source/glsl/generate.cpp

   1 #include <msp/core/hash.h>
   2 #include <msp/core/raii.h>
   3 #include <msp/strings/lexicalcast.h>
   4 #include "builtin.h"
   5 #include "generate.h"
   6
   7 using namespace std;
   8
   9 namespace Msp {
  10 namespace GL {
  11 namespace SL {
  12
  13 void DeclarationCombiner::apply(Stage &stage)
  14 {
  15         stage.content.visit(*this);
  16         NodeRemover().apply(stage, nodes_to_remove);
  17 }
  18
  19 void DeclarationCombiner::visit(Block &block)
  20 {
  21         if(current_block)
  22                 return;
  23
  24         TraversingVisitor::visit(block);
  25 }
  26
  27 void DeclarationCombiner::visit(VariableDeclaration &var)
  28 {
  29         VariableDeclaration *&ptr = variables[var.name];
  30         if(ptr)
  31         {
  32                 ptr->type = var.type;
  33                 if(var.init_expression)
  34                         ptr->init_expression = var.init_expression;
  35                 if(var.layout)
  36                 {
  37                         if(ptr->layout)
  38                         {
  39                                 for(vector<Layout::Qualifier>::iterator i=var.layout->qualifiers.begin(); i!=var.layout->qualifiers.end(); ++i)
  40                                 {
  41                                         bool found = false;
  42                                         for(vector<Layout::Qualifier>::iterator j=ptr->layout->qualifiers.begin(); (!found && j!=ptr->layout->qualifiers.end()); ++j)
  43                                                 if(j->name==i->name)
  44                                                 {
  45                                                         j->has_value = i->value;
  46                                                         j->value = i->value;
  47                                                         found = true;
  48                                                 }
  49
  50                                         if(!found)
  51                                                 ptr->layout->qualifiers.push_back(*i);
  52                                 }
  53                         }
  54                         else
  55                                 ptr->layout = var.layout;
  56                 }
  57                 nodes_to_remove.insert(&var);
  58         }
  59         else
  60                 ptr = &var;
  61 }
  62
  63
  64 ConstantSpecializer::ConstantSpecializer():
  65         values(0)
  66 { }
  67
  68 void ConstantSpecializer::apply(Stage &stage, const map<string, int> *v)
  69 {
  70         values = v;
  71         stage.content.visit(*this);
  72 }
  73
  74 void ConstantSpecializer::visit(VariableDeclaration &var)
  75 {
  76         bool specializable = false;
  77         if(var.layout)
  78         {
  79                 vector<Layout::Qualifier> &qualifiers = var.layout->qualifiers;
  80                 for(vector<Layout::Qualifier>::iterator i=qualifiers.begin(); i!=qualifiers.end(); ++i)
  81                         if(i->name=="constant_id")
  82                         {
  83                                 specializable = true;
  84                                 if(values)
  85                                         qualifiers.erase(i);
  86                                 else if(i->value==-1)
  87                                         i->value = hash32(var.name)&0x7FFFFFFF;
  88                                 break;
  89                         }
  90
  91                 if(qualifiers.empty())
  92                         var.layout = 0;
  93         }
  94
  95         if(specializable && values)
  96         {
  97                 map<string, int>::const_iterator i = values->find(var.name);
  98                 if(i!=values->end())
  99                 {
 100                         RefPtr<Literal> literal = new Literal;
 101                         if(var.type=="bool")
 102                         {
 103                                 literal->token = (i->second ? "true" : "false");
 104                                 literal->value = static_cast<bool>(i->second);
 105                         }
 106                         else if(var.type=="int")
 107                         {
 108                                 literal->token = lexical_cast<string>(i->second);
 109                                 literal->value = i->second;
 110                         }
 111                         var.init_expression = literal;
 112                 }
 113         }
 114 }
 115
