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 +1,62 @@
+# Find the QGLViewer headers and libraries
+# Tries to find the library by looking at headers / lib file.
+#
+# Defines:
+#   QGLViewer_FOUND : True if QGLViewer is found
+#
+# Provides 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
+  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)