bext - External Dependencies for BRL-CAD

bext builds third-party libraries and helper tools used by BRL-CAD. By default it prefers suitable system packages and builds local copies only when they are needed.

Quick start

Clone the repository, configure a build directory, and build:

git clone https://github.com/BRL-CAD/bext
mkdir bext_build
cd bext_build
cmake ../bext -DCMAKE_BUILD_TYPE=Release
cmake --build . --config Release --parallel 8

Submodules are populated on demand during configure. For checkout and platform setup details, see INSTALL.md.

How selection works

Build selection happens in three layers:

1. USE_* options decide which dependency families are in scope.
2. For in-scope packages, the default behavior is to use a suitable system package if one is found and build a local copy only when needed.
3. ENABLE_<pkg>=ON or OFF overrides one package explicitly.

Default USE_* values:

• USE_BRLCAD=ON
• USE_BRLCAD_EXTRA=ON
• USE_GDAL=ON
• USE_QT=ON
• USE_TCL=ON
• USE_APPLESEED=OFF
• USE_OSPRAY=OFF

ENABLE_ALL=ON changes step 2 by preferring local builds for packages in the active USE_* groups. It does not turn on groups whose USE_* option is OFF.

When bext is driven from a BRL-CAD build, BRLCAD_COMPONENTS can further narrow some BRL-CAD-related packages to only those needed by the requested component set.

Common recipes

Default behavior:

cmake ../bext -DCMAKE_BUILD_TYPE=Release

Bundled builds for the default active groups:

cmake ../bext -DENABLE_ALL=ON -DCMAKE_BUILD_TYPE=Release

Minimal BRL-CAD-oriented build without extras, GDAL, Qt, or Tcl/Tk:

cmake ../bext \
  -DUSE_BRLCAD_EXTRA=OFF \
  -DUSE_GDAL=OFF \
  -DUSE_QT=OFF \
  -DUSE_TCL=OFF \
  -DCMAKE_BUILD_TYPE=Release

Everything on:

cmake ../bext \
  -DENABLE_ALL=ON \
  -DUSE_APPLESEED=ON \
  -DUSE_OSPRAY=ON \
  -DCMAKE_BUILD_TYPE=Release

Build outputs

By default, CMAKE_INSTALL_PREFIX is the build directory. bext creates two output trees under that prefix:

• install/ - files intended to be bundled with downstream software
• noinstall/ - build-only tools and compile-time-only assets

When BRL-CAD consumes a bext build, BRLCAD_EXT_DIR should point at the parent directory containing both install/ and noinstall/.

Using the build outputs with BRL-CAD

If your bext build directory is ../bext_build, configure BRL-CAD with:

git clone https://github.com/BRL-CAD/brlcad
mkdir brlcad_build
cd brlcad_build
cmake ../brlcad -DBRLCAD_EXT_DIR=../bext_build -DCMAKE_BUILD_TYPE=Release
cmake --build . --config Release --parallel 8

If you built Qt in bext, also enable Qt in BRL-CAD:

cmake ../brlcad \
  -DBRLCAD_EXT_DIR=../bext_build \
  -DBRLCAD_ENABLE_QT=ON \
  -DCMAKE_BUILD_TYPE=Release

More information

• INSTALL.md - platform prerequisites, checkout options, and setup caveats
• DEPENDENCIES.md - package-to-group reference, output classification, and dependency addition workflow
• NOTES.md - maintainer notes and submodule procedures