DepthStencilState.h

#pragma once
 
namespace Cogs
{
  struct DepthStencilState
  {
    enum DepthFunction
    {
      Never = 0,
      Less,
      LessOrEqual,
      Equal,
      GreaterOrEqual,
      Greater,
      NotEqual,
      Always
    };
 
    bool depthEnabled;
 
    bool writeEnabled;
 
    DepthFunction depthFunction;
 
    static DepthStencilState DefaultState()
    {
      DepthStencilState depthStencilState = {
        true, // Depth test enabled.
        true, // Depth writes enabled.
        DepthStencilState::Less // "Less" comparison function.
      };
 
      return depthStencilState;
    }
  };
}
 
namespace std
{
  template<>
  struct hash<Cogs::DepthStencilState>
  {
    std::size_t operator()(const Cogs::DepthStencilState & ds) const
    {
      return std::hash<int>()(ds.depthFunction | (ds.depthEnabled ? 8 : 0) | (ds.writeEnabled ? 16 : 0));
    }
  };
 
  template<>
  struct equal_to<Cogs::DepthStencilState>
  {
    bool operator()(const Cogs::DepthStencilState & lhs, const Cogs::DepthStencilState & rhs) const
    {
      return lhs.depthEnabled == rhs.depthEnabled && lhs.writeEnabled == rhs.writeEnabled && lhs.depthFunction == rhs.depthFunction;
    }
  };
}