1) | CONTENTS_PLAYER_CLIP
				| CONTENTS_MONSTER_CLIP | CONTENTS_MIST)))
			side->contents |= CONTENTS_SOLID;

		// hints and skips are never detail, and have no content
		if (side->surf & (SURF_HINT | SURF_SKIP)) {
			side->contents = 0;
			side->surf &= ~CONTENTS_DETAIL;
		}

		// find the plane number
		plane_num = PlaneFromPoints(planepts[0], planepts[1], planepts[2]);
		if (plane_num == -1) {
			Com_Verbose("Entity %i, Brush %i: plane with no normal\n", b->entity_num, b->brush_num);
			continue;
		}

		// see if the plane has been used already
		for (k = 0; k < b->num_sides; k++) {
			s2 = b->original_sides + k;
			if (s2->plane_num == plane_num) {
				Com_Verbose("Entity %i, Brush %i: duplicate plane\n", b->entity_num, b->brush_num);
				break;
			}
			if (s2->plane_num == (plane_num ^ 1)) {
				Com_Verbose("Entity %i, Brush %i: mirrored plane\n", b->entity_num, b->brush_num);
				break;
			}
		}
		if (k != b->num_sides)
			continue; // duplicated

		// keep this side
		side = b->original_sides + b->num_sides;
		side->plane_num = plane_num;
		side->texinfo = TexinfoForBrushTexture(&map_planes[plane_num], &td, vec3_origin);

		// save the td off in case there is an origin brush and we
		// have to recalculate the texinfo
		map_brush_textures[num_map_brush_sides] = td;

		num_map_brush_sides++;
		b->num_sides++;
	} while (true);

//.........这里部分代码省略.........
			backfaceAngle = FloatForKey(e, "_backfacecull");
		else if ( KeyExists(e, "_bfc") )
			backfaceAngle = FloatForKey(e, "_bfc");
		else
			backfaceAngle = 90.0f;

		/* walk entity patches */
		for( p = e->patches; p != NULL; p = e->patches )
		{
			/* setup projector */
			if( VectorCompare( e->origin, vec3_origin ) )
			{
				VectorAdd( p->eMins, p->eMaxs, origin );
				VectorScale( origin, 0.5f, origin );
			}
			else
				VectorCopy( e->origin, origin );
			
			VectorCopy( e2->origin, target );
			VectorSubtract( target, origin, delta );
			
			/* setup projection plane */
			distance = VectorNormalize( delta, projection );
			projection[ 3 ] = DotProduct( origin, projection );
			
			/* create projectors */
			if( distance > 0.125f )
			{
				/* tesselate the patch */
				iterations = IterationsForCurve( p->longestCurve, patchSubdivisions );
				subdivided = SubdivideMesh2( p->mesh, iterations );
				
				/* fit it to the curve and remove colinear verts on rows/columns */
				PutMeshOnCurve( *subdivided );
				mesh = RemoveLinearMeshColumnsRows( subdivided );
				FreeMesh( subdivided );
				
				/* offset by projector origin */
				for( j = 0; j < (mesh->width * mesh->height); j++ )
					VectorAdd( mesh->verts[ j ].xyz, e->origin, mesh->verts[ j ].xyz );
				
				/* iterate through the mesh quads */
				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;
						
						/* get drawverts */
						dv[ 0 ] = &mesh->verts[ pw[ r + 0 ] ];
						dv[ 1 ] = &mesh->verts[ pw[ r + 1 ] ];
						dv[ 2 ] = &mesh->verts[ pw[ r + 2 ] ];
						dv[ 3 ] = &mesh->verts[ pw[ r + 3 ] ];
						
						/* planar? (nuking this optimization as it doesn't work on non-rectangular quads) */
						plane[ 0 ] = 0.0f;	/* stupid msvc */
						if( 0 && PlaneFromPoints( plane, dv[ 0 ]->xyz, dv[ 1 ]->xyz, dv[ 2 ]->xyz ) && fabs( DotProduct( dv[ 1 ]->xyz, plane ) - plane[ 3 ] ) <= PLANAR_EPSILON )
						{
							/* make a quad projector */
							MakeDecalProjector( i, p->shaderInfo, projection, distance, 4, dv, cos(backfaceAngle / 180.0f * Q_PI), lightmapScale, lightmapAxis, minlight, minvertexlight, ambient, colormod, smoothNormals);
						}
						else
						{
							/* make first triangle */
							MakeDecalProjector( i, p->shaderInfo, projection, distance, 3, dv, cos(backfaceAngle / 180.0f * Q_PI), lightmapScale, lightmapAxis, minlight, minvertexlight, ambient, colormod, smoothNormals);
							
