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

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• Hash : a1ceb87b
  Author :
  Date : 2020-02-25T11:58:19
  

  Vulkan:Refactor precision emulation code
  
  GLSL, ESSL, and HLSL translators all had the same code to emulate
  precision so migrate that code to base class.
  This is a structural change to prepare for honoring precision
  qualifiers in the Vulkan translator as well, which is done in a
  follow-on commit.
  
  Bug: angleproject:3078
  Change-Id: Id85bba83543189e3bbc4002be92b056e63afc8de
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2072644
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Tim Van Patten <timvp@google.com>
  Commit-Queue: Tobin Ehlis <tobine@google.com>
  

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• src/compiler/translator/TranslatorESSL.cpp

• //
  // Copyright 2002 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/translator/TranslatorESSL.h"
  
  #include "angle_gl.h"
  #include "compiler/translator/BuiltInFunctionEmulatorGLSL.h"
  #include "compiler/translator/OutputESSL.h"
  #include "compiler/translator/tree_ops/RecordConstantPrecision.h"
  
  namespace sh
  {
  
  TranslatorESSL::TranslatorESSL(sh::GLenum type, ShShaderSpec spec)
      : TCompiler(type, spec, SH_ESSL_OUTPUT)
  {}
  
  void TranslatorESSL::initBuiltInFunctionEmulator(BuiltInFunctionEmulator *emu,
                                                   ShCompileOptions compileOptions)
  {
      if (compileOptions & SH_EMULATE_ATAN2_FLOAT_FUNCTION)
      {
          InitBuiltInAtanFunctionEmulatorForGLSLWorkarounds(emu);
      }
  }
  
  bool TranslatorESSL::translate(TIntermBlock *root,
                                 ShCompileOptions compileOptions,
                                 PerformanceDiagnostics * /*perfDiagnostics*/)
  {
      TInfoSinkBase &sink = getInfoSink().obj;
  
      int shaderVer = getShaderVersion();
      if (shaderVer > 100)
      {
          sink << "#version " << shaderVer << " es\n";
      }
  
      // Write built-in extension behaviors.
      writeExtensionBehavior(compileOptions);
  
      // Write pragmas after extensions because some drivers consider pragmas
      // like non-preprocessor tokens.
      writePragma(compileOptions);
  
      bool precisionEmulation = false;
      if (!emulatePrecisionIfNeeded(root, sink, &precisionEmulation, SH_ESSL_OUTPUT))
          return false;
  
      if (!RecordConstantPrecision(this, root, &getSymbolTable()))
      {
          return false;
      }
  
      // Write emulated built-in functions if needed.
      if (!getBuiltInFunctionEmulator().isOutputEmpty())
      {
          sink << "// BEGIN: Generated code for built-in function emulation\n\n";
          if (getShaderType() == GL_FRAGMENT_SHADER)
          {
              sink << "#if defined(GL_FRAGMENT_PRECISION_HIGH)\n"
                   << "#define emu_precision highp\n"
                   << "#else\n"
                   << "#define emu_precision mediump\n"
                   << "#endif\n\n";
          }
          else
          {
              sink << "#define emu_precision highp\n";
          }
  
          getBuiltInFunctionEmulator().outputEmulatedFunctions(sink);
          sink << "// END: Generated code for built-in function emulation\n\n";
      }
  
      // Write array bounds clamping emulation if needed.
      getArrayBoundsClamper().OutputClampingFunctionDefinition(sink);
  
      if (getShaderType() == GL_FRAGMENT_SHADER)
      {
          EmitEarlyFragmentTestsGLSL(*this, sink);
      }
  
      if (getShaderType() == GL_COMPUTE_SHADER)
      {
          EmitWorkGroupSizeGLSL(*this, sink);
      }
  
      if (getShaderType() == GL_GEOMETRY_SHADER_EXT)
      {
          WriteGeometryShaderLayoutQualifiers(
              sink, getGeometryShaderInputPrimitiveType(), getGeometryShaderInvocations(),
              getGeometryShaderOutputPrimitiveType(), getGeometryShaderMaxVertices());
      }
  
