radiant/csg.cpp

   1 /*
   2    Copyright (C) 1999-2006 Id Software, Inc. and contributors.
   3    For a list of contributors, see the accompanying CONTRIBUTORS file.
   4
   5    This file is part of GtkRadiant.
   6
   7    GtkRadiant is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    GtkRadiant is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GtkRadiant; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20  */
  21
  22 #include "csg.h"
  23
  24 #include "debugging/debugging.h"
  25
  26 #include <list>
  27
  28 #include "map.h"
  29 #include "brushmanip.h"
  30 #include "brushnode.h"
  31 #include "grid.h"
  32 /*
  33 void Face_makeBrush( Face& face, const Brush& brush, brush_vector_t& out, float offset ){
  34         if ( face.contributes() ) {
  35                 out.push_back( new Brush( brush ) );
  36                 Face* newFace = out.back()->addFace( face );
  37                 if ( newFace != 0 ) {
  38                         newFace->flipWinding();
  39                         newFace->getPlane().offset( offset );
  40                         newFace->planeChanged();
  41                 }
  42         }
  43 }
  44 */
  45
  46 void Face_makeBrush( Face& face, const Brush& brush, brush_vector_t& out, float offset ){
  47         if ( face.contributes() ) {
  48                 out.push_back( new Brush( brush ) );
  49                 //face.getPlane().offset( -offset );
  50                 //face.planeChanged();
  51                 Face* newFace = out.back()->addFace( face );
  52                 if ( newFace != 0 ) {
  53                         newFace->flipWinding();
  54                         newFace->getPlane().offset( offset );
  55                         newFace->planeChanged();
  56                 }
  57         }
  58 }
  59
  60 void Face_makeRoom( Face &face, const Brush &brush, brush_vector_t &out, float offset ){
  61         if ( face.contributes() ) {
  62                 face.getPlane().offset( offset );
  63                 out.push_back( new Brush( brush ) );
  64                 face.getPlane().offset( -offset );
  65                 Face* newFace = out.back()->addFace( face );
  66                 if ( newFace != 0 ) {
  67                         newFace->flipWinding();
  68                         newFace->planeChanged();
  69                 }
  70         }
  71 }
  72
  73 void Brush_makeHollow( const Brush &brush, brush_vector_t &out, float offset ){
  74         Brush_forEachFace( brush, [&]( Face &face ) {
  75                 Face_makeBrush( face, brush, out, offset );
  76         } );
  77 }
  78
  79 void Brush_makeRoom( const Brush &brush, brush_vector_t &out, float offset ){
  80         Brush_forEachFace( brush, [&]( Face &face ) {
  81                 Face_makeRoom( face, brush, out, offset );
  82         } );
  83 }
  84
  85 class BrushHollowSelectedWalker : public scene::Graph::Walker
  86 {
  87 float m_offset;
  88 bool m_makeRoom;
  89 public:
  90 BrushHollowSelectedWalker( float offset, bool makeRoom )
  91         : m_offset( offset ), m_makeRoom( makeRoom ){
  92 }
  93
  94 bool pre( const scene::Path& path, scene::Instance& instance ) const {
  95         if ( path.top().get().visible() ) {
  96                 Brush* brush = Node_getBrush( path.top() );
  97                 if ( brush != 0
  98                          && Instance_getSelectable( instance )->isSelected()
  99                          && path.size() > 1 ) {
 100                         brush_vector_t out;
 101
 102                         if ( m_makeRoom ) {
 103                                 Brush_makeRoom(* brush, out, m_offset );
 104                         }
 105                         else
 106                         {
 107                                 Brush_makeHollow(* brush, out, m_offset );
 108                         }
 109
 110                         for ( brush_vector_t::const_iterator i = out.begin(); i != out.end(); ++i )
 111                         {
 112                                 ( *i )->removeEmptyFaces();
 113                                 NodeSmartReference node( ( new BrushNode() )->node() );
 114                                 Node_getBrush( node )->copy( *( *i ) );
 115                                 delete ( *i );
 116                                 Node_getTraversable( path.parent() )->insert( node );
 117                         }
 118                 }
 119         }
 120         return true;
 121 }
 122 };
 123
 124 typedef std::list<Brush*> brushlist_t;
 125
 126 class BrushGatherSelected : public scene::Graph::Walker
 127 {
 128 brush_vector_t& m_brushlist;
 129 public:
 130 BrushGatherSelected( brush_vector_t& brushlist )
 131         : m_brushlist( brushlist ){
 132 }
 133
 134 bool pre( const scene::Path& path, scene::Instance& instance ) const {
