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

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• Hash : a07b4213
  Author :
  Date : 2018-03-22T16:13:13
  

  Move AST transformations to a subdirectory
  
  Move AST transformations to compiler/translator/tree_ops.
  
  BUG=angleproject:2409
  TEST=angle_unittests
  
  Change-Id: I9c620e98707d22d005da6192fe7d1b4e8030aadd
  Reviewed-on: https://chromium-review.googlesource.com/975550
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

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• src/compiler/translator/tree_ops/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/tree_ops/ClampFragDepth.h"
  
  #include "compiler/translator/ImmutableString.h"
  #include "compiler/translator/SymbolTable.h"
  #include "compiler/translator/tree_util/BuiltIn_autogen.h"
  #include "compiler/translator/tree_util/FindSymbolNode.h"
  #include "compiler/translator/tree_util/IntermNode_util.h"
  #include "compiler/translator/tree_util/RunAtTheEndOfShader.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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