							/* make second triangle */
							dv[ 1 ] = dv[ 2 ];
							dv[ 2 ] = dv[ 3 ];
							MakeDecalProjector( i, p->shaderInfo, projection, distance, 3, dv, cos(backfaceAngle / 180.0f * Q_PI), lightmapScale, lightmapAxis, minlight, minvertexlight, ambient, colormod, smoothNormals);
						}
					}
				}
				
				/* clean up */
				free( mesh );
			}
			
			/* remove patch from entity (fixme: leak!) */
			e->patches = p->next;
			
			/* push patch to worldspawn (enable this to debug projectors) */
			#if 0
				p->next = entities[ 0 ].patches;
				entities[ 0 ].patches = p;
			#endif
		}
	}
	
	/* emit some stats */
	Sys_FPrintf( SYS_VRB, "%9d decal projectors\n", numProjectors );
}

//.........这里部分代码省略.........
		if( e2 == NULL )
		{
			MsgDev( D_WARN, "Decal entity without a valid target, ignoring.\n" );
			continue;
		}
		
		/* walk entity patches */
		for( p = e->patches; p != NULL; p = e->patches )
		{
			/* setup projector */
			if( VectorCompare( e->origin, vec3_origin ) )
			{
				VectorAdd( p->eMins, p->eMaxs, origin );
				VectorScale( origin, 0.5f, origin );
			}
			else VectorCopy( e->origin, origin );
			
			VectorCopy( e2->origin, target );
			VectorSubtract( target, origin, delta );
			
			/* setup projection plane */
			distance = VectorNormalizeLength2( delta, projection );
			projection[ 3 ] = DotProduct( origin, projection );
			
			/* create projectors */
			if( distance > 0.125f )
			{
				/* tesselate the patch */
				iterations = IterationsForCurve( p->longestCurve, patch_subdivide->integer );
				subdivided = SubdivideMesh2( p->mesh, iterations );
				
				/* fit it to the curve and remove colinear verts on rows/columns */
				PutMeshOnCurve( *subdivided );
				mesh = RemoveLinearMeshColumnsRows( subdivided );
				FreeMesh( subdivided );
				
				/* offset by projector origin */
				for( j = 0; j < (mesh->width * mesh->height); j++ )
					VectorAdd( mesh->verts[ j ].xyz, e->origin, mesh->verts[ j ].xyz );
				
				/* iterate through the mesh quads */
				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;
						
						/* get drawverts */
						dv[ 0 ] = &mesh->verts[ pw[ r + 0 ] ];
						dv[ 1 ] = &mesh->verts[ pw[ r + 1 ] ];
						dv[ 2 ] = &mesh->verts[ pw[ r + 2 ] ];
						dv[ 3 ] = &mesh->verts[ pw[ r + 3 ] ];
						
						/* planar? (nuking this optimization as it doesn't work on non-rectangular quads) */
						plane[ 0 ] = 0.0f;	/* stupid msvc */
						if( 0 && PlaneFromPoints( plane, dv[ 0 ]->xyz, dv[ 1 ]->xyz, dv[ 2 ]->xyz ) &&
							fabs( DotProduct( dv[ 1 ]->xyz, plane ) - plane[ 3 ] ) <= PLANAR_EPSILON )
						{
							/* make a quad projector */
							MakeDecalProjector( p->shaderInfo, projection, distance, 4, dv );
						}
						else
						{
							/* make first triangle */
							MakeDecalProjector( p->shaderInfo, projection, distance, 3, dv );
							
							/* make second triangle */
							dv[ 1 ] = dv[ 2 ];
							dv[ 2 ] = dv[ 3 ];
							MakeDecalProjector( p->shaderInfo, projection, distance, 3, dv );
						}
					}
				}
				
				/* clean up */
				Mem_Free( mesh );
			}
			
			/* remove patch from entity (fixme: leak!) */
			e->patches = p->next;
			
			/* push patch to worldspawn (enable this to debug projectors) */
#if 0
			p->next = entities[ 0 ].patches;
			entities[ 0 ].patches = p;
#endif
		}
	}
	
	/* emit some stats */
	MsgDev( D_NOTE, "%9d decal projectors\n", numProjectors );
}

//.........这里部分代码省略.........
		projection = omniProjection;
		iDist = 1.0f / ( radius * 2.0f );