 135         if ( path.top().get().visible() ) {
 136                 Brush* brush = Node_getBrush( path.top() );
 137                 if ( brush != 0
 138                          && Instance_getSelectable( instance )->isSelected() ) {
 139                         m_brushlist.push_back( brush );
 140                 }
 141         }
 142         return true;
 143 }
 144 };
 145
 146 class BrushDeleteSelected : public scene::Graph::Walker
 147 {
 148 public:
 149 bool pre( const scene::Path& path, scene::Instance& instance ) const {
 150         return true;
 151 }
 152 void post( const scene::Path& path, scene::Instance& instance ) const {
 153         if ( path.top().get().visible() ) {
 154                 Brush* brush = Node_getBrush( path.top() );
 155                 if ( brush != 0
 156                          && Instance_getSelectable( instance )->isSelected()
 157                          && path.size() > 1 ) {
 158                         Path_deleteTop( path );
 159                 }
 160         }
 161 }
 162 };
 163
 164 void Scene_BrushMakeHollow_Selected( scene::Graph& graph, bool makeRoom ){
 165         GlobalSceneGraph().traverse( BrushHollowSelectedWalker( GetGridSize(), makeRoom ) );
 166         GlobalSceneGraph().traverse( BrushDeleteSelected() );
 167 }
 168
 169 /*
 170    =============
 171    CSG_MakeHollow
 172    =============
 173  */
 174
 175 void CSG_MakeHollow( void ){
 176         UndoableCommand undo( "brushHollow" );
 177
 178         Scene_BrushMakeHollow_Selected( GlobalSceneGraph(), false );
 179
 180         SceneChangeNotify();
 181 }
 182
 183 void CSG_MakeRoom( void ){
 184         UndoableCommand undo( "brushRoom" );
 185
 186         Scene_BrushMakeHollow_Selected( GlobalSceneGraph(), true );
 187
 188         SceneChangeNotify();
 189 }
 190
 191 template<typename Type>
 192 class RemoveReference
 193 {
 194 public:
 195 typedef Type type;
 196 };
 197
 198 template<typename Type>
 199 class RemoveReference<Type&>
 200 {
 201 public:
 202 typedef Type type;
 203 };
 204
 205 template<typename Functor>
 206 class Dereference
 207 {
 208 const Functor& functor;
 209 public:
 210 Dereference( const Functor& functor ) : functor( functor ){
 211 }
 212 get_result_type<Functor> operator()( typename RemoveReference<get_argument<Functor, 0>>::type *firstArgument ) const {
 213         return functor( *firstArgument );
 214 }
 215 };
 216
 217 template<typename Functor>
 218 inline Dereference<Functor> makeDereference( const Functor& functor ){
 219         return Dereference<Functor>( functor );
 220 }
 221
 222 typedef Face* FacePointer;
 223 const FacePointer c_nullFacePointer = 0;
 224
 225 template<typename Predicate>
 226 Face* Brush_findIf( const Brush& brush, const Predicate& predicate ){
 227         Brush::const_iterator i = std::find_if( brush.begin(), brush.end(), makeDereference( predicate ) );
 228         return i == brush.end() ? c_nullFacePointer : *i; // uses c_nullFacePointer instead of 0 because otherwise gcc 4.1 attempts conversion to int
 229 }
 230
 231 template<typename Caller>
 232 class BindArguments1
 233 {
 234 typedef get_argument<Caller, 1> FirstBound;
 235 FirstBound firstBound;
 236 public:
 237 BindArguments1( FirstBound firstBound )
 238         : firstBound( firstBound ){
 239 }
 240
 241 get_result_type<Caller> operator()( get_argument<Caller, 0> firstArgument ) const {
 242         return Caller::call( firstArgument, firstBound );
 243 }
 244 };
 245
 246 template<typename Caller>
 247 class BindArguments2
 248 {
 249 typedef get_argument<Caller, 1> FirstBound;
 250 typedef get_argument<Caller, 2> SecondBound;
 251 FirstBound firstBound;
 252 SecondBound secondBound;
 253 public:
 254 BindArguments2( FirstBound firstBound, SecondBound secondBound )
 255         : firstBound( firstBound ), secondBound( secondBound ){
 256 }
 257
 258 get_result_type<Caller> operator()( get_argument<Caller, 0> firstArgument ) const {
 259         return Caller::call( firstArgument, firstBound, secondBound );
 260 }
 261 };
 262
 263 template<typename Caller, typename FirstBound, typename SecondBound>
 264 BindArguments2<Caller> bindArguments( const Caller& caller, FirstBound firstBound, SecondBound secondBound ){
 265         return BindArguments2<Caller>( firstBound, secondBound );
 266 }
 267
 268 inline bool Face_testPlane( const Face& face, const Plane3& plane, bool flipped ){
 269         return face.contributes() && !Winding_TestPlane( face.getWinding(), plane, flipped );
 270 }
 271
 272 typedef Function<bool ( const Face &, const Plane3 &, bool ), Face_testPlane> FaceTestPlane;
 273
 274
 275 /// \brief Returns true if
 276 /// \li !flipped && brush is BACK or ON
 277 /// \li flipped && brush is FRONT or ON
