Add spherical surface support to GPU (OptiX) runner for High Flux Solar Furnace

[Copilot]

The GPU (OptiX) runner crashed on the High Flux Solar Furnace example file because the OptixCSP pipeline had no SPHERICAL surface type — only FLAT, PARABOLIC, MESH, and CYLINDER. The HFSF file uses spherical surfaces (s) with hexagonal apertures (h).

GPU pipeline additions

• soltrace_type.h — Added SPHERICAL to SurfaceType enum
• Surface.h — Added SurfaceSpherical class holding vertex curvature c = 1/R
• GeometryDataST.h — Added 6 GPU geometry structs (Rectangle_Spherical, Circle_Spherical, Hexagon_Spherical, Annulus_Spherical, Triangle_Spherical, Quadrilateral_Spherical) with corresponding Type enum entries (15–20), setters, and union members
• Soltrace.h — Added 6 *_SPHERICAL entries to OpticalEntityType (SBT offsets 13–18); NUM_OPTICAL_ENTITY_TYPES is now 19
• intersection.cu — Added spherical_solve() and spherical_world_normal() device helpers plus 6 __intersection__*_spherical kernels:

// Sphere x²+y²+(z-R)²=R² with R=1/c, substituting P=O+t*D:
// A·t² + B·t + C = 0
//   A = dx²+dy²+dz²
//   B = 2·(ox·dx + oy·dy + (oz−R)·dz)
//   C = ox²+oy² + oz·(oz−2R)
// Normal at hit (lx, ly): N = normalize(−c·lx, −c·ly, √(1−c²·(lx²+ly²)))

• geometry_manager.cpp — SPHERICAL branch added for all 6 aperture SBT offset assignments
• CspElement.cpp — SPHERICAL geometry data conversion for all 6 aperture types
• pipeline_manager.cpp — 6 new IntersectionKernelMap entries for spherical shader names
• optix_runner.cpp — case SurfaceType::SPHERE: maps SolTrace::Data::Sphere → OptixCSP::SurfaceSpherical

Tests

Added high_flux_solar_furnace_test.cpp with two tests:

• OptixRunnerCanRun — loads HFSF, runs GPU trace, asserts non-zero ray interactions
• OptixRunnerResultsConsistentWithNativeRunner — compares GPU vs. native total hit count within 10% relative tolerance (10 000 rays, fixed seed, no stochastic errors)

• Fixes High Flux Solar Furnace not supported by GPU runner #168

[jmaack24]

This is a pathological case that should get handled in SimulationData rather than accounted for here.

[jmaack24]

This doesn't filter out hits that are on the top half of the sphere as is done traditionally in SolTrace

[jmaack24]

We should probably rename parabolic_ray_to_local since it is being used in a spherical function.

[Copilot]

Pull request overview

This PR extends the OptiX (GPU) simulation pipeline to support SolTrace spherical (s) surfaces (including spherical variants of the supported aperture types), fixing crashes when running the High Flux Solar Furnace example, and adds/updates unit tests plus input validation in the simulation data model.

Changes:

• Added a SPHERICAL surface type to the OptiX pipeline, including GPU geometry payloads and OptiX intersection programs for spherical apertures.
• Wired spherical surface conversion/mapping through OptiX runner setup, geometry/SBT management, and pipeline kernel registration.
• Added a High Flux Solar Furnace regression test and refactored/expanded OptiX geometry intersection tests; added validation for surface/aperture constructors with accompanying tests.

Reviewed changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
google-tests/unit-tests/simulation_runner/optix_runner/high_flux_solar_furnace_test.cpp	New regression tests exercising spherical+hexagon geometry via the GPU runner.
google-tests/unit-tests/simulation_runner/optix_runner/geometry_intersection_test.cpp	Refactors common intersection assertions and adds spherical intersection coverage.
google-tests/unit-tests/simulation_runner/optix_runner/CMakeLists.txt	Registers the new HFSF unit test in the OptiX test target.
google-tests/unit-tests/simulation_runner/native_runner/sphere_calculator_test.cpp	Adjusts tests to set invalid parameters post-construction for constructor validation changes.
google-tests/unit-tests/simulation_runner/native_runner/parabola_calculator_test.cpp	Same as above for parabola calculator coverage.
google-tests/unit-tests/simulation_runner/native_runner/cylinder_calculator_test.cpp	Same as above for cylinder calculator and rectangle dimension validation.
google-tests/unit-tests/simulation_data/surface_test.cpp	Adds validation-focused unit tests for multiple surface types.
google-tests/unit-tests/simulation_data/aperture_test.cpp	Adds validation-focused unit tests for multiple aperture types.
coretrace/simulation_runner/optix_runner/OptixCSP/src/shaders/Soltrace.h	Extends OptiX SBT optical entity type enum with spherical variants.
coretrace/simulation_runner/optix_runner/OptixCSP/src/shaders/intersection.cu	Implements spherical intersection helper math and 6 spherical intersection programs.
coretrace/simulation_runner/optix_runner/OptixCSP/src/shaders/GeometryDataST.h	Adds spherical geometry payload structs, enum entries, setters/getters, and union members.
coretrace/simulation_runner/optix_runner/OptixCSP/src/core/Surface.h	Adds SurfaceSpherical to represent spherical curvature in OptixCSP.
coretrace/simulation_runner/optix_runner/OptixCSP/src/core/soltrace_type.h	Adds SPHERICAL to OptixCSP SurfaceType.
coretrace/simulation_runner/optix_runner/OptixCSP/src/core/pipeline_manager.cpp	Registers spherical intersection program names in the kernel map.
coretrace/simulation_runner/optix_runner/OptixCSP/src/core/geometry_manager.cpp	Assigns spherical SBT offsets for each aperture type during geometry collection.
coretrace/simulation_runner/optix_runner/OptixCSP/src/core/CspElement.cpp	Converts spherical elements into the new spherical GPU geometry payloads.
coretrace/simulation_runner/optix_runner/optix_runner.cpp	Maps SolTrace Sphere surfaces to OptixCSP SurfaceSpherical during setup.
coretrace/simulation_data/surface.hpp	Adds a virtual validate() hook and calls it from surface constructors.
coretrace/simulation_data/surface.cpp	Implements surface validation logic for cone/cylinder/parabola/sphere.
coretrace/simulation_data/aperture.hpp	Adds a virtual validate() hook and calls it from aperture constructors.
coretrace/simulation_data/aperture.cpp	Implements aperture validation logic for multiple aperture types.

