void D3D9DeviceEx::UpdateFog() {
    auto& rs = m_state.renderStates;

    bool fogEnabled = rs[D3DRS_FOGENABLE] != FALSE;

    bool pixelFog   = rs[D3DRS_FOGTABLEMODE]  != D3DFOG_NONE && fogEnabled;
    bool vertexFog  = rs[D3DRS_FOGVERTEXMODE] != D3DFOG_NONE && fogEnabled && !pixelFog;

    auto UpdateFogConstants = [&](D3DFOGMODE FogMode) {
      if (m_flags.test(D3D9DeviceFlag::DirtyFogColor)) {
        m_flags.clr(D3D9DeviceFlag::DirtyFogColor);
        UpdatePushConstant<D3D9RenderStateItem::FogColor>();
      }

      if (FogMode == D3DFOG_LINEAR) {
        if (m_flags.test(D3D9DeviceFlag::DirtyFogStart)) {
          m_flags.clr(D3D9DeviceFlag::DirtyFogStart);
          UpdatePushConstant<D3D9RenderStateItem::FogStart>();
        }

        if (m_flags.test(D3D9DeviceFlag::DirtyFogEnd)) {
          m_flags.clr(D3D9DeviceFlag::DirtyFogEnd);
          UpdatePushConstant<D3D9RenderStateItem::FogEnd>();
        }
      }
      else {
        if (m_flags.test(D3D9DeviceFlag::DirtyFogDensity)) {
          m_flags.clr(D3D9DeviceFlag::DirtyFogDensity);
          UpdatePushConstant<D3D9RenderStateItem::FogDensity>();
        }
      }
    };

    if (vertexFog) {
      D3DFOGMODE mode = D3DFOGMODE(rs[D3DRS_FOGVERTEXMODE]);

      UpdateFogConstants(mode);
      EmitCs([cMode = mode] (DxvkContext* ctx) {
        ctx->setSpecConstant(D3D9SpecConstantId::FogEnabled,    true);
        ctx->setSpecConstant(D3D9SpecConstantId::VertexFogMode, cMode);
        ctx->setSpecConstant(D3D9SpecConstantId::PixelFogMode,  D3DFOG_NONE);
      });
    }
    else if (pixelFog) {
      D3DFOGMODE mode = D3DFOGMODE(rs[D3DRS_FOGTABLEMODE]);

      UpdateFogConstants(mode);
      EmitCs([cMode = mode] (DxvkContext* ctx) {
        ctx->setSpecConstant(D3D9SpecConstantId::FogEnabled,    true);
        ctx->setSpecConstant(D3D9SpecConstantId::VertexFogMode, D3DFOG_NONE);
        ctx->setSpecConstant(D3D9SpecConstantId::PixelFogMode,  cMode);
      });
    }
    else {
      EmitCs([] (DxvkContext* ctx) {
        ctx->setSpecConstant(D3D9SpecConstantId::FogEnabled,    false);
        ctx->setSpecConstant(D3D9SpecConstantId::VertexFogMode, D3DFOG_NONE);
        ctx->setSpecConstant(D3D9SpecConstantId::PixelFogMode,  D3DFOG_NONE);
      });
    }
  }