 278 bool Brush_testPlane( const Brush& brush, const Plane3& plane, bool flipped ){
 279         brush.evaluateBRep();
 280 #if 1
 281         for ( Brush::const_iterator i( brush.begin() ); i != brush.end(); ++i )
 282         {
 283                 if ( Face_testPlane( *( *i ), plane, flipped ) ) {
 284                         return false;
 285                 }
 286         }
 287         return true;
 288 #else
 289         return Brush_findIf( brush, bindArguments( FaceTestPlane(), makeReference( plane ), flipped ) ) == 0;
 290 #endif
 291 }
 292
 293 brushsplit_t Brush_classifyPlane( const Brush& brush, const Plane3& plane ){
 294         brush.evaluateBRep();
 295         brushsplit_t split;
 296         for ( Brush::const_iterator i( brush.begin() ); i != brush.end(); ++i )
 297         {
 298                 if ( ( *i )->contributes() ) {
 299                         split += Winding_ClassifyPlane( ( *i )->getWinding(), plane );
 300                 }
 301         }
 302         return split;
 303 }
 304
 305 bool Brush_subtract( const Brush& brush, const Brush& other, brush_vector_t& ret_fragments ){
 306         if ( aabb_intersects_aabb( brush.localAABB(), other.localAABB() ) ) {
 307                 brush_vector_t fragments;
 308                 fragments.reserve( other.size() );
 309                 Brush back( brush );
 310
 311                 for ( Brush::const_iterator i( other.begin() ); i != other.end(); ++i )
 312                 {
 313                         if ( ( *i )->contributes() ) {
 314                                 brushsplit_t split = Brush_classifyPlane( back, ( *i )->plane3() );
 315                                 if ( split.counts[ePlaneFront] != 0
 316                                          && split.counts[ePlaneBack] != 0 ) {
 317                                         fragments.push_back( new Brush( back ) );
 318                                         Face* newFace = fragments.back()->addFace( *( *i ) );
 319                                         if ( newFace != 0 ) {
 320                                                 newFace->flipWinding();
 321                                         }
 322                                         back.addFace( *( *i ) );
 323                                 }
 324                                 else if ( split.counts[ePlaneBack] == 0 ) {
 325                                         for ( brush_vector_t::iterator i = fragments.begin(); i != fragments.end(); ++i )
 326                                         {
 327                                                 delete( *i );
 328                                         }
 329                                         return false;
 330                                 }
 331                         }
 332                 }
 333                 ret_fragments.insert( ret_fragments.end(), fragments.begin(), fragments.end() );
 334                 return true;
 335         }
 336         return false;
 337 }
 338
 339 class SubtractBrushesFromUnselected : public scene::Graph::Walker
 340 {
 341 const brush_vector_t& m_brushlist;
 342 std::size_t& m_before;
 343 std::size_t& m_after;
 344 public:
 345 SubtractBrushesFromUnselected( const brush_vector_t& brushlist, std::size_t& before, std::size_t& after )
 346         : m_brushlist( brushlist ), m_before( before ), m_after( after ){
 347 }
 348
 349 bool pre( const scene::Path& path, scene::Instance& instance ) const {
 350         return true;
 351 }
 352
 353 void post( const scene::Path& path, scene::Instance& instance ) const {
 354         if ( path.top().get().visible() ) {
 355                 Brush* brush = Node_getBrush( path.top() );
 356                 if ( brush != 0
 357                          && !Instance_getSelectable( instance )->isSelected() ) {
 358                         brush_vector_t buffer[2];
 359                         bool swap = false;
 360                         Brush* original = new Brush( *brush );
 361                         buffer[static_cast<std::size_t>( swap )].push_back( original );
 362
 363                         {
 364                                 for ( brush_vector_t::const_iterator i( m_brushlist.begin() ); i != m_brushlist.end(); ++i )
 365                                 {
 366                                         for ( brush_vector_t::iterator j( buffer[static_cast<std::size_t>( swap )].begin() ); j != buffer[static_cast<std::size_t>( swap )].end(); ++j )
 367                                         {
 368                                                 if ( Brush_subtract( *( *j ), *( *i ), buffer[static_cast<std::size_t>( !swap )] ) ) {
 369                                                         delete ( *j );
 370                                                 }
 371                                                 else
