Update to box2d 2.4.1

src/libraries/box2d/b2_api.h

@@ -0,0 +1,52 @@
+// MIT License
+
+// Copyright (c) 2019 Erin Catto
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#ifndef B2_API_H
+#define B2_API_H
+
+#ifdef B2_SHARED
+  #if defined _WIN32 || defined __CYGWIN__
+    #ifdef box2d_EXPORTS
+      #ifdef __GNUC__
+        #define B2_API __attribute__ ((dllexport))
+      #else
+        #define B2_API __declspec(dllexport)
+      #endif
+    #else
+      #ifdef __GNUC__
+        #define B2_API __attribute__ ((dllimport))
+      #else
+        #define B2_API __declspec(dllimport)
+      #endif
+    #endif
+  #else
+    #if __GNUC__ >= 4
+      #define B2_API __attribute__ ((visibility ("default")))
+    #else
+      #define B2_API
+    #endif
+  #endif
+#else
+  #define B2_API
+#endif
+
+#endif

src/libraries/box2d/b2_block_allocator.h

@@ -23,7 +23,8 @@
 #ifndef B2_BLOCK_ALLOCATOR_H
 #define B2_BLOCK_ALLOCATOR_H
 
-#include "box2d/b2_settings.h"
+#include "b2_api.h"
+#include "b2_settings.h"
 
 const int32 b2_blockSizeCount = 14;
 
@@ -33,7 +34,7 @@ struct b2Chunk;
 /// This is a small object allocator used for allocating small
 /// objects that persist for more than one time step.
 /// See: http://www.codeproject.com/useritems/Small_Block_Allocator.asp
-class b2BlockAllocator
+class B2_API b2BlockAllocator
 {
 public:
 	b2BlockAllocator();

src/libraries/box2d/b2_body.h

@@ -23,6 +23,7 @@
 #ifndef B2_BODY_H
 #define B2_BODY_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 #include "b2_shape.h"
 
@@ -44,19 +45,15 @@ enum b2BodyType
 	b2_staticBody = 0,
 	b2_kinematicBody,
 	b2_dynamicBody
-
-	// TODO_ERIN
-	//b2_bulletBody,
 };
 
 /// A body definition holds all the data needed to construct a rigid body.
 /// You can safely re-use body definitions. Shapes are added to a body after construction.
-struct b2BodyDef
+struct B2_API b2BodyDef
 {
 	/// This constructor sets the body definition default values.
 	b2BodyDef()
 	{
-		userData = nullptr;
 		position.Set(0.0f, 0.0f);
 		angle = 0.0f;
 		linearVelocity.Set(0.0f, 0.0f);
@@ -121,14 +118,14 @@ struct b2BodyDef
 	bool enabled;
 
 	/// Use this to store application specific body data.
-	void* userData;
+	b2BodyUserData userData;
 
 	/// Scale the gravity applied to this body.
 	float gravityScale;
 };
 
 /// A rigid body. These are created via b2World::CreateBody.
-class b2Body
+class B2_API b2Body
 {
 public:
 	/// Creates a fixture and attach it to this body. Use this function if you need
@@ -379,10 +376,10 @@ public:
 	const b2Body* GetNext() const;
 
 	/// Get the user data pointer that was provided in the body definition.
-	void* GetUserData() const;
+	b2BodyUserData& GetUserData();
 
 	/// Set the user data. Use this to store your application specific data.
-	void SetUserData(void* data);
+	void SetUserData(b2BodyUserData& data);
 
 	/// Get the parent world of this body.
 	b2World* GetWorld();
@@ -398,7 +395,7 @@ private:
 	friend class b2ContactManager;
 	friend class b2ContactSolver;
 	friend class b2Contact;
-	
+
 	friend class b2DistanceJoint;
 	friend class b2FrictionJoint;
 	friend class b2GearJoint;
@@ -471,7 +468,7 @@ private:
 
 	float m_sleepTime;
 
-	void* m_userData;
+	b2BodyUserData m_userData;
 };
 
 inline b2BodyType b2Body::GetType() const
@@ -734,16 +731,16 @@ inline const b2Body* b2Body::GetNext() const
 	return m_next;
 }
 
-inline void b2Body::SetUserData(void* data)
-{
-	m_userData = data;
-}
-
-inline void* b2Body::GetUserData() const
+inline b2BodyUserData& b2Body::GetUserData()
 {
 	return m_userData;
 }
 
+inline void b2Body::SetUserData(b2BodyUserData& userData)
+{
+	m_userData = userData;
+}
+
 inline void b2Body::ApplyForce(const b2Vec2& force, const b2Vec2& point, bool wake)
 {
 	if (m_type != b2_dynamicBody)

src/libraries/box2d/b2_broad_phase.h

@@ -23,11 +23,12 @@
 #ifndef B2_BROAD_PHASE_H
 #define B2_BROAD_PHASE_H
 
+#include "b2_api.h"
 #include "b2_settings.h"
 #include "b2_collision.h"
 #include "b2_dynamic_tree.h"
 
-struct b2Pair
+struct B2_API b2Pair
 {
 	int32 proxyIdA;
 	int32 proxyIdB;
@@ -36,7 +37,7 @@ struct b2Pair
 /// The broad-phase is used for computing pairs and performing volume queries and ray casts.
 /// This broad-phase does not persist pairs. Instead, this reports potentially new pairs.
 /// It is up to the client to consume the new pairs and to track subsequent overlap.
-class b2BroadPhase
+class B2_API b2BroadPhase
 {
 public:
 

src/libraries/box2d/b2_chain_shape.h

@@ -23,6 +23,7 @@
 #ifndef B2_CHAIN_SHAPE_H
 #define B2_CHAIN_SHAPE_H
 
+#include "b2_api.h"
 #include "b2_shape.h"
 
 class b2EdgeShape;
@@ -32,7 +33,7 @@ class b2EdgeShape;
 /// This provides a counter-clockwise winding like the polygon shape.
 /// Connectivity information is used to create smooth collisions.
 /// @warning the chain will not collide properly if there are self-intersections.
-class b2ChainShape : public b2Shape
+class B2_API b2ChainShape : public b2Shape
 {
 public:
 	b2ChainShape();

src/libraries/box2d/b2_circle_shape.h

@@ -23,10 +23,11 @@
 #ifndef B2_CIRCLE_SHAPE_H
 #define B2_CIRCLE_SHAPE_H
 
+#include "b2_api.h"
 #include "b2_shape.h"
 
 /// A solid circle shape
-class b2CircleShape : public b2Shape
+class B2_API b2CircleShape : public b2Shape
 {
 public:
 	b2CircleShape();

src/libraries/box2d/b2_collision.h

@@ -23,9 +23,11 @@
 #ifndef B2_COLLISION_H
 #define B2_COLLISION_H
 
-#include "b2_math.h"
 #include <limits.h>
 
+#include "b2_api.h"
+#include "b2_math.h"
+
 /// @file
 /// Structures and functions used for computing contact points, distance
 /// queries, and TOI queries.
@@ -39,7 +41,7 @@ const uint8 b2_nullFeature = UCHAR_MAX;
 
 /// The features that intersect to form the contact point
 /// This must be 4 bytes or less.
-struct b2ContactFeature
+struct B2_API b2ContactFeature
 {
 	enum Type
 	{
@@ -54,7 +56,7 @@ struct b2ContactFeature
 };
 
