Add GeometricTools as a bext module

This is preliminary - setting up to replace our copies of "ported" GTE
algorithms with calls to the upstream copies directly.  The key part of
GTE for our use case is header only, so treating it like Eigen and
staging it in noinstall.

.gitmodules

@@ -304,3 +304,6 @@
 	url = https://github.com/BRL-CAD/geogram.git
 	branch = RELEASE
         ignore = dirty
+[submodule "gte/GeometricTools"]
+	path = gte/GeometricTools
+	url = https://github.com/BRL-CAD/GeometricTools

CMake/FindGTE.cmake

@@ -0,0 +1,40 @@
+# Find GeometricTools Mathematics headers
+#
+# Once done this will define
+#
+#  GTE_FOUND - system has GTE Mathematics headers
+#  GTE_INCLUDE_DIR - the GTE include directory
+#
+# and the following imported target:
+#
+#  GTE::GTE- Provides include dir for GeometricTools Mathematics headers
+
+set(_GTE_SEARCHES)
+
+# Search GTE_ROOT first if it is set.
+if(GTE_ROOT)
+  set(_GTE_SEARCH_ROOT PATHS ${GTE_ROOT} NO_DEFAULT_PATH)
+  list(APPEND _GTE_SEARCHES _GTE_SEARCH_ROOT)
+endif()
+
+# Try each search configuration.
+foreach(search ${_GTE_SEARCHES})
+	find_path(GTE_INCLUDE_DIR NAMES GTE/Mathematics/ConvexHull3.h ${${search}} PATH_SUFFIXES include)
+endforeach()
+
+mark_as_advanced(GTE_INCLUDE_DIR)
+
+# handle the QUIETLY and REQUIRED arguments and set ZLIB_FOUND to TRUE if
+# all listed variables are TRUE
+include(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(GTE REQUIRED_VARS GTE_INCLUDE_DIR)
+
+if(GTE_FOUND)
+    set(GTE_INCLUDE_DIRS ${GTE_INCLUDE_DIR})
+
+    if(NOT TARGET GTE::GTE)
+      add_library(GTE::GTE UNKNOWN IMPORTED)
+      set_target_properties(GTE::GTE PROPERTIES
+        INTERFACE_INCLUDE_DIRECTORIES "${GTE_INCLUDE_DIRS}")
+    endif()
+endif()

dependencies.cmake

@@ -227,6 +227,11 @@ add_project(assetimport GROUPS "BRLCAD")
 # http://opencv.org
 add_project(opencv GROUPS "BRLCAD_EXTRA")
 
+# GeometricTools - a collection of geometry algorithms.
+# https://github.com/davideberly/GeometricTools
+add_project(gte GROUPS "BRLCAD")
+
+
 # OpenMesh Library - library for representing and manipulating polygonal meshes
 # https://www.graphics.rwth-aachen.de/software/openmesh/
 add_project(openmesh GROUPS "BRLCAD_EXTRA")

gte/CMakeLists.txt

@@ -0,0 +1,53 @@
+# Decide if we're using GeometricTools
+cad_enable(GTE "libbg")
+
+unset(ENGEN_BUNDLED CACHE)
+
+if (NOT ENABLE_GTE AND NOT DISABLE_GTE)
+
+  # https://github.com/davideberly/GeometricTools
+  find_package(GTE)
+
+  if (NOT TARGET GTE::GTE)
+    set(ENABLE_GTE "ON" CACHE BOOL "Enable GeometricTools build")
+  endif (NOT TARGET GTE::GTE)
+
+endif (NOT ENABLE_GTE AND NOT DISABLE_GTE)
+
+set(ENABLE_GTE "${ENABLE_GTE}" CACHE BOOL "Enable GeometricTools build")
+
+# Decision made
+
+if (ENABLE_GTE)
+
+  git_submodule_init(GeometricTools GTE/CMakeLists.txt)
+
+  TargetDeps(GTE)
+
+  ExternalProject_Add(GTE_BLD
+    URL "${CMAKE_CURRENT_SOURCE_DIR}/GeometricTools"
+    BUILD_ALWAYS ${EXT_BUILD_ALWAYS} ${LOG_OPTS}
+    PATCH_COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/gte.patch
+    CMAKE_ARGS
+    ${BUILD_TYPE_SPECIFIER}
+    -DCMAKE_INSTALL_PREFIX=${CMAKE_NOBUNDLE_INSTALL_PREFIX}
+    LOG_CONFIGURE ${EXT_BUILD_QUIET}
+    LOG_BUILD ${EXT_BUILD_QUIET}
+    LOG_INSTALL ${EXT_BUILD_QUIET}
+    LOG_OUTPUT_ON_FAILURE ${EXT_BUILD_QUIET}
+    STEP_TARGETS install
+    )
+
+  TargetInstallDeps(GTE GTE_DEPENDS)
+
+  set(GTE_BUNDLED TRUE CACHE BOOL "GeometricTools bundle flag")
+
+endif (ENABLE_GTE)
+
+# Local Variables:
+# tab-width: 8
+# mode: cmake
+# indent-tabs-mode: t
+# End:
+# ex: shiftwidth=2 tabstop=8
+

gte/gte.deps

@@ -0,0 +1,2 @@
+PATCH
+

gte/gte.patch

@@ -0,0 +1,23 @@
+diff -Naur GeometricTools/CMakeLists.txt GTE_BLD/CMakeLists.txt
+--- GeometricTools/CMakeLists.txt	1969-12-31 19:00:00.000000000 -0500
++++ GTE_BLD/CMakeLists.txt	2024-07-31 16:48:17.163077007 -0400
+@@ -0,0 +1,19 @@
++cmake_minimum_required(VERSION 3.8)
++
++project(GTE)
++
++file(GLOB GTE_MFILES "${CMAKE_SOURCE_DIR}/GTE/Mathematics/*")
++
++if(NOT DEFINED INCLUDE_DIR)
++  set(INCLUDE_DIR include)
++endif(NOT DEFINED INCLUDE_DIR)
++
++install(FILES ${GTE_MFILES} DESTINATION ${INCLUDE_DIR}/GTE/Mathematics)
++
++# Local Variables:
++# tab-width: 8
++# mode: cmake
++# indent-tabs-mode: t
++# End:
++# ex: shiftwidth=2 tabstop=8
++