source/glsl/generate.cpp

   1 #include <msp/core/algorithm.h>
   2 #include <msp/core/hash.h>
   3 #include <msp/core/raii.h>
   4 #include "generate.h"
   5
   6 using namespace std;
   7
   8 namespace Msp {
   9 namespace GL {
  10 namespace SL {
  11
  12 void ConstantIdAssigner::apply(Module &module, const Features &features)
  13 {
  14         for(Stage &s: module.stages)
  15                 s.content.visit(*this);
  16
  17         for(VariableDeclaration *v: auto_constants)
  18         {
  19                 unsigned id = hash32(v->name)%features.constant_id_range;
  20                 while(used_ids.count(id))
  21                         id = (id+1)%features.constant_id_range;
  22
  23                 auto i = find_member(v->layout->qualifiers, string("constant_id"), &Layout::Qualifier::name);
  24                 if(i!=v->layout->qualifiers.end())
  25                         i->value = id;
  26
  27                 used_ids.insert(id);
  28         }
  29 }
  30
  31 void ConstantIdAssigner::visit(VariableDeclaration &var)
  32 {
  33         if(var.layout)
  34         {
  35                 auto i = find_member(var.layout->qualifiers, string("constant_id"), &Layout::Qualifier::name);
  36                 if(i!=var.layout->qualifiers.end() && i->has_value)
  37                 {
  38                         if(i->value==-1)
  39                                 auto_constants.push_back(&var);
  40                         else
  41                                 used_ids.insert(i->value);
  42                 }
  43         }
  44 }
  45
  46
  47 string InterfaceGenerator::get_out_prefix(Stage::Type type)
  48 {
  49         if(type==Stage::VERTEX)
  50                 return "_vs_out_";
  51         else if(type==Stage::GEOMETRY)
  52                 return "_gs_out_";
  53         else
  54                 return string();
  55 }
  56
  57 void InterfaceGenerator::apply(Stage &s)
  58 {
  59         stage = &s;
  60         iface_target_block = &stage->content;
  61         if(stage->previous)
  62                 in_prefix = get_out_prefix(stage->previous->type);
  63         out_prefix = get_out_prefix(stage->type);
  64         s.content.visit(*this);
  65         NodeRemover().apply(s, nodes_to_remove);
  66 }
  67
  68 void InterfaceGenerator::visit(Block &block)
  69 {
  70         SetForScope<Block *> set_block(current_block, &block);
  71         for(auto i=block.body.begin(); i!=block.body.end(); ++i)
  72         {
  73                 assignment_insert_point = i;
  74                 if(&block==&stage->content)
  75                         iface_insert_point = i;
  76
  77                 (*i)->visit(*this);
  78         }
  79 }
  80
  81 string InterfaceGenerator::change_prefix(const string &name, const string &prefix) const
  82 {
  83         unsigned offset = (name.compare(0, in_prefix.size(), in_prefix) ? 0 : in_prefix.size());
  84         return prefix+name.substr(offset);
  85 }
  86
  87 VariableDeclaration *InterfaceGenerator::generate_interface(VariableDeclaration &var, const string &iface, const string &name)
  88 {
  89         if(stage->content.variables.count(name))
  90                 return 0;
  91
  92         if(stage->type==Stage::GEOMETRY && !copy_block && var.interface=="out" && var.array)
  93                 return 0;
  94
  95         VariableDeclaration* iface_var = new VariableDeclaration;
  96         iface_var->sampling = var.sampling;
  97         iface_var->interface = iface;
  98         iface_var->type = var.type;
  99         iface_var->name = name;
 100         /* Geometry shader inputs are always arrays.  But if we're bringing in an
 101         entire block, the array is on the block and not individual variables. */
 102         if(stage->type==Stage::GEOMETRY && !copy_block)
 103                 iface_var->array = ((var.array && var.interface!="in") || iface=="in");
 104         else
 105                 iface_var->array = var.array;
 106         if(iface_var->array)
 107                 iface_var->array_size = var.array_size;
 108         if(iface=="in")
 109         {
 110                 iface_var->layout = var.layout;
 111                 iface_var->linked_declaration = &var;
 112                 var.linked_declaration = iface_var;
 113         }
 114
 115         iface_target_block->body.insert(iface_insert_point, iface_var);
 116         iface_target_block->variables.insert(make_pair(name, iface_var));
 117         if(iface_target_block==&stage->content && iface=="in")
 118                 declared_inputs.push_back(iface_var);
 119
 120         return iface_var;
 121 }
 122
 123 InterfaceBlock *InterfaceGenerator::generate_interface(InterfaceBlock &out_block)
 124 {
 125         if(stage->interface_blocks.count("in "+out_block.block_name))
 126                 return 0;
 127
 128         InterfaceBlock *in_block = new InterfaceBlock;
 129         in_block->interface = "in";
 130         in_block->block_name = out_block.block_name;
 131         in_block->members = new Block;
 132         in_block->instance_name = out_block.instance_name;
 133         if(stage->type==Stage::GEOMETRY)
 134                 in_block->array = true;