 /// Contact ids to facilitate warm starting.
-union b2ContactID
+union B2_API b2ContactID
 {
 	b2ContactFeature cf;
 	uint32 key;					///< Used to quickly compare contact ids.
@@ -70,7 +72,7 @@ union b2ContactID
 /// This structure is stored across time steps, so we keep it small.
 /// Note: the impulses are used for internal caching and may not
 /// provide reliable contact forces, especially for high speed collisions.
-struct b2ManifoldPoint
+struct B2_API b2ManifoldPoint
 {
 	b2Vec2 localPoint;		///< usage depends on manifold type
 	float normalImpulse;	///< the non-penetration impulse
@@ -94,7 +96,7 @@ struct b2ManifoldPoint
 /// account for movement, which is critical for continuous physics.
 /// All contact scenarios must be expressed in one of these types.
 /// This structure is stored across time steps, so we keep it small.
-struct b2Manifold
+struct B2_API b2Manifold
 {
 	enum Type
 	{
@@ -111,7 +113,7 @@ struct b2Manifold
 };
 
 /// This is used to compute the current state of a contact manifold.
-struct b2WorldManifold
+struct B2_API b2WorldManifold
 {
 	/// Evaluate the manifold with supplied transforms. This assumes
 	/// modest motion from the original state. This does not change the
@@ -137,18 +139,18 @@ enum b2PointState
 
 /// Compute the point states given two manifolds. The states pertain to the transition from manifold1
 /// to manifold2. So state1 is either persist or remove while state2 is either add or persist.
-void b2GetPointStates(b2PointState state1[b2_maxManifoldPoints], b2PointState state2[b2_maxManifoldPoints],
+B2_API void b2GetPointStates(b2PointState state1[b2_maxManifoldPoints], b2PointState state2[b2_maxManifoldPoints],
 					  const b2Manifold* manifold1, const b2Manifold* manifold2);
 
 /// Used for computing contact manifolds.
-struct b2ClipVertex
+struct B2_API b2ClipVertex
 {
 	b2Vec2 v;
 	b2ContactID id;
 };
 
 /// Ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
-struct b2RayCastInput
+struct B2_API b2RayCastInput
 {
 	b2Vec2 p1, p2;
 	float maxFraction;
@@ -156,14 +158,14 @@ struct b2RayCastInput
 
 /// Ray-cast output data. The ray hits at p1 + fraction * (p2 - p1), where p1 and p2
 /// come from b2RayCastInput.
-struct b2RayCastOutput
+struct B2_API b2RayCastOutput
 {
 	b2Vec2 normal;
 	float fraction;
 };
 
 /// An axis aligned bounding box.
-struct b2AABB
+struct B2_API b2AABB
 {
 	/// Verify that the bounds are sorted.
 	bool IsValid() const;
@@ -220,36 +222,36 @@ struct b2AABB
 };
 
 /// Compute the collision manifold between two circles.
-void b2CollideCircles(b2Manifold* manifold,
+B2_API void b2CollideCircles(b2Manifold* manifold,
 					  const b2CircleShape* circleA, const b2Transform& xfA,
 					  const b2CircleShape* circleB, const b2Transform& xfB);
 
 /// Compute the collision manifold between a polygon and a circle.
-void b2CollidePolygonAndCircle(b2Manifold* manifold,
+B2_API void b2CollidePolygonAndCircle(b2Manifold* manifold,
 							   const b2PolygonShape* polygonA, const b2Transform& xfA,
 							   const b2CircleShape* circleB, const b2Transform& xfB);
 
 /// Compute the collision manifold between two polygons.
-void b2CollidePolygons(b2Manifold* manifold,
+B2_API void b2CollidePolygons(b2Manifold* manifold,
 					   const b2PolygonShape* polygonA, const b2Transform& xfA,
 					   const b2PolygonShape* polygonB, const b2Transform& xfB);
 
 /// Compute the collision manifold between an edge and a circle.
-void b2CollideEdgeAndCircle(b2Manifold* manifold,
+B2_API void b2CollideEdgeAndCircle(b2Manifold* manifold,
 							   const b2EdgeShape* polygonA, const b2Transform& xfA,
 							   const b2CircleShape* circleB, const b2Transform& xfB);
 
 /// Compute the collision manifold between an edge and a polygon.
-void b2CollideEdgeAndPolygon(b2Manifold* manifold,
+B2_API void b2CollideEdgeAndPolygon(b2Manifold* manifold,
 							   const b2EdgeShape* edgeA, const b2Transform& xfA,
 							   const b2PolygonShape* circleB, const b2Transform& xfB);
 
 /// Clipping for contact manifolds.
-int32 b2ClipSegmentToLine(b2ClipVertex vOut[2], const b2ClipVertex vIn[2],
+B2_API int32 b2ClipSegmentToLine(b2ClipVertex vOut[2], const b2ClipVertex vIn[2],
 							const b2Vec2& normal, float offset, int32 vertexIndexA);
 
 /// Determine if two generic shapes overlap.
-bool b2TestOverlap(	const b2Shape* shapeA, int32 indexA,
+B2_API bool b2TestOverlap(	const b2Shape* shapeA, int32 indexA,
 					const b2Shape* shapeB, int32 indexB,
 					const b2Transform& xfA, const b2Transform& xfB);
 

