G4OpticalSurface
===================


G4DAE surface
--------------

::

    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearPoolCoverSurface         <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__AdDetails__AdSurfacesAll__RSOilSurface                      <OpticalSurface f3 m1 t0 v1 pBACKSCATTERCONSTANT:4,SPECULARSPIKECONSTANT:4,REFLECTIVITY:12,SPECULARLOBECONSTANT:4 > 
    __dd__Geometry__AdDetails__AdSurfacesAll__ESRAirSurfaceTop                  <OpticalSurface f0 m1 t0 v0 pREFLECTIVITY:31 > 
    __dd__Geometry__AdDetails__AdSurfacesAll__ESRAirSurfaceBot                  <OpticalSurface f0 m1 t0 v0 pREFLECTIVITY:31 > 
    __dd__Geometry__AdDetails__AdSurfacesAll__SSTOilSurface                     <OpticalSurface f3 m1 t0 v1 pREFLECTIVITY:4 > 
    __dd__Geometry__AdDetails__AdSurfacesAll__AdCableTraySurface                <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__AdDetails__AdSurfacesNear__SSTWaterSurfaceNear1             <OpticalSurface f3 m1 t0 v1 pREFLECTIVITY:4 > 
    __dd__Geometry__AdDetails__AdSurfacesNear__SSTWaterSurfaceNear2             <OpticalSurface f3 m1 t0 v1 pREFLECTIVITY:4 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__PmtMtTopRingSurface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__PmtMtBaseRingSurface          <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__PmtMtRib1Surface              <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__PmtMtRib2Surface              <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__PmtMtRib3Surface              <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__LegInIWSTubSurface            <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__TablePanelSurface             <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__SupportRib1Surface            <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__SupportRib5Surface            <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__SlopeRib1Surface              <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__SlopeRib5Surface              <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__ADVertiCableTraySurface       <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__ShortParCableTraySurface      <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearInnInPiperSurface        <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearInnOutPiperSurface       <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearIWSCurtainSurface        <OpticalSurface f3 m1 t0 v0.2 pBACKSCATTERCONSTANT:2,SPECULARSPIKECONSTANT:2,REFLECTIVITY:34,SPECULARLOBECONSTANT:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__LegInOWSTubSurface            <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__UnistrutRib6Surface          <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__UnistrutRib7Surface          <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__UnistrutRib3Surface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__UnistrutRib5Surface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__UnistrutRib4Surface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__UnistrutRib1Surface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__UnistrutRib2Surface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__UnistrutRib8Surface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__UnistrutRib9Surface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__TopShortCableTraySurface     <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__TopCornerCableTraySurface     <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__VertiCableTraySurface         <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearOutInPiperSurface        <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearOutOutPiperSurface       <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearOWSLinerSurface          <OpticalSurface f3 m1 t0 v0.2 pBACKSCATTERCONSTANT:2,SPECULARSPIKECONSTANT:2,REFLECTIVITY:34,SPECULARLOBECONSTANT:2 > 
    __dd__Geometry__PoolDetails__PoolSurfacesAll__LegInDeadTubSurface           <OpticalSurface f3 m1 t0 v1 pRINDEX:2,REFLECTIVITY:2 > 
    __dd__Geometry__PoolDetails__NearPoolSurfaces__NearDeadLinerSurface         <OpticalSurface f3 m1 t0 v0.2 pBACKSCATTERCONSTANT:2,SPECULARSPIKECONSTANT:2,REFLECTIVITY:34,SPECULARLOBECONSTANT:2 > 

Maybe should translate the finish into Chroma via setting 

* `reflect_specular` for finish 0 (polished) 
* `reflect_diffuse` for finish 3 (ground) 


`materials/include/G4OpticalSurface.hh`::

    132 
    133     G4OpticalSurface(const G4String& name,
    134              G4OpticalSurfaceModel model = glisur,
    135              G4OpticalSurfaceFinish finish = polished,
    136              G4SurfaceType type = dielectric_dielectric,
    137              G4double value = 1.0);
    138         // Constructor of an optical surface object.
    139 


`materials/include/G4SurfaceProperty.hh`::

     66 enum G4SurfaceType
     67 {
     68    dielectric_metal,            // dielectric-metal interface
     69    dielectric_dielectric,       // dielectric-dielectric interface
     70    dielectric_LUT,              // dielectric-Look-Up-Table interface
     71    firsov,                      // for Firsov Process
     72    x_ray                        // for x-ray mirror process
     73 };



Geant4 Surface
---------------

`processes/optical/src/G4OpBoundaryProcess.cc`


DAE/GDML persisted
--------------------

* glisur value **Polish**
* non-glisur value  **SigmaAlpha**

::

    242 /*
    243  * Create opticalsurface element with attributes from G4OpticalSurface*
    244  * append to first argument element
    245  * 
    246  * from G4GDMLWriteSolids::OpticalSurfaceWrite
    247  */
    248 void G4DAEWriteStructure::
    249 OpticalSurfaceWrite(xercesc::DOMElement* targetElement,
    250                     const G4OpticalSurface* const surf)
    251 {
    252    xercesc::DOMElement* optElement = NewElement("opticalsurface");
    253    G4OpticalSurfaceModel smodel = surf->GetModel();
    254    G4double sval = (smodel==glisur) ? surf->GetPolish() : surf->GetSigmaAlpha();
    255 
    256    optElement->setAttributeNode(NewNCNameAttribute("name", surf->GetName()));
    257    optElement->setAttributeNode(NewAttribute("model", smodel));
    258    optElement->setAttributeNode(NewAttribute("finish", surf->GetFinish()));
    259    optElement->setAttributeNode(NewAttribute("type", surf->GetType()));
    260    optElement->setAttributeNode(NewAttribute("value", sval));
    261 
    262    G4MaterialPropertiesTable* ptable = surf->GetMaterialPropertiesTable();
    263    PropertyWrite( optElement, ptable );
    264 
    265    targetElement->appendChild(optElement);
    266 }



Chroma Surface
----------------

::

    __device__ int
    propagate_at_surface(Photon &p, State &s, curandState &rng, Geometry *geometry,
                         bool use_weights=false)
    {
        Surface *surface = geometry->surfaces[s.surface_index];

        if (surface->model == SURFACE_COMPLEX)
            return propagate_complex(p, s, rng, surface, use_weights);
        else if (surface->model == SURFACE_WLS)
            return propagate_at_wls(p, s, rng, surface, use_weights);
        else {
            // use default surface model: do a combination of specular and
            // diffuse reflection, detection, and absorption based on relative
            // probabilties

            // since the surface properties are interpolated linearly, we are
            // guaranteed that they still sum to 1.0.
            float detect = interp_property(surface, p.wavelength, surface->detect);
            float absorb = interp_property(surface, p.wavelength, surface->absorb);
            float reflect_diffuse = interp_property(surface, p.wavelength, surface->reflect_diffuse);
            float reflect_specular = interp_property(surface, p.wavelength, surface->reflect_specular);