kc3-lang/angle/src/compiler/translator/ClampFragDepth.cpp

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• Hash : 391bda23
  Author :
  Date : 2018-02-23T11:43:14
  

  Generate code for initializing built-in variables
  
  gen_builtin_symbols.py now generates code for initializing built-in
  variable symbols as well. Some of the variable symbols are static, but
  some of them also get initialized dynamically based on values in
  ShBuiltInResources.
  
  The static symbols have get functions in a header file so they can be
  referenced from AST traversers as well without doing a lookup.
  
  BUG=angleproject:2267
  TEST=angle_unittests, angle_end2end_tests
  
  Change-Id: Ida7f3aeb06d2bce0f737f1483b1bd5833aeddd2e
  Reviewed-on: https://chromium-review.googlesource.com/911768
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

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• src/compiler/translator/ClampFragDepth.cpp

• //
  // Copyright (c) 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.
  //
  // ClampFragDepth.cpp: Limit the value that is written to gl_FragDepth to the range [0.0, 1.0].
  // The clamping is run at the very end of shader execution, and is only performed if the shader
  // statically accesses gl_FragDepth.
  //
  
  #include "compiler/translator/ClampFragDepth.h"
  
  #include "compiler/translator/BuiltIn_autogen.h"
  #include "compiler/translator/FindSymbolNode.h"
  #include "compiler/translator/ImmutableString.h"
  #include "compiler/translator/IntermNode_util.h"
  #include "compiler/translator/RunAtTheEndOfShader.h"
  #include "compiler/translator/SymbolTable.h"
  
  namespace sh
  {
  
  void ClampFragDepth(TIntermBlock *root, TSymbolTable *symbolTable)
  {
      // Only clamp gl_FragDepth if it's used in the shader.
      if (!FindSymbolNode(root, ImmutableString("gl_FragDepth")))
      {
          return;
      }
  
      TIntermSymbol *fragDepthNode = new TIntermSymbol(BuiltInVariable::gl_FragDepth());
  
      TIntermTyped *minFragDepthNode = CreateZeroNode(TType(EbtFloat, EbpHigh, EvqConst));
  
      TConstantUnion *maxFragDepthConstant = new TConstantUnion();
      maxFragDepthConstant->setFConst(1.0);
      TIntermConstantUnion *maxFragDepthNode =
          new TIntermConstantUnion(maxFragDepthConstant, TType(EbtFloat, EbpHigh, EvqConst));
  
      // clamp(gl_FragDepth, 0.0, 1.0)
      TIntermSequence *clampArguments = new TIntermSequence();
      clampArguments->push_back(fragDepthNode->deepCopy());
      clampArguments->push_back(minFragDepthNode);
      clampArguments->push_back(maxFragDepthNode);
      TIntermTyped *clampedFragDepth =
          CreateBuiltInFunctionCallNode("clamp", clampArguments, *symbolTable, 100);
  
      // gl_FragDepth = clamp(gl_FragDepth, 0.0, 1.0)
      TIntermBinary *assignFragDepth = new TIntermBinary(EOpAssign, fragDepthNode, clampedFragDepth);
  
      RunAtTheEndOfShader(root, assignFragDepth, symbolTable);
  }
  
  }  // namespace sh
  

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