src/libraries/box2d/b2_common.h

@@ -0,0 +1,138 @@
+// MIT License
+
+// Copyright (c) 2019 Erin Catto
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#ifndef B2_COMMON_H
+#define B2_COMMON_H
+
+#include "b2_settings.h"
+
+#include <stddef.h>
+#include <assert.h>
+#include <float.h>
+
+#if !defined(NDEBUG)
+	#define b2DEBUG
+#endif
+
+#define B2_NOT_USED(x) ((void)(x))
+#define b2Assert(A) assert(A)
+
+#define	b2_maxFloat		FLT_MAX
+#define	b2_epsilon		FLT_EPSILON
+#define b2_pi			3.14159265359f
+
+/// @file
+/// Global tuning constants based on meters-kilograms-seconds (MKS) units.
+///
+
+// Collision
+
+/// The maximum number of contact points between two convex shapes. Do
+/// not change this value.
+#define b2_maxManifoldPoints	2
+
+/// This is used to fatten AABBs in the dynamic tree. This allows proxies
+/// to move by a small amount without triggering a tree adjustment.
+/// This is in meters.
+#define b2_aabbExtension		(0.1f * b2_lengthUnitsPerMeter)
+
+/// This is used to fatten AABBs in the dynamic tree. This is used to predict
+/// the future position based on the current displacement.
+/// This is a dimensionless multiplier.
+#define b2_aabbMultiplier		4.0f
+
+/// A small length used as a collision and constraint tolerance. Usually it is
+/// chosen to be numerically significant, but visually insignificant. In meters.
+#define b2_linearSlop			(0.005f * b2_lengthUnitsPerMeter)
+
+/// A small angle used as a collision and constraint tolerance. Usually it is
+/// chosen to be numerically significant, but visually insignificant.
+#define b2_angularSlop			(2.0f / 180.0f * b2_pi)
+
+/// The radius of the polygon/edge shape skin. This should not be modified. Making
+/// this smaller means polygons will have an insufficient buffer for continuous collision.
+/// Making it larger may create artifacts for vertex collision.
+#define b2_polygonRadius		(2.0f * b2_linearSlop)
+
+/// Maximum number of sub-steps per contact in continuous physics simulation.
+#define b2_maxSubSteps			8
+
+
+// Dynamics
+
+/// Maximum number of contacts to be handled to solve a TOI impact.
+#define b2_maxTOIContacts			32
+
+/// The maximum linear position correction used when solving constraints. This helps to
+/// prevent overshoot. Meters.
+#define b2_maxLinearCorrection		(0.2f * b2_lengthUnitsPerMeter)
+
+/// The maximum angular position correction used when solving constraints. This helps to
+/// prevent overshoot.
+#define b2_maxAngularCorrection		(8.0f / 180.0f * b2_pi)
+
+/// The maximum linear translation of a body per step. This limit is very large and is used
+/// to prevent numerical problems. You shouldn't need to adjust this. Meters.
+#define b2_maxTranslation			(2.0f * b2_lengthUnitsPerMeter)
+#define b2_maxTranslationSquared	(b2_maxTranslation * b2_maxTranslation)
+
+/// The maximum angular velocity of a body. This limit is very large and is used
+/// to prevent numerical problems. You shouldn't need to adjust this.
+#define b2_maxRotation				(0.5f * b2_pi)
+#define b2_maxRotationSquared		(b2_maxRotation * b2_maxRotation)
+
+/// This scale factor controls how fast overlap is resolved. Ideally this would be 1 so
+/// that overlap is removed in one time step. However using values close to 1 often lead
+/// to overshoot.
+#define b2_baumgarte				0.2f
+#define b2_toiBaumgarte				0.75f
+
+
+// Sleep
+
+/// The time that a body must be still before it will go to sleep.
+#define b2_timeToSleep				0.5f
+
+/// A body cannot sleep if its linear velocity is above this tolerance.
+#define b2_linearSleepTolerance		(0.01f * b2_lengthUnitsPerMeter)
+
+/// A body cannot sleep if its angular velocity is above this tolerance.
+#define b2_angularSleepTolerance	(2.0f / 180.0f * b2_pi)
+
+/// Dump to a file. Only one dump file allowed at a time.
+void b2OpenDump(const char* fileName);
+void b2Dump(const char* string, ...);
+void b2CloseDump();
+
+/// Version numbering scheme.
+/// See http://en.wikipedia.org/wiki/Software_versioning
+struct b2Version
+{
+	int32 major;		///< significant changes
+	int32 minor;		///< incremental changes
+	int32 revision;		///< bug fixes
+};
+
+/// Current version.
+extern B2_API b2Version b2_version;
+
+#endif

src/libraries/box2d/b2_contact.h

@@ -23,6 +23,7 @@
 #ifndef B2_CONTACT_H
 #define B2_CONTACT_H
 
+#include "b2_api.h"
 #include "b2_collision.h"
 #include "b2_fixture.h"
 #include "b2_math.h"
@@ -50,12 +51,18 @@ inline float b2MixRestitution(float restitution1, float restitution2)
 	return restitution1 > restitution2 ? restitution1 : restitution2;
 }
 
+/// Restitution mixing law. This picks the lowest value.
+inline float b2MixRestitutionThreshold(float threshold1, float threshold2)
+{
+	return threshold1 < threshold2 ? threshold1 : threshold2;
+}
+
 typedef b2Contact* b2ContactCreateFcn(	b2Fixture* fixtureA, int32 indexA,
 										b2Fixture* fixtureB, int32 indexB,
 										b2BlockAllocator* allocator);
 typedef void b2ContactDestroyFcn(b2Contact* contact, b2BlockAllocator* allocator);
 
-struct b2ContactRegister
+struct B2_API b2ContactRegister
 {
 	b2ContactCreateFcn* createFcn;
 	b2ContactDestroyFcn* destroyFcn;
@@ -67,7 +74,7 @@ struct b2ContactRegister
 /// is an edge. A contact edge belongs to a doubly linked list
 /// maintained in each attached body. Each contact has two contact
 /// nodes, one for each attached body.
-struct b2ContactEdge
+struct B2_API b2ContactEdge
 {
 	b2Body* other;			///< provides quick access to the other body attached.
 	b2Contact* contact;		///< the contact
@@ -78,7 +85,7 @@ struct b2ContactEdge
 /// The class manages contact between two shapes. A contact exists for each overlapping
 /// AABB in the broad-phase (except if filtered). Therefore a contact object may exist
 /// that has no contact points.
-class b2Contact
+class B2_API b2Contact
 {
 public:
 
@@ -139,6 +146,16 @@ public:
 	/// Reset the restitution to the default value.
 	void ResetRestitution();
 
+	/// Override the default restitution velocity threshold mixture. You can call this in b2ContactListener::PreSolve.
+	/// The value persists until you set or reset.
+	void SetRestitutionThreshold(float threshold);
+
+	/// Get the restitution threshold.
+	float GetRestitutionThreshold() const;
+
+	/// Reset the restitution threshold to the default value.
+	void ResetRestitutionThreshold();
+
 	/// Set the desired tangent speed for a conveyor belt behavior. In meters per second.
 	void SetTangentSpeed(float speed);
 
@@ -219,6 +236,7 @@ protected:
 
 	float m_friction;
 	float m_restitution;
+	float m_restitutionThreshold;
 
 	float m_tangentSpeed;
 };
@@ -340,6 +358,21 @@ inline void b2Contact::ResetRestitution()
 	m_restitution = b2MixRestitution(m_fixtureA->m_restitution, m_fixtureB->m_restitution);
 }
 
+inline void b2Contact::SetRestitutionThreshold(float threshold)
+{
+	m_restitutionThreshold = threshold;
+}
+
+inline float b2Contact::GetRestitutionThreshold() const
+{
+	return m_restitutionThreshold;
+}
+
+inline void b2Contact::ResetRestitutionThreshold()
+{
+	m_restitutionThreshold = b2MixRestitutionThreshold(m_fixtureA->m_restitutionThreshold, m_fixtureB->m_restitutionThreshold);
+}
+
 inline void b2Contact::SetTangentSpeed(float speed)
 {
 	m_tangentSpeed = speed;

src/libraries/box2d/b2_contact_manager.h

@@ -23,6 +23,7 @@
 #ifndef B2_CONTACT_MANAGER_H
 #define B2_CONTACT_MANAGER_H
 
+#include "b2_api.h"
 #include "b2_broad_phase.h"
 
 class b2Contact;
@@ -31,7 +32,7 @@ class b2ContactListener;
 class b2BlockAllocator;
 
 // Delegate of b2World.
-class b2ContactManager
+class B2_API b2ContactManager
 {
 public:
 	b2ContactManager();
@@ -44,7 +45,7 @@ public:
 	void Destroy(b2Contact* c);
 
 	void Collide();
-            
+
 	b2BroadPhase m_broadPhase;
 	b2Contact* m_contactList;
 	int32 m_contactCount;

src/libraries/box2d/b2_distance.h

@@ -23,13 +23,14 @@
 #ifndef B2_DISTANCE_H
 #define B2_DISTANCE_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 
 class b2Shape;
 
