kc3-lang/angle/src/compiler/translator/tree_ops/DeclareAndInitBuiltinsForInstancedMultiview.cpp

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• Hash : 6f80f0f0
  Author :
  Date : 2022-08-06T02:29:19
  

  Translator: Clean up the compile flag passing interface
  
  Historically, compile flags were sent to the translator as a bitmask.
  Recently, we were getting close to running out of bits.  Additionally,
  direct-to-metal work had started to introduce constants to be passed to
  the translator, which were misplaced in ShBuiltInResources and Caps.
  Recent work on Pixel Local Storage adds even more constants, aggravating
  the situation.
  
  In this change, the interface to passing compile flags is reworked.  A
  struct is passed (instead of a bitmask) that has one bit for each flag.
  This can be indefinitely extended.  Additionally, the constants needed
  by metal and PLS are also placed in this struct.  In turn, the backends
  can set these options directly, and don't have to hack them into Caps to
  further get hacked into ShBuiltInResources.
  
  Bug: angleproject:7559
  Change-Id: If93f1e1b8818ad3a0ac708ab04ab93b4b397d114
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3812562
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com>
  Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com>
  Auto-Submit: Shahbaz Youssefi <syoussefi@chromium.org>
  

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• src/compiler/translator/tree_ops/DeclareAndInitBuiltinsForInstancedMultiview.cpp

• //
  // Copyright 2017 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // Applies the necessary AST transformations to support multiview rendering through instancing.
  // Check the header file For more information.
  //
  
  #include "compiler/translator/tree_ops/DeclareAndInitBuiltinsForInstancedMultiview.h"
  
  #include "compiler/translator/Compiler.h"
  #include "compiler/translator/StaticType.h"
  #include "compiler/translator/SymbolTable.h"
  #include "compiler/translator/tree_ops/InitializeVariables.h"
  #include "compiler/translator/tree_util/BuiltIn.h"
  #include "compiler/translator/tree_util/FindMain.h"
  #include "compiler/translator/tree_util/IntermNode_util.h"
  #include "compiler/translator/tree_util/IntermTraverse.h"
  #include "compiler/translator/tree_util/ReplaceVariable.h"
  #include "compiler/translator/util.h"
  
  namespace sh
  {
  
  namespace
  {
  
  constexpr const ImmutableString kViewIDVariableName("ViewID_OVR");
  constexpr const ImmutableString kInstanceIDVariableName("InstanceID");
  constexpr const ImmutableString kMultiviewBaseViewLayerIndexVariableName(
      "multiviewBaseViewLayerIndex");
  
  // Adds the InstanceID and ViewID_OVR initializers to the end of the initializers' sequence.
  void InitializeViewIDAndInstanceID(const TVariable *viewID,
                                     const TVariable *instanceID,
                                     unsigned numberOfViews,
                                     const TSymbolTable &symbolTable,
                                     TIntermSequence *initializers)
  {
      // Create an unsigned numberOfViews node.
      TConstantUnion *numberOfViewsUnsignedConstant = new TConstantUnion();
      numberOfViewsUnsignedConstant->setUConst(numberOfViews);
      TIntermConstantUnion *numberOfViewsUint =
          new TIntermConstantUnion(numberOfViewsUnsignedConstant, TType(EbtUInt, EbpLow, EvqConst));
  
      // Create a uint(gl_InstanceID) node.
      TIntermSequence glInstanceIDSymbolCastArguments;
      glInstanceIDSymbolCastArguments.push_back(new TIntermSymbol(BuiltInVariable::gl_InstanceID()));
      TIntermAggregate *glInstanceIDAsUint = TIntermAggregate::CreateConstructor(
          TType(EbtUInt, EbpHigh, EvqTemporary), &glInstanceIDSymbolCastArguments);
  
      // Create a uint(gl_InstanceID) / numberOfViews node.
      TIntermBinary *normalizedInstanceID =
          new TIntermBinary(EOpDiv, glInstanceIDAsUint, numberOfViewsUint);
  
      // Create an int(uint(gl_InstanceID) / numberOfViews) node.
      TIntermSequence normalizedInstanceIDCastArguments;
      normalizedInstanceIDCastArguments.push_back(normalizedInstanceID);
      TIntermAggregate *normalizedInstanceIDAsInt = TIntermAggregate::CreateConstructor(
          TType(EbtInt, EbpHigh, EvqTemporary), &normalizedInstanceIDCastArguments);
  
      // Create an InstanceID = int(uint(gl_InstanceID) / numberOfViews) node.
      TIntermBinary *instanceIDInitializer =
          new TIntermBinary(EOpAssign, new TIntermSymbol(instanceID), normalizedInstanceIDAsInt);
      initializers->push_back(instanceIDInitializer);
  
      // Create a uint(gl_InstanceID) % numberOfViews node.
      TIntermBinary *normalizedViewID =
          new TIntermBinary(EOpIMod, glInstanceIDAsUint->deepCopy(), numberOfViewsUint->deepCopy());
  
      // Create a ViewID_OVR = uint(gl_InstanceID) % numberOfViews node.
      TIntermBinary *viewIDInitializer =
          new TIntermBinary(EOpAssign, new TIntermSymbol(viewID), normalizedViewID);
      initializers->push_back(viewIDInitializer);
  }
  
  // Adds a branch to write int(ViewID_OVR) to either gl_ViewportIndex or gl_Layer. The branch is
  // added to the end of the initializers' sequence.
  void SelectViewIndexInVertexShader(const TVariable *viewID,
                                     const TVariable *multiviewBaseViewLayerIndex,
                                     TIntermSequence *initializers,
                                     const TSymbolTable &symbolTable)
  {
      // Create an int(ViewID_OVR) node.
      TIntermSequence viewIDSymbolCastArguments;
      viewIDSymbolCastArguments.push_back(new TIntermSymbol(viewID));
      TIntermAggregate *viewIDAsInt = TIntermAggregate::CreateConstructor(
          TType(EbtInt, EbpHigh, EvqTemporary), &viewIDSymbolCastArguments);
  
