Major fixes

liquidfun/Box2D/Box2D/Collision/Shapes/b2PolygonShape.cpp

@@ -262,9 +262,27 @@ void b2PolygonShape::ComputeDistance(const b2Transform& xf, const b2Vec2& p, flo
 	B2_NOT_USED(childIndex);
 
 	b2Vec2 pLocal = b2MulT(xf.q, p - xf.p);
+
+    // If the nearest point is a corner, then the dot products of the normals on each of its edges will be positive.
+    int32 prevI = m_count - 1;
+	for (int32 i = 0; i < m_count; ++i)
+	{
+		const b2Vec2& beforeNorm = m_normals[prevI]; // The normal of point i and the point i-1
+		const b2Vec2& afterNorm = m_normals[i]; // The normal of point i and the point i+1
+		b2Vec2 dist = pLocal - m_vertices[i];
+		if (b2Dot(dist, beforeNorm) > 0.0f && b2Dot(dist, afterNorm) > 0.0f)
+		{
+			*distance = dist.Length();
+			*normal = b2Mul(xf.q, dist);
+            if (*distance > 0.0f)
+                *normal /= *distance;
+			return;
+		}
+		prevI = i;
+	}
+
 	float32 maxDistance = -FLT_MAX;
 	b2Vec2 normalForMaxDistance = pLocal;
-
 	for (int32 i = 0; i < m_count; ++i)
 	{
 		float32 dot = b2Dot(m_normals[i], pLocal - m_vertices[i]);
@@ -274,31 +292,8 @@ void b2PolygonShape::ComputeDistance(const b2Transform& xf, const b2Vec2& p, flo
 			normalForMaxDistance = m_normals[i];
 		}
 	}
-
-	if (maxDistance > 0)
-	{
-		b2Vec2 minDistance = normalForMaxDistance;
-		float32 minDistance2 = maxDistance * maxDistance;
-		for (int32 i = 0; i < m_count; ++i)
-		{
-			b2Vec2 distance = pLocal - m_vertices[i];
-			float32 distance2 = distance.LengthSquared();
-			if (minDistance2 > distance2)
-			{
-				minDistance = distance;
-				minDistance2 = distance2;
-			}
-		}
-
-		*distance = b2Sqrt(minDistance2);
-		*normal = b2Mul(xf.q, minDistance);
-		normal->Normalize();
-	}
-	else
-	{
-		*distance = maxDistance;
-		*normal = b2Mul(xf.q, normalForMaxDistance);
-	}
+    *distance = maxDistance;
+    *normal = b2Mul(xf.q, normalForMaxDistance);
 }
 
 bool b2PolygonShape::RayCast(b2RayCastOutput* output, const b2RayCastInput& input,

liquidfun/Box2D/Box2D/Common/b2Settings.h

@@ -82,10 +82,12 @@ typedef unsigned long long uint64;
 #endif
 #endif
 
+
 /// @file
 /// Global tuning constants based on meters-kilograms-seconds (MKS) units.
 ///
 
+
 // Collision
 
 /// The maximum number of contact points between two convex shapes. Do
@@ -196,6 +198,14 @@ typedef unsigned long long uint64;
 /// The time into the future that collisions against barrier particles will be detected.
 #define b2_barrierCollisionTime 2.5f
 
+/// Multiplier for the radius of a particle when colliding with a fixture.
+/// Originally the diameter was used, so a multiplier of 2 would restore that behaviour.
+#define b2_fixtureParticleCollisionRadiusScaler 1
+
+/// Prevents directional bias when solving elastic triads
+#define b2_elasticPreserveVelocity
+
+
 // Sleep
 
 /// The time that a body must be still before it will go to sleep.
@@ -207,6 +217,7 @@ typedef unsigned long long uint64;
 /// A body cannot sleep if its angular velocity is above this tolerance.
 #define b2_angularSleepTolerance	(2.0f / 180.0f * b2_pi)
 
+
 // Memory Allocation
 
 /// Implement this function to use your own memory allocator.
@@ -236,9 +247,11 @@ void b2SetNumAllocs(const int32 numAllocs);
 /// Get number of calls to b2Alloc minus number of calls to b2Free.
 int32 b2GetNumAllocs();
 
+
 /// Logging function.
 void b2Log(const char* string, ...);
 
+
 /// Version numbering scheme.
 /// See http://en.wikipedia.org/wiki/Software_versioning
 struct b2Version

liquidfun/Box2D/Box2D/Dynamics/b2World.cpp

@@ -1057,6 +1057,11 @@ void b2World::ClearForces()
 		body->m_force.SetZero();
 		body->m_torque = 0.0f;
 	}
+
+	for (b2ParticleSystem* p = m_particleSystemList; p; p = p->GetNext())
+	{
+		p->m_hasForce = false;
+	}
 }
 
 struct b2WorldQueryWrapper

liquidfun/Box2D/Box2D/Particle/b2ParticleGroup.cpp

@@ -36,7 +36,9 @@ b2ParticleGroup::b2ParticleGroup()
 
 	m_timestamp = -1;
 	m_mass = 0;
+	m_invMass = 0;
 	m_inertia = 0;
+	m_invInertia = 0;
 	m_center = b2Vec2_zero;
 	m_linearVelocity = b2Vec2_zero;
 	m_angularVelocity = 0;
@@ -79,9 +81,12 @@ void b2ParticleGroup::UpdateStatistics() const
 		}
 		if (m_mass > 0)
 		{
-			m_center *= 1 / m_mass;
-			m_linearVelocity *= 1 / m_mass;
+			m_invMass = 1 / m_mass;
+			m_center *= m_invMass;
+			m_linearVelocity *= m_invMass;
 		}
+		else
+			m_invMass = 0;
 		m_inertia = 0;
 		m_angularVelocity = 0;
 		for (int32 i = m_firstIndex; i < m_lastIndex; i++)
@@ -93,8 +98,11 @@ void b2ParticleGroup::UpdateStatistics() const
 		}
 		if (m_inertia > 0)
 		{
-			m_angularVelocity *= 1 / m_inertia;
+			m_invInertia = 1 / m_inertia;
+			m_angularVelocity *= m_invInertia;
 		}
+		else
+			m_invInertia = 0;
 		m_timestamp = m_system->m_timestamp;
 	}
 }

liquidfun/Box2D/Box2D/Particle/b2ParticleGroup.h

@@ -271,8 +271,8 @@ class b2ParticleGroup
 	b2ParticleGroup* m_next;
 
 	mutable int32 m_timestamp;
-	mutable float32 m_mass;
-	mutable float32 m_inertia;
+	mutable float32 m_mass, m_invMass;
+	mutable float32 m_inertia, m_invInertia;
 	mutable b2Vec2 m_center;
 	mutable b2Vec2 m_linearVelocity;
 	mutable float32 m_angularVelocity;