 /// A distance proxy is used by the GJK algorithm.
 /// It encapsulates any shape.
-struct b2DistanceProxy
+struct B2_API b2DistanceProxy
 {
 	b2DistanceProxy() : m_vertices(nullptr), m_count(0), m_radius(0.0f) {}
 
@@ -61,7 +62,7 @@ struct b2DistanceProxy
 
 /// Used to warm start b2Distance.
 /// Set count to zero on first call.
-struct b2SimplexCache
+struct B2_API b2SimplexCache
 {
 	float metric;		///< length or area
 	uint16 count;
@@ -71,8 +72,8 @@ struct b2SimplexCache
 
 /// Input for b2Distance.
 /// You have to option to use the shape radii
-/// in the computation. Even 
-struct b2DistanceInput
+/// in the computation. Even
+struct B2_API b2DistanceInput
 {
 	b2DistanceProxy proxyA;
 	b2DistanceProxy proxyB;
@@ -82,7 +83,7 @@ struct b2DistanceInput
 };
 
 /// Output for b2Distance.
-struct b2DistanceOutput
+struct B2_API b2DistanceOutput
 {
 	b2Vec2 pointA;		///< closest point on shapeA
 	b2Vec2 pointB;		///< closest point on shapeB
@@ -93,12 +94,12 @@ struct b2DistanceOutput
 /// Compute the closest points between two shapes. Supports any combination of:
 /// b2CircleShape, b2PolygonShape, b2EdgeShape. The simplex cache is input/output.
 /// On the first call set b2SimplexCache.count to zero.
-void b2Distance(b2DistanceOutput* output,
-				b2SimplexCache* cache, 
+B2_API void b2Distance(b2DistanceOutput* output,
+				b2SimplexCache* cache,
 				const b2DistanceInput* input);
 
 /// Input parameters for b2ShapeCast
-struct b2ShapeCastInput
+struct B2_API b2ShapeCastInput
 {
 	b2DistanceProxy proxyA;
 	b2DistanceProxy proxyB;
@@ -108,7 +109,7 @@ struct b2ShapeCastInput
 };
 
 /// Output results for b2ShapeCast
-struct b2ShapeCastOutput
+struct B2_API b2ShapeCastOutput
 {
 	b2Vec2 point;
 	b2Vec2 normal;
@@ -118,7 +119,7 @@ struct b2ShapeCastOutput
 
 /// Perform a linear shape cast of shape B moving and shape A fixed. Determines the hit point, normal, and translation fraction.
 /// @returns true if hit, false if there is no hit or an initial overlap
-bool b2ShapeCast(b2ShapeCastOutput* output, const b2ShapeCastInput* input);
+B2_API bool b2ShapeCast(b2ShapeCastOutput* output, const b2ShapeCastInput* input);
 
 //////////////////////////////////////////////////////////////////////////
 

src/libraries/box2d/b2_distance_joint.h

@@ -23,14 +23,14 @@
 #ifndef B2_DISTANCE_JOINT_H
 #define B2_DISTANCE_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Distance joint definition. This requires defining an anchor point on both
-/// bodies and the non-zero length of the distance joint. The definition uses local anchor points
-/// so that the initial configuration can violate the constraint
-/// slightly. This helps when saving and loading a game.
-/// @warning Do not use a zero or short length.
-struct b2DistanceJointDef : public b2JointDef
+/// bodies and the non-zero distance of the distance joint. The definition uses
+/// local anchor points so that the initial configuration can violate the
+/// constraint slightly. This helps when saving and loading a game.
+struct B2_API b2DistanceJointDef : public b2JointDef
 {
 	b2DistanceJointDef()
 	{
@@ -38,12 +38,14 @@ struct b2DistanceJointDef : public b2JointDef
 		localAnchorA.Set(0.0f, 0.0f);
 		localAnchorB.Set(0.0f, 0.0f);
 		length = 1.0f;
+		minLength = 0.0f;
+		maxLength = FLT_MAX;
 		stiffness = 0.0f;
 		damping = 0.0f;
 	}
 
-	/// Initialize the bodies, anchors, and length using the world
-	/// anchors.
+	/// Initialize the bodies, anchors, and rest length using world space anchors.
+	/// The minimum and maximum lengths are set to the rest length.
 	void Initialize(b2Body* bodyA, b2Body* bodyB,
 					const b2Vec2& anchorA, const b2Vec2& anchorB);
 
@@ -53,10 +55,16 @@ struct b2DistanceJointDef : public b2JointDef
 	/// The local anchor point relative to bodyB's origin.
 	b2Vec2 localAnchorB;
 
-	/// The natural length between the anchor points.
+	/// The rest length of this joint. Clamped to a stable minimum value.
 	float length;
 
-	/// The linear stiffness in N/m. A value of 0 disables softness.
+	/// Minimum length. Clamped to a stable minimum value.
+	float minLength;
+
+	/// Maximum length. Must be greater than or equal to the minimum length.
+	float maxLength;
+
+	/// The linear stiffness in N/m.
 	float stiffness;
 
 	/// The linear damping in N*s/m.
@@ -65,7 +73,7 @@ struct b2DistanceJointDef : public b2JointDef
 
 /// A distance joint constrains two points on two bodies to remain at a fixed
 /// distance from each other. You can view this as a massless, rigid rod.
-class b2DistanceJoint : public b2Joint
+class B2_API b2DistanceJoint : public b2Joint
 {
 public:
 
@@ -86,11 +94,30 @@ public:
 	/// The local anchor point relative to bodyB's origin.
 	const b2Vec2& GetLocalAnchorB() const  { return m_localAnchorB; }
 
-	/// Set/get the natural length.
-	/// Manipulating the length can lead to non-physical behavior when the frequency is zero.
-	void SetLength(float length) { m_length = length; }
+	/// Get the rest length
 	float GetLength() const { return m_length; }
 
+	/// Set the rest length
+	/// @returns clamped rest length
+	float SetLength(float length);
+
+	/// Get the minimum length
+	float GetMinLength() const { return m_minLength; }
+
+	/// Set the minimum length
+	/// @returns the clamped minimum length
+	float SetMinLength(float minLength);
+
+	/// Get the maximum length
+	float GetMaxLength() const { return m_maxLength; }
+
+	/// Set the maximum length
+	/// @returns the clamped maximum length
+	float SetMaxLength(float maxLength);
+
+	/// Get the current length
+	float GetCurrentLength() const;
+
 	/// Set/get the linear stiffness in N/m
 	void SetStiffness(float stiffness) { m_stiffness = stiffness; }
 	float GetStiffness() const { return m_stiffness; }
@@ -102,6 +129,9 @@ public:
 	/// Dump joint to dmLog
 	void Dump() override;
 
+	///
+	void Draw(b2Draw* draw) const override;
+
 protected:
 
 	friend class b2Joint;
@@ -114,13 +144,17 @@ protected:
 	float m_stiffness;
 	float m_damping;
 	float m_bias;
+	float m_length;
+	float m_minLength;
+	float m_maxLength;
 
 	// Solver shared
 	b2Vec2 m_localAnchorA;
 	b2Vec2 m_localAnchorB;
 	float m_gamma;
 	float m_impulse;
-	float m_length;
+	float m_lowerImpulse;
+	float m_upperImpulse;
 