 372                                                 {
 373                                                         buffer[static_cast<std::size_t>( !swap )].push_back( ( *j ) );
 374                                                 }
 375                                         }
 376                                         buffer[static_cast<std::size_t>( swap )].clear();
 377                                         swap = !swap;
 378                                 }
 379                         }
 380
 381                         brush_vector_t& out = buffer[static_cast<std::size_t>( swap )];
 382
 383                         if ( out.size() == 1 && out.back() == original ) {
 384                                 delete original;
 385                         }
 386                         else
 387                         {
 388                                 ++m_before;
 389                                 for ( brush_vector_t::const_iterator i = out.begin(); i != out.end(); ++i )
 390                                 {
 391                                         ++m_after;
 392                                         ( *i )->removeEmptyFaces();
 393                                         if ( !( *i )->empty() ) {
 394                                                 NodeSmartReference node( ( new BrushNode() )->node() );
 395                                                 Node_getBrush( node )->copy( *( *i ) );
 396                                                 delete ( *i );
 397                                                 Node_getTraversable( path.parent() )->insert( node );
 398                                         }
 399                                         else{
 400                                                 delete ( *i );
 401                                         }
 402                                 }
 403                                 Path_deleteTop( path );
 404                         }
 405                 }
 406         }
 407 }
 408 };
 409
 410 void CSG_Subtract(){
 411         brush_vector_t selected_brushes;
 412         GlobalSceneGraph().traverse( BrushGatherSelected( selected_brushes ) );
 413
 414         if ( selected_brushes.empty() ) {
 415                 globalOutputStream() << "CSG Subtract: No brushes selected.\n";
 416         }
 417         else
 418         {
 419                 globalOutputStream() << "CSG Subtract: Subtracting " << Unsigned( selected_brushes.size() ) << " brushes.\n";
 420
 421                 UndoableCommand undo( "brushSubtract" );
 422
 423                 // subtract selected from unselected
 424                 std::size_t before = 0;
 425                 std::size_t after = 0;
 426                 GlobalSceneGraph().traverse( SubtractBrushesFromUnselected( selected_brushes, before, after ) );
 427                 globalOutputStream() << "CSG Subtract: Result: "
 428                                                          << Unsigned( after ) << " fragment" << ( after == 1 ? "" : "s" )
 429                                                          << " from " << Unsigned( before ) << " brush" << ( before == 1 ? "" : "es" ) << ".\n";
 430
 431                 SceneChangeNotify();
 432         }
 433 }
 434
 435 class BrushSplitByPlaneSelected : public scene::Graph::Walker
 436 {
 437 const Vector3& m_p0;
 438 const Vector3& m_p1;
 439 const Vector3& m_p2;
 440 const char* m_shader;
 441 const TextureProjection& m_projection;
 442 EBrushSplit m_split;
 443 public:
 444 BrushSplitByPlaneSelected( const Vector3& p0, const Vector3& p1, const Vector3& p2, const char* shader, const TextureProjection& projection, EBrushSplit split )
 445         : m_p0( p0 ), m_p1( p1 ), m_p2( p2 ), m_shader( shader ), m_projection( projection ), m_split( split ){
 446 }
 447
 448 bool pre( const scene::Path& path, scene::Instance& instance ) const {
 449         return true;
 450 }
 451
 452 void post( const scene::Path& path, scene::Instance& instance ) const {
 453         if ( path.top().get().visible() ) {
 454                 Brush* brush = Node_getBrush( path.top() );
 455                 if ( brush != 0
 456                          && Instance_getSelectable( instance )->isSelected() ) {
 457                         Plane3 plane( plane3_for_points( m_p0, m_p1, m_p2 ) );
 458                         if ( plane3_valid( plane ) ) {
 459                                 brushsplit_t split = Brush_classifyPlane( *brush, m_split == eFront ? plane3_flipped( plane ) : plane );
 460                                 if ( split.counts[ePlaneBack] && split.counts[ePlaneFront] ) {
 461                                         // the plane intersects this brush
 462                                         if ( m_split == eFrontAndBack ) {