		/* set corner */
		VectorSet( xyz, points[ 0 ][ 0 ] - radius, points[ 0 ][ 1 ] - radius, points[ 0 ][ 2 ] + radius );

		/* make x axis texture matrix (yz) */
		VectorSet( temp.texMat[ 0 ][ 0 ], 0.0f, iDist, 0.0f );
		temp.texMat[ 0 ][ 0 ][ 3 ] = -DotProduct( temp.texMat[ 0 ][ 0 ], xyz );
		VectorSet( temp.texMat[ 0 ][ 1 ], 0.0f, 0.0f, iDist );
		temp.texMat[ 0 ][ 1 ][ 3 ] = -DotProduct( temp.texMat[ 0 ][ 1 ], xyz );

		/* make y axis texture matrix (xz) */
		VectorSet( temp.texMat[ 1 ][ 0 ], iDist, 0.0f, 0.0f );
		temp.texMat[ 1 ][ 0 ][ 3 ] = -DotProduct( temp.texMat[ 1 ][ 0 ], xyz );
		VectorSet( temp.texMat[ 1 ][ 1 ], 0.0f, 0.0f, iDist );
		temp.texMat[ 1 ][ 1 ][ 3 ] = -DotProduct( temp.texMat[ 1 ][ 1 ], xyz );

		/* make z axis texture matrix (xy) */
		VectorSet( temp.texMat[ 2 ][ 0 ], iDist, 0.0f, 0.0f );
		temp.texMat[ 2 ][ 0 ][ 3 ] = -DotProduct( temp.texMat[ 2 ][ 0 ], xyz );
		VectorSet( temp.texMat[ 2 ][ 1 ], 0.0f, iDist, 0.0f );
		temp.texMat[ 2 ][ 1 ][ 3 ] = -DotProduct( temp.texMat[ 2 ][ 1 ], xyz );

		/* setup decal points */
		VectorSet( dv[ 0 ].xyz, points[ 0 ][ 0 ] - radius, points[ 0 ][ 1 ] - radius, points[ 0 ][ 2 ] + radius );
		VectorSet( dv[ 1 ].xyz, points[ 0 ][ 0 ] - radius, points[ 0 ][ 1 ] + radius, points[ 0 ][ 2 ] + radius );
		VectorSet( dv[ 2 ].xyz, points[ 0 ][ 0 ] + radius, points[ 0 ][ 1 ] + radius, points[ 0 ][ 2 ] + radius );
		VectorSet( dv[ 3 ].xyz, points[ 0 ][ 0 ] + radius, points[ 0 ][ 1 ] - radius, points[ 0 ][ 2 ] + radius );
	}
	else
	{
		/* set up unidirectional */
		temp.omnidirectional = qfalse;

		/* set up decal points */
		VectorCopy( points[ 0 ], dv[ 0 ].xyz );
		VectorCopy( points[ 1 ], dv[ 1 ].xyz );
		VectorCopy( points[ 2 ], dv[ 2 ].xyz );
		VectorCopy( points[ 3 ], dv[ 3 ].xyz );

		/* make texture matrix */
		if ( !MakeTextureMatrix( temp.texMat[ 0 ], projection, &dv[ 0 ], &dv[ 1 ], &dv[ 2 ] ) )
		{
			return;
		}
	}

	/* bound the projector */
	ClearBounds( temp.mins, temp.maxs );

	for ( i = 0; i < numPoints; i++ )
	{
		AddPointToBounds( dv[ i ].xyz, temp.mins, temp.maxs );
		VectorMA( dv[ i ].xyz, projection[ 3 ], projection, xyz );
		AddPointToBounds( xyz, temp.mins, temp.maxs );
	}

	/* make bounding sphere */
	VectorAdd( temp.mins, temp.maxs, temp.center );
	VectorScale( temp.center, 0.5f, temp.center );
	VectorSubtract( temp.maxs, temp.center, xyz );
	temp.radius = VectorLength( xyz );
	temp.radius2 = temp.radius * temp.radius;

	/* frustum cull the projector (fixme: this uses a stale frustum!) */
	if ( R_CullPointAndRadius( temp.center, temp.radius ) == CULL_OUT )
	{
		return;
	}

	/* make the front plane */
	if ( !PlaneFromPoints( temp.planes[ 0 ], dv[ 0 ].xyz, dv[ 1 ].xyz, dv[ 2 ].xyz ) )
	{
		return;
	}