 	// Solver temp
 	int32 m_indexA;
@@ -130,10 +164,12 @@ protected:
 	b2Vec2 m_rB;
 	b2Vec2 m_localCenterA;
 	b2Vec2 m_localCenterB;
+	float m_currentLength;
 	float m_invMassA;
 	float m_invMassB;
 	float m_invIA;
 	float m_invIB;
+	float m_softMass;
 	float m_mass;
 };
 

src/libraries/box2d/b2_draw.h

@@ -23,10 +23,11 @@
 #ifndef B2_DRAW_H
 #define B2_DRAW_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 
 /// Color for debug drawing. Each value has the range [0,1].
-struct b2Color
+struct B2_API b2Color
 {
 	b2Color() {}
 	b2Color(float rIn, float gIn, float bIn, float aIn = 1.0f)
@@ -44,7 +45,7 @@ struct b2Color
 
 /// Implement and register this class with a b2World to provide debug drawing of physics
 /// entities in your game.
-class b2Draw
+class B2_API b2Draw
 {
 public:
 	b2Draw();
@@ -65,7 +66,7 @@ public:
 
 	/// Get the drawing flags.
 	uint32 GetFlags() const;
-	
+
 	/// Append flags to the current flags.
 	void AppendFlags(uint32 flags);
 
@@ -80,10 +81,10 @@ public:
 
 	/// Draw a circle.
 	virtual void DrawCircle(const b2Vec2& center, float radius, const b2Color& color) = 0;
-	
+
 	/// Draw a solid circle.
 	virtual void DrawSolidCircle(const b2Vec2& center, float radius, const b2Vec2& axis, const b2Color& color) = 0;
-	
+
 	/// Draw a line segment.
 	virtual void DrawSegment(const b2Vec2& p1, const b2Vec2& p2, const b2Color& color) = 0;
 

src/libraries/box2d/b2_dynamic_tree.h

@@ -23,13 +23,14 @@
 #ifndef B2_DYNAMIC_TREE_H
 #define B2_DYNAMIC_TREE_H
 
+#include "b2_api.h"
 #include "b2_collision.h"
 #include "b2_growable_stack.h"
 
 #define b2_nullNode (-1)
 
 /// A node in the dynamic tree. The client does not interact with this directly.
-struct b2TreeNode
+struct B2_API b2TreeNode
 {
 	bool IsLeaf() const
 	{
@@ -64,7 +65,7 @@ struct b2TreeNode
 /// object to move by small amounts without triggering a tree update.
 ///
 /// Nodes are pooled and relocatable, so we use node indices rather than pointers.
-class b2DynamicTree
+class B2_API b2DynamicTree
 {
 public:
 	/// Constructing the tree initializes the node pool.
@@ -156,9 +157,6 @@ private:
 
 	int32 m_freeList;
 
-	/// This is used to incrementally traverse the tree for re-balancing.
-	uint32 m_path;
-
 	int32 m_insertionCount;
 };
 

src/libraries/box2d/b2_edge_shape.h

@@ -23,12 +23,13 @@
 #ifndef B2_EDGE_SHAPE_H
 #define B2_EDGE_SHAPE_H
 
+#include "b2_api.h"
 #include "b2_shape.h"
 
 /// A line segment (edge) shape. These can be connected in chains or loops
 /// to other edge shapes. Edges created independently are two-sided and do
-/// no provide smooth movement across junctions. 
-class b2EdgeShape : public b2Shape
+/// no provide smooth movement across junctions.
+class B2_API b2EdgeShape : public b2Shape
 {
 public:
 	b2EdgeShape();
@@ -60,7 +61,7 @@ public:
 
 	/// @see b2Shape::ComputeMass
 	void ComputeMass(b2MassData* massData, float density) const override;
-	
+
 	/// These are the edge vertices
 	b2Vec2 m_vertex1, m_vertex2;
 

src/libraries/box2d/b2_fixture.h

@@ -23,6 +23,7 @@
 #ifndef B2_FIXTURE_H
 #define B2_FIXTURE_H
 
+#include "b2_api.h"
 #include "b2_body.h"
 #include "b2_collision.h"
 #include "b2_shape.h"
@@ -33,7 +34,7 @@ class b2BroadPhase;
 class b2Fixture;
 
 /// This holds contact filtering data.
-struct b2Filter
+struct B2_API b2Filter
 {
 	b2Filter()
 	{
@@ -57,15 +58,15 @@ struct b2Filter
 
 /// A fixture definition is used to create a fixture. This class defines an
 /// abstract fixture definition. You can reuse fixture definitions safely.
-struct b2FixtureDef
+struct B2_API b2FixtureDef
 {
 	/// The constructor sets the default fixture definition values.
 	b2FixtureDef()
 	{
 		shape = nullptr;
-		userData = nullptr;
 		friction = 0.2f;
 		restitution = 0.0f;
+		restitutionThreshold = 1.0f * b2_lengthUnitsPerMeter;
 		density = 0.0f;
 		isSensor = false;
 	}
@@ -75,7 +76,7 @@ struct b2FixtureDef
 	const b2Shape* shape;
 
 	/// Use this to store application specific fixture data.
-	void* userData;
+	b2FixtureUserData userData;
 
 	/// The friction coefficient, usually in the range [0,1].
 	float friction;
@@ -83,6 +84,10 @@ struct b2FixtureDef
 	/// The restitution (elasticity) usually in the range [0,1].
 	float restitution;
 
+	/// Restitution velocity threshold, usually in m/s. Collisions above this
+	/// speed have restitution applied (will bounce).
+	float restitutionThreshold;
+
 	/// The density, usually in kg/m^2.
 	float density;
 
@@ -95,7 +100,7 @@ struct b2FixtureDef
 };
 
 /// This proxy is used internally to connect fixtures to the broad-phase.
-struct b2FixtureProxy
+struct B2_API b2FixtureProxy
 {
 	b2AABB aabb;
 	b2Fixture* fixture;
@@ -108,7 +113,7 @@ struct b2FixtureProxy
 /// such as friction, collision filters, etc.
 /// Fixtures are created via b2Body::CreateFixture.
 /// @warning you cannot reuse fixtures.
-class b2Fixture
+class B2_API b2Fixture
 {
 public:
 	/// Get the type of the child shape. You can use this to down cast to the concrete shape.
@@ -151,10 +156,10 @@ public:
 
 	/// Get the user data that was assigned in the fixture definition. Use this to
 	/// store your application specific data.
-	void* GetUserData() const;
+	b2FixtureUserData& GetUserData();
 
 	/// Set the user data. Use this to store your application specific data.
-	void SetUserData(void* data);
+	void SetUserData(b2FixtureUserData& userData);
 
 	/// Test a point for containment in this fixture.
 	/// @param p a point in world coordinates.
@@ -192,6 +197,13 @@ public:
 	/// existing contacts.
 	void SetRestitution(float restitution);
 
+	/// Get the restitution velocity threshold.
+	float GetRestitutionThreshold() const;
+
+	/// Set the restitution threshold. This will _not_ change the restitution threshold of
+	/// existing contacts.
+	void SetRestitutionThreshold(float threshold);
+
 	/// Get the fixture's AABB. This AABB may be enlarge and/or stale.
 	/// If you need a more accurate AABB, compute it using the shape and
 	/// the body transform.
@@ -229,6 +241,7 @@ protected:
 
 	float m_friction;
 	float m_restitution;
+	float m_restitutionThreshold;
 
 	b2FixtureProxy* m_proxies;
 	int32 m_proxyCount;
@@ -237,7 +250,7 @@ protected:
 
 	bool m_isSensor;
 