 116
 117 void BlockHierarchyResolver::enter(Block &block)
 118 {
 119         block.parent = current_block;
 120 }
 121
 122
 123 TypeResolver::TypeResolver():
 124         stage(0)
 125 { }
 126
 127 void TypeResolver::apply(Stage &s)
 128 {
 129         stage = &s;
 130         s.types.clear();
 131         s.content.visit(*this);
 132 }
 133
 134 TypeDeclaration *TypeResolver::resolve_type(const string &name)
 135 {
 136         map<string, TypeDeclaration *>::iterator i = stage->types.find(name);
 137         if(i!=stage->types.end())
 138         {
 139                 map<TypeDeclaration *, TypeDeclaration *>::iterator j = alias_map.find(i->second);
 140                 return (j!=alias_map.end() ? j->second : i->second);
 141         }
 142         else
 143                 return 0;
 144 }
 145
 146 void TypeResolver::visit(BasicTypeDeclaration &type)
 147 {
 148         type.base_type = resolve_type(type.base);
 149
 150         if(type.kind==BasicTypeDeclaration::VECTOR && type.base_type)
 151                 if(BasicTypeDeclaration *basic_base = dynamic_cast<BasicTypeDeclaration *>(type.base_type))
 152                         if(basic_base->kind==BasicTypeDeclaration::VECTOR)
 153                         {
 154                                 type.kind = BasicTypeDeclaration::MATRIX;
 155                                 type.size |= basic_base->size<<16;
 156                         }
 157
 158         if(type.kind==BasicTypeDeclaration::ALIAS && type.base_type)
 159                 alias_map[&type] = type.base_type;
 160
 161         stage->types.insert(make_pair(type.name, &type));
 162 }
 163
 164 void TypeResolver::visit(ImageTypeDeclaration &type)
 165 {
 166         type.base_type = resolve_type(type.base);
 167         stage->types.insert(make_pair(type.name, &type));
 168 }
 169
 170 void TypeResolver::visit(StructDeclaration &strct)
 171 {
 172         stage->types.insert(make_pair(strct.name, &strct));
 173         TraversingVisitor::visit(strct);
 174 }
 175
 176 void TypeResolver::visit(VariableDeclaration &var)
 177 {
 178         var.type_declaration = resolve_type(var.type);
 179 }
 180
 181 void TypeResolver::visit(FunctionDeclaration &func)
 182 {
 183         func.return_type_declaration = resolve_type(func.return_type);
 184         TraversingVisitor::visit(func);
 185 }
 186
 187
 188 VariableResolver::VariableResolver():
 189         stage(0),
 190         r_members(0),
 191         record_target(false),
 192         r_self_referencing(false),
 193         r_assignment_target(0)
 194 { }
 195
 196 void VariableResolver::apply(Stage &s)
 197 {
 198         stage = &s;
 199         s.interface_blocks.clear();
 200         s.content.visit(*this);
 201 }
 202
 203 void VariableResolver::enter(Block &block)
 204 {
 205         block.variables.clear();
 206 }
 207
 208 void VariableResolver::visit(VariableReference &var)
 209 {
 210         var.declaration = 0;
 211         r_members = 0;
 212         /* Look for variable declarations in the block hierarchy first.  Interface
 213         blocks are always defined in the top level so we can't accidentally skip
 214         one. */
 215         for(Block *block=current_block; (!var.declaration && block); block=block->parent)
 216         {
 217                 map<string, VariableDeclaration *>::iterator i = block->variables.find(var.name);
 218                 if(i!=block->variables.end())
 219                         var.declaration = i->second;
 220         }
 221
 222         if(!var.declaration)
 223         {
 224                 const map<string, InterfaceBlock *> &blocks = stage->interface_blocks;
 225                 map<string, InterfaceBlock *>::const_iterator i = blocks.find("_"+var.name);
 226                 if(i!=blocks.end())
 227                 {
 228                         /* The name refers to an interface block with an instance name rather
 229                         than a variable.  Prepare a new syntax tree node accordingly. */
 230                         r_iface_ref = new InterfaceBlockReference;
 231                         r_iface_ref->source = var.source;
 232                         r_iface_ref->line = var.line;
 233                         r_iface_ref->name = var.name;
 234                         r_iface_ref->declaration = i->second;
 235                         r_members = &i->second->members.variables;
 236                 }
 237                 else
 238                 {
 239                         // Look for the variable in anonymous interface blocks.
