From 11350334d07fbbe67064449e48bf30fd01727039 Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Sat, 2 May 2015 22:07:03 +0200
Subject: [PATCH] Add assertion to prevent invalid use of FrameRateMeter

---
 panda/src/grutil/frameRateMeter.cxx | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/panda/src/grutil/frameRateMeter.cxx b/panda/src/grutil/frameRateMeter.cxx
index 58457c01a7..cbd0beb187 100644
--- a/panda/src/grutil/frameRateMeter.cxx
+++ b/panda/src/grutil/frameRateMeter.cxx
@@ -180,6 +180,10 @@ clear_window() {
 ////////////////////////////////////////////////////////////////////
 bool FrameRateMeter::
 cull_callback(CullTraverser *trav, CullTraverserData &data) {
+  // This triggers when you try to parent a frame rate meter into
+  // the scene graph yourself.  Instead, use setup_window().
+  nassertr(_display_region != NULL, false);
+
   Thread *current_thread = trav->get_current_thread();
 
   // Statistics