kc3-lang/angle/samples/shader_translator

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• Author : Martin Radev
  Date : 2017-07-07 18:52:09
  Hash : c39a19aa
  Message : Select viewport index in the GLSL/ESSL vertex shader The patch enables viewport selection for multiview rendering in the GLSL/ESSL vertex shader through the use of the GL_NV_viewport_array2 extension. The AST is modified only for GLSL and ESSL to include the viewport selection expression after ViewID_OVR's initialization. BUG=angleproject:2062 TEST=angle_unittests Change-Id: Iee05bb5a4b687ed53ddbdd466f1572227b1f0cde

• shader_translator.cpp

• //
  // Copyright (c) 2002-2013 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 "GLSLANG/ShaderLang.h"
  
  #include <assert.h>
  #include <math.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sstream>
  #include <vector>
  #include "angle_gl.h"
  
  //
  // Return codes from main.
  //
  enum TFailCode
  {
      ESuccess = 0,
      EFailUsage,
      EFailCompile,
      EFailCompilerCreate,
  };
  
  static void usage();
  static sh::GLenum FindShaderType(const char *fileName);
  static bool CompileFile(char *fileName, ShHandle compiler, ShCompileOptions compileOptions);
  static void LogMsg(const char *msg, const char *name, const int num, const char *logName);
  static void PrintVariable(const std::string &prefix, size_t index, const sh::ShaderVariable &var);
  static void PrintActiveVariables(ShHandle compiler);
  
  // If NUM_SOURCE_STRINGS is set to a value > 1, the input file data is
  // broken into that many chunks. This will affect file/line numbering in
  // the preprocessor.
  const unsigned int NUM_SOURCE_STRINGS = 1;
  typedef std::vector<char *> ShaderSource;
  static bool ReadShaderSource(const char *fileName, ShaderSource &source);
  static void FreeShaderSource(ShaderSource &source);
  
  static bool ParseGLSLOutputVersion(const std::string &, ShShaderOutput *outResult);
  static bool ParseIntValue(const std::string &, int emptyDefault, int *outValue);
  
  //
  // Set up the per compile resources
  //
  void GenerateResources(ShBuiltInResources *resources)
  {
      sh::InitBuiltInResources(resources);
  
      resources->MaxVertexAttribs = 8;
      resources->MaxVertexUniformVectors = 128;
      resources->MaxVaryingVectors = 8;
      resources->MaxVertexTextureImageUnits = 0;
      resources->MaxCombinedTextureImageUnits = 8;
      resources->MaxTextureImageUnits = 8;
      resources->MaxFragmentUniformVectors = 16;
      resources->MaxDrawBuffers = 1;
      resources->MaxDualSourceDrawBuffers     = 1;
  
      resources->OES_standard_derivatives = 0;
      resources->OES_EGL_image_external = 0;
  }
  
  int main(int argc, char *argv[])
  {
      TFailCode failCode = ESuccess;
  
      ShCompileOptions compileOptions = 0;
      int numCompiles = 0;
      ShHandle vertexCompiler = 0;
      ShHandle fragmentCompiler = 0;
      ShHandle computeCompiler  = 0;
      ShShaderSpec spec = SH_GLES2_SPEC;
      ShShaderOutput output = SH_ESSL_OUTPUT;
  
      sh::Initialize();
  
      ShBuiltInResources resources;
      GenerateResources(&resources);
  