	/* make the back plane */
	VectorSubtract( vec3_origin, temp.planes[ 0 ], temp.planes[ 1 ] );
	VectorMA( dv[ 0 ].xyz, projection[ 3 ], projection, xyz );
	temp.planes[ 1 ][ 3 ] = DotProduct( xyz, temp.planes[ 1 ] );

	/* make the side planes */
	for ( i = 0; i < numPoints; i++ )
	{
		VectorMA( dv[ i ].xyz, projection[ 3 ], projection, xyz );

		if ( !PlaneFromPoints( temp.planes[ i + 2 ], dv[( i + 1 ) % numPoints ].xyz, dv[ i ].xyz, xyz ) )
		{
			return;
		}
	}

	/* create a new projector */
	dp = &tr.refdef.decalProjectors[ r_numDecalProjectors & DECAL_PROJECTOR_MASK ];
	Com_Memcpy( dp, &temp, sizeof( *dp ) );

	/* we have a winner */
	r_numDecalProjectors++;
}

//.........这里部分代码省略.........
			Tri[i].flag = 0;

		// For every node that's not currently used, find what triangle it
		// lies on, and the error at this node
		for(i=0, biggesterror=0; i<NumNodes[0]; i++)
		{
			if(Node[i].used) continue;
			for(j=0, Node[i].tri=-1; (j<NumTris[0]) && (Node[i].tri==-1); j++)
			{
				if( side(Node[i].p[j1],          Node[i].p[j2],
					     Node[Tri[j].v[0]].p[j1],Node[Tri[j].v[0]].p[j2],
					     Node[Tri[j].v[1]].p[j1],Node[Tri[j].v[1]].p[j2]) < 0. ) continue;
				if( side(Node[i].p[j1],          Node[i].p[j2],
					     Node[Tri[j].v[1]].p[j1],Node[Tri[j].v[1]].p[j2],
					     Node[Tri[j].v[2]].p[j1],Node[Tri[j].v[2]].p[j2]) < 0. ) continue;
				if( side(Node[i].p[j1],          Node[i].p[j2],
					     Node[Tri[j].v[2]].p[j1],Node[Tri[j].v[2]].p[j2],
					     Node[Tri[j].v[0]].p[j1],Node[Tri[j].v[0]].p[j2]) < 0. ) continue;
				Node[i].tri = j;
			}
			if(Node[i].tri < 0)
			{
                          /*
				ghCursorCurrent = ghCursorDefault;
				SetCursor(ghCursorCurrent);
                          */
				g_FuncTable.m_pfnMessageBox(g_pRadiantWnd,
					"Error: Couldn't find the triangle bounding a point.",
					"Decimation Error",MB_ICONEXCLAMATION, NULL);
				return;
			}
			if(!Tri[Node[i].tri].flag)
			{
				PlaneFromPoints(Node[Tri[Node[i].tri].v[0]].p,
				                Node[Tri[Node[i].tri].v[1]].p,
				                Node[Tri[Node[i].tri].v[2]].p,
								&Tri[Node[i].tri].plane);
				Tri[Node[i].tri].flag = 1;
			}
			Node[i].error =
				Node[i].p[j0] - (Tri[Node[i].tri].plane.dist -
							     Tri[Node[i].tri].plane.normal[j1]*Node[i].p[j1] -
								 Tri[Node[i].tri].plane.normal[j2]*Node[i].p[j2]  )/
								 Tri[Node[i].tri].plane.normal[j0];
			biggesterror = max(biggesterror,Absolute(Node[i].error));
		}
		if(biggesterror == 0)
			NumNodesToSave = NumNodesUsed;
		else
		{
			// For all current triangles, build a list of worst-case nodes
			memset(TriTable,0,NH*NV*2*sizeof(TRITABLE));
			for(i=0; i<NumNodes[0]; i++)
			{
				if(Node[i].used) continue;
				if(Absolute(Node[i].error) > TriTable[Node[i].tri].error)
				{
					TriTable[Node[i].tri].error = (float)(Absolute(Node[i].error));
					TriTable[Node[i].tri].node  = i;
				}
			}
			qsort( (void *)TriTable, (size_t)(NumTris[0]), sizeof(TRITABLE), (int (*)(const void *, const void *))compare );
			for(i=0; i<NumTris[0] && NumNodesUsed < NumNodesToSave && TriTable[i].error > 0.5*biggesterror; i++)
			{
				if(Node[TriTable[i].node].used) continue;  // shouldn't happen
				NumNodesUsed++;

