text: //
  // Copyright (c) 2008-2020 the Urho3D project.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // 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. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  
  #pragma once
  
  #include "../../Container/HashMap.h"
  #include "../../Graphics/ShaderVariation.h"
  #include "../../Container/RefCounted.h"
  
  namespace Urho3D
  {
  
  /// Combined information for specific vertex and pixel shaders.
  class ShaderProgram : public RefCounted
  {
      URHO3D_REFCOUNTED(ShaderProgram, RefCounted)
  
  public:
      /// Construct.
      ShaderProgram(ShaderVariation* vertexShader, ShaderVariation* pixelShader)
      {
          const HashMap<StringHash, ShaderParameter>& vsParams = vertexShader->GetParameters();
          for (HashMap<StringHash, ShaderParameter>::ConstIterator i = vsParams.Begin(); i != vsParams.End(); ++i)
              parameters_[i->first_] = i->second_;
  
          const HashMap<StringHash, ShaderParameter>& psParams = pixelShader->GetParameters();
          for (HashMap<StringHash, ShaderParameter>::ConstIterator i = psParams.Begin(); i != psParams.End(); ++i)
              parameters_[i->first_] = i->second_;
  
          // Optimize shader parameter lookup by rehashing to next power of two
          parameters_.Rehash(NextPowerOfTwo(parameters_.Size()));
      }
  
      /// Combined parameters from the vertex and pixel shader.
      HashMap<StringHash, ShaderParameter> parameters_;
  };
  
  }
  