diff --git a/modules/gfx/src/impl/fast_spheres.cc b/modules/gfx/src/impl/fast_spheres.cc
index e2014f365230fa4bcd739caf5900a1dedf88c31d..af8745b6d1e658fec12c2b81cecd1256cc9dde34 100644
--- a/modules/gfx/src/impl/fast_spheres.cc
+++ b/modules/gfx/src/impl/fast_spheres.cc
@@ -21,6 +21,7 @@
   Author: Ansgar Philippsen
 */
 
+#include <ost/config.hh>
 #if OST_SHADER_SUPPORT_ENABLED
 #include <ost/gfx/shader.hh>
 #endif