From 91c024ebece37921988b111bfbf1e6f958d10dd4 Mon Sep 17 00:00:00 2001
From: andy <andy>
Date: Fri, 10 Mar 2006 19:46:16 +0000
Subject: [PATCH] When we are asked to produce no force on a Surface (e.g. a
 weight that is "off"), make sure the force is actually zero.  Kind of a hack
 -- a better idea would be flag to set at a higher level.

---
 src/FDM/YASim/Surface.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/FDM/YASim/Surface.cpp b/src/FDM/YASim/Surface.cpp
index 24d318842..8e7bafaa6 100644
--- a/src/FDM/YASim/Surface.cpp
+++ b/src/FDM/YASim/Surface.cpp
@@ -158,6 +158,13 @@ void Surface::calcForce(float* v, float rho, float* out, float* torque)
 	return;
     }
 
+    // special case this so the logic below doesn't produce a non-zero
+    // force; should probably have a "no force" flag instead...
+    if(_cx == 0. && _cy == 0. && _cz == 0.) {
+        for(int i=0; i<3; i++) out[i] = torque[i] = 0.;
+        return;
+    }
+
     Math::mul3(1/vel, v, out);
 
     // Convert to the surface's coordinates
-- 
2.39.5