 135         else
 136                 in_block->array = out_block.array;
 137         in_block->linked_block = &out_block;
 138         out_block.linked_block = in_block;
 139
 140         {
 141                 SetFlag set_copy(copy_block, true);
 142                 SetForScope<Block *> set_target(iface_target_block, in_block->members.get());
 143                 SetForScope<NodeList<Statement>::iterator> set_ins_pt(iface_insert_point, in_block->members->body.end());
 144                 if(out_block.struct_declaration)
 145                         out_block.struct_declaration->members.visit(*this);
 146                 else if(out_block.members)
 147                         out_block.members->visit(*this);
 148         }
 149
 150         iface_target_block->body.insert(iface_insert_point, in_block);
 151         stage->interface_blocks.insert(make_pair("in "+in_block->block_name, in_block));
 152         if(!in_block->instance_name.empty())
 153                 stage->interface_blocks.insert(make_pair(in_block->instance_name, in_block));
 154
 155         SetFlag set_scope(function_scope, false);
 156         SetForScope<Block *> set_block(current_block, &stage->content);
 157         in_block->visit(*this);
 158
 159         return in_block;
 160 }
 161
 162 ExpressionStatement &InterfaceGenerator::insert_assignment(const string &left, Expression *right)
 163 {
 164         Assignment *assign = new Assignment;
 165         VariableReference *ref = new VariableReference;
 166         ref->name = left;
 167         assign->left = ref;
 168         assign->oper = &Operator::get_operator("=", Operator::BINARY);
 169         assign->right = right;
 170
 171         ExpressionStatement *stmt = new ExpressionStatement;
 172         stmt->expression = assign;
 173         current_block->body.insert(assignment_insert_point, stmt);
 174         stmt->visit(*this);
 175
 176         return *stmt;
 177 }
 178
 179 void InterfaceGenerator::visit(VariableReference &var)
 180 {
 181         if(var.declaration || !stage->previous)
 182                 return;
 183         /* Don't pull a variable from previous stage if we just generated an output
 184         interface in this stage */
 185         if(stage->content.variables.count(var.name))
 186                 return;
 187
 188         const map<string, VariableDeclaration *> &prev_vars = stage->previous->content.variables;
 189         auto i = prev_vars.find(var.name);
 190         if(i==prev_vars.end() || i->second->interface!="out")
 191                 i = prev_vars.find(in_prefix+var.name);
 192         if(i!=prev_vars.end() && i->second->interface=="out")
 193         {
 194                 if(stage->type==Stage::GEOMETRY && i->second->array)
 195                         stage->diagnostics.push_back(Diagnostic(Diagnostic::WARN, var.source, var.line,
 196                                 format("Can't access '%s' through automatic interface because it's an array", var.name)));
 197                 else
 198                 {
 199                         generate_interface(*i->second, "in", i->second->name);
 200                         var.name = i->second->name;
 201                 }
 202                 return;
 203         }
 204
 205         const map<string, InterfaceBlock *> &prev_blocks = stage->previous->interface_blocks;
 206         auto j = prev_blocks.find(var.name);
 207         if(j!=prev_blocks.end() && j->second->interface=="out")
 208         {
 209                 generate_interface(*j->second);
 210                 /* Let VariableResolver convert the variable reference into an interface
 211                 block reference. */
 212                 return;
 213         }
 214
 215         for(const auto &kvp: prev_blocks)
 216                 if(kvp.second->instance_name.empty() && kvp.second->struct_declaration)
 217                 {
 218                         const map<string, VariableDeclaration *> &iface_vars = kvp.second->struct_declaration->members.variables;
 219                         i = iface_vars.find(var.name);
 220                         if(i!=iface_vars.end())
 221                         {
 222                                 generate_interface(*kvp.second);
 223                                 return;
 224                         }
 225                 }
 226 }
 227
 228 void InterfaceGenerator::visit(VariableDeclaration &var)
 229 {
 230         if(copy_block)
 231                 generate_interface(var, "in", var.name);
 232         else if(var.interface=="out")
 233         {
 234                 /* For output variables in function scope, generate a global interface
 235                 and replace the local declaration with an assignment. */
 236                 VariableDeclaration *out_var = 0;
 237                 if(function_scope && (out_var=generate_interface(var, "out", var.name)))
 238                 {
 239                         out_var->source = var.source;
 240                         out_var->line = var.line;
 241                         nodes_to_remove.insert(&var);
 242                         if(var.init_expression)
 243                         {
