diff --git a/project/src/renderer/opengl/OpenGLS3D.cpp b/project/src/renderer/opengl/OpenGLS3D.cpp
index dfed22f79..b512bdd37 100644
--- a/project/src/renderer/opengl/OpenGLS3D.cpp
+++ b/project/src/renderer/opengl/OpenGLS3D.cpp
@@ -308,7 +308,8 @@ value lime_gl_s3d_set_focal_length (value length)
       ctx->mS3D.mFocalLength = val_float (length);
 
    }
-
+   
+   return alloc_null ();
 }
 DEFINE_PRIM (lime_gl_s3d_set_focal_length,1);
 
@@ -336,6 +337,8 @@ value lime_gl_s3d_set_eye_separation (value separation)
       ctx->mS3D.mEyeSeparation = val_float (separation);
 
    }
+   
+   return alloc_null ();
 
 }
 DEFINE_PRIM (lime_gl_s3d_set_eye_separation,1);