/*
* R_AddPortalSurface
*/
portalSurface_t *R_AddPortalSurface( const entity_t *ent, const mesh_t *mesh, 
	const vec3_t mins, const vec3_t maxs, const shader_t *shader )
{
	unsigned int i;
	float dist;
	cplane_t plane, untransformed_plane;
	vec3_t v[3];
	portalSurface_t *portalSurface;

	if( !mesh ) {
		return NULL;
	}

	if( R_FASTSKY() && !( shader->flags & (SHADER_PORTAL_CAPTURE|SHADER_PORTAL_CAPTURE2) ) ) {
		// r_fastsky doesn't affect portalmaps
		return NULL;
	}

	for( i = 0; i < 3; i++ ) {
		VectorCopy( mesh->xyzArray[mesh->elems[i]], v[i] );
	}

	PlaneFromPoints( v, &untransformed_plane );
	untransformed_plane.dist += DotProduct( ent->origin, untransformed_plane.normal );
	CategorizePlane( &untransformed_plane );

	if( shader->flags & SHADER_AUTOSPRITE )
	{
		vec3_t centre;

		// autosprites are quads, facing the viewer
		if( mesh->numVerts < 4 ) {
			return NULL;
		}

		// compute centre as average of 4 vertices
		VectorCopy( mesh->xyzArray[mesh->elems[3]], centre );
		for( i = 0; i < 3; i++ )
			VectorAdd( centre, v[i], centre );
		VectorMA( ent->origin, 0.25, centre, centre );

		VectorNegate( &rn.viewAxis[AXIS_FORWARD], plane.normal );
		plane.dist = DotProduct( plane.normal, centre );
		CategorizePlane( &plane );
	}
	else
	{
		vec3_t temp;
		mat3_t entity_rotation;

		// regular surfaces
		if( !Matrix3_Compare( ent->axis, axis_identity ) )
		{
			Matrix3_Transpose( ent->axis, entity_rotation );

			for( i = 0; i < 3; i++ ) {
				VectorCopy( v[i], temp );
				Matrix3_TransformVector( entity_rotation, temp, v[i] ); 
				VectorMA( ent->origin, ent->scale, v[i], v[i] );
			}

			PlaneFromPoints( v, &plane );
			CategorizePlane( &plane );
		}
		else
		{
			plane = untransformed_plane;
		}
	}

	if( ( dist = PlaneDiff( rn.viewOrigin, &plane ) ) <= BACKFACE_EPSILON )
	{
		// behind the portal plane
		if( !( shader->flags & SHADER_PORTAL_CAPTURE2 ) ) {
			return NULL;
		}

		// we need to render the backplane view
	}

	// check if portal view is opaque due to alphagen portal
	if( shader->portalDistance && dist > shader->portalDistance ) {
		return NULL;
	}

	// find the matching portal plane
	for( i = 0; i < rn.numPortalSurfaces; i++ ) {
		portalSurface = &rn.portalSurfaces[i];

		if( portalSurface->entity == ent &&
			portalSurface->shader == shader &&
			DotProduct( portalSurface->plane.normal, plane.normal ) > 0.99f &&
			fabs( portalSurface->plane.dist - plane.dist ) < 0.1f ) {
				goto addsurface;
		}
	}

//.........这里部分代码省略.........

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, qtrue))
				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);
}

int FindMetaTriangle( metaTriangle_t *src, bspDrawVert_t *a, bspDrawVert_t *b, bspDrawVert_t *c, int planeNum ){
	int triIndex;
	vec3_t dir;



	/* detect degenerate triangles fixme: do something proper here */
	VectorSubtract( a->xyz, b->xyz, dir );
	if ( VectorLength( dir ) < 0.125f ) {
		return -1;
	}
	VectorSubtract( b->xyz, c->xyz, dir );
	if ( VectorLength( dir ) < 0.125f ) {
		return -1;
	}
	VectorSubtract( c->xyz, a->xyz, dir );
	if ( VectorLength( dir ) < 0.125f ) {
		return -1;
	}

	/* find plane */
	if ( planeNum >= 0 ) {
		/* because of precision issues with small triangles, try to use the specified plane */
		src->planeNum = planeNum;
		VectorCopy( mapplanes[ planeNum ].normal, src->plane );
		src->plane[ 3 ] = mapplanes[ planeNum ].dist;
	}
	else
	{
		/* calculate a plane from the triangle's points (and bail if a plane can't be constructed) */
		src->planeNum = -1;
		if ( PlaneFromPoints( src->plane, a->xyz, b->xyz, c->xyz ) == qfalse ) {
			return -1;
		}
	}

