text: //
  // Copyright 2020 Pixar
  //
  // Licensed under the Apache License, Version 2.0 (the "Apache License")
  // with the following modification; you may not use this file except in
  // compliance with the Apache License and the following modification to it:
  // Section 6. Trademarks. is deleted and replaced with:
  //
  // 6. Trademarks. This License does not grant permission to use the trade
  //    names, trademarks, service marks, or product names of the Licensor
  //    and its affiliates, except as required to comply with Section 4(c) of
  //    the License and to reproduce the content of the NOTICE file.
  //
  // You may obtain a copy of the Apache License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the Apache License with the above modification is
  // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied. See the Apache License for the specific
  // language governing permissions and limitations under the Apache License.
  //
  #ifndef PXR_IMAGING_HGI_METAL_SHADERPROGRAM_H
  #define PXR_IMAGING_HGI_METAL_SHADERPROGRAM_H
  
  #include "pxr/imaging/hgi/shaderProgram.h"
  
  #include "pxr/imaging/hgiMetal/api.h"
  #include "pxr/imaging/hgiMetal/shaderFunction.h"
  
  #include <vector>
  
  #include <Metal/Metal.h>
  
  PXR_NAMESPACE_OPEN_SCOPE
  
  
  ///
  /// \class HgiMetalShaderProgram
  ///
  /// Metal implementation of HgiShaderProgram
  ///
  class HgiMetalShaderProgram final : public HgiShaderProgram {
  public:
      HGIMETAL_API
      ~HgiMetalShaderProgram() override;
  
      HGIMETAL_API
      bool IsValid() const override;
  
      HGIMETAL_API
      std::string const& GetCompileErrors() override;
  
      HGIMETAL_API
      HgiShaderFunctionHandleVector const& GetShaderFunctions() const override;
  
      HGIMETAL_API
      size_t GetByteSizeOfResource() const override;
  
      HGIMETAL_API
      uint64_t GetRawResource() const override;
  
      HGIMETAL_API
      id<MTLFunction> GetVertexFunction() const {
          return _vertexFunction;
      }
  
      HGIMETAL_API
      id<MTLFunction> GetFragmentFunction() const {
          return _fragmentFunction;
      }
  
      HGIMETAL_API
      id<MTLFunction> GetComputeFunction() const {
          return _computeFunction;
      }
  
      HGIMETAL_API
      id<MTLFunction> GetPostTessVertexFunction() const {
          return _postTessVertexFunction;
      }
  
  protected:
      friend class HgiMetal;
  
      HGIMETAL_API
      HgiMetalShaderProgram(HgiShaderProgramDesc const& desc);
  
  private:
      HgiMetalShaderProgram() = delete;
      HgiMetalShaderProgram & operator=(const HgiMetalShaderProgram&) = delete;
      HgiMetalShaderProgram(const HgiMetalShaderProgram&) = delete;
  
  private:
      std::string _errors;
      
      id<MTLFunction> _vertexFunction;
      id<MTLFunction> _fragmentFunction;
      id<MTLFunction> _computeFunction;
      id<MTLFunction> _postTessVertexFunction;
  };
  
  
  PXR_NAMESPACE_CLOSE_SCOPE
  
  #endif
  