From c87a8a5c713a5863fe4cbe24bd26dbd45a443650 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Mon, 14 Sep 2020 15:30:09 +0300
Subject: [PATCH] Add a CMake option for robust geom predicates

---
 libs/geom/CMakeLists.txt                      | 14 +++++++++++---
 libs/geom/include/psemek/geom/incircle.hpp    |  8 ++++++++
 libs/geom/include/psemek/geom/orientation.hpp |  8 ++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/libs/geom/CMakeLists.txt b/libs/geom/CMakeLists.txt
index 2493f342..814df922 100644
--- a/libs/geom/CMakeLists.txt
+++ b/libs/geom/CMakeLists.txt
@@ -1,9 +1,17 @@
-find_package(Boost REQUIRED)
-find_package(GMP REQUIRED)
+option(PSEMEK_GEOM_ROBUST_PREDICATES "Use robust geometric predicates" OFF)
+
+if(PSEMEK_GEOM_ROBUST_PREDICATES)
+	find_package(Boost REQUIRED)
+	find_package(GMP REQUIRED)
+endif()
 
 file(GLOB_RECURSE PSEMEK_GEOM_HEADERS "include/*.hpp")
 file(GLOB_RECURSE PSEMEK_GEOM_SOURCES "source/*.cpp")
 
 add_library(geom ${PSEMEK_GEOM_HEADERS} ${PSEMEK_GEOM_SOURCES})
 target_include_directories(geom PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/include")
-target_link_libraries(geom PUBLIC util Boost::boost GMP)
+target_link_libraries(geom PUBLIC util)
+if(PSEMEK_GEOM_ROBUST_PREDICATES)
+	target_link_libraries(geom PUBLIC Boost::boost GMP)
+	target_compile_definitions(geom PUBLIC -DPSEMEK_GEOM_ROBUST_PREDICATES=1)
+endif()
diff --git a/libs/geom/include/psemek/geom/incircle.hpp b/libs/geom/include/psemek/geom/incircle.hpp
index 7491724f..92e5ed24 100644
--- a/libs/geom/include/psemek/geom/incircle.hpp
+++ b/libs/geom/include/psemek/geom/incircle.hpp
@@ -4,7 +4,9 @@
 #include <psemek/geom/point.hpp>
 #include <psemek/geom/orientation.hpp>
 
+#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
 #include <boost/multiprecision/gmp.hpp>
+#endif
 
 #include <type_traits>
 
@@ -12,7 +14,11 @@ namespace psemek::geom
 {
 
 	template <typename T>
+#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
 	std::enable_if_t<!std::is_floating_point_v<T>, sign_t>
+#else
+	sign_t
+#endif
 		in_circle(point<T, 2> const & p0, point<T, 2> const & p1, point<T, 2> const & p2, point<T, 2> const & p3)
 	{
 		auto proj = [](point<T, 2> const & p)
@@ -25,6 +31,7 @@ namespace psemek::geom
 		return orientation(proj(p0), proj(p1), proj(p2), proj(p3));
 	}
 
+#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
 	template <typename T>
 	std::enable_if_t<std::is_floating_point_v<T>, sign_t>
 		in_circle(point<T, 2> const & p0, point<T, 2> const & p1, point<T, 2> const & p2, point<T, 2> const & p3)
@@ -67,5 +74,6 @@ namespace psemek::geom
 			return in_circle(cast<exact_type>(p0), cast<exact_type>(p1), cast<exact_type>(p2), cast<exact_type>(p3));
 		}
 	}
+#endif
 
 }
diff --git a/libs/geom/include/psemek/geom/orientation.hpp b/libs/geom/include/psemek/geom/orientation.hpp
index 41d9a452..ab77c9aa 100644
--- a/libs/geom/include/psemek/geom/orientation.hpp
+++ b/libs/geom/include/psemek/geom/orientation.hpp
@@ -4,7 +4,9 @@
 #include <psemek/geom/point.hpp>
 #include <psemek/geom/sign.hpp>
 
+#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
 #include <boost/multiprecision/gmp.hpp>
+#endif
 
 #include <limits>
 #include <type_traits>
@@ -14,7 +16,11 @@ namespace psemek::geom
 
 	// TODO: generic implementation
 	template <typename T>
+#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
 	std::enable_if_t<!std::is_floating_point_v<T>, sign_t>
+#else
+	sign_t
+#endif
 		orientation(point<T, 2> const & p0, point<T, 2> const & p1, point<T, 2> const & p2)
 	{
 		T const d = det(p1 - p0, p2 - p0);
@@ -27,6 +33,7 @@ namespace psemek::geom
 			return sign_t::zero;
 	}
 
+#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
 	template <typename T>
 	std::enable_if_t<std::is_floating_point_v<T>, sign_t>
 		orientation(point<T, 2> const & p0, point<T, 2> const & p1, point<T, 2> const & p2)
@@ -50,6 +57,7 @@ namespace psemek::geom
 			return orientation(cast<exact_type>(p0), cast<exact_type>(p1), cast<exact_type>(p2));
 		}
 	}
+#endif
 
 	template <typename T>
 	sign_t orientation(point<T, 3> const & p0, point<T, 3> const & p1, point<T, 3> const & p2, point<T, 3> const & p3)