class CConduitTestBackFaceCulling : public CRhinoDisplayConduit
{
public:
    CConduitTestBackFaceCulling(const ON_Brep* brep, const CRhinoObject* obj);
    ~CConduitTestBackFaceCulling() = default;

    bool ExecConduit(
        CRhinoDisplayPipeline& dp, // pipeline executing this conduit
        UINT nChannel,             // current channel within the pipeline
        bool& bTerminate           // channel termination flag
    );

private:
    const ON_Brep * m_Brep;
    const CRhinoObject* mObject;
};

CConduitTestBackFaceCulling::CConduitTestBackFaceCulling(const ON_Brep* brep, const CRhinoObject* obj)
    : CRhinoDisplayConduit(CSupportChannels::SC_CALCBOUNDINGBOX | CSupportChannels::SC_PREDRAWOBJECTS | CSupportChannels::SC_DRAWOBJECT),
    m_Brep(brep), mObject(obj)
{
}

bool CConduitTestBackFaceCulling::ExecConduit(CRhinoDisplayPipeline& dp, UINT nChannel, bool& bTerminate)
{
    UNREFERENCED_PARAMETER(bTerminate);

    // Determine which channel we're currently executing in...
    switch (nChannel)
    {
    case CSupportChannels::SC_CALCBOUNDINGBOX:
    {
        ON_BoundingBox  bbox;
        m_Brep->GetTightBoundingBox(bbox, false);
        // Now adjust the channel attribute's bounding box with the accumulated one...
        m_pChannelAttrs->m_BoundingBox.Union(bbox);
    }
    break;

    case CSupportChannels::SC_DRAWOBJECT:
    {
        if (m_pChannelAttrs->m_pObject == mObject)
        {
            m_pChannelAttrs->m_bDrawObject = false;
        }
    }
    break;

    case CSupportChannels::SC_PREDRAWOBJECTS:
    {
        dp.PushDepthTesting(false);
        m_pDisplayAttrs->m_bShowIsocurves = false;
        m_pDisplayAttrs->m_bCullBackfaces = true;

        ON_Brep* brep = const_cast<ON_Brep*>(m_Brep);

        CDisplayPipelineMaterial material;
        material.m_FrontMaterial.m_diffuse = ON_Color(0, 0, 255);
        material.m_BackMaterial.m_diffuse = ON_Color(0, 0, 255);
        dp.DrawShadedBrep(brep, &material, 0);
		//dp.DrawShadedBrep(*brep, &material); //in Rhino5

        m_pDisplayAttrs->m_bShowIsocurves = true;
        m_pDisplayAttrs->m_bCullBackfaces = false;
        dp.PopDepthTesting();
       
    }
    break;
    }

    return true;
}

#pragma region TestBackFaceCullingCmd command

class CCommandTestBackFaceCullingCmd : public CRhinoCommand
{
public:
    CCommandTestBackFaceCullingCmd() {}
    ~CCommandTestBackFaceCullingCmd() {}
    UUID CommandUUID()
    {
        // {D7C7E039-5232-41B4-A573-725667752FEB}
        static const GUID TestBackFaceCullingCmdCommand_UUID =
        { 0xD7C7E039, 0x5232, 0x41B4, { 0xA5, 0x73, 0x72, 0x56, 0x67, 0x75, 0x2F, 0xEB } };
        return TestBackFaceCullingCmdCommand_UUID;
    }
    const wchar_t* EnglishCommandName() { return L"TestBackFaceCullingCmd"; }
    const wchar_t* LocalCommandName() const { return L"TestBackFaceCullingCmd"; }
    CRhinoCommand::result RunCommand(const CRhinoCommandContext&);
};

// The one and only CCommandTestBackFaceCullingCmd object
static class CCommandTestBackFaceCullingCmd theTestBackFaceCullingCmdCommand;

CRhinoCommand::result CCommandTestBackFaceCullingCmd::RunCommand(const CRhinoCommandContext& context)
{
    CRhinoGetObject go;
    go.SetCommandPrompt(L"Select brep");
    go.SetGeometryFilter(ON::brep_object);
    go.GetObjects(1, 1);
    if (go.CommandResult() != success)
        return go.CommandResult();

    CRhinoObjRef ref = go.Object(0);
    const ON_Brep * brep = ref.Brep();

    const CRhinoObject * obj = ref.Object();

    CConduitTestBackFaceCulling conduit(brep, obj);
    conduit.Enable();

    RhinoApp().ActiveDoc()->Regen();

    CRhinoGetPoint gp;
    gp.SetCommandPrompt(L"Select point to stop conduit");
    gp.GetPoint();

    conduit.Disable();
    context.m_doc.Regen();
    return CRhinoCommand::success;
}

#pragma endregion