      argc--;
      argv++;
      for (; (argc >= 1) && (failCode == ESuccess); argc--, argv++)
      {
          if (argv[0][0] == '-')
          {
              switch (argv[0][1])
              {
                case 'i': compileOptions |= SH_INTERMEDIATE_TREE; break;
                case 'o': compileOptions |= SH_OBJECT_CODE; break;
                case 'u': compileOptions |= SH_VARIABLES; break;
                case 'p': resources.WEBGL_debug_shader_precision = 1; break;
                case 's':
                  if (argv[0][2] == '=')
                  {
                      switch (argv[0][3])
                      {
                          case 'e':
                              if (argv[0][4] == '3')
                              {
                                  if (argv[0][5] == '1')
                                  {
                                      spec = SH_GLES3_1_SPEC;
                                  }
                                  else
                                  {
                                      spec = SH_GLES3_SPEC;
                                  }
                              }
                              else
                              {
                                  spec = SH_GLES2_SPEC;
                              }
                              break;
                          case 'w':
                              if (argv[0][4] == '3')
                              {
                                  spec = SH_WEBGL3_SPEC;
                              }
                              else if (argv[0][4] == '2')
                              {
                                  spec = SH_WEBGL2_SPEC;
                              }
                              else if (argv[0][4] == 'n')
                              {
                                  spec = SH_WEBGL_SPEC;
                              }
                              else
                              {
                                  spec = SH_WEBGL_SPEC;
                                  resources.FragmentPrecisionHigh = 1;
                              }
                              break;
                          default:
                              failCode = EFailUsage;
                      }
                  }
                  else
                  {
                      failCode = EFailUsage;
                  }
                  break;
                case 'b':
                  if (argv[0][2] == '=')
                  {
                      switch (argv[0][3])
                      {
                          case 'e':
                              output = SH_ESSL_OUTPUT;
                              compileOptions |= SH_INITIALIZE_UNINITIALIZED_LOCALS;
                              break;
                          case 'g':
                              if (!ParseGLSLOutputVersion(&argv[0][sizeof("-b=g") - 1], &output))
                              {
                                  failCode = EFailUsage;
                              }
                              compileOptions |= SH_INITIALIZE_UNINITIALIZED_LOCALS;
                              break;
                          case 'h':
                              if (argv[0][4] == '1' && argv[0][5] == '1')
                              {
                                  output = SH_HLSL_4_1_OUTPUT;
                              }
                              else
                              {
                                  output = SH_HLSL_3_0_OUTPUT;
                              }
                              break;
                          default:
                              failCode = EFailUsage;
                      }
                  }
                  else
                  {
                      failCode = EFailUsage;
                  }
                  break;
                case 'x':
                  if (argv[0][2] == '=')
                  {
                      // clang-format off
                      switch (argv[0][3])
                      {
                        case 'i': resources.OES_EGL_image_external = 1; break;
                        case 'd': resources.OES_standard_derivatives = 1; break;
                        case 'r': resources.ARB_texture_rectangle = 1; break;
                        case 'b':
                            if (ParseIntValue(&argv[0][sizeof("-x=b") - 1], 1,
                                              &resources.MaxDualSourceDrawBuffers))
                            {
                                resources.EXT_blend_func_extended = 1;
                            }
                            else
                            {
                                failCode = EFailUsage;
                            }
                            break;
                        case 'w':
                            if (ParseIntValue(&argv[0][sizeof("-x=w") - 1], 1,
                                              &resources.MaxDrawBuffers))
                            {
                                resources.EXT_draw_buffers = 1;
                            }
                            else
                            {
                                failCode = EFailUsage;
                            }
                            break;
                        case 'g': resources.EXT_frag_depth = 1; break;
                        case 'l': resources.EXT_shader_texture_lod = 1; break;
                        case 'f': resources.EXT_shader_framebuffer_fetch = 1; break;
                        case 'n': resources.NV_shader_framebuffer_fetch = 1; break;
                        case 'a': resources.ARM_shader_framebuffer_fetch = 1; break;
                        case 'm':
                            resources.OVR_multiview = 1;
                            compileOptions |= SH_INITIALIZE_BUILTINS_FOR_INSTANCED_MULTIVIEW;
                            compileOptions |= SH_SELECT_VIEW_IN_NV_GLSL_VERTEX_SHADER;
                            break;
                        case 'y': resources.EXT_YUV_target = 1; break;
                        default: failCode = EFailUsage;
                      }
                      // clang-format on
                  }
                  else
                  {
                      failCode = EFailUsage;
                  }
                  break;
                default: failCode = EFailUsage;
              }
          }
          else
          {
              if (spec != SH_GLES2_SPEC && spec != SH_WEBGL_SPEC)
              {
                  resources.MaxDrawBuffers = 8;
                  resources.MaxVertexTextureImageUnits = 16;
                  resources.MaxTextureImageUnits       = 16;
              }
              ShHandle compiler = 0;
              switch (FindShaderType(argv[0]))
              {
                case GL_VERTEX_SHADER:
                  if (vertexCompiler == 0)
                  {
                      vertexCompiler =
                          sh::ConstructCompiler(GL_VERTEX_SHADER, spec, output, &resources);
                  }
                  compiler = vertexCompiler;
                  break;
                case GL_FRAGMENT_SHADER:
                  if (fragmentCompiler == 0)
                  {
                      fragmentCompiler =
                          sh::ConstructCompiler(GL_FRAGMENT_SHADER, spec, output, &resources);
                  }
                  compiler = fragmentCompiler;
                  break;
                case GL_COMPUTE_SHADER:
                    if (computeCompiler == 0)
                    {
                        computeCompiler =
                            sh::ConstructCompiler(GL_COMPUTE_SHADER, spec, output, &resources);
                    }
                    compiler = computeCompiler;
                    break;
  
                default: break;
              }
              if (compiler)
              {
                  bool compiled = CompileFile(argv[0], compiler, compileOptions);
  
