IBRT

IBRT is the Interactive BRL-CAD Ray Tracer. This repository now holds our application and our OSPRay plugins, not a vendored OSPRay source tree.

IBRT is currently beta software. Expect incomplete features and report reproducible problems through the repository's GitHub issue tracker.

What Lives Here

• apps/IBRT The Qt desktop viewer, render worker, and test suite.
• plugins/brl_cad The BRL-CAD OSPRay plugin built as ospray_module_brl_cad.
• docs Project-specific build notes, layout notes, and performance plans.

Dependency Model

OSPRay, Qt, Embree, rkcommon, ISPCRT, TBB, and related runtime dependencies come from an external bext install tree supplied at CMake configure time with BEXT_INSTALL_DIR. Alternatively, point BRLCAD_EXT_DIR at the bext build directory (the one holding install/ and noinstall/, as BRL-CAD does); the install tree is then BRLCAD_EXT_DIR/install.

This repo does not vendor or build OSPRay itself anymore.

Build

You need:

• a bext install tree, typically something like <bext>/.build/install
• a BRL-CAD install prefix
• CMake 3.20+
• a working C++ toolchain

Example:

cmake -S . -B build/local \
  -DBEXT_INSTALL_DIR=/path/to/bext/.build/install \
  -DBRLCAD_PREFIX=/path/to/brlcad/install
cmake --build build/local
ctest --test-dir build/local --output-on-failure

If Qt is not part of the supplied bext install, extend CMAKE_PREFIX_PATH when configuring.

Debug and Release

A Debug or Release IBRT build must use BRL-CAD and bext built in the same configuration; on Windows the two cannot be mixed. IBRT uses one configuration per build directory, so Debug and Release builds coexist and you switch by choosing a preset:

cmake --preset everything/Release && cmake --build --preset everything/Release
cmake --preset everything/Debug   && cmake --build --preset everything/Debug   # needs Debug deps

Each preset builds into build/everything/<Config>. everything is shorthand for everything/Release. A configure-time check fails fast with a clear message if the dependencies do not match the build type.

More detail lives in docs/building.md.

Runtime Notes

• IBRT and IBRTRenderWorker use OSPRay from the supplied bext install.
• The BRL-CAD plugin is built in this repo and deployed into the local runtime output for the app, worker, and tests.
• Demo BRL-CAD databases are loaded from BRLCAD_PREFIX/share/db and copied into local viewer runtimes when available.

Repository Docs

• Building
• Repo Layout
• Performance Notes
• Release Checklist