RasterizerState.h

#pragma once
 
namespace Cogs
{
  struct RasterizerState
  {
    enum CullMode
    {
      Front = 0,
      Back,
      None
    };
 
    bool wireFrame;
 
    CullMode cullMode;
 
    bool frontCounterClockwise;
 
    bool multiSample;
 
    float depthBias;
 
    float slopeScaledDepthBias;
 
    float depthBiasClamp;
 
    bool scissor;
 
    bool noDepthClip = false;
 
    static RasterizerState DefaultState()
    {
      static RasterizerState rasterizerState = {
        false, // No wire frame, filled primitives
        RasterizerState::None, // No face culling
        false, // Clockwise polygon winding order
        true, // Enable multi sampling
        0.0f, // No depth bias
        0.0f, // No slope scaled depth bias
        0.0f, // Do not clamp the depth bias
        false, // No scissor rect
        false   // Depth clip enabled.
      };
 
      return rasterizerState;
    }
  };
}
 
namespace std
{
  template<>
  struct hash<Cogs::RasterizerState>
  {
    std::size_t operator()(const Cogs::RasterizerState & rs) const
    {
      unsigned int simple =
        rs.cullMode |
        (rs.wireFrame ? 4 : 0) |
        (rs.frontCounterClockwise ? 8 : 0) |
        (rs.multiSample ? 16 : 0) |
        (rs.scissor ? 32 : 0) |
        (rs.noDepthClip ? 64 : 0);
      return
        std::hash<int>()(simple) ^
        (13 * std::hash<float>()(rs.depthBias) ^
        (13 * std::hash<float>()(rs.slopeScaledDepthBias) ^
        (13 * std::hash<float>()(rs.depthBiasClamp))));
    }
  };
 
  template<>
  struct equal_to<Cogs::RasterizerState>
  {
    bool operator()(const Cogs::RasterizerState & lhs, const Cogs::RasterizerState & rhs) const
    {
      return
        (lhs.wireFrame == rhs.wireFrame) &&
        (lhs.cullMode == rhs.cullMode) &&
        (lhs.frontCounterClockwise == rhs.frontCounterClockwise) &&
        (lhs.multiSample == rhs.multiSample) &&
        (lhs.depthBias == rhs.depthBias) &&
        (lhs.slopeScaledDepthBias == rhs.slopeScaledDepthBias) &&
        (lhs.depthBiasClamp == rhs.depthBiasClamp) &&
        (lhs.scissor == rhs.scissor) &&
        (lhs.noDepthClip == rhs.noDepthClip);
    }
  };
}