 244                                 ExpressionStatement &stmt = insert_assignment(var.name, var.init_expression->clone());
 245                                 stmt.source = var.source;
 246                                 stmt.line = var.line;
 247                                 return;
 248                         }
 249                 }
 250         }
 251         else if(var.interface=="in" && current_block==&stage->content)
 252         {
 253                 if(var.name.compare(0, 3, "gl_"))
 254                         declared_inputs.push_back(&var);
 255
 256                 /* Try to link input variables in global scope with output variables from
 257                 previous stage. */
 258                 if(!var.linked_declaration && stage->previous)
 259                 {
 260                         const map<string, VariableDeclaration *> &prev_vars = stage->previous->content.variables;
 261                         auto i = prev_vars.find(var.name);
 262                         if(i!=prev_vars.end() && i->second->interface=="out")
 263                         {
 264                                 var.linked_declaration = i->second;
 265                                 i->second->linked_declaration = &var;
 266                         }
 267                 }
 268         }
 269
 270         TraversingVisitor::visit(var);
 271 }
 272
 273 void InterfaceGenerator::visit(InterfaceBlock &iface)
 274 {
 275         if(iface.interface=="in")
 276         {
 277                 /* Try to link input blocks with output blocks sharing the same block
 278                 name from previous stage. */
 279                 if(!iface.linked_block && stage->previous)
 280                 {
 281                         const map<string, InterfaceBlock *> &prev_blocks = stage->previous->interface_blocks;
 282                         auto i = prev_blocks.find("out "+iface.block_name);
 283                         if(i!=prev_blocks.end())
 284                         {
 285                                 iface.linked_block = i->second;
 286                                 i->second->linked_block = &iface;
 287                         }
 288                 }
 289         }
 290
 291         TraversingVisitor::visit(iface);
 292 }
 293
 294 void InterfaceGenerator::visit(FunctionDeclaration &func)
 295 {
 296         SetFlag set_scope(function_scope, true);
 297         // Skip parameters because they're not useful here
 298         func.body.visit(*this);
 299 }
 300
 301 void InterfaceGenerator::visit(Passthrough &pass)
 302 {
 303         // Pass through all input variables declared so far.
 304         vector<VariableDeclaration *> pass_vars = declared_inputs;
 305
 306         if(stage->previous)
 307         {
 308                 for(const auto &kvp: stage->previous->content.variables)
 309                 {
 310                         if(kvp.second->interface!="out")
 311                                 continue;
 312
 313                         /* Pass through output variables from the previous stage, but only
 314                         those which are not already linked to an input here. */
 315                         if(!kvp.second->linked_declaration && generate_interface(*kvp.second, "in", kvp.second->name))
 316                                 pass_vars.push_back(kvp.second);
 317                 }
 318         }
 319
 320         if(stage->type==Stage::GEOMETRY)
 321         {
 322                 /* Special case for geometry shader: copy gl_Position from input to
 323                 output. */
 324                 InterfaceBlockReference *ref = new InterfaceBlockReference;
 325                 ref->name = "gl_in";
 326
 327                 BinaryExpression *subscript = new BinaryExpression;
 328                 subscript->left = ref;
 329                 subscript->oper = &Operator::get_operator("[", Operator::BINARY);
 330                 subscript->right = pass.subscript;
 331
 332                 MemberAccess *memacc = new MemberAccess;
 333                 memacc->left = subscript;
 334                 memacc->member = "gl_Position";
 335
 336                 insert_assignment("gl_Position", memacc);
 337         }
 338
 339         for(VariableDeclaration *v: pass_vars)
 340         {
 341                 string out_name = change_prefix(v->name, out_prefix);
 342                 generate_interface(*v, "out", out_name);
 343
 344                 VariableReference *ref = new VariableReference;
 345                 ref->name = v->name;
 346                 if(pass.subscript)
 347                 {
 348                         BinaryExpression *subscript = new BinaryExpression;
 349                         subscript->left = ref;
 350                         subscript->oper = &Operator::get_operator("[", Operator::BINARY);
 351                         subscript->right = pass.subscript;
 352                         insert_assignment(out_name, subscript);
 353                 }
 354                 else
 355                         insert_assignment(out_name, ref);
 356         }
 357
 358         nodes_to_remove.insert(&pass);
 359 }
 360
 361 } // namespace SL
 362 } // namespace GL
 363 } // namespace Msp