commit 653d09dc1b8e3f3bae722524ec059f9fc76b73e8
Author: leszek <leszek@koltunski.pl>
Date:   Wed Mar 15 23:01:45 2017 +0000

    as clearing Depth has been fixed in 580f7d10, we can now use this API in the 'FBO' app.

diff --git a/src/main/java/org/distorted/examples/fbo/FBORenderer.java b/src/main/java/org/distorted/examples/fbo/FBORenderer.java
index 4fffa0c..266584f 100644
--- a/src/main/java/org/distorted/examples/fbo/FBORenderer.java
+++ b/src/main/java/org/distorted/examples/fbo/FBORenderer.java
@@ -75,8 +75,7 @@ class FBORenderer implements GLSurfaceView.Renderer
         if( depth ) mRoot.glEnable (GLES30.GL_DEPTH_TEST);
         else        mRoot.glDisable(GLES30.GL_DEPTH_TEST);
 
-        // TODO for some reason this does not work - investigate.
-        //mRoot.glDepthMask(depth);
+        mRoot.glDepthMask(depth);
 
         // we can also, to save memory, delete/recreate
         // the depth buffer each time. This is optional.