      // Create a gl_ViewportIndex node.
      TIntermSymbol *viewportIndexSymbol = new TIntermSymbol(BuiltInVariable::gl_ViewportIndex());
  
      // Create a { gl_ViewportIndex = int(ViewID_OVR) } node.
      TIntermBlock *viewportIndexInitializerInBlock = new TIntermBlock();
      viewportIndexInitializerInBlock->appendStatement(
          new TIntermBinary(EOpAssign, viewportIndexSymbol, viewIDAsInt));
  
      // Create a gl_Layer node.
      TIntermSymbol *layerSymbol = new TIntermSymbol(BuiltInVariable::gl_LayerVS());
  
      // Create an int(ViewID_OVR) + multiviewBaseViewLayerIndex node
      TIntermBinary *sumOfViewIDAndBaseViewIndex = new TIntermBinary(
          EOpAdd, viewIDAsInt->deepCopy(), new TIntermSymbol(multiviewBaseViewLayerIndex));
  
      // Create a { gl_Layer = int(ViewID_OVR) + multiviewBaseViewLayerIndex } node.
      TIntermBlock *layerInitializerInBlock = new TIntermBlock();
      layerInitializerInBlock->appendStatement(
          new TIntermBinary(EOpAssign, layerSymbol, sumOfViewIDAndBaseViewIndex));
  
      // Create a node to compare whether the base view index uniform is less than zero.
      TIntermBinary *multiviewBaseViewLayerIndexZeroComparison =
          new TIntermBinary(EOpLessThan, new TIntermSymbol(multiviewBaseViewLayerIndex),
                            CreateZeroNode(TType(EbtInt, EbpHigh, EvqConst)));
  
      // Create an if-else statement to select the code path.
      TIntermIfElse *multiviewBranch =
          new TIntermIfElse(multiviewBaseViewLayerIndexZeroComparison,
                            viewportIndexInitializerInBlock, layerInitializerInBlock);
  
      initializers->push_back(multiviewBranch);
  }
  
  }  // namespace
  
  bool DeclareAndInitBuiltinsForInstancedMultiview(TCompiler *compiler,
                                                   TIntermBlock *root,
                                                   unsigned numberOfViews,
                                                   GLenum shaderType,
                                                   const ShCompileOptions &compileOptions,
                                                   ShShaderOutput shaderOutput,
                                                   TSymbolTable *symbolTable)
  {
      ASSERT(shaderType == GL_VERTEX_SHADER || shaderType == GL_FRAGMENT_SHADER);
  
      TQualifier viewIDQualifier = (shaderType == GL_VERTEX_SHADER) ? EvqFlatOut : EvqFlatIn;
      const TVariable *viewID =
          new TVariable(symbolTable, kViewIDVariableName,
                        new TType(EbtUInt, EbpHigh, viewIDQualifier), SymbolType::AngleInternal);
  
      DeclareGlobalVariable(root, viewID);
      if (!ReplaceVariable(compiler, root, BuiltInVariable::gl_ViewID_OVR(), viewID))
      {
          return false;
      }
      if (shaderType == GL_VERTEX_SHADER)
      {
          // Replacing gl_InstanceID with InstanceID should happen before adding the initializers of
          // InstanceID and ViewID.
          const TType *instanceIDVariableType = StaticType::Get<EbtInt, EbpHigh, EvqGlobal, 1, 1>();
          const TVariable *instanceID =
              new TVariable(symbolTable, kInstanceIDVariableName, instanceIDVariableType,
                            SymbolType::AngleInternal);
          DeclareGlobalVariable(root, instanceID);
          if (!ReplaceVariable(compiler, root, BuiltInVariable::gl_InstanceID(), instanceID))
          {
              return false;
          }
  
          TIntermSequence initializers;
          InitializeViewIDAndInstanceID(viewID, instanceID, numberOfViews, *symbolTable,
                                        &initializers);
  
          // The AST transformation which adds the expression to select the viewport index should
          // be done only for the GLSL and ESSL output.
          const bool selectView = compileOptions.selectViewInNvGLSLVertexShader;
          // Assert that if the view is selected in the vertex shader, then the output is
          // either GLSL or ESSL.
          ASSERT(!selectView || IsOutputGLSL(shaderOutput) || IsOutputESSL(shaderOutput));
          if (selectView)
          {
              // Add a uniform to switch between side-by-side and layered rendering.
              const TType *baseLayerIndexVariableType =
                  StaticType::Get<EbtInt, EbpHigh, EvqUniform, 1, 1>();
              const TVariable *multiviewBaseViewLayerIndex =
                  new TVariable(symbolTable, kMultiviewBaseViewLayerIndexVariableName,
                                baseLayerIndexVariableType, SymbolType::AngleInternal);
              DeclareGlobalVariable(root, multiviewBaseViewLayerIndex);
  
              // Setting a value to gl_ViewportIndex or gl_Layer should happen after ViewID_OVR's
              // initialization.
              SelectViewIndexInVertexShader(viewID, multiviewBaseViewLayerIndex, &initializers,
                                            *symbolTable);
          }
  
          // Insert initializers at the beginning of main().
          TIntermBlock *initializersBlock = new TIntermBlock();
          initializersBlock->getSequence()->swap(initializers);
          TIntermBlock *mainBody = FindMainBody(root);
          mainBody->getSequence()->insert(mainBody->getSequence()->begin(), initializersBlock);
      }
  
      return compiler->validateAST(root);
  }
  
  }  // namespace sh
  

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