 463                                                 NodeSmartReference node( ( new BrushNode() )->node() );
 464                                                 Brush* fragment = Node_getBrush( node );
 465                                                 fragment->copy( *brush );
 466                                                 Face* newFace = fragment->addPlane( m_p0, m_p1, m_p2, m_shader, m_projection );
 467                                                 if ( newFace != 0 && m_split != eFront ) {
 468                                                         newFace->flipWinding();
 469                                                 }
 470                                                 fragment->removeEmptyFaces();
 471                                                 ASSERT_MESSAGE( !fragment->empty(), "brush left with no faces after split" );
 472
 473                                                 Node_getTraversable( path.parent() )->insert( node );
 474                                                 {
 475                                                         scene::Path fragmentPath = path;
 476                                                         fragmentPath.top() = makeReference( node.get() );
 477                                                         selectPath( fragmentPath, true );
 478                                                 }
 479                                         }
 480
 481                                         Face* newFace = brush->addPlane( m_p0, m_p1, m_p2, m_shader, m_projection );
 482                                         if ( newFace != 0 && m_split == eFront ) {
 483                                                 newFace->flipWinding();
 484                                         }
 485                                         brush->removeEmptyFaces();
 486                                         ASSERT_MESSAGE( !brush->empty(), "brush left with no faces after split" );
 487                                 }
 488                                 else
 489                                 // the plane does not intersect this brush
 490                                 if ( m_split != eFrontAndBack && split.counts[ePlaneBack] != 0 ) {
 491                                         // the brush is "behind" the plane
 492                                         Path_deleteTop( path );
 493                                 }
 494                         }
 495                 }
 496         }
 497 }
 498 };
 499
 500 void Scene_BrushSplitByPlane( scene::Graph& graph, const Vector3& p0, const Vector3& p1, const Vector3& p2, const char* shader, EBrushSplit split ){
 501         TextureProjection projection;
 502         TexDef_Construct_Default( projection );
 503         graph.traverse( BrushSplitByPlaneSelected( p0, p1, p2, shader, projection, split ) );
 504         SceneChangeNotify();
 505 }
 506
 507
 508 class BrushInstanceSetClipPlane : public scene::Graph::Walker
 509 {
 510 Plane3 m_plane;
 511 public:
 512 BrushInstanceSetClipPlane( const Plane3& plane )
 513         : m_plane( plane ){
 514 }
 515
 516 bool pre( const scene::Path& path, scene::Instance& instance ) const {
 517         BrushInstance* brush = Instance_getBrush( instance );
 518         if ( brush != 0
 519                  && path.top().get().visible()
 520                  && brush->isSelected() ) {
 521                 BrushInstance& brushInstance = *brush;
 522                 brushInstance.setClipPlane( m_plane );
 523         }
 524         return true;
 525 }
 526 };
 527
 528 void Scene_BrushSetClipPlane( scene::Graph& graph, const Plane3& plane ){
 529         graph.traverse( BrushInstanceSetClipPlane( plane ) );
 530 }
 531
 532 /*
 533    =============
 534    CSG_Merge
 535    =============
 536  */
 537 bool Brush_merge( Brush& brush, const brush_vector_t& in, bool onlyshape ){
 538         // gather potential outer faces
 539
 540         {
 541                 typedef std::vector<const Face*> Faces;
 542                 Faces faces;
 543                 for ( brush_vector_t::const_iterator i( in.begin() ); i != in.end(); ++i )
 544                 {
 545                         ( *i )->evaluateBRep();
 546                         for ( Brush::const_iterator j( ( *i )->begin() ); j != ( *i )->end(); ++j )
 547                         {
 548                                 if ( !( *j )->contributes() ) {
 549                                         continue;
 550                                 }
 551
 552                                 const Face& face1 = *( *j );
 553
 554                                 bool skip = false;
 555                                 // test faces of all input brushes
 556                                 //!\todo SPEEDUP: Flag already-skip faces and only test brushes from i+1 upwards.
