kc3-lang/angle/src/compiler/BuiltInFunctionEmulator.cpp

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• Author : zmo@google.com
  Date : 2011-09-16 00:53:26
  Hash : a3b4ab4c
  Message : Further work on the function emulation. This is to work around driver bugs. We added more functions, and removed some unnecessary ones. Remove the function group because we have flags for each function now. Use more macros instead of functions. Don't emit global precision because that will affect all later code. ANGLEBUG=196 TEST=build and test on Mac ATI/NVIDIA, fixes the failing webgl glsl conformance tests. Review URL: http://codereview.appspot.com/5011053 git-svn-id: https://angleproject.googlecode.com/svn/trunk@754 736b8ea6-26fd-11df-bfd4-992fa37f6226

• src/compiler/BuiltInFunctionEmulator.cpp

• //
  // Copyright (c) 2002-2011 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.
  //
  
  #include "compiler/BuiltInFunctionEmulator.h"
  
  #include "compiler/SymbolTable.h"
  
  namespace {
  
  // we use macros here instead of function definitions to work around more GLSL
  // compiler bugs, in particular on NVIDIA hardware on Mac OSX. Macros are
  // problematic because if the argument has side-effects they will be repeatedly
  // evaluated. This is unlikely to show up in real shaders, but is something to
  // consider.
  const char* kFunctionEmulationVertexSource[] = {
      "#error no emulation for atan(float, float)",
      "vec2 webgl_atan_emu(vec2 y, vec2 x) { return vec2(atan(y[0], x[0]), atan(y[1], x[1])); }",
      "vec3 webgl_atan_emu(vec3 y, vec3 x) { return vec3(atan(y[0], x[0]), atan(y[1], x[1]), atan(y[2], x[2])); }",
      "vec4 webgl_atan_emu(vec4 y, vec4 x) { return vec4(atan(y[0], x[0]), atan(y[1], x[1]), atan(y[2], x[2]), atan(y[3], x[3])); }",
  
      "#error no emulation for cos(float)",
      "#error no emulation for cos(vec2)",
      "#error no emulation for cos(vec3)",
      "#error no emulation for cos(vec4)",
  
      "#define webgl_distance_emu(x, y) ((x) >= (y) ? (x) - (y) : (y) - (x))",
      "#error no emulation for distance(vec2, vec2)",
      "#error no emulation for distance(vec3, vec3)",
      "#error no emulation for distance(vec4, vec4)",
  
      "#define webgl_dot_emu(x, y) ((x) * (y))",
      "#error no emulation for dot(vec2, vec2)",
      "#error no emulation for dot(vec3, vec3)",
      "#error no emulation for dot(vec4, vec4)",
  
      "#define webgl_length_emu(x) ((x) >= 0.0 ? (x) : -(x))",
      "#error no emulation for length(vec2)",
      "#error no emulation for length(vec3)",
      "#error no emulation for length(vec4)",
  
      "#error no emulation for mod(float, float)",
      "vec2 webgl_mod_emu(vec2 x, vec2 y) { return vec2(mod(x[0], y[0]), mod(x[1], y[1])); }",
      "vec3 webgl_mod_emu(vec3 x, vec3 y) { return vec3(mod(x[0], y[0]), mod(x[1], y[1]), mod(x[2], y[2])); }",
      "vec4 webgl_mod_emu(vec4 x, vec4 y) { return vec4(mod(x[0], y[0]), mod(x[1], y[1]), mod(x[2], y[2]), mod(x[3], y[3])); }",
  
      "#define webgl_normalize_emu(x) ((x) == 0.0 ? 0.0 : ((x) > 0.0 ? 1.0 : -1.0))",
      "#error no emulation for normalize(vec2)",
      "#error no emulation for normalize(vec3)",
      "#error no emulation for normalize(vec4)",
  
      "#define webgl_reflect_emu(I, N) ((I) - 2.0 * (N) * (I) * (N))",
      "#error no emulation for reflect(vec2, vec2)",
      "#error no emulation for reflect(vec3, vec3)",
      "#error no emulation for reflect(vec4, vec4)"
  };
  
  const char* kFunctionEmulationFragmentSource[] = {
      "#error no emulation for atan(float, float)",
      "#error no emulation for atan(vec2, vec2)",
      "#error no emulation for atan(vec3, vec3)",
      "#error no emulation for atan(vec4, vec4)",
  