                  LogMsg("BEGIN", "COMPILER", numCompiles, "INFO LOG");
                  std::string log = sh::GetInfoLog(compiler);
                  puts(log.c_str());
                  LogMsg("END", "COMPILER", numCompiles, "INFO LOG");
                  printf("\n\n");
  
                  if (compiled && (compileOptions & SH_OBJECT_CODE))
                  {
                      LogMsg("BEGIN", "COMPILER", numCompiles, "OBJ CODE");
                      std::string code = sh::GetObjectCode(compiler);
                      puts(code.c_str());
                      LogMsg("END", "COMPILER", numCompiles, "OBJ CODE");
                      printf("\n\n");
                  }
                  if (compiled && (compileOptions & SH_VARIABLES))
                  {
                      LogMsg("BEGIN", "COMPILER", numCompiles, "VARIABLES");
                      PrintActiveVariables(compiler);
                      LogMsg("END", "COMPILER", numCompiles, "VARIABLES");
                      printf("\n\n");
                  }
                  if (!compiled)
                    failCode = EFailCompile;
                  ++numCompiles;
              }
              else
              {
                  failCode = EFailCompilerCreate;
              }
          }
      }
  
      if ((vertexCompiler == 0) && (fragmentCompiler == 0) && (computeCompiler == 0))
          failCode = EFailUsage;
      if (failCode == EFailUsage)
          usage();
  
      if (vertexCompiler)
          sh::Destruct(vertexCompiler);
      if (fragmentCompiler)
          sh::Destruct(fragmentCompiler);
      if (computeCompiler)
          sh::Destruct(computeCompiler);
  
      sh::Finalize();
  
      return failCode;
  }
  
  //
  //   print usage to stdout
  //
  void usage()
  {
      // clang-format off
      printf(
          "Usage: translate [-i -o -u -l -p -b=e -b=g -b=h9 -x=i -x=d] file1 file2 ...\n"
          "Where: filename : filename ending in .frag or .vert\n"
          "       -i       : print intermediate tree\n"
          "       -o       : print translated code\n"
          "       -u       : print active attribs, uniforms, varyings and program outputs\n"
          "       -p       : use precision emulation\n"
          "       -s=e2    : use GLES2 spec (this is by default)\n"
          "       -s=e3    : use GLES3 spec\n"
          "       -s=e31   : use GLES31 spec (in development)\n"
          "       -s=w     : use WebGL 1.0 spec\n"
          "       -s=wn    : use WebGL 1.0 spec with no highp support in fragment shaders\n"
          "       -s=w2    : use WebGL 2.0 spec\n"
          "       -b=e     : output GLSL ES code (this is by default)\n"
          "       -b=g     : output GLSL code (compatibility profile)\n"
          "       -b=g[NUM]: output GLSL code (NUM can be 130, 140, 150, 330, 400, 410, 420, 430, "
          "440, 450)\n"
          "       -b=h9    : output HLSL9 code\n"
          "       -b=h11   : output HLSL11 code\n"
          "       -x=i     : enable GL_OES_EGL_image_external\n"
          "       -x=d     : enable GL_OES_EGL_standard_derivatives\n"
          "       -x=r     : enable ARB_texture_rectangle\n"
          "       -x=b[NUM]: enable EXT_blend_func_extended (NUM default 1)\n"
          "       -x=w[NUM]: enable EXT_draw_buffers (NUM default 1)\n"
          "       -x=g     : enable EXT_frag_depth\n"
          "       -x=l     : enable EXT_shader_texture_lod\n"
          "       -x=f     : enable EXT_shader_framebuffer_fetch\n"
          "       -x=n     : enable NV_shader_framebuffer_fetch\n"
          "       -x=a     : enable ARM_shader_framebuffer_fetch\n"
          "       -x=m     : enable OVR_multiview\n"
          "       -x=y     : enable YUV_target\n");
      // clang-format on
  }
  