      // Write translated shader.
      TOutputESSL outputESSL(sink, getArrayIndexClampingStrategy(), getHashFunction(), getNameMap(),
                             &getSymbolTable(), getShaderType(), shaderVer, precisionEmulation,
                             compileOptions);
  
      root->traverse(&outputESSL);
  
      return true;
  }
  
  bool TranslatorESSL::shouldFlattenPragmaStdglInvariantAll()
  {
      // If following the spec to the letter, we should not flatten this pragma.
      // However, the spec's wording means that the pragma applies only to outputs.
      // This contradicts the spirit of using the pragma,
      // because if the pragma is used in a vertex shader,
      // the only way to be able to link it to a fragment shader
      // is to manually qualify each of fragment shader's inputs as invariant.
      // Which defeats the purpose of this pragma - temporarily make all varyings
      // invariant for debugging.
      // Thus, we should be non-conformant to spec's letter here and flatten.
      return true;
  }
  
  void TranslatorESSL::writeExtensionBehavior(ShCompileOptions compileOptions)
  {
      TInfoSinkBase &sink                   = getInfoSink().obj;
      const TExtensionBehavior &extBehavior = getExtensionBehavior();
      for (TExtensionBehavior::const_iterator iter = extBehavior.begin(); iter != extBehavior.end();
           ++iter)
      {
          if (iter->second != EBhUndefined)
          {
              const bool isMultiview = (iter->first == TExtension::OVR_multiview) ||
                                       (iter->first == TExtension::OVR_multiview2);
              if (getResources().NV_shader_framebuffer_fetch &&
                  iter->first == TExtension::EXT_shader_framebuffer_fetch)
              {
                  sink << "#extension GL_NV_shader_framebuffer_fetch : "
                       << GetBehaviorString(iter->second) << "\n";
              }
              else if (getResources().NV_draw_buffers && iter->first == TExtension::EXT_draw_buffers)
              {
                  sink << "#extension GL_NV_draw_buffers : " << GetBehaviorString(iter->second)
                       << "\n";
              }
              else if (isMultiview)
              {
                  // Only either OVR_multiview OR OVR_multiview2 should be emitted.
                  if ((iter->first != TExtension::OVR_multiview) ||
                      !IsExtensionEnabled(extBehavior, TExtension::OVR_multiview2))
                  {
                      EmitMultiviewGLSL(*this, compileOptions, iter->first, iter->second, sink);
                  }
              }
              else if (iter->first == TExtension::EXT_geometry_shader)
              {
                  sink << "#ifdef GL_EXT_geometry_shader\n"
                       << "#extension GL_EXT_geometry_shader : " << GetBehaviorString(iter->second)
                       << "\n"
                       << "#elif defined GL_OES_geometry_shader\n"
                       << "#extension GL_OES_geometry_shader : " << GetBehaviorString(iter->second)
                       << "\n";
                  if (iter->second == EBhRequire)
                  {
                      sink << "#else\n"
                           << "#error \"No geometry shader extensions available.\" // Only generate "
                              "this if the extension is \"required\"\n";
                  }
                  sink << "#endif\n";
              }
              else if (iter->first == TExtension::ANGLE_multi_draw)
              {
                  // Don't emit anything. This extension is emulated
                  ASSERT((compileOptions & SH_EMULATE_GL_DRAW_ID) != 0);
                  continue;
              }
              else if (iter->first == TExtension::ANGLE_base_vertex_base_instance)
              {
                  // Don't emit anything. This extension is emulated
                  ASSERT((compileOptions & SH_EMULATE_GL_BASE_VERTEX_BASE_INSTANCE) != 0);
                  continue;
              }
              else if (iter->first == TExtension::WEBGL_video_texture)
              {
                  // Don't emit anything. This extension is emulated
                  // TODO(crbug.com/776222): support external image.
                  continue;
              }
              else
              {
                  sink << "#extension " << GetExtensionNameString(iter->first) << " : "
                       << GetBehaviorString(iter->second) << "\n";
              }
          }
      }
  }
  
  }  // namespace sh
  

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