      "webgl_emu_precision float webgl_cos_emu(webgl_emu_precision float a) { return cos(a); }",
      "webgl_emu_precision vec2 webgl_cos_emu(webgl_emu_precision vec2 a) { return cos(a); }",
      "webgl_emu_precision vec3 webgl_cos_emu(webgl_emu_precision vec3 a) { return cos(a); }",
      "webgl_emu_precision vec4 webgl_cos_emu(webgl_emu_precision vec4 a) { return cos(a); }",
  
      "#error no emulation for distance(float, float)",
      "#error no emulation for distance(vec2, vec2)",
      "#error no emulation for distance(vec3, vec3)",
      "#error no emulation for distance(vec4, vec4)",
  
      "#error no emulation for dot(float, float)",
      "#error no emulation for dot(vec2, vec2)",
      "#error no emulation for dot(vec3, vec3)",
      "#error no emulation for dot(vec4, vec4)",
  
      "#error no emulation for length(float)",
      "#error no emulation for length(vec2)",
      "#error no emulation for length(vec3)",
      "#error no emulation for length(vec4)",
  
      "#error no emulation for mod(float, float)",
      "#error no emulation for mod(vec2, vec2)",
      "#error no emulation for mod(vec3, vec3)",
      "#error no emulation for mod(vec4, vec4)",
  
      "#error no emulation for normalize(float)",
      "#error no emulation for normalize(vec2)",
      "#error no emulation for normalize(vec3)",
      "#error no emulation for normalize(vec4)",
  
      "#error no emulation for reflect(float, float)",
      "#error no emulation for reflect(vec2, vec2)",
      "#error no emulation for reflect(vec3, vec3)",
      "#error no emulation for reflect(vec4, vec4)"
  };
  
  const bool kFunctionEmulationVertexMask[] = {
  #if defined(__APPLE__)
      // Work around ATI driver bugs in Mac.
      false, // TFunctionAtan1_1
      false, // TFunctionAtan2_2
      false, // TFunctionAtan3_3
      false, // TFunctionAtan4_4
      false, // TFunctionCos1
      false, // TFunctionCos2
      false, // TFunctionCos3
      false, // TFunctionCos4
      true,  // TFunctionDistance1_1
      false, // TFunctionDistance2_2
      false, // TFunctionDistance3_3
      false, // TFunctionDistance4_4
      true,  // TFunctionDot1_1
      false, // TFunctionDot2_2
      false, // TFunctionDot3_3
      false, // TFunctionDot4_4
      true,  // TFunctionLength1
      false, // TFunctionLength2
      false, // TFunctionLength3
      false, // TFunctionLength4
      false, // TFunctionMod1_1
      false, // TFunctionMod2_2
      false, // TFunctionMod3_3
      false, // TFunctionMod4_4
      true,  // TFunctionNormalize1
      false, // TFunctionNormalize2
      false, // TFunctionNormalize3
      false, // TFunctionNormalize4
      true,  // TFunctionReflect1_1
      false, // TFunctionReflect2_2
      false, // TFunctionReflect3_3
      false, // TFunctionReflect4_4
  #else
      // Work around D3D driver bug in Win.
      false, // TFunctionAtan1_1
      true,  // TFunctionAtan2_2
      true,  // TFunctionAtan3_3
      true,  // TFunctionAtan4_4
      false, // TFunctionCos1
      false, // TFunctionCos2
      false, // TFunctionCos3
      false, // TFunctionCos4
      false, // TFunctionDistance1_1
      false, // TFunctionDistance2_2
      false, // TFunctionDistance3_3
      false, // TFunctionDistance4_4
      false, // TFunctionDot1_1
      false, // TFunctionDot2_2
      false, // TFunctionDot3_3
      false, // TFunctionDot4_4
      false, // TFunctionLength1
      false, // TFunctionLength2
      false, // TFunctionLength3
      false, // TFunctionLength4
      false, // TFunctionMod1_1
      true,  // TFunctionMod2_2
      true,  // TFunctionMod3_3
      true,  // TFunctionMod4_4
      false, // TFunctionNormalize1
      false, // TFunctionNormalize2
      false, // TFunctionNormalize3
      false, // TFunctionNormalize4
      false, // TFunctionReflect1_1
      false, // TFunctionReflect2_2
      false, // TFunctionReflect3_3
      false, // TFunctionReflect4_4
  #endif
      false  // TFunctionUnknown
  };
  
