OptiXRap Orientation : translates GGeo->OptiX

• orientation : Opticks Codebase Orientation for Developers
• https://bitbucket.org/simoncblyth/opticks/src/master/optixrap/
• https://bitbucket.org/simoncblyth/opticks/src/master/optixrap/OGeo.cc

OScene

steering for creation of OptiX context

OGeo

top level construction of OptiX geometry OGeo

OEvent

used for uploading gensteps and downloading hits

OSensorLib

buffer of sensor efficiencies and GPU angular efficiency texture

OCtx

experiment with a watertight wrapper around OptiX 5/6 that exposes no OptiX types in its interface

Other classes:

OContext.hh
OTracer.hh
OPropertyLib.hh
OTex.hh
OBuffer.hh
OTexture.hh
OFormat.hh
OConfig.hh
OPropagator.hh
OptiXUtil.hh
OptiXTest.hh
OSourceLib.hh
ORng.hh
OProg.hh
OLaunchTest.hh
OGeometry.hh
OGeoStat.hh
OFunc.hh
OError.hh
ODevice.hh
OColors.hh
OBufPair.hh
OBufBase.hh
OBuf.hh
OAccel.hh

OptiX CUDA Sources

• intersect_analytic.cu : General Analytic CSG intersection
  • intersect_analytic.cu : buffers
  • intersect_analytic.cu : bounds
  • intersect_analytic.cu : intersect
• OSensorLibGeoTest

Thoughts about migrating to OptiX 7

optixTrace Payload Restricted to 8*32b, no more PerRayData struct

• moving from uint4 identity to a single identity int (nodeIndex or tripletIdentity) that allows lookups into identity buffers would just allow all of cu/PerRayData_propagate.h to squeeze into 8 slots.
• should the identity buffers for all GMergedMesh be combined into one (with offsets being done to the indices) and a global identity index used ?

How much in SBT and how much in buffers ?

SBT is like laying down inputs to shader programs. What is the benefit of access from there as opposed to access from general global memory ?

With CSG trees vary in size greatly ?

Hmm all the geometry intersect examples getting their data from SBT : optixGetSbtDataPointer()

primIdx

700pdf p19

Primitives inside a build input are indexed starting from zero. This primitive index is accessible inside the IS, AH and CH program. The application can choose to offset this index for all primitives in a build input with no overhead at runtime. This can be particularly useful when data for consecutive build inputs is stored consecutively in device memory. The primitiveIndexOffset is only used when reporting the intersection primitive.

IAS can reference multiple GAS handles

• is it advantageous to have separate IAS for each GAS ?
• or one IAS for the entire geometry ?

GAS

Opticks GParts is generally concatenation of multiple GParts each from single solids. Each solid being a CSG node tree.

In OptiX < 7 used rtBuffer at geometry context with primBuffer, partBuffer, tranBuffer, …