  //
  //   Deduce the shader type from the filename.  Files must end in one of the
  //   following extensions:
  //
  //   .frag*    = fragment shader
  //   .vert*    = vertex shader
  //
  sh::GLenum FindShaderType(const char *fileName)
  {
      assert(fileName);
  
      const char *ext = strrchr(fileName, '.');
  
      if (ext && strcmp(ext, ".sl") == 0)
          for (; ext > fileName && ext[0] != '.'; ext--);
  
      ext = strrchr(fileName, '.');
      if (ext)
      {
          if (strncmp(ext, ".frag", 5) == 0)
              return GL_FRAGMENT_SHADER;
          if (strncmp(ext, ".vert", 5) == 0)
              return GL_VERTEX_SHADER;
          if (strncmp(ext, ".comp", 5) == 0)
              return GL_COMPUTE_SHADER;
      }
  
      return GL_FRAGMENT_SHADER;
  }
  
  //
  //   Read a file's data into a string, and compile it using sh::Compile
  //
  bool CompileFile(char *fileName, ShHandle compiler, ShCompileOptions compileOptions)
  {
      ShaderSource source;
      if (!ReadShaderSource(fileName, source))
          return false;
  
      int ret = sh::Compile(compiler, &source[0], source.size(), compileOptions);
  
      FreeShaderSource(source);
      return ret ? true : false;
  }
  
  void LogMsg(const char *msg, const char *name, const int num, const char *logName)
  {
      printf("#### %s %s %d %s ####\n", msg, name, num, logName);
  }
  
  void PrintVariable(const std::string &prefix, size_t index, const sh::ShaderVariable &var)
  {
      std::string typeName;
      switch (var.type)
      {
        case GL_FLOAT: typeName = "GL_FLOAT"; break;
        case GL_FLOAT_VEC2: typeName = "GL_FLOAT_VEC2"; break;
        case GL_FLOAT_VEC3: typeName = "GL_FLOAT_VEC3"; break;
        case GL_FLOAT_VEC4: typeName = "GL_FLOAT_VEC4"; break;
        case GL_INT: typeName = "GL_INT"; break;
        case GL_INT_VEC2: typeName = "GL_INT_VEC2"; break;
        case GL_INT_VEC3: typeName = "GL_INT_VEC3"; break;
        case GL_INT_VEC4: typeName = "GL_INT_VEC4"; break;
        case GL_UNSIGNED_INT: typeName = "GL_UNSIGNED_INT"; break;
        case GL_UNSIGNED_INT_VEC2: typeName = "GL_UNSIGNED_INT_VEC2"; break;
        case GL_UNSIGNED_INT_VEC3: typeName = "GL_UNSIGNED_INT_VEC3"; break;
        case GL_UNSIGNED_INT_VEC4: typeName = "GL_UNSIGNED_INT_VEC4"; break;
        case GL_BOOL: typeName = "GL_BOOL"; break;
        case GL_BOOL_VEC2: typeName = "GL_BOOL_VEC2"; break;
        case GL_BOOL_VEC3: typeName = "GL_BOOL_VEC3"; break;
        case GL_BOOL_VEC4: typeName = "GL_BOOL_VEC4"; break;
        case GL_FLOAT_MAT2: typeName = "GL_FLOAT_MAT2"; break;
        case GL_FLOAT_MAT3: typeName = "GL_FLOAT_MAT3"; break;
        case GL_FLOAT_MAT4: typeName = "GL_FLOAT_MAT4"; break;
        case GL_FLOAT_MAT2x3: typeName = "GL_FLOAT_MAT2x3"; break;
        case GL_FLOAT_MAT3x2: typeName = "GL_FLOAT_MAT3x2"; break;
        case GL_FLOAT_MAT4x2: typeName = "GL_FLOAT_MAT4x2"; break;
        case GL_FLOAT_MAT2x4: typeName = "GL_FLOAT_MAT2x4"; break;
        case GL_FLOAT_MAT3x4: typeName = "GL_FLOAT_MAT3x4"; break;
        case GL_FLOAT_MAT4x3: typeName = "GL_FLOAT_MAT4x3"; break;
  