  const bool kFunctionEmulationFragmentMask[] = {
      false, // TFunctionAtan1_1
      false, // TFunctionAtan2_2
      false, // TFunctionAtan3_3
      false, // TFunctionAtan4_4
  #if defined(__APPLE__)
      // Work around a ATI driver bug in Mac that causes crashes.
      true,  // TFunctionCos1
      true,  // TFunctionCos2
      true,  // TFunctionCos3
      true,  // TFunctionCos4
  #else
      false, // TFunctionCos1
      false, // TFunctionCos2
      false, // TFunctionCos3
      false, // TFunctionCos4
  #endif
      false, // TFunctionDistance1_1
      false, // TFunctionDistance2_2
      false, // TFunctionDistance3_3
      false, // TFunctionDistance4_4
      false, // TFunctionDot1_1
      false, // TFunctionDot2_2
      false, // TFunctionDot3_3
      false, // TFunctionDot4_4
      false, // TFunctionLength1
      false, // TFunctionLength2
      false, // TFunctionLength3
      false, // TFunctionLength4
      false, // TFunctionMod1_1
      false, // TFunctionMod2_2
      false, // TFunctionMod3_3
      false, // TFunctionMod4_4
      false, // TFunctionNormalize1
      false, // TFunctionNormalize2
      false, // TFunctionNormalize3
      false, // TFunctionNormalize4
      false, // TFunctionReflect1_1
      false, // TFunctionReflect2_2
      false, // TFunctionReflect3_3
      false, // TFunctionReflect4_4
      false  // TFunctionUnknown
  };
  
  class BuiltInFunctionEmulationMarker : public TIntermTraverser {
  public:
      BuiltInFunctionEmulationMarker(BuiltInFunctionEmulator& emulator)
          : mEmulator(emulator)
      {
      }
  
      virtual bool visitUnary(Visit visit, TIntermUnary* node)
      {
          if (visit == PreVisit) {
              bool needToEmulate = mEmulator.SetFunctionCalled(
                  node->getOp(), node->getOperand()->getType());
              if (needToEmulate)
                  node->setUseEmulatedFunction();
          }
          return true;
      }
  
      virtual bool visitAggregate(Visit visit, TIntermAggregate* node)
      {
          if (visit == PreVisit) {
              // Here we handle all the built-in functions instead of the ones we
              // currently identified as problematic.
              switch (node->getOp()) {
                  case EOpLessThan:
                  case EOpGreaterThan:
                  case EOpLessThanEqual:
                  case EOpGreaterThanEqual:
                  case EOpVectorEqual:
                  case EOpVectorNotEqual:
                  case EOpMod:
                  case EOpPow:
                  case EOpAtan:
                  case EOpMin:
                  case EOpMax:
                  case EOpClamp:
                  case EOpMix:
                  case EOpStep:
                  case EOpSmoothStep:
                  case EOpDistance:
                  case EOpDot:
                  case EOpCross:
                  case EOpFaceForward:
                  case EOpReflect:
                  case EOpRefract:
                  case EOpMul:
                      break;
                  default:
                      return true;
              };
              const TIntermSequence& sequence = node->getSequence();
              // Right now we only handle built-in functions with two parameters.
              if (sequence.size() != 2)
                  return true;
              TIntermTyped* param1 = sequence[0]->getAsTyped();
              TIntermTyped* param2 = sequence[1]->getAsTyped();
              if (!param1 || !param2)
                  return true;
              bool needToEmulate = mEmulator.SetFunctionCalled(
                  node->getOp(), param1->getType(), param2->getType());
              if (needToEmulate)
                  node->setUseEmulatedFunction();
          }
          return true;
      }
  
  private:
      BuiltInFunctionEmulator& mEmulator;
  };
  