 240                         for(i=blocks.begin(); (!var.declaration && i!=blocks.end()); ++i)
 241                                 if(i->second->instance_name.empty())
 242                                 {
 243                                         map<string, VariableDeclaration *>::iterator j = i->second->members.variables.find(var.name);
 244                                         if(j!=i->second->members.variables.end())
 245                                                 var.declaration = j->second;
 246                                 }
 247                 }
 248         }
 249
 250         if(var.declaration)
 251                 if(StructDeclaration *strct = dynamic_cast<StructDeclaration *>(var.declaration->type_declaration))
 252                         r_members = &strct->members.variables;
 253
 254         if(record_target)
 255         {
 256                 if(r_assignment_target)
 257                 {
 258                         /* More than one variable reference found in assignment target.
 259                         Unable to determine what the primary target is. */
 260                         record_target = false;
 261                         r_assignment_target = 0;
 262                 }
 263                 else
 264                         r_assignment_target = var.declaration;
 265         }
 266         else if(var.declaration && var.declaration==r_assignment_target)
 267                 r_self_referencing = true;
 268 }
 269
 270 void VariableResolver::visit(InterfaceBlockReference &iface)
 271 {
 272         iface.declaration = 0;
 273         for(Block *block=current_block; block; block=block->parent)
 274         {
 275                 map<string, InterfaceBlock *>::iterator i = stage->interface_blocks.find("_"+iface.name);
 276                 if(i!=stage->interface_blocks.end())
 277                 {
 278                         iface.declaration = i->second;
 279                         r_members = &i->second->members.variables;
 280                         break;
 281                 }
 282         }
 283 }
 284
 285 void VariableResolver::visit(MemberAccess &memacc)
 286 {
 287         r_members = 0;
 288         r_iface_ref = 0;
 289         memacc.left->visit(*this);
 290
 291         if(r_iface_ref)
 292                 memacc.left = r_iface_ref;
 293         r_iface_ref = 0;
 294
 295         memacc.declaration = 0;
 296         if(r_members)
 297         {
 298                 map<string, VariableDeclaration *>::iterator i = r_members->find(memacc.member);
 299                 if(i!=r_members->end())
 300                 {
 301                         memacc.declaration = i->second;
 302                         if(StructDeclaration *strct = dynamic_cast<StructDeclaration *>(i->second->type_declaration))
 303                                 r_members = &strct->members.variables;
 304                 }
 305                 else
 306                         r_members = 0;
 307         }
 308 }
 309
 310 void VariableResolver::visit(UnaryExpression &unary)
 311 {
 312         TraversingVisitor::visit(unary);
 313         r_members = 0;
 314         r_iface_ref = 0;
 315 }
 316
 317 void VariableResolver::visit(BinaryExpression &binary)
 318 {
 319         if(binary.oper->token[0]=='[')
 320         {
 321                 {
 322                         /* The subscript expression is not a part of the primary assignment
 323                         target. */
 324                         SetFlag set(record_target, false);
 325                         binary.right->visit(*this);
 326                 }
 327                 r_members = 0;
 328                 r_iface_ref = 0;
 329                 binary.left->visit(*this);
 330                 if(r_iface_ref)
 331                         binary.left = r_iface_ref;
 332         }
 333         else
 334         {
 335                 TraversingVisitor::visit(binary);
 336                 r_members = 0;
 337         }
 338
 339         r_iface_ref = 0;
 340 }
 341
 342 void VariableResolver::visit(Assignment &assign)
 343 {
 344         {
 345                 SetFlag set(record_target);
 346                 r_assignment_target = 0;
 347                 assign.left->visit(*this);
 348                 assign.target_declaration = r_assignment_target;
 349         }
 350
 351         r_self_referencing = false;