Suppressed comments (2)

google-tests/unit-tests/simulation_runner/optix_runner/high_flux_solar_furnace_test.cpp:123

• Hit counting in the native-vs-OptiX consistency check ignores TRANSMIT events, which can make the ratio comparison fail even when both runners behave consistently for transmissive optics.

                RayEvent rev = rec->get_event(j);
                if (rev == RayEvent::ABSORB || rev == RayEvent::REFLECT)
                    ++native_total_hits;
            }

google-tests/unit-tests/simulation_runner/optix_runner/high_flux_solar_furnace_test.cpp:161

• Hit counting for the OptiX run ignores TRANSMIT events, which can make the GPU-vs-native comparison fail for transmissive optics.

                RayEvent rev = rec->get_event(j);
                if (rev == RayEvent::ABSORB || rev == RayEvent::REFLECT)
                    ++optix_total_hits;
            }

---

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[jmaack24]

My concerns were addressed

[jmaack24]

Summary of changes I made after Copilot changes

PR Summary

This PR adds spherical-surface support for the GPU OptiX runner used by the High Flux Solar Furnace workflow, hardens surface/aperture validation, and expands tests around geometry intersection behavior.

Why This Change

The OptiX path needed end-to-end handling for spherical surfaces and improved guardrails for invalid geometry metadata. This branch also improves test coverage and stabilizes tolerance behavior for intersection-related assertions.

What Changed

Features

• Added spherical surface support in the OptiX runner pipeline.
• Extended geometry/surface data plumbing from simulation data into OptiX-side structures.
• Updated shader intersection logic to correctly handle spherical cases.

Validation and Robustness

• Added validation for required surface and aperture fields.
• Removed unused shader variables and made cleanup/refactor adjustments related to spherical/rectangular intersection paths.
• Final naming cleanup for parabola local-ray transform helper.

Tests

• Added basic spherical intersection tests for the OptiX runner.
• Added High Flux Solar Furnace OptiX-focused tests in:
  • google-tests/unit-tests/simulation_runner/optix_runner/high_flux_solar_furnace_test.cpp
• Refactored shared intersection test code and updated tolerance strategy (including relative-error checks), settling on 10% tolerance where appropriate.
• Added/updated simulation-data tests for surface/aperture behavior.

Scope of Files

Primary implementation areas:

• coretrace/simulation_runner/optix_runner/OptixCSP/src/shaders/intersection.cu
• coretrace/simulation_runner/optix_runner/OptixCSP/src/shaders/GeometryDataST.h
• coretrace/simulation_runner/optix_runner/OptixCSP/src/core/CspElement.cpp
• coretrace/simulation_data/surface.cpp
• coretrace/simulation_data/aperture.cpp

Primary test areas:

• google-tests/unit-tests/simulation_runner/optix_runner/geometry_intersection_test.cpp
• google-tests/unit-tests/simulation_runner/optix_runner/high_flux_solar_furnace_test.cpp
• google-tests/unit-tests/simulation_data/surface_test.cpp
• google-tests/unit-tests/simulation_data/aperture_test.cpp

Change Size

• 21 files changed
• 1475 insertions
• 1009 deletions

Reviewer Notes

• Most of the complexity/risk is in GPU-side intersection math and data layout compatibility between host/device structures.
• Test tolerance changes were iterated to reduce brittleness while preserving meaningful signal for regression detection.
• Branch is clean and synchronized with remote at the time of summary generation.

[taylorbrown75]

Looks good. Solar furnace example works on gpu.