glslc/src/shader_stage.cc

// Copyright 2015 The Shaderc Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "shader_stage.h"

#include <algorithm>
#include <tuple>

#include "libshaderc_util/file_finder.h"
#include "libshaderc_util/resources.h"

#include "file.h"
#include "file_includer.h"

using shaderc_util::string_piece;

namespace {

// Maps an identifier to a language.
struct LanguageMapping {
  const char* id;
  EShLanguage language;
};

}  // anonymous namespace

namespace glslc {

EShLanguage GetShaderStageFromFileName(const string_piece& filename) {
  // Add new stage types here.
  static const LanguageMapping kStringToStage[] = {
      {"vert", EShLangVertex},      {"frag", EShLangFragment},
      {"tesc", EShLangTessControl}, {"tese", EShLangTessEvaluation},
      {"geom", EShLangGeometry},    {"comp", EShLangCompute}};

  const string_piece extension = glslc::GetFileExtension(filename);
  if (extension.empty()) return EShLangCount;

  for (const auto& entry : kStringToStage) {
    if (extension == entry.id) return entry.language;
  }
  return EShLangCount;
}

EShLanguage MapStageNameToLanguage(const string_piece& stage_name) {
  const LanguageMapping string_to_stage[] = {
      {"vertex", EShLangVertex},           {"fragment", EShLangFragment},
      {"tesscontrol", EShLangTessControl}, {"tesseval", EShLangTessEvaluation},
      {"geometry", EShLangGeometry},       {"compute", EShLangCompute}};

  for (const auto& entry : string_to_stage) {
    if (stage_name == entry.id) return entry.language;
  }
  return EShLangCount;
}

EShLanguage GetShaderStageFromCmdLine(const string_piece& f_shader_stage) {
  size_t equal_pos = f_shader_stage.find_first_of("=");
  if (equal_pos == std::string::npos) return EShLangCount;
  return MapStageNameToLanguage(f_shader_stage.substr(equal_pos + 1));
}

}  // namespace glslc