 352         assign.right->visit(*this);
 353         assign.self_referencing = (r_self_referencing || assign.oper->token[0]!='=');
 354
 355         r_members = 0;
 356         r_iface_ref = 0;
 357 }
 358
 359 void VariableResolver::visit(FunctionCall &call)
 360 {
 361         TraversingVisitor::visit(call);
 362         r_members = 0;
 363         r_iface_ref = 0;
 364 }
 365
 366 void VariableResolver::visit(VariableDeclaration &var)
 367 {
 368         if(!block_interface.empty() && var.interface.empty())
 369                 var.interface = block_interface;
 370
 371         TraversingVisitor::visit(var);
 372         current_block->variables.insert(make_pair(var.name, &var));
 373 }
 374
 375 void VariableResolver::visit(InterfaceBlock &iface)
 376 {
 377         /* Block names can be reused in different interfaces.  Prefix the name with
 378         the first character of the interface to avoid conflicts. */
 379         stage->interface_blocks.insert(make_pair(iface.interface+iface.name, &iface));
 380         if(!iface.instance_name.empty())
 381                 stage->interface_blocks.insert(make_pair("_"+iface.instance_name, &iface));
 382
 383         SetForScope<string> set_iface(block_interface, iface.interface);
 384         TraversingVisitor::visit(iface);
 385 }
 386
 387
 388 void FunctionResolver::apply(Stage &s)
 389 {
 390         stage = &s;
 391         s.functions.clear();
 392         s.content.visit(*this);
 393 }
 394
 395 void FunctionResolver::visit(FunctionCall &call)
 396 {
 397         map<string, FunctionDeclaration *>::iterator i = stage->functions.find(call.name);
 398         if(i!=stage->functions.end())
 399                 call.declaration = i->second;
 400
 401         TraversingVisitor::visit(call);
 402 }
 403
 404 void FunctionResolver::visit(FunctionDeclaration &func)
 405 {
 406         FunctionDeclaration *&stage_decl = stage->functions[func.name];
 407         vector<FunctionDeclaration *> &decls = declarations[func.name];
 408         if(func.definition==&func)
 409         {
 410                 stage_decl = &func;
 411
 412                 // Set all previous declarations to use this definition.
 413                 for(vector<FunctionDeclaration *>::iterator i=decls.begin(); i!=decls.end(); ++i)
 414                 {
 415                         (*i)->definition = func.definition;
 416                         (*i)->body.body.clear();
 417                 }
 418         }
 419         else
 420         {
 421                 func.definition = 0;
 422                 if(!stage_decl)
 423                         stage_decl = &func;
 424                 else
 425                         func.definition = stage_decl->definition;
 426         }
 427         decls.push_back(&func);
 428
 429         TraversingVisitor::visit(func);
 430 }
 431
 432
 433 InterfaceGenerator::InterfaceGenerator():
 434         stage(0),
 435         function_scope(false),
 436         iface_block(0),
 437         copy_block(false),
 438         iface_target_block(0)
 439 { }
 440
 441 string InterfaceGenerator::get_out_prefix(Stage::Type type)
 442 {
 443         if(type==Stage::VERTEX)
 444                 return "_vs_out_";
 445         else if(type==Stage::GEOMETRY)
 446                 return "_gs_out_";
 447         else
 448                 return string();
 449 }
 450
 451 void InterfaceGenerator::apply(Stage &s)
 452 {
 453         stage = &s;
 454         iface_target_block = &stage->content;
 455         if(stage->previous)
 456                 in_prefix = get_out_prefix(stage->previous->type);
 457         out_prefix = get_out_prefix(stage->type);
 458         s.content.visit(*this);
 459         NodeRemover().apply(s, nodes_to_remove);
 460 }
 461
 462 void InterfaceGenerator::visit(Block &block)
 463 {
 464         SetForScope<Block *> set_block(current_block, &block);
 465         for(NodeList<Statement>::iterator i=block.body.begin(); i!=block.body.end(); ++i)
 466         {
 467                 assignment_insert_point = i;
 468                 if(&block==&stage->content)
 469                         iface_insert_point = i;
 470
 471                 (*i)->visit(*this);
 472         }
 473 }
 474
 475 string InterfaceGenerator::change_prefix(const string &name, const string &prefix) const
 476 {