  }  // anonymous namepsace
  
  BuiltInFunctionEmulator::BuiltInFunctionEmulator(ShShaderType shaderType)
  {
      if (shaderType == SH_FRAGMENT_SHADER) {
          mFunctionMask = kFunctionEmulationFragmentMask;
          mFunctionSource = kFunctionEmulationFragmentSource;
      } else {
          mFunctionMask = kFunctionEmulationVertexMask;
          mFunctionSource = kFunctionEmulationVertexSource;
      }
  }
  
  bool BuiltInFunctionEmulator::SetFunctionCalled(
      TOperator op, const TType& param)
  {
      TBuiltInFunction function = IdentifyFunction(op, param);
      return SetFunctionCalled(function);
  }
  
  bool BuiltInFunctionEmulator::SetFunctionCalled(
      TOperator op, const TType& param1, const TType& param2)
  {
      TBuiltInFunction function = IdentifyFunction(op, param1, param2);
      return SetFunctionCalled(function);
  }
  
  bool BuiltInFunctionEmulator::SetFunctionCalled(
      BuiltInFunctionEmulator::TBuiltInFunction function) {
      if (function == TFunctionUnknown || mFunctionMask[function] == false)
          return false;
      for (size_t i = 0; i < mFunctions.size(); ++i) {
          if (mFunctions[i] == function)
              return true;
      }
      mFunctions.push_back(function);
      return true;
  }
  
  void BuiltInFunctionEmulator::OutputEmulatedFunctionDefinition(
      TInfoSinkBase& out, bool withPrecision) const
  {
      if (mFunctions.size() == 0)
          return;
      out << "// BEGIN: Generated code for built-in function emulation\n\n";
      if (withPrecision) {
          out << "#if defined(GL_FRAGMENT_PRECISION_HIGH)\n"
              << "#define webgl_emulation_precision highp\n"
              << "#else\n"
              << "#define webgl_emulation_precision mediump\n"
              << "#endif\n\n";
      } else {
          out << "#define webgl_emulation_precision\n\n";
      }
      for (size_t i = 0; i < mFunctions.size(); ++i) {
          out << mFunctionSource[mFunctions[i]] << "\n\n";
      }
      out << "// END: Generated code for built-in function emulation\n\n";
  }
  
  BuiltInFunctionEmulator::TBuiltInFunction
  BuiltInFunctionEmulator::IdentifyFunction(
      TOperator op, const TType& param)
  {
      if (param.getNominalSize() > 4)
          return TFunctionUnknown;
      unsigned int function = TFunctionUnknown;
      switch (op) {
          case EOpCos:
              function = TFunctionCos1;
              break;
          case EOpLength:
              function = TFunctionLength1;
              break;
          case EOpNormalize:
              function = TFunctionNormalize1;
              break;
          default:
              break;
      }
      if (function == TFunctionUnknown)
          return TFunctionUnknown;
      if (param.isVector())
          function += param.getNominalSize() - 1;
      return static_cast<TBuiltInFunction>(function);
  }
  
  BuiltInFunctionEmulator::TBuiltInFunction
  BuiltInFunctionEmulator::IdentifyFunction(
      TOperator op, const TType& param1, const TType& param2)
  {
      // Right now for all the emulated functions with two parameters, the two
      // parameters have the same type.
      if (param1.isVector() != param2.isVector() ||
          param1.getNominalSize() != param2.getNominalSize() ||
          param1.getNominalSize() > 4)
          return TFunctionUnknown;
  
      unsigned int function = TFunctionUnknown;
      switch (op) {
          case EOpAtan:
              function = TFunctionAtan1_1;
              break;
          case EOpDistance:
              function = TFunctionDistance1_1;
              break;
          case EOpDot:
              function = TFunctionDot1_1;
              break;
          case EOpMod:
              function = TFunctionMod1_1;
              break;
          case EOpReflect:
              function = TFunctionReflect1_1;
              break;
          default:
              break;
      }
      if (function == TFunctionUnknown)
          return TFunctionUnknown;
      if (param1.isVector())
          function += param1.getNominalSize() - 1;
      return static_cast<TBuiltInFunction>(function);
  }
  
  void BuiltInFunctionEmulator::MarkBuiltInFunctionsForEmulation(
      TIntermNode* root)
  {
      ASSERT(root);
  
      BuiltInFunctionEmulationMarker marker(*this);
      root->traverse(&marker);
  }
  
  void BuiltInFunctionEmulator::Cleanup()
  {
      mFunctions.clear();
  }
  
  //static
  TString BuiltInFunctionEmulator::GetEmulatedFunctionName(
      const TString& name)
  {
      ASSERT(name[name.length() - 1] == '(');
      return "webgl_" + name.substr(0, name.length() - 1) + "_emu(";
  }