 557                                 for ( brush_vector_t::const_iterator k( in.begin() ); !skip && k != in.end(); ++k )
 558                                 {
 559                                         if ( k != i ) { // don't test a brush against itself
 560                                                 for ( Brush::const_iterator l( ( *k )->begin() ); !skip && l != ( *k )->end(); ++l )
 561                                                 {
 562                                                         const Face& face2 = *( *l );
 563
 564                                                         // face opposes another face
 565                                                         if ( plane3_opposing( face1.plane3(), face2.plane3() ) ) {
 566                                                                 // skip opposing planes
 567                                                                 skip  = true;
 568                                                                 break;
 569                                                         }
 570                                                 }
 571                                         }
 572                                 }
 573
 574                                 // check faces already stored
 575                                 for ( Faces::const_iterator m = faces.begin(); !skip && m != faces.end(); ++m )
 576                                 {
 577                                         const Face& face2 = *( *m );
 578
 579                                         // face equals another face
 580                                         if ( plane3_equal( face1.plane3(), face2.plane3() ) ) {
 581                                                 //if the texture/shader references should be the same but are not
 582                                                 if ( !onlyshape && !shader_equal( face1.getShader().getShader(), face2.getShader().getShader() ) ) {
 583                                                         return false;
 584                                                 }
 585                                                 // skip duplicate planes
 586                                                 skip = true;
 587                                                 break;
 588                                         }
 589
 590                                         // face1 plane intersects face2 winding or vice versa
 591                                         if ( Winding_PlanesConcave( face1.getWinding(), face2.getWinding(), face1.plane3(), face2.plane3() ) ) {
 592                                                 // result would not be convex
 593                                                 return false;
 594                                         }
 595                                 }
 596
 597                                 if ( !skip ) {
 598                                         faces.push_back( &face1 );
 599                                 }
 600                         }
 601                 }
 602                 for ( Faces::const_iterator i = faces.begin(); i != faces.end(); ++i )
 603                 {
 604                         if ( !brush.addFace( *( *i ) ) ) {
 605                                 // result would have too many sides
 606                                 return false;
 607                         }
 608                 }
 609         }
 610
 611         brush.removeEmptyFaces();
 612
 613         return true;
 614 }
 615
 616 void CSG_Merge( void ){
 617         brush_vector_t selected_brushes;
 618
 619         // remove selected
 620         GlobalSceneGraph().traverse( BrushGatherSelected( selected_brushes ) );
 621
 622         if ( selected_brushes.empty() ) {
 623                 globalOutputStream() << "CSG Merge: No brushes selected.\n";
 624                 return;
 625         }
 626
 627         if ( selected_brushes.size() < 2 ) {
 628                 globalOutputStream() << "CSG Merge: At least two brushes have to be selected.\n";
 629                 return;
 630         }
 631
 632         globalOutputStream() << "CSG Merge: Merging " << Unsigned( selected_brushes.size() ) << " brushes.\n";
 633
 634         UndoableCommand undo( "brushMerge" );
 635
 636         scene::Path merged_path = GlobalSelectionSystem().ultimateSelected().path();
 637
 638         NodeSmartReference node( ( new BrushNode() )->node() );
 639         Brush* brush = Node_getBrush( node );
 640         // if the new brush would not be convex
 641         if ( !Brush_merge( *brush, selected_brushes, true ) ) {
 642                 globalOutputStream() << "CSG Merge: Failed - result would not be convex.\n";
 643         }
 644         else
 645         {
 646                 ASSERT_MESSAGE( !brush->empty(), "brush left with no faces after merge" );
 647
 648                 // free the original brushes
 649                 GlobalSceneGraph().traverse( BrushDeleteSelected() );
 650
 651                 merged_path.pop();
 652                 Node_getTraversable( merged_path.top() )->insert( node );
 653                 merged_path.push( makeReference( node.get() ) );
 654
 655                 selectPath( merged_path, true );
 656
 657                 globalOutputStream() << "CSG Merge: Succeeded.\n";
 658                 SceneChangeNotify();
 659         }
 660 }