        case GL_SAMPLER_2D: typeName = "GL_SAMPLER_2D"; break;
        case GL_SAMPLER_3D:
            typeName = "GL_SAMPLER_3D";
            break;
        case GL_SAMPLER_CUBE:
            typeName = "GL_SAMPLER_CUBE";
            break;
        case GL_SAMPLER_CUBE_SHADOW:
            typeName = "GL_SAMPLER_CUBE_SHADOW";
            break;
        case GL_SAMPLER_2D_SHADOW:
            typeName = "GL_SAMPLER_2D_ARRAY_SHADOW";
            break;
        case GL_SAMPLER_2D_ARRAY:
            typeName = "GL_SAMPLER_2D_ARRAY";
            break;
        case GL_SAMPLER_2D_ARRAY_SHADOW:
            typeName = "GL_SAMPLER_2D_ARRAY_SHADOW";
            break;
        case GL_SAMPLER_2D_MULTISAMPLE:
            typeName = "GL_SAMPLER_2D_MULTISAMPLE";
            break;
        case GL_IMAGE_2D:
            typeName = "GL_IMAGE_2D";
            break;
        case GL_IMAGE_3D:
            typeName = "GL_IMAGE_3D";
            break;
        case GL_IMAGE_CUBE:
            typeName = "GL_IMAGE_CUBE";
            break;
        case GL_IMAGE_2D_ARRAY:
            typeName = "GL_IMAGE_2D_ARRAY";
            break;
  
        case GL_INT_SAMPLER_2D:
            typeName = "GL_INT_SAMPLER_2D";
            break;
        case GL_INT_SAMPLER_3D:
            typeName = "GL_INT_SAMPLER_3D";
            break;
        case GL_INT_SAMPLER_CUBE:
            typeName = "GL_INT_SAMPLER_CUBE";
            break;
        case GL_INT_SAMPLER_2D_ARRAY:
            typeName = "GL_INT_SAMPLER_2D_ARRAY";
            break;
        case GL_INT_SAMPLER_2D_MULTISAMPLE:
            typeName = "GL_INT_SAMPLER_2D_MULTISAMPLE";
            break;
        case GL_INT_IMAGE_2D:
            typeName = "GL_INT_IMAGE_2D";
            break;
        case GL_INT_IMAGE_3D:
            typeName = "GL_INT_IMAGE_3D";
            break;
        case GL_INT_IMAGE_CUBE:
            typeName = "GL_INT_IMAGE_CUBE";
            break;
        case GL_INT_IMAGE_2D_ARRAY:
            typeName = "GL_INT_IMAGE_2D_ARRAY";
            break;
  
        case GL_UNSIGNED_INT_SAMPLER_2D:
            typeName = "GL_UNSIGNED_INT_SAMPLER_2D";
            break;
        case GL_UNSIGNED_INT_SAMPLER_3D:
            typeName = "GL_UNSIGNED_INT_SAMPLER_3D";
            break;
        case GL_UNSIGNED_INT_SAMPLER_CUBE:
            typeName = "GL_UNSIGNED_INT_SAMPLER_CUBE";
            break;
        case GL_UNSIGNED_INT_SAMPLER_2D_ARRAY:
            typeName = "GL_UNSIGNED_INT_SAMPLER_2D_ARRAY";
            break;
        case GL_UNSIGNED_INT_ATOMIC_COUNTER:
            typeName = "GL_UNSIGNED_INT_ATOMIC_COUNTER";
            break;
        case GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE:
            typeName = "GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE";
            break;
        case GL_UNSIGNED_INT_IMAGE_2D:
            typeName = "GL_UNSIGNED_INT_IMAGE_2D";
            break;
        case GL_UNSIGNED_INT_IMAGE_3D:
            typeName = "GL_UNSIGNED_INT_IMAGE_3D";
            break;
        case GL_UNSIGNED_INT_IMAGE_CUBE:
            typeName = "GL_UNSIGNED_INT_IMAGE_CUBE";
            break;
        case GL_UNSIGNED_INT_IMAGE_2D_ARRAY:
            typeName = "GL_UNSIGNED_INT_IMAGE_2D_ARRAY";
            break;
  
        case GL_SAMPLER_EXTERNAL_OES: typeName = "GL_SAMPLER_EXTERNAL_OES"; break;
        case GL_SAMPLER_EXTERNAL_2D_Y2Y_EXT:
            typeName = "GL_SAMPLER_EXTERNAL_2D_Y2Y_EXT";
            break;
        default: typeName = "UNKNOWN"; break;
      }
  
      printf("%s %u : name=%s, type=%s, arraySize=%u\n", prefix.c_str(),
             static_cast<unsigned int>(index), var.name.c_str(), typeName.c_str(), var.arraySize);
      if (var.fields.size())
      {
          std::string structPrefix;
          for (size_t i = 0; i < prefix.size(); ++i)
              structPrefix += ' ';
          printf("%s  struct %s\n", structPrefix.c_str(), var.structName.c_str());
          structPrefix += "    field";
          for (size_t i = 0; i < var.fields.size(); ++i)
              PrintVariable(structPrefix, i, var.fields[i]);
      }
  }
  