	/* ydnar 2002-10-03: repair any bogus normals (busted ase import kludge) */
	if ( VectorLength( a->normal ) <= 0.0f ) {
		VectorCopy( src->plane, a->normal );
	}
	if ( VectorLength( b->normal ) <= 0.0f ) {
		VectorCopy( src->plane, b->normal );
	}
	if ( VectorLength( c->normal ) <= 0.0f ) {
		VectorCopy( src->plane, c->normal );
	}

	/* ydnar 2002-10-04: set lightmap axis if not already set */
	if ( !( src->si->compileFlags & C_VERTEXLIT ) &&
		 src->lightmapAxis[ 0 ] == 0.0f && src->lightmapAxis[ 1 ] == 0.0f && src->lightmapAxis[ 2 ] == 0.0f ) {
		/* the shader can specify an explicit lightmap axis */
		if ( src->si->lightmapAxis[ 0 ] || src->si->lightmapAxis[ 1 ] || src->si->lightmapAxis[ 2 ] ) {
			VectorCopy( src->si->lightmapAxis, src->lightmapAxis );
		}

		/* new axis-finding code */
		else{
			CalcLightmapAxis( src->plane, src->lightmapAxis );
		}
	}

	/* fill out the src triangle */
	src->indexes[ 0 ] = FindMetaVertex( a );
	src->indexes[ 1 ] = FindMetaVertex( b );
	src->indexes[ 2 ] = FindMetaVertex( c );

	/* try to find an existing triangle */
	#ifdef USE_EXHAUSTIVE_SEARCH
	{
		int i;
		metaTriangle_t  *tri;


		for ( i = 0, tri = metaTriangles; i < numMetaTriangles; i++, tri++ )
		{
			if ( memcmp( src, tri, sizeof( metaTriangle_t ) ) == 0 ) {
				return i;
			}
		}
	}
	#endif

	/* get a new triangle */
	triIndex = AddMetaTriangle();

	/* add the triangle */
	memcpy( &metaTriangles[ triIndex ], src, sizeof( metaTriangle_t ) );

	/* return the triangle index */
	return triIndex;
}

/*
===========
MakeBrushPlanes
===========
*/
qboolean MakeBrushPlanes (brush_t *b)
{
    int		i, j;
    int		planenum;
    side_t	*s;
    int		contents;
    bface_t	*f;
    vec3_t	origin;

    //
    // if the origin key is set (by an origin brush), offset all of the values
    //
    GetVectorForKey (&entities[b->entitynum], "origin", origin);

    //
    // convert to mapplanes
    //
    for (i=0 ; i<b->numsides ; i++)
    {
        s = &brushsides[b->firstside + i];
        for (j=0 ; j<3 ; j++)
        {
            VectorSubtract (s->planepts[j], origin, s->planepts[j]);
        }
        planenum = PlaneFromPoints (s->planepts[0], s->planepts[1], s->planepts[2]);
        if (planenum == -1)
        {
            printf ("Entity %i, Brush %i: plane with no normal\n"
                    , b->entitynum, b->brushnum);
            continue;
        }

        //
        // see if the plane has been used already
        //
        for (f=b->hulls[0].faces ; f ; f=f->next)
        {
            if (f->planenum == planenum || f->planenum == (planenum^1) )
            {
                char *pszClass = "Unknown Class";
                if ( b->entitynum )
                {
                    entity_t	*e = entities + b->entitynum;
                    pszClass = ValueForKey(e, "classname" );
                }

                printf( "Entity %i, Brush %i: A '%s' @(%.0f,%.0f,%.0f) has a coplanar plane at (%.0f, %.0f, %.0f), texture %s\n",
                        b->entitynum, b->brushnum, pszClass, origin[0], origin[1], origin[2], s->planepts[0][0]+origin[0], s->planepts[0][1]+origin[1], s->planepts[0][2]+origin[2], s->td.name );
                return false;
            }
        }

        f = malloc(sizeof(*f));
        memset (f, 0, sizeof(*f));

        f->planenum = planenum;
        f->plane = &mapplanes[planenum];
        f->next = b->hulls[0].faces;
        b->hulls[0].faces = f;
        f->texinfo = onlyents ? 0 : TexinfoForBrushTexture (f->plane, &s->td, origin);
    }

    return true;
}

//	projects decal onto a polygon
void ProjectDecalOntoWinding( decalProjector_t* dp, int numPoints, vec3_t points[ 2 ][ MAX_DECAL_VERTS ],
	const idWorldSurface* surf, mbrush46_model_t* bmodel ) {
	//	make a plane from the winding
	vec4_t plane;
	if ( !PlaneFromPoints( plane, points[ 0 ][ 0 ], points[ 0 ][ 1 ], points[ 0 ][ 2 ] ) ) {
		return;
	}