 477         unsigned offset = (name.compare(0, in_prefix.size(), in_prefix) ? 0 : in_prefix.size());
 478         return prefix+name.substr(offset);
 479 }
 480
 481 VariableDeclaration *InterfaceGenerator::generate_interface(VariableDeclaration &var, const string &iface, const string &name)
 482 {
 483         if(stage->content.variables.count(name))
 484                 return 0;
 485
 486         VariableDeclaration* iface_var = new VariableDeclaration;
 487         iface_var->sampling = var.sampling;
 488         iface_var->interface = iface;
 489         iface_var->type = var.type;
 490         iface_var->name = name;
 491         /* Geometry shader inputs are always arrays.  But if we're bringing in an
 492         entire block, the array is on the block and not individual variables. */
 493         if(stage->type==Stage::GEOMETRY && !copy_block)
 494                 iface_var->array = ((var.array && var.interface!="in") || iface=="in");
 495         else
 496                 iface_var->array = var.array;
 497         if(iface_var->array)
 498                 iface_var->array_size = var.array_size;
 499         if(iface=="in")
 500         {
 501                 iface_var->layout = var.layout;
 502                 iface_var->linked_declaration = &var;
 503                 var.linked_declaration = iface_var;
 504         }
 505
 506         iface_target_block->body.insert(iface_insert_point, iface_var);
 507         iface_target_block->variables.insert(make_pair(name, iface_var));
 508
 509         return iface_var;
 510 }
 511
 512 InterfaceBlock *InterfaceGenerator::generate_interface(InterfaceBlock &out_block)
 513 {
 514         if(stage->interface_blocks.count("in"+out_block.name))
 515                 return 0;
 516
 517         InterfaceBlock *in_block = new InterfaceBlock;
 518         in_block->interface = "in";
 519         in_block->name = out_block.name;
 520         in_block->instance_name = out_block.instance_name;
 521         if(stage->type==Stage::GEOMETRY)
 522                 in_block->array = true;
 523         else
 524                 in_block->array = out_block.array;
 525         in_block->linked_block = &out_block;
 526         out_block.linked_block = in_block;
 527
 528         {
 529                 SetFlag set_copy(copy_block, true);
 530                 SetForScope<Block *> set_target(iface_target_block, &in_block->members);
 531                 SetForScope<NodeList<Statement>::iterator> set_ins_pt(iface_insert_point, in_block->members.body.end());
 532                 out_block.members.visit(*this);
 533         }
 534
 535         iface_target_block->body.insert(iface_insert_point, in_block);
 536         stage->interface_blocks.insert(make_pair("in"+in_block->name, in_block));
 537         if(!in_block->instance_name.empty())
 538                 stage->interface_blocks.insert(make_pair("_"+in_block->instance_name, in_block));
 539
 540         SetFlag set_scope(function_scope, false);
 541         SetForScope<Block *> set_block(current_block, &stage->content);
 542         in_block->visit(*this);
 543
 544         return in_block;
 545 }
 546
 547 ExpressionStatement &InterfaceGenerator::insert_assignment(const string &left, Expression *right)
 548 {
 549         Assignment *assign = new Assignment;
 550         VariableReference *ref = new VariableReference;
 551         ref->name = left;
 552         assign->left = ref;
 553         assign->oper = &Operator::get_operator("=", Operator::BINARY);
 554         assign->right = right;
 555
 556         ExpressionStatement *stmt = new ExpressionStatement;
 557         stmt->expression = assign;
 558         current_block->body.insert(assignment_insert_point, stmt);
 559         stmt->visit(*this);
 560
 561         return *stmt;
 562 }
 563
 564 void InterfaceGenerator::visit(VariableReference &var)
 565 {
 566         if(var.declaration || !stage->previous)
 567                 return;
 568         /* Don't pull a variable from previous stage if we just generated an output
 569         interface in this stage */
 570         if(stage->content.variables.count(var.name))
 571                 return;
 572
 573         const map<string, VariableDeclaration *> &prev_vars = stage->previous->content.variables;
 574         map<string, VariableDeclaration *>::const_iterator i = prev_vars.find(var.name);
 575         if(i==prev_vars.end() || i->second->interface!="out")
