fixed divide by zero in springs and attractors

memo · Jun 13, 2013 · df0ee5f · df0ee5f
1 parent 71d073c
commit df0ee5f
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Showing 3 changed files with 3 additions and 3 deletions.
diff --git a/src/MSAPhysicsAttraction.h b/src/MSAPhysicsAttraction.h
@@ -32,7 +32,7 @@ namespace msa {
 				T delta = this->_b->getPosition() - this->_a->getPosition();
 				float deltaLength2 = delta.lengthSquared();
 
-				float force = _strength * (this->_b->getMass()) * (this->_a->getMass()) / (deltaLength2 + 0.001);		// to avoid divide by zero
+				float force = deltaLength2 > 0 ? _strength * (this->_b->getMass()) * (this->_a->getMass()) / deltaLength2 : 0;
 
 				T deltaForce = delta * force;
 

diff --git a/src/MSAPhysicsParticle.h b/src/MSAPhysicsParticle.h
@@ -117,7 +117,7 @@ namespace msa {
 		inline ParticleT<T>* ParticleT<T>::setMass(float t) {
 			if(t==0) t=0.00001f;
 			_mass = t;
-			_invMass = 1.0f/t;
+			_invMass = t > 0 ? 1.0f/t : 0;
 			return this;
 		}
 

diff --git a/src/MSAPhysicsSpring.h b/src/MSAPhysicsSpring.h
@@ -45,7 +45,7 @@ namespace msa {
 				T delta = this->_b->getPosition() - this->_a->getPosition();
 				float deltaLength2 = delta.lengthSquared();
 				float deltaLength = sqrt(deltaLength2);	// TODO: fast approximation of square root (1st order Taylor-expansion at a neighborhood of the rest length r (one Newton-Raphson iteration with initial guess r))
-				float force = _strength * (deltaLength - _restLength) / (deltaLength * (this->_a->getInvMass() + this->_b->getInvMass()));
+				float force = deltaLength > 0 ? _strength * (deltaLength - _restLength) / (deltaLength * (this->_a->getInvMass() + this->_b->getInvMass())) : 0;
 
 
 				T deltaForce = delta * force;