From b6a5754127557b6c3ef47f766b7513cdb38ae6a4 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 14 Apr 2010 13:39:43 +0000
Subject: [PATCH] Added minimum frame delay of 1/100th second when using on
 demand rendering to avoid creating a CPU lock.

---
 src/osgViewer/ViewerBase.cpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/osgViewer/ViewerBase.cpp b/src/osgViewer/ViewerBase.cpp
index e85d9d30a..37dec743d 100644
--- a/src/osgViewer/ViewerBase.cpp
+++ b/src/osgViewer/ViewerBase.cpp
@@ -599,7 +599,17 @@ int ViewerBase::run()
         osg::Timer_t startFrameTick = osg::Timer::instance()->tick();
         if (_runFrameScheme==ON_DEMAND)
         {
-            if (checkNeedToDoFrame()) frame();
+            if (checkNeedToDoFrame())
+            {
+                frame();
+            }
+            else
+            {
+                // we don't need to render a frame but we don't want to spin the run loop so make sure the minimum
+                // loop time is 1/100th of second, if not otherwise set, so enabling the frame microSleep below to
+                // avoid consume excessive CPU resources.
+                if (minFrameTime==0.0) minFrameTime=0.01;
+            }
         }
         else
         {