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angular_generalization

  • move decision about backwards qe zeroing into accessor ?

new API : get_pmtid_qe_angular

"get_pmtid_qe_angular(pmtid,energy,lposcost,minus_cos_theta_aoi)":
  • lposcost (cosine of polar angle of local PMT boundary intersect position, "local_z/radius")
    • 0->1 : z>0 forward hemisphere of PMT
    • -1->0 : z<0 backward hemisphere of PMT : this would indicate a bug as PMT not sensitive at -ve z
  • minus_cos_theta (mct: dot product of PMT intersection point outwards normal and photon momentum direction)
    • minus_cos_theta > 0 : outwards going photons, with the normal
    • minus_cos_theta = 0 : grazing incidence, perpendicular to normal
    • minus_cos_theta < 0 : inwards going photons, against the normal

where "get_pmtid_qe_angular" used ? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`

Needed from C4CustomART::doIt

how to handle the implementation version change ?

Q:Can the different impls be encapsulated within the accessor ? A:Use with more args, but want version 0 to be current impl.

how to get local_position_theta in c4 ?

176 inline double C4CustomART::local_z( const G4Track& aTrack )
177 {
178     const G4AffineTransform& transform = aTrack.GetTouchable()->GetHistory()->GetTopTransform();
179     G4ThreeVector localPoint = transform.TransformPoint(theGlobalPoint);
180     zlocal = localPoint.z() ;
181 #ifdef C4_DEBUG
182     lposcost = localPoint.cosTheta() ;
183 #endif
184     return zlocal  ;
185 }

local_position_theta (aka lposcost) in Opticks

CSGOptiX/CSGOptiX7.cu:

579         const float3 P2 = mesh.vertex[ tri.z ];
580         const float3 P = ( 1.0f-barys.x-barys.y)*P0 + barys.x*P1 + barys.y*P2;
581
588         const float3 Ng = cross( P1-P0, P2-P0 );
589         // local normal from cross product of vectors between vertices : HMM is winding order correct : TODO: check sense of normal
590
591         const float3 N = normalize( optixTransformNormalFromObjectToWorldSpace( Ng ) );
592
593         float t = optixGetRayTmax() ;
594
601         float lposcost = normalize_z(P); // scuda.h


666 extern "C" __global__ void __intersection__is()
667 {
668
669 #if defined(DEBUG_PIDX)
670     //printf("//__intersection__is\n");
671 #endif
672
673     HitGroupData* hg  = (HitGroupData*)optixGetSbtDataPointer();
674     int nodeOffset = hg->prim.nodeOffset ;
675
676     const CSGNode* node = params.node + nodeOffset ;  // root of tree
677     const float4* plan = params.plan ;
678     const qat4*   itra = params.itra ;
679
680     const float  t_min = optixGetRayTmin() ;
681     const float3 ray_origin = optixGetObjectRayOrigin();
682     const float3 ray_direction = optixGetObjectRayDirection();
683
684     float4 isect ; // .xyz normal .w distance
685     if(intersect_prim(isect, node, plan, itra, t_min , ray_origin, ray_direction ))
686     {
687         const float lposcost = normalize_z(ray_origin + isect.w*ray_direction ) ;  // scuda.h
688         const unsigned hitKind = 0u ;     // only up to 127:0x7f : could use to customize how attributes interpreted
689         const unsigned boundary = node->boundary() ;  // all CSGNode in the tree for one CSGPrim tree have same boundary
690
691 #ifdef WITH_PRD
692         if(optixReportIntersection( isect.w, hitKind))
693         {
694             quad2* prd = SOPTIX_getPRD<quad2>(); // access prd addr from RG program
695             prd->q0.f = isect ;  // .w:distance and .xyz:normal which starts as the local frame one
696             prd->set_boundary(boundary) ;
697             prd->set_lposcost(lposcost);
698         }

scuda.h:

562 SUTIL_INLINE SUTIL_HOSTDEVICE float normalize_z(const float3& v)  // CLHEP ThreeVector calls this cosTheta
563 {
564   return v.z / sqrtf(dot(v, v));
565 }