[Sofa.GUI.Qt] Add cmake module for QGLViewer

Sofa/GUI/Qt/CMakeLists.txt

@@ -74,7 +74,7 @@ if(Sofa.GL_FOUND)
     option(SOFA_GUI_QT_ENABLE_QGLVIEWER "Compile the QGLViewer for the Qt GUI" ON)
 
     if(SOFA_GUI_QT_ENABLE_QGLVIEWER)
-        find_package(QGLViewer QUIET)
+        find_package(QGLViewer)
         if(NOT QGLViewer_FOUND)
             add_subdirectory(libQGLViewer/QGLViewer)
         endif()

cmake/Modules/FindQGLViewer.cmake

@@ -0,0 +1,69 @@
+# Find the QGLViewer headers and libraries
+# Behavior is to first look for config files.
+# If no config files were found, tries to find
+# the library by looking at headers / lib file.
+#
+# Defines:
+#   QGLViewer_FOUND : True if QGLViewer is found
+#
+# Provides target QGLViewer.
+
+find_package(QGLViewer NO_MODULE QUIET)
+
+if(NOT TARGET QGLViewer)
+
+  if(NOT QGLViewer_INCLUDE_DIR)
+    find_path(QGLViewer_INCLUDE_DIR
+      NAMES qglviewer.h
+      PATH_SUFFIXES include/QGLViewer
+    )
+  endif()
+
+  if(NOT QGLViewer_LIBRARY)
+  find_library(QGLViewer_LIBRARY
+    NAMES QGLViewer QGLViewer-qt5
+    PATH_SUFFIXES lib
+  )
+  endif()
+
+  if(QGLViewer_INCLUDE_DIR AND QGLViewer_LIBRARY)
+    set(QGLViewer_FOUND TRUE)
+  else()
+    if(QGLViewer_FIND_REQUIRED)
+      message(FATAL_ERROR "Cannot find QGLViewer")
+    endif()
+  endif()
+
+  # Same checks as Sofa.GUI.Qt
+  # i.e find Qt5, then if not, Qt6, then if not error
+  find_package(Qt5 COMPONENTS Core QUIET)
+  if (NOT Qt5Core_FOUND)
+      if(${CMAKE_VERSION} VERSION_GREATER "3.16.0")
+          find_package(Qt6 COMPONENTS Core CoreTools QUIET)
+      endif()
+  endif()
+
+  if (Qt5Core_FOUND)
+      find_package(Qt5 COMPONENTS Core Charts Gui Xml OpenGL Widgets REQUIRED)
+      set(QT_TARGETS Qt5::Core Qt5::Charts Qt5::Gui Qt5::Xml Qt5::OpenGL Qt5::Widgets)
+  elseif (Qt6Core_FOUND)
+      find_package(Qt6 COMPONENTS Gui Charts GuiTools Widgets WidgetsTools OpenGLWidgets Xml REQUIRED)
+      set(QT_TARGETS ${QT_TARGETS} Qt::Core Qt::Charts Qt::Gui Qt::Widgets Qt::OpenGLWidgets Qt::Xml)
+  endif()
+
+  if(QGLViewer_FOUND)
+    set(QGLViewer_LIBRARIES ${QGLViewer_LIBRARY})
+    set(QGLViewer_INCLUDE_DIRS ${QGLViewer_INCLUDE_DIR})
+
+    if(NOT QGLViewer_FIND_QUIETLY)
+      message(STATUS "Found QGLViewer: ${QGLVIEWER_LIBRARIES}")
+    endif(NOT QGLViewer_FIND_QUIETLY)
+
+    if(NOT TARGET QGLViewer)
+      add_library(QGLViewer INTERFACE IMPORTED)
+      set_property(TARGET QGLViewer PROPERTY INTERFACE_LINK_LIBRARIES "${QGLViewer_LIBRARIES}" ${QT_TARGETS})
+      set_property(TARGET QGLViewer PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${QGLViewer_INCLUDE_DIR}")
+    endif()
+  endif()
+  mark_as_advanced(QGLViewer_INCLUDE_DIR QGLViewer_LIBRARY)
+endif()