	//	omnidirectional projectors need plane type
	float pd;
	int axis;
	float alpha = 1.f;
	if ( dp->omnidirectional ) {
		pd = 1.0f;

		//	fade by distance from plane
		float d = DotProduct( dp->center, plane ) - plane[ 3 ];
		alpha = 1.0f - ( fabs( d ) / dp->radius );
		if ( alpha < 0.0f ) {
			return;
		}
		if ( alpha > 1.0f ) {
			alpha = 1.0f;
		}

		//	set projection axis
		vec3_t absNormal;
		absNormal[ 0 ] = fabs( plane[ 0 ] );
		absNormal[ 1 ] = fabs( plane[ 1 ] );
		absNormal[ 2 ] = fabs( plane[ 2 ] );
		if ( absNormal[ 2 ] >= absNormal[ 0 ] && absNormal[ 2 ] >= absNormal[ 1 ] ) {
			axis = 2;
		} else if ( absNormal[ 0 ] >= absNormal[ 1 ] && absNormal[ 0 ] >= absNormal[ 2 ] ) {
			axis = 0;
		} else {
			axis = 1;
		}
	} else {
		//	backface check
		pd = DotProduct( dp->planes[ 0 ], plane );
		if ( pd < -0.0001f ) {
			return;
		}

		//	directional decals use first texture matrix
		axis = 0;
	}

	//	chop the winding by all the projector planes
	int pingPong = 0;
	for ( int i = 0; i < dp->numPlanes; i++ ) {
		ChopWindingBehindPlane( numPoints, points[ pingPong ], &numPoints, points[ !pingPong ], dp->planes[ i ], 0.0f );
		pingPong ^= 1;
		if ( numPoints < 3 ) {
			return;
		}
		if ( numPoints == MAX_DECAL_VERTS ) {
			break;
		}
	}

	//	find first free decal (fixme: optimize this)
	int count = ( bmodel == tr.world->bmodels ? MAX_WORLD_DECALS : MAX_ENTITY_DECALS );
	mbrush46_decal_t* oldest = &bmodel->decals[ 0 ];
	mbrush46_decal_t* decal = bmodel->decals;
	int i;
	for ( i = 0; i < count; i++, decal++ ) {
		//	try to find an empty decal slot
		if ( decal->shader == NULL ) {
			break;
		}

		//	find oldest decal
		if ( decal->fadeEndTime < oldest->fadeEndTime ) {
			oldest = decal;
		}
	}

	//	guess we have to use the oldest decal
	if ( i >= count ) {
		decal = oldest;
	}

	//	r_speeds useful info
	tr.pc.c_decalSurfacesCreated++;

	//	set it up (fixme: get the shader before this happens)
	decal->parent = surf;
	decal->shader = dp->shader;
	decal->fadeStartTime = dp->fadeStartTime;
	decal->fadeEndTime = dp->fadeEndTime;
	decal->fogIndex = surf->fogIndex;

	//	add points
	decal->numVerts = numPoints;
	polyVert_t* vert = decal->verts;
	for ( i = 0; i < numPoints; i++, vert++ ) {
		//	set xyz
		VectorCopy( points[ pingPong ][ i ], vert->xyz );
//.........这里部分代码省略.........

/*
* R_UpdatePortalSurface
*/
void R_UpdatePortalSurface( portalSurface_t *portalSurface, const mesh_t *mesh,
	const vec3_t mins, const vec3_t maxs, const shader_t *shader ) {
	unsigned int i;
	float dist;
	cplane_t plane, untransformed_plane;
	vec3_t v[3];
	const entity_t *ent;

	if( !mesh || !portalSurface ) {
		return;
	}

	ent = portalSurface->entity;

	for( i = 0; i < 3; i++ ) {
		VectorCopy( mesh->xyzArray[mesh->elems[i]], v[i] );
	}

	PlaneFromPoints( v, &untransformed_plane );
	untransformed_plane.dist += DotProduct( ent->origin, untransformed_plane.normal );
	untransformed_plane.dist += 1; // nudge along the normal a bit
	CategorizePlane( &untransformed_plane );

	if( shader->flags & SHADER_AUTOSPRITE ) {
		vec3_t centre;

