text: /*     Copyright 2019 Diligent Graphics LLC
   *  
   *  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
   * 
   *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF ANY PROPRIETARY RIGHTS.
   *
   *  In no event and under no legal theory, whether in tort (including negligence), 
   *  contract, or otherwise, unless required by applicable law (such as deliberate 
   *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
   *  liable for any damages, including any direct, indirect, special, incidental, 
   *  or consequential damages of any character arising as a result of this License or 
   *  out of the use or inability to use the software (including but not limited to damages 
   *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
   *  all other commercial damages or losses), even if such Contributor has been advised 
   *  of the possibility of such damages.
   */
  
  //--------------------------------------------------------------------------------------
  // Copyright 2013 Intel Corporation
  // All Rights Reserved
  //
  // Permission is granted to use, copy, distribute and prepare derivative works of this
  // software for any purpose and without fee, provided, that the above copyright notice
  // and this statement appear in all copies.  Intel makes no representations about the
  // suitability of this software for any purpose.  THIS SOFTWARE IS PROVIDED "AS IS."
  // INTEL SPECIFICALLY DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, AND ALL LIABILITY,
  // INCLUDING CONSEQUENTIAL AND OTHER INDIRECT DAMAGES, FOR THE USE OF THIS SOFTWARE,
  // INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PROPRIETARY RIGHTS, AND INCLUDING THE
  // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  Intel does not
  // assume any responsibility for any errors which may appear in this software nor any
  // responsibility to update it.
  //--------------------------------------------------------------------------------------
  #pragma once
  
  #include <set>
  #include <vector>
  #include <sstream>
  #include <iomanip>
  #include "../../GraphicsEngine/interface/Shader.h"
  #include "../../../Platforms/Basic/interface/DebugUtilities.h"
  
  
  namespace Diligent
  {
  
  class ShaderMacroHelper
  {
  public:
      template <typename DefintionType>
      void AddShaderMacro(const Char* Name, DefintionType Definition)
      {
          std::ostringstream ss;
          ss << Definition;
          AddShaderMacro<const Char*>(Name, ss.str().c_str());
      }
  
      void Finalize()
      {
          if (!m_bIsFinalized)
          {
              m_Macros.emplace_back(nullptr, nullptr);
              m_bIsFinalized = true;
          }
      }
  
      void Reopen()
      {
          if (m_bIsFinalized)
          {
              VERIFY_EXPR(m_Macros.size() > 0 && m_Macros.back().Name == nullptr && m_Macros.back().Definition == nullptr);
              m_Macros.pop_back();
              m_bIsFinalized = false;
          }
      }
  
      void Clear()
      {
          m_Macros.clear();
          m_DefinitionsPool.clear();
          m_bIsFinalized = false;
      }
  
      operator const ShaderMacro*()
      {
          if (m_Macros.size() > 0 && !m_bIsFinalized)
              Finalize();
          return m_Macros.size() ? m_Macros.data() : nullptr;
      }
  
      void RemoveMacro(const Char* Name)
      {
          size_t i = 0;
          while (i < m_Macros.size() && m_Macros[i].Definition != nullptr)
          {
              if (strcmp(m_Macros[i].Name, Name) == 0)
              {
                  m_Macros.erase(m_Macros.begin() + i);
                  break;
              }
              else
              {
                  ++i;
              }
          }
      }
  
      template <typename DefintionType>
      void UpdateMacro(const Char* Name, DefintionType Definition)
      {
          RemoveMacro(Name);
          AddShaderMacro(Name, Definition);
      }
  
  private:
      std::vector<ShaderMacro> m_Macros;
      std::set<std::string>    m_DefinitionsPool;
      bool                     m_bIsFinalized = false;
  };
  
  template <>
  inline void ShaderMacroHelper::AddShaderMacro(const Char* Name, const Char* Definition)
  {
      Reopen();
      auto* PooledDefinition = m_DefinitionsPool.insert(Definition).first->c_str();
      m_Macros.emplace_back(Name, PooledDefinition);
  }
  
  template <>
  inline void ShaderMacroHelper::AddShaderMacro(const Char* Name, bool Definition)
  {
      AddShaderMacro(Name, Definition ? "1" : "0");
  }
  
  template <>
  inline void ShaderMacroHelper::AddShaderMacro(const Char* Name, float Definition)
  {
      std::ostringstream ss;
  
      // Make sure that when floating point represents integer, it is still
      // written as float: 1024.0, but not 1024. This is essnetial to
      // avoid type conversion issues in GLES.
      if (Definition == static_cast<float>(static_cast<int>(Definition)))
          ss << std::fixed << std::setprecision(1);
  
      ss << Definition;
      AddShaderMacro<const Char*>(Name, ss.str().c_str());
  }
  
  template <>
  inline void ShaderMacroHelper::AddShaderMacro(const Char* Name, Uint32 Definition)
  {
      // Make sure that uint constants have the 'u' suffix to avoid problems in GLES.
      std::ostringstream ss;
      ss << Definition << 'u';
      AddShaderMacro<const Char*>(Name, ss.str().c_str());
  }
  
  } // namespace Diligent
  