  static void PrintActiveVariables(ShHandle compiler)
  {
      const std::vector<sh::Uniform> *uniforms       = sh::GetUniforms(compiler);
      const std::vector<sh::Varying> *varyings       = sh::GetVaryings(compiler);
      const std::vector<sh::Attribute> *attributes   = sh::GetAttributes(compiler);
      const std::vector<sh::OutputVariable> *outputs = sh::GetOutputVariables(compiler);
      for (size_t varCategory = 0; varCategory < 4; ++varCategory)
      {
          size_t numVars = 0;
          std::string varCategoryName;
          if (varCategory == 0)
          {
              numVars = uniforms->size();
              varCategoryName = "uniform";
          }
          else if (varCategory == 1)
          {
              numVars = varyings->size();
              varCategoryName = "varying";
          }
          else if (varCategory == 2)
          {
              numVars = attributes->size();
              varCategoryName = "attribute";
          }
          else
          {
              numVars         = outputs->size();
              varCategoryName = "output";
          }
  
          for (size_t i = 0; i < numVars; ++i)
          {
              const sh::ShaderVariable *var;
              if (varCategory == 0)
                  var = &((*uniforms)[i]);
              else if (varCategory == 1)
                  var = &((*varyings)[i]);
              else if (varCategory == 2)
                  var = &((*attributes)[i]);
              else
                  var = &((*outputs)[i]);
  
              PrintVariable(varCategoryName, i, *var);
          }
          printf("\n");
      }
  }
  
  static bool ReadShaderSource(const char *fileName, ShaderSource &source)
  {
      FILE *in = fopen(fileName, "rb");
      if (!in)
      {
          printf("Error: unable to open input file: %s\n", fileName);
          return false;
      }
  
      // Obtain file size.
      fseek(in, 0, SEEK_END);
      size_t count = ftell(in);
      rewind(in);
  
      int len = (int)ceil((float)count / (float)NUM_SOURCE_STRINGS);
      source.reserve(NUM_SOURCE_STRINGS);
      // Notice the usage of do-while instead of a while loop here.
      // It is there to handle empty files in which case a single empty
      // string is added to vector.
      do
      {
          char *data = new char[len + 1];
          size_t nread = fread(data, 1, len, in);
          data[nread] = '\0';
          source.push_back(data);
  
          count -= nread;
      }
      while (count > 0);
  
      fclose(in);
      return true;
  }
  
  static void FreeShaderSource(ShaderSource &source)
  {
      for (ShaderSource::size_type i = 0; i < source.size(); ++i)
      {
          delete [] source[i];
      }
      source.clear();
  }
  
  static bool ParseGLSLOutputVersion(const std::string &num, ShShaderOutput *outResult)
  {
      if (num.length() == 0)
      {
          *outResult = SH_GLSL_COMPATIBILITY_OUTPUT;
          return true;
      }
      std::istringstream input(num);
      int value;
      if (!(input >> value && input.eof()))
      {
          return false;
      }
  
      switch (value)
      {
          case 130:
              *outResult = SH_GLSL_130_OUTPUT;
              return true;
          case 140:
              *outResult = SH_GLSL_140_OUTPUT;
              return true;
          case 150:
              *outResult = SH_GLSL_150_CORE_OUTPUT;
              return true;
          case 330:
              *outResult = SH_GLSL_330_CORE_OUTPUT;
              return true;
          case 400:
              *outResult = SH_GLSL_400_CORE_OUTPUT;
              return true;
          case 410:
              *outResult = SH_GLSL_410_CORE_OUTPUT;
              return true;
          case 420:
              *outResult = SH_GLSL_420_CORE_OUTPUT;
              return true;
          case 430:
              *outResult = SH_GLSL_430_CORE_OUTPUT;
              return true;
          case 440:
              *outResult = SH_GLSL_440_CORE_OUTPUT;
              return true;
          case 450:
              *outResult = SH_GLSL_450_CORE_OUTPUT;
              return true;
          default:
              break;
      }
      return false;
  }
  
  static bool ParseIntValue(const std::string &num, int emptyDefault, int *outValue)
  {
      if (num.length() == 0)
      {
          *outValue = emptyDefault;
          return true;
      }
  
      std::istringstream input(num);
      int value;
      if (!(input >> value && input.eof()))
      {
          return false;
      }
      *outValue = value;
      return true;
  }