From 020e5bc7093a8a07b89edd92e6c12496457b7ad6 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Thu, 21 Jan 2021 14:47:50 +0100
Subject: [PATCH] CMake: workaround for possibly failing OpenGL check in vtk9

---
 CMakeLists.txt                               | 7 ++++++-
 cMake/FreeCAD_Helpers/PrintFinalReport.cmake | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f4dabf7657a7..5b177362e649 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,6 +50,12 @@ if(NOT FREECAD_LIBPACK_USE OR FREECAD_LIBPACK_CHECKFILE_CLBUNDLER)
     find_package(ZLIB REQUIRED)
     find_package(PyCXX REQUIRED)
     SetupOpenCasCade()
+    if(BUILD_GUI)
+        # Do this before the check for SMESH because it depends on vtk
+        # that may have its own OpenGL check but possibly fails and leaves
+        # OPENGL_gl_LIBRARY empty that results into linker errors
+        SetupOpenGL()
+    endif(BUILD_GUI)
     SetupSalomeSMESH()
     if (BUILD_FEM_NETGEN)
         find_package(NETGEN)
@@ -64,7 +70,6 @@ if(NOT FREECAD_LIBPACK_USE OR FREECAD_LIBPACK_CHECKFILE_CLBUNDLER)
     SetupFreetype()
 
     if(BUILD_GUI)
-        SetupOpenGL()
         SetupCoin3D()
         SetupSpaceball()
         SetupShibokenAndPyside()
diff --git a/cMake/FreeCAD_Helpers/PrintFinalReport.cmake b/cMake/FreeCAD_Helpers/PrintFinalReport.cmake
index 744fdd8ce9b1..96ea7de919c2 100644
--- a/cMake/FreeCAD_Helpers/PrintFinalReport.cmake
+++ b/cMake/FreeCAD_Helpers/PrintFinalReport.cmake
@@ -163,6 +163,7 @@ macro(PrintFinalReport)
         message(STATUS "Freetype:            disabled")
     endif(FREECAD_USE_FREETYPE)
 
+    message(STATUS "OpenGL:              ${OPENGL_gl_LIBRARY}")
     message(STATUS "OpenGLU:             ${OPENGL_glu_LIBRARY} [${OPENGL_glu_LIBRARY}][${OPENGL_INCLUDE_DIR}]")
 
     message(STATUS "Coin3D:              [${COIN3D_LIBRARIES}] [${COIN3D_INCLUDE_DIRS}]")