 576                 i = prev_vars.find(in_prefix+var.name);
 577         if(i!=prev_vars.end() && i->second->interface=="out")
 578         {
 579                 generate_interface(*i->second, "in", i->second->name);
 580                 var.name = i->second->name;
 581                 return;
 582         }
 583
 584         const map<string, InterfaceBlock *> &prev_blocks = stage->previous->interface_blocks;
 585         map<string, InterfaceBlock *>::const_iterator j = prev_blocks.find("_"+var.name);
 586         if(j!=prev_blocks.end() && j->second->interface=="out")
 587         {
 588                 generate_interface(*j->second);
 589                 /* Let VariableResolver convert the variable reference into an interface
 590                 block reference. */
 591                 return;
 592         }
 593
 594         for(j=prev_blocks.begin(); j!=prev_blocks.end(); ++j)
 595                 if(j->second->instance_name.empty())
 596                 {
 597                         i = j->second->members.variables.find(var.name);
 598                         if(i!=j->second->members.variables.end())
 599                         {
 600                                 generate_interface(*j->second);
 601                                 return;
 602                         }
 603                 }
 604 }
 605
 606 void InterfaceGenerator::visit(VariableDeclaration &var)
 607 {
 608         if(copy_block)
 609         {
 610                 generate_interface(var, "in", var.name);
 611                 return;
 612         }
 613
 614         if(iface_block)
 615         {
 616                 if(iface_block->linked_block)
 617                 {
 618                         // Link all variables to their counterparts in the linked block.
 619                         const map<string, VariableDeclaration *> &linked_vars = iface_block->linked_block->members.variables;
 620                         map<string, VariableDeclaration *>::const_iterator i = linked_vars.find(var.name);
 621                         if(i!=linked_vars.end())
 622                         {
 623                                 var.linked_declaration = i->second;
 624                                 var.linked_declaration->linked_declaration = &var;
 625                         }
 626                 }
 627                 return;
 628         }
 629
 630         if(var.interface=="out")
 631         {
 632                 /* For output variables in function scope, generate a global interface
 633                 and replace the local declaration with an assignment. */
 634                 VariableDeclaration *out_var = 0;
 635                 if(function_scope && (out_var=generate_interface(var, "out", var.name)))
 636                 {
 637                         out_var->source = var.source;
 638                         out_var->line = var.line;
 639                         nodes_to_remove.insert(&var);
 640                         if(var.init_expression)
 641                         {
 642                                 ExpressionStatement &stmt = insert_assignment(var.name, var.init_expression->clone());
 643                                 stmt.source = var.source;
 644                                 stmt.line = var.line;
 645                                 return;
 646                         }
 647                 }
 648         }
 649         else if(var.interface=="in")
 650         {
 651                 /* Try to link input variables in global scope with output variables from
 652                 previous stage. */
 653                 if(current_block==&stage->content && !var.linked_declaration && stage->previous)
 654                 {
 655                         const map<string, VariableDeclaration *> &prev_vars = stage->previous->content.variables;
 656                         map<string, VariableDeclaration *>::const_iterator i = prev_vars.find(var.name);
 657                         if(i!=prev_vars.end() && i->second->interface=="out")
 658                         {
 659                                 var.linked_declaration = i->second;
 660                                 i->second->linked_declaration = &var;
 661                         }
 662                 }
 663         }
 664
 665         TraversingVisitor::visit(var);
 666 }
 667
 668 void InterfaceGenerator::visit(InterfaceBlock &iface)