		// autosprites are quads, facing the viewer
		if( mesh->numVerts < 4 ) {
			return;
		}

		// compute centre as average of 4 vertices
		VectorCopy( mesh->xyzArray[mesh->elems[3]], centre );
		for( i = 0; i < 3; i++ )
			VectorAdd( centre, v[i], centre );
		VectorMA( ent->origin, 0.25, centre, centre );

		VectorNegate( &rn.viewAxis[AXIS_FORWARD], plane.normal );
		plane.dist = DotProduct( plane.normal, centre );
		CategorizePlane( &plane );
	} else {
		vec3_t temp;
		mat3_t entity_rotation;

		// regular surfaces
		if( !Matrix3_Compare( ent->axis, axis_identity ) ) {
			Matrix3_Transpose( ent->axis, entity_rotation );

			for( i = 0; i < 3; i++ ) {
				VectorCopy( v[i], temp );
				Matrix3_TransformVector( entity_rotation, temp, v[i] );
				VectorMA( ent->origin, ent->scale, v[i], v[i] );
			}

			PlaneFromPoints( v, &plane );
			CategorizePlane( &plane );
		} else {
			plane = untransformed_plane;
		}
	}

	if( ( dist = PlaneDiff( rn.viewOrigin, &plane ) ) <= BACKFACE_EPSILON ) {
		// behind the portal plane
		if( !( shader->flags & SHADER_PORTAL_CAPTURE2 ) ) {
			return;
		}

		// we need to render the backplane view
	}

	// check if portal view is opaque due to alphagen portal
	if( shader->portalDistance && dist > shader->portalDistance ) {
		return;
	}

	portalSurface->plane = plane;
	portalSurface->untransformed_plane = untransformed_plane;

	AddPointToBounds( mins, portalSurface->mins, portalSurface->maxs );
	AddPointToBounds( maxs, portalSurface->mins, portalSurface->maxs );
	VectorAdd( portalSurface->mins, portalSurface->maxs, portalSurface->centre );
	VectorScale( portalSurface->centre, 0.5, portalSurface->centre );
}

//.........这里部分代码省略.........
				AUTOEXPAND_BY_REALLOC(mapplanes, (nummapplanes + 64) << 1, allocatedmapplanes, 1024);

				/* make points and back points */
				for(j = 0; j < 3; j++)
				{
					/* get vertex */
					dv = &ds->verts[ds->indexes[i + j]];

					/* copy xyz */
					VectorCopy(dv->xyz, points[j]);
					VectorCopy(dv->xyz, backs[j]);

					/* find nearest axial to normal and push back points opposite */
					/* note: this doesn't work as well as simply using the plane of the triangle, below */
					for(k = 0; k < 3; k++)
					{
						if(fabs(dv->normal[k]) >= fabs(dv->normal[(k + 1) % 3]) &&
						   fabs(dv->normal[k]) >= fabs(dv->normal[(k + 2) % 3]))
						{
							backs[j][k] += dv->normal[k] < 0.0f ? 64.0f : -64.0f;
							break;
						}
					}
				}

				VectorCopy(points[0], points[3]);	// for cyclic usage

				/* make plane for triangle */
				// div0: add some extra spawnflags:
				//   0: snap normals to axial planes for extrusion
				//   8: extrude with the original normals
				//  16: extrude only with up/down normals (ideal for terrain)
				//  24: extrude by distance zero (may need engine changes)
				if(PlaneFromPoints(plane, points[0], points[1], points[2], qtrue))
				{
					vec3_t          bestNormal;
					float           backPlaneDistance = 2;

					if(spawnFlags & 8)	// use a DOWN normal
					{
						if(spawnFlags & 16)
						{
							// 24: normal as is, and zero width (broken)
							VectorCopy(plane, bestNormal);
						}
						else
						{
							// 8: normal as is
							VectorCopy(plane, bestNormal);
						}
					}
					else
					{
						if(spawnFlags & 16)
						{
							// 16: UP/DOWN normal
							VectorSet(bestNormal, 0, 0, (plane[2] >= 0 ? 1 : -1));
						}
						else
						{
							// 0: axial normal
							if(fabs(plane[0]) > fabs(plane[1]))	// x>y
								if(fabs(plane[1]) > fabs(plane[2]))	// x>y, y>z
									VectorSet(bestNormal, (plane[0] >= 0 ? 1 : -1), 0, 0);
								else	// x>y, z>=y
								if(fabs(plane[0]) > fabs(plane[2]))	// x>z, z>=y