download and build freeglut if not available

CMakeLists.txt

@@ -25,16 +25,6 @@ if(USE_OPENMP)
         message(STATUS "No OpenMP found, no multithreading.")
     endif()
 endif()
-
-find_package(OpenGL)
-if(NOT OpenGL_FOUND)
-    message(WARNING "OpenGL not found, not compiling graphics programs.")
-else(NOT OpenGL_FOUND)
-    find_package(GLUT)
-    if(NOT GLUT_FOUND)
-        message(WARNING "GLUT not found, not compiling graphics programs.")
-    endif(NOT GLUT_FOUND)
-endif(NOT OpenGL_FOUND)
     
 add_subdirectory(math)
 add_subdirectory(others)

graphics/CMakeLists.txt

@@ -1,3 +1,25 @@
+find_package(OpenGL REQUIRED)
+find_package(GLUT)
+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
+                    -DFREEGLUT_BUILD_STATIC_LIBS=ON
+                    -DFREEGLUT_BUILD_DEMOS=OFF
+        PREFIX ${CMAKE_CURRENT_BINARY_DIR}/freeglut
+        BUILD_IN_SOURCE ON
+        INSTALL_COMMAND ""
+    )
+    ExternalProject_Get_Property(FREEGLUT SOURCE_DIR)
+    set(FREEGLUT_DIR ${SOURCE_DIR})
+endif(NOT GLUT_FOUND)
+
 # If necessary, use the RELATIVE flag, otherwise each source file may be listed
 # with full pathname. RELATIVE may makes it easier to extract an executable name
 # automatically.
@@ -9,18 +31,25 @@ 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(${testname} OpenMP::OpenMP_CXX)
+        target_link_libraries(${testname} PRIVATE OpenMP::OpenMP_CXX)
     endif()
-    if (GLUT_FOUND)
-        if(APPLE)
-            target_compile_options(${testname} PUBLIC -Wno-deprecated)
-        endif(APPLE)
-        target_compile_definitions(${testname} PUBLIC GLUT_FOUND)
-        target_include_directories(${testname} PUBLIC ${GLUT_INCLUDE_DIRS})
-        target_link_libraries(${testname} OpenGL::GL ${GLUT_LIBRARIES})
-    endif(GLUT_FOUND)
+    
+    if(NOT GLUT_FOUND)
+        add_dependencies(${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)
+    else()
+        target_include_directories(${testname} PRIVATE ${GLUT_INCLUDE_DIRS})
+        target_link_libraries(${testname} PRIVATE OpenGL::GL ${GLUT_LIBRARIES})
+    endif()
+    
+    if(APPLE)
+        target_compile_options(${testname} PRIVATE -Wno-deprecated)
+    endif(APPLE)
+    
     install(TARGETS ${testname} DESTINATION "bin/graphics")
 
 endforeach( testsourcefile ${APP_SOURCES} )

graphics/spirograph.cpp

@@ -25,13 +25,11 @@
 #ifdef _OPENMP
 #include <omp.h>
 #endif
-#ifdef GLUT_FOUND  // this is set by CMAKE automatically, if available
 #ifdef __APPLE__
 #include <GLUT/glut.h>  // include path on Macs is different
 #else
 #include <GL/glut.h>
 #endif  // __APPLE__
-#endif  // GLUT_FOUND
 
 /**
  * @namespace spirograph Functions related to spirograph.cpp
@@ -114,7 +112,6 @@ void test() {
     fp.close();
 }
 
-#ifdef GLUT_FOUND  // this is set by CMAKE automatically, if available
 /** A wrapper that is not available in all GLUT implementations.
  */
 static inline void glutBitmapString(void *font, char *message) {
@@ -214,12 +211,13 @@ void timer_cb(int t) {
     glutTimerFunc(25, timer_cb, 0);
     glutPostRedisplay();
 }
-#endif
+
 }  // namespace spirograph
 
 /** Main function */
 int main(int argc, char **argv) {
-#ifdef GLUT_FOUND
+    spirograph::test();
+
     glutInit(&argc, argv);
     glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
     glutCreateWindow("Spirograph");
@@ -228,9 +226,6 @@ int main(int argc, char **argv) {
     glutTimerFunc(25, spirograph::timer_cb, 0);
     glutDisplayFunc(spirograph::test2);
     glutMainLoop();
-#else
-    spirograph::test();
-#endif
 
     return 0;
 }