 669 {
 670         if(iface.interface=="in")
 671         {
 672                 /* Try to link input blocks with output blocks sharing the same block
 673                 name from previous stage. */
 674                 if(!iface.linked_block && stage->previous)
 675                 {
 676                         const map<string, InterfaceBlock *> &prev_blocks = stage->previous->interface_blocks;
 677                         map<string, InterfaceBlock *>::const_iterator i = prev_blocks.find("out"+iface.name);
 678                         if(i!=prev_blocks.end())
 679                         {
 680                                 iface.linked_block = i->second;
 681                                 i->second->linked_block = &iface;
 682                         }
 683                 }
 684         }
 685
 686         SetForScope<InterfaceBlock *> set_iface(iface_block, &iface);
 687         TraversingVisitor::visit(iface);
 688 }
 689
 690 void InterfaceGenerator::visit(FunctionDeclaration &func)
 691 {
 692         SetFlag set_scope(function_scope, true);
 693         // Skip parameters because they're not useful here
 694         func.body.visit(*this);
 695 }
 696
 697 void InterfaceGenerator::visit(Passthrough &pass)
 698 {
 699         vector<VariableDeclaration *> pass_vars;
 700
 701         // Pass through all input variables of this stage.
 702         for(map<string, VariableDeclaration *>::const_iterator i=stage->content.variables.begin(); i!=stage->content.variables.end(); ++i)
 703                 if(i->second->interface=="in")
 704                         pass_vars.push_back(i->second);
 705
 706         if(stage->previous)
 707         {
 708                 const map<string, VariableDeclaration *> &prev_vars = stage->previous->content.variables;
 709                 for(map<string, VariableDeclaration *>::const_iterator i=prev_vars.begin(); i!=prev_vars.end(); ++i)
 710                 {
 711                         if(i->second->interface!="out")
 712                                 continue;
 713
 714                         /* Pass through output variables from the previous stage, but only
 715                         those which are not already linked to an input here. */
 716                         if(!i->second->linked_declaration && generate_interface(*i->second, "in", i->second->name))
 717                                 pass_vars.push_back(i->second);
 718                 }
 719         }
 720
 721         if(stage->type==Stage::GEOMETRY)
 722         {
 723                 /* Special case for geometry shader: copy gl_Position from input to
 724                 output. */
 725                 InterfaceBlockReference *ref = new InterfaceBlockReference;
 726                 ref->name = "gl_in";
 727
 728                 BinaryExpression *subscript = new BinaryExpression;
 729                 subscript->left = ref;
 730                 subscript->oper = &Operator::get_operator("[", Operator::BINARY);
 731                 subscript->right = pass.subscript;
 732
 733                 MemberAccess *memacc = new MemberAccess;
 734                 memacc->left = subscript;
 735                 memacc->member = "gl_Position";
 736
 737                 insert_assignment("gl_Position", memacc);
 738         }
 739
 740         for(vector<VariableDeclaration *>::const_iterator i=pass_vars.begin(); i!=pass_vars.end(); ++i)
 741         {
 742                 string out_name = change_prefix((*i)->name, out_prefix);
 743                 generate_interface(**i, "out", out_name);
 744
 745                 VariableReference *ref = new VariableReference;
 746                 ref->name = (*i)->name;
 747                 if(pass.subscript)
 748                 {
 749                         BinaryExpression *subscript = new BinaryExpression;
 750                         subscript->left = ref;
 751                         subscript->oper = &Operator::get_operator("[", Operator::BINARY);
 752                         subscript->right = pass.subscript;
 753                         insert_assignment(out_name, subscript);
 754                 }
 755                 else
 756                         insert_assignment(out_name, ref);
 757         }
 758
 759         nodes_to_remove.insert(&pass);
 760 }
 761
 762 } // namespace SL
 763 } // namespace GL
 764 } // namespace Msp