-	void* m_userData;
+	b2FixtureUserData m_userData;
 };
 
 inline b2Shape::Type b2Fixture::GetType() const
@@ -265,14 +278,14 @@ inline const b2Filter& b2Fixture::GetFilterData() const
 	return m_filter;
 }
 
-inline void* b2Fixture::GetUserData() const
+inline b2FixtureUserData& b2Fixture::GetUserData()
 {
 	return m_userData;
 }
 
-inline void b2Fixture::SetUserData(void* data)
+inline void b2Fixture::SetUserData(b2FixtureUserData& userData)
 {
-	m_userData = data;
+	m_userData = userData;
 }
 
 inline b2Body* b2Fixture::GetBody()
@@ -326,6 +339,16 @@ inline void b2Fixture::SetRestitution(float restitution)
 	m_restitution = restitution;
 }
 
+inline float b2Fixture::GetRestitutionThreshold() const
+{
+	return m_restitutionThreshold;
+}
+
+inline void b2Fixture::SetRestitutionThreshold(float threshold)
+{
+	m_restitutionThreshold = threshold;
+}
+
 inline bool b2Fixture::TestPoint(const b2Vec2& p) const
 {
 	return m_shape->TestPoint(m_body->GetTransform(), p);

src/libraries/box2d/b2_friction_joint.h

@@ -23,10 +23,11 @@
 #ifndef B2_FRICTION_JOINT_H
 #define B2_FRICTION_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Friction joint definition.
-struct b2FrictionJointDef : public b2JointDef
+struct B2_API b2FrictionJointDef : public b2JointDef
 {
 	b2FrictionJointDef()
 	{
@@ -56,7 +57,7 @@ struct b2FrictionJointDef : public b2JointDef
 
 /// Friction joint. This is used for top-down friction.
 /// It provides 2D translational friction and angular friction.
-class b2FrictionJoint : public b2Joint
+class B2_API b2FrictionJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;

src/libraries/box2d/b2_gear_joint.h

@@ -27,7 +27,8 @@
 
 /// Gear joint definition. This definition requires two existing
 /// revolute or prismatic joints (any combination will work).
-struct b2GearJointDef : public b2JointDef
+/// @warning bodyB on the input joints must both be dynamic
+struct B2_API b2GearJointDef : public b2JointDef
 {
 	b2GearJointDef()
 	{
@@ -57,7 +58,7 @@ struct b2GearJointDef : public b2JointDef
 /// of length or units of 1/length.
 /// @warning You have to manually destroy the gear joint if joint1 or joint2
 /// is destroyed.
-class b2GearJoint : public b2Joint
+class B2_API b2GearJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;

src/libraries/box2d/b2_growable_stack.h

@@ -23,9 +23,10 @@
 #ifndef B2_GROWABLE_STACK_H
 #define B2_GROWABLE_STACK_H
 
-#include "b2_settings.h"
 #include <string.h>
 
+#include "b2_settings.h"
+
 /// This is a growable LIFO stack with an initial capacity of N.
 /// If the stack size exceeds the initial capacity, the heap is used
 /// to increase the size of the stack.

src/libraries/box2d/b2_joint.h

@@ -23,6 +23,7 @@
 #ifndef B2_JOINT_H
 #define B2_JOINT_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 
 class b2Body;
@@ -47,7 +48,7 @@ enum b2JointType
 	e_motorJoint
 };
 
-struct b2Jacobian
+struct B2_API b2Jacobian
 {
 	b2Vec2 linear;
 	float angularA;
@@ -59,7 +60,7 @@ struct b2Jacobian
 /// is an edge. A joint edge belongs to a doubly linked list
 /// maintained in each attached body. Each joint has two joint
 /// nodes, one for each attached body.
-struct b2JointEdge
+struct B2_API b2JointEdge
 {
 	b2Body* other;			///< provides quick access to the other body attached.
 	b2Joint* joint;			///< the joint
@@ -68,12 +69,11 @@ struct b2JointEdge
 };
 
 /// Joint definitions are used to construct joints.
-struct b2JointDef
+struct B2_API b2JointDef
 {
 	b2JointDef()
 	{
 		type = e_unknownJoint;
-		userData = nullptr;
 		bodyA = nullptr;
 		bodyB = nullptr;
 		collideConnected = false;
@@ -83,7 +83,7 @@ struct b2JointDef
 	b2JointType type;
 
 	/// Use this to attach application specific data to your joints.
-	void* userData;
+	b2JointUserData userData;
 
 	/// The first attached body.
 	b2Body* bodyA;
@@ -96,18 +96,18 @@ struct b2JointDef
 };
 
 /// Utility to compute linear stiffness values from frequency and damping ratio
-void b2LinearStiffness(float& stiffness, float& damping,
+B2_API void b2LinearStiffness(float& stiffness, float& damping,
 	float frequencyHertz, float dampingRatio,
 	const b2Body* bodyA, const b2Body* bodyB);
 
 /// Utility to compute rotational stiffness values frequency and damping ratio
-void b2AngularStiffness(float& stiffness, float& damping,
+B2_API void b2AngularStiffness(float& stiffness, float& damping,
 	float frequencyHertz, float dampingRatio,
 	const b2Body* bodyA, const b2Body* bodyB);
 
 /// The base joint class. Joints are used to constraint two bodies together in
 /// various fashions. Some joints also feature limits and motors.
-class b2Joint
+class B2_API b2Joint
 {
 public:
 
@@ -137,10 +137,10 @@ public:
 	const b2Joint* GetNext() const;
 
 	/// Get the user data pointer.
-	void* GetUserData() const;
+	b2JointUserData& GetUserData();
 
 	/// Set the user data pointer.
-	void SetUserData(void* data);
+	void SetUserData(b2JointUserData& userData);
 
 	/// Short-cut function to determine if either body is enabled.
 	bool IsEnabled() const;
@@ -190,7 +190,7 @@ protected:
 	bool m_islandFlag;
 	bool m_collideConnected;
 
-	void* m_userData;
+	b2JointUserData m_userData;
 };
 
 inline b2JointType b2Joint::GetType() const
@@ -218,14 +218,14 @@ inline const b2Joint* b2Joint::GetNext() const
 	return m_next;
 }
 
-inline void* b2Joint::GetUserData() const
+inline b2JointUserData& b2Joint::GetUserData()
 {
 	return m_userData;
 }
 
-inline void b2Joint::SetUserData(void* data)
+inline void b2Joint::SetUserData(b2JointUserData& userData)
 {
-	m_userData = data;
+	m_userData = userData;
 }
 
 inline bool b2Joint::GetCollideConnected() const

src/libraries/box2d/b2_math.h

@@ -23,20 +23,22 @@
 #ifndef B2_MATH_H
 #define B2_MATH_H
 
+#include <math.h>
+
+#include "b2_api.h"
 #include "b2_settings.h"
-#include <cmath>
 
 /// This function is used to ensure that a floating point number is not a NaN or infinity.
 inline bool b2IsValid(float x)
 {
-	return std::isfinite(x);
+	return isfinite(x);
 }
 
 #define	b2Sqrt(x)	sqrtf(x)
 #define	b2Atan2(y, x)	atan2f(y, x)
 
 /// A 2D column vector.
-struct b2Vec2
+struct B2_API b2Vec2
 {
 	/// Default constructor does nothing (for performance).
 	b2Vec2() {}
@@ -52,7 +54,7 @@ struct b2Vec2
 
 	/// Negate this vector.
 	b2Vec2 operator -() const { b2Vec2 v; v.Set(-x, -y); return v; }
-	
+
 	/// Read from and indexed element.
 	float operator () (int32 i) const
 	{
@@ -70,7 +72,7 @@ struct b2Vec2
 	{
 		x += v.x; y += v.y;
 	}
-	
+
 	/// Subtract a vector from this vector.
 	void operator -= (const b2Vec2& v)
 	{
@@ -127,7 +129,7 @@ struct b2Vec2
 };
 
 /// A 2D column vector with 3 elements.
-struct b2Vec3
+struct B2_API b2Vec3
 {
 	/// Default constructor does nothing (for performance).
 	b2Vec3() {}
@@ -166,7 +168,7 @@ struct b2Vec3
 };
 
 /// A 2-by-2 matrix. Stored in column-major order.
-struct b2Mat22
+struct B2_API b2Mat22
 {
 	/// The default constructor does nothing (for performance).
 	b2Mat22() {}
@@ -240,7 +242,7 @@ struct b2Mat22
 };
 
 /// A 3-by-3 matrix. Stored in column-major order.
-struct b2Mat33
+struct B2_API b2Mat33
 {
 	/// The default constructor does nothing (for performance).
 	b2Mat33() {}
@@ -282,7 +284,7 @@ struct b2Mat33
 };
 
 /// Rotation
-struct b2Rot
+struct B2_API b2Rot
 {
 	b2Rot() {}
 
@@ -333,7 +335,7 @@ struct b2Rot
 
 /// A transform contains translation and rotation. It is used to represent
 /// the position and orientation of rigid frames.
-struct b2Transform
+struct B2_API b2Transform
 {
 	/// The default constructor does nothing.
 	b2Transform() {}
@@ -363,7 +365,7 @@ struct b2Transform
 /// Shapes are defined with respect to the body origin, which may
 /// no coincide with the center of mass. However, to support dynamics
 /// we must interpolate the center of mass position.
-struct b2Sweep
+struct B2_API b2Sweep
 {
 	/// Get the interpolated transform at a specific time.
 	/// @param transform the output transform
@@ -387,7 +389,7 @@ struct b2Sweep
 };
 
 /// Useful constant
-extern const b2Vec2 b2Vec2_zero;
+extern B2_API const b2Vec2 b2Vec2_zero;
 
 /// Perform the dot product on two vectors.
 inline float b2Dot(const b2Vec2& a, const b2Vec2& b)
@@ -681,10 +683,11 @@ inline bool b2IsPowerOfTwo(uint32 x)
 	return result;
 }
 
+// https://fgiesen.wordpress.com/2012/08/15/linear-interpolation-past-present-and-future/
 inline void b2Sweep::GetTransform(b2Transform* xf, float beta) const
 {
-	xf->p = c0 + beta * (c - c0);
-	float angle = a0 + beta * (a - a0);
+	xf->p = (1.0f - beta) * c0 + beta * c;
+	float angle = (1.0f - beta) * a0 + beta * a;
 	xf->q.Set(angle);
 
 	// Shift to origin

src/libraries/box2d/b2_motor_joint.h

@@ -23,10 +23,11 @@
 #ifndef B2_MOTOR_JOINT_H
 #define B2_MOTOR_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Motor joint definition.
-struct b2MotorJointDef : public b2JointDef
+struct B2_API b2MotorJointDef : public b2JointDef
 {
 	b2MotorJointDef()
 	{
@@ -46,7 +47,7 @@ struct b2MotorJointDef : public b2JointDef
 
 	/// The bodyB angle minus bodyA angle in radians.
 	float angularOffset;
-	
+
 	/// The maximum motor force in N.
 	float maxForce;
 
@@ -60,7 +61,7 @@ struct b2MotorJointDef : public b2JointDef
 /// A motor joint is used to control the relative motion
 /// between two bodies. A typical usage is to control the movement
 /// of a dynamic body with respect to the ground.
-class b2MotorJoint : public b2Joint
+class B2_API b2MotorJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;

src/libraries/box2d/b2_mouse_joint.h

@@ -23,11 +23,12 @@
 #ifndef B2_MOUSE_JOINT_H
 #define B2_MOUSE_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Mouse joint definition. This requires a world target point,
 /// tuning parameters, and the time step.
-struct b2MouseJointDef : public b2JointDef
+struct B2_API b2MouseJointDef : public b2JointDef
 {
 	b2MouseJointDef()
 	{
@@ -61,7 +62,7 @@ struct b2MouseJointDef : public b2JointDef
 /// NOTE: this joint is not documented in the manual because it was
 /// developed to be used in the testbed. If you want to learn how to
 /// use the mouse joint, look at the testbed.
-class b2MouseJoint : public b2Joint
+class B2_API b2MouseJoint : public b2Joint
 {
 public:
 
@@ -113,7 +114,7 @@ protected:
 	float m_stiffness;
 	float m_damping;
 	float m_beta;
-	
+
 	// Solver shared
 	b2Vec2 m_impulse;
 	float m_maxForce;

src/libraries/box2d/b2_polygon_shape.h

@@ -22,13 +22,14 @@
 #ifndef B2_POLYGON_SHAPE_H
 #define B2_POLYGON_SHAPE_H
 
+#include "b2_api.h"
 #include "b2_shape.h"
 
 /// A solid convex polygon. It is assumed that the interior of the polygon is to
 /// the left of each edge.
 /// Polygons have a maximum number of vertices equal to b2_maxPolygonVertices.
 /// In most cases you should not need many vertices for a convex polygon.
-class b2PolygonShape : public b2Shape
+class B2_API b2PolygonShape : public b2Shape
 {
 public:
 	b2PolygonShape();

src/libraries/box2d/b2_prismatic_joint.h

@@ -23,6 +23,7 @@
 #ifndef B2_PRISMATIC_JOINT_H
 #define B2_PRISMATIC_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Prismatic joint definition. This requires defining a line of
@@ -31,7 +32,7 @@
 /// can violate the constraint slightly. The joint translation is zero
 /// when the local anchor points coincide in world space. Using local
 /// anchors and a local axis helps when saving and loading a game.
-struct b2PrismaticJointDef : public b2JointDef
+struct B2_API b2PrismaticJointDef : public b2JointDef
 {
 	b2PrismaticJointDef()
 	{
@@ -87,7 +88,7 @@ struct b2PrismaticJointDef : public b2JointDef
 /// along an axis fixed in bodyA. Relative rotation is prevented. You can
 /// use a joint limit to restrict the range of motion and a joint motor to
 /// drive the motion or to model joint friction.
-class b2PrismaticJoint : public b2Joint
+class B2_API b2PrismaticJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;

src/libraries/box2d/b2_pulley_joint.h

@@ -23,13 +23,14 @@
 #ifndef B2_PULLEY_JOINT_H
 #define B2_PULLEY_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 const float b2_minPulleyLength = 2.0f;
 
 /// Pulley joint definition. This requires two ground anchors,
 /// two dynamic body anchor points, and a pulley ratio.
-struct b2PulleyJointDef : public b2JointDef
+struct B2_API b2PulleyJointDef : public b2JointDef
 {
 	b2PulleyJointDef()
 	{
@@ -80,7 +81,7 @@ struct b2PulleyJointDef : public b2JointDef
 /// work better when combined with prismatic joints. You should also cover the
 /// the anchor points with static shapes to prevent one side from going to
 /// zero length.
-class b2PulleyJoint : public b2Joint
+class B2_API b2PulleyJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;
@@ -129,7 +130,7 @@ protected:
 	b2Vec2 m_groundAnchorB;
 	float m_lengthA;
 	float m_lengthB;
-	
+
 	// Solver shared
 	b2Vec2 m_localAnchorA;
 	b2Vec2 m_localAnchorB;

src/libraries/box2d/b2_revolute_joint.h

@@ -23,6 +23,7 @@
 #ifndef B2_REVOLUTE_JOINT_H
 #define B2_REVOLUTE_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Revolute joint definition. This requires defining an anchor point where the
@@ -35,7 +36,7 @@
 /// 1. you might not know where the center of mass will be.
 /// 2. if you add/remove shapes from a body and recompute the mass,
 ///    the joints will be broken.
-struct b2RevoluteJointDef : public b2JointDef
+struct B2_API b2RevoluteJointDef : public b2JointDef
 {
 	b2RevoluteJointDef()
 	{
@@ -90,7 +91,7 @@ struct b2RevoluteJointDef : public b2JointDef
 /// a joint limit that specifies a lower and upper angle. You can use a motor
 /// to drive the relative rotation about the shared point. A maximum motor torque
 /// is provided so that infinite forces are not generated.
-class b2RevoluteJoint : public b2Joint
+class B2_API b2RevoluteJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;
@@ -161,7 +162,7 @@ public:
 	void Draw(b2Draw* draw) const override;
 
 protected:
-	
+
 	friend class b2Joint;
 	friend class b2GearJoint;
 

src/libraries/box2d/b2_rope.h

@@ -23,6 +23,7 @@
 #ifndef B2_ROPE_H
 #define B2_ROPE_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 
 class b2Draw;
@@ -41,11 +42,12 @@ enum b2BendingModel
 	b2_pbdAngleBendingModel,
 	b2_xpbdAngleBendingModel,
 	b2_pbdDistanceBendingModel,
-	b2_pbdHeightBendingModel
+	b2_pbdHeightBendingModel,
+	b2_pbdTriangleBendingModel
 };
 
 ///
-struct b2RopeTuning
+struct B2_API b2RopeTuning
 {
 	b2RopeTuning()
 	{
@@ -75,8 +77,8 @@ struct b2RopeTuning
 	bool warmStart;
 };
 
-/// 
-struct b2RopeDef
+///
+struct B2_API b2RopeDef
 {
 	b2RopeDef()
 	{
@@ -95,8 +97,8 @@ struct b2RopeDef
 	b2RopeTuning tuning;
 };
 
-/// 
-class b2Rope
+///
+class B2_API b2Rope
 {
 public:
 	b2Rope();
@@ -125,6 +127,7 @@ private:
 	void SolveBend_XPBD_Angle(float dt);
 	void SolveBend_PBD_Distance();
 	void SolveBend_PBD_Height();
+	void SolveBend_PBD_Triangle();
 	void ApplyBendForces(float dt);
 
 	b2Vec2 m_position;

src/libraries/box2d/b2_settings.h

@@ -23,143 +23,123 @@
 #ifndef B2_SETTINGS_H
 #define B2_SETTINGS_H
 
-#include <stddef.h>
-#include <assert.h>
-#include <float.h>
-
-void loveAssert(bool test, const char* teststr);
-
-#if !defined(NDEBUG)
-	#define b2DEBUG
-#endif
-
-#define B2_NOT_USED(x) ((void)(x))
-//#define b2Assert(A) assert(A)
-#define b2Assert(A) loveAssert((A), #A)
-
-typedef signed char	int8;
-typedef signed short int16;
-typedef signed int int32;
-typedef unsigned char uint8;
-typedef unsigned short uint16;
-typedef unsigned int uint32;
-
-#define	b2_maxFloat		FLT_MAX
-#define	b2_epsilon		FLT_EPSILON
-#define b2_pi			3.14159265359f
+#include "b2_types.h"
+#include "b2_api.h"
 
 /// @file
-/// Global tuning constants based on meters-kilograms-seconds (MKS) units.
+/// Settings that can be overriden for your application
 ///
 
-// Collision
+/// Define this macro in your build if you want to override settings
+#ifdef B2_USER_SETTINGS
 
-/// The maximum number of contact points between two convex shapes. Do
-/// not change this value.
-#define b2_maxManifoldPoints	2
+/// This is a user file that includes custom definitions of the macros, structs, and functions
+/// defined below.
+#include "b2_user_settings.h"
+
+#else
+
+#include <stdarg.h>
+#include <stdint.h>
+
+// Tunable Constants
+
+/// You can use this to change the length scale used by your game.
+/// For example for inches you could use 39.4.
+#define b2_lengthUnitsPerMeter 1.0f
 
 /// The maximum number of vertices on a convex polygon. You cannot increase
 /// this too much because b2BlockAllocator has a maximum object size.
 #define b2_maxPolygonVertices	8
 
-/// This is used to fatten AABBs in the dynamic tree. This allows proxies
-/// to move by a small amount without triggering a tree adjustment.
-/// This is in meters.
-#define b2_aabbExtension		0.1f
+// User data
 
-/// This is used to fatten AABBs in the dynamic tree. This is used to predict
-/// the future position based on the current displacement.
-/// This is a dimensionless multiplier.
-#define b2_aabbMultiplier		4.0f
+/// You can define this to inject whatever data you want in b2Body
+struct B2_API b2BodyUserData
+{
+	b2BodyUserData()
+	{
+		pointer = 0;
+	}
 
-/// A small length used as a collision and constraint tolerance. Usually it is
-/// chosen to be numerically significant, but visually insignificant.
-#define b2_linearSlop			0.005f
+	/// For legacy compatibility
+	uintptr_t pointer;
+};
 
-/// A small angle used as a collision and constraint tolerance. Usually it is
-/// chosen to be numerically significant, but visually insignificant.
-#define b2_angularSlop			(2.0f / 180.0f * b2_pi)
+/// You can define this to inject whatever data you want in b2Fixture
+struct B2_API b2FixtureUserData
+{
+	b2FixtureUserData()
+	{
+		pointer = 0;
+	}
 
-/// The radius of the polygon/edge shape skin. This should not be modified. Making
-/// this smaller means polygons will have an insufficient buffer for continuous collision.
-/// Making it larger may create artifacts for vertex collision.
-#define b2_polygonRadius		(2.0f * b2_linearSlop)
+	/// For legacy compatibility
+	uintptr_t pointer;
+};
 
-/// Maximum number of sub-steps per contact in continuous physics simulation.
-#define b2_maxSubSteps			8
+/// You can define this to inject whatever data you want in b2Joint
+struct B2_API b2JointUserData
+{
+	b2JointUserData()
+	{
+		pointer = 0;
+	}
 
-
-// Dynamics
-
-/// Maximum number of contacts to be handled to solve a TOI impact.
-