From a8aad71d03bb8ccbb66b9ab78c5e2e018eb8d868 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 13 Mar 2009 11:01:11 +0000
Subject: [PATCH] Fixed for division by zero issue.

---
 src/osgParticle/FluidProgram.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/osgParticle/FluidProgram.cpp b/src/osgParticle/FluidProgram.cpp
index 76dddeae0..f5b06c18d 100644
--- a/src/osgParticle/FluidProgram.cpp
+++ b/src/osgParticle/FluidProgram.cpp
@@ -40,11 +40,11 @@ void osgParticle::FluidProgram::execute(double dt)
             osg::Vec3 wind_force = - relative_wind * Area * (_viscosityCoefficient + _densityCoefficient*relative_wind.length());
             osg::Vec3 wind_accel = wind_force * particle->getMassInv();
 
-            double critical_dt2 = relative_wind.length2()/wind_accel.length2();
             double compenstated_dt = dt;
-            if (critical_dt2 < dt*dt)
+            if (relative_wind.length2() < dt*dt*wind_accel.length2())
             {
                 // osg::notify(osg::NOTICE)<<"** Could be critical: dt="<<dt<<" critical_dt="<<sqrtf(critical_dt2)<<std::endl;
+                double critical_dt2 = relative_wind.length2()/wind_accel.length2();
                 compenstated_dt = sqrtf(critical_dt2)*0.8f;
             }