compile FREEGLUT as a subdirectory. this maintains a consistency

graphics/CMakeLists.txt

@@ -4,21 +4,38 @@ if(OpenGL_FOUND)
     if(NOT GLUT_FOUND)
         message("FreeGLUT library will be downloaded and built.")
         include(ExternalProject)
-        # Include GLFW
         ExternalProject_Add (
             FREEGLUT
             URL https://sourceforge.net/projects/freeglut/files/freeglut/3.2.1/freeglut-3.2.1.tar.gz
             URL_MD5 cd5c670c1086358598a6d4a9d166949d
-            CMAKE_ARGS  -DCMAKE_BUILD_TYPE=RelWithDebInfo
-                        -DFREEGLUT_BUILD_SHARED_LIBS=ON
+            CMAKE_GENERATOR ${CMAKE_GENERATOR}
+            CMAKE_GENERATOR_TOOLSET ${CMAKE_GENERATOR_TOOLSET}
+            CMAKE_GENERATOR_PLATFORM ${CMAKE_GENERATOR_PLATFORM}
+            CMAKE_ARGS  -DCMAKE_BUILD_TYPE=Release
+                        -DFREEGLUT_BUILD_SHARED_LIBS=OFF
                         -DFREEGLUT_BUILD_STATIC_LIBS=ON
                         -DFREEGLUT_BUILD_DEMOS=OFF
             PREFIX ${CMAKE_CURRENT_BINARY_DIR}/freeglut
-            BUILD_IN_SOURCE ON
+            # BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/freeglut-build
+            # BUILD_IN_SOURCE ON
+            # UPDATE_COMMAND ""
             INSTALL_COMMAND ""
+            CONFIGURE_COMMAND ""
+            BUILD_COMMAND ""
         )
         ExternalProject_Get_Property(FREEGLUT SOURCE_DIR)
-        set(FREEGLUT_DIR ${SOURCE_DIR})
+        ExternalProject_Get_Property(FREEGLUT BINARY_DIR)
+        set(FREEGLUT_BIN_DIR ${BINARY_DIR})
+        set(FREEGLUT_SRC_DIR ${SOURCE_DIR})
+        # add_library(libfreeglut STATIC IMPORTED)
+        # set_target_properties(libfreeglut PROPERTIES IMPORTED_LOCATION ${FREEGLUT_BIN_DIR})
+
+        set(FREEGLUT_BUILD_DEMOS OFF CACHE BOOL "")
+        set(FREEGLUT_BUILD_SHARED_LIBS OFF CACHE BOOL "")
+        set(FREEGLUT_BUILD_STATIC_LIBS ON CACHE BOOL "")
+        add_subdirectory(${FREEGLUT_SRC_DIR} ${FREEGLUT_BIN_DIR})
+        # add_subdirectory(${BINARY_DIR})
+        # find_package(FreeGLUT)
     endif(NOT GLUT_FOUND)
 else(OpenGL_FOUND)
     message(WARNING "OPENGL not found. Will not build graphical outputs.")
@@ -35,7 +52,7 @@ foreach( testsourcefile ${APP_SOURCES} )
     string( REPLACE ".cpp" "" testname ${testsourcefile} )
     add_executable( ${testname} ${testsourcefile} )
 
-    # set_target_properties(${testname} PROPERTIES LINKER_LANGUAGE CXX)
+    set_target_properties(${testname} PROPERTIES LINKER_LANGUAGE CXX)
     if(OpenMP_CXX_FOUND)
         target_link_libraries(${testname} PRIVATE OpenMP::OpenMP_CXX)
     endif()
@@ -43,9 +60,11 @@ foreach( testsourcefile ${APP_SOURCES} )
     if(OpenGL_FOUND)
         if(NOT GLUT_FOUND)
             add_dependencies(${testname} FREEGLUT)
-            target_include_directories(${testname} PRIVATE ${FREEGLUT_DIR}/include)
-            target_link_directories(${testname} PRIVATE ${FREEGLUT_DIR}/lib)
-            target_link_libraries(${testname} PRIVATE freeglut OpenGL::GL)
+            target_include_directories(${testname} PRIVATE ${FREEGLUT_SRC_DIR}/include)
+            target_link_directories(${testname} PRIVATE ${FREEGLUT_BIN_DIR}/lib)
+            target_link_libraries(${testname} PRIVATE OpenGL::GL freeglut_static)
+            # target_include_directories(${testname} PRIVATE ${FREEGLUT_INCLUDE_DIRS})
+            # target_link_libraries(${testname} INTERFACE freeglut_static)
         else()
             target_include_directories(${testname} PRIVATE ${GLUT_INCLUDE_DIRS})
             target_link_libraries(${testname} PRIVATE OpenGL::GL ${GLUT_LIBRARIES})

graphics/spirograph.cpp

@@ -13,6 +13,13 @@
  * src="https://upload.wikimedia.org/wikipedia/commons/3/39/Resonance_Cascade.svg"
  * alt="Spirograph geometry from Wikipedia" style="width: 250px"/></a>
  */
+#ifdef USE_GLUT
+#ifdef __APPLE__
+#include <GLUT/glut.h>  // include path on Macs is different
+#else
+#include <GL/glut.h>
+#endif  // __APPLE__
+#endif
 #define _USE_MATH_DEFINES /**< required for MSVC compiler */
 #include <array>
 #include <cmath>
@@ -25,13 +32,6 @@
 #ifdef _OPENMP
 #include <omp.h>
 #endif
-#ifdef USE_GLUT
-#ifdef __APPLE__
-#include <GLUT/glut.h>  // include path on Macs is different
-#else
-#include <GL/glut.h>
-#endif  // __APPLE__
-#endif
 
 /**
  * @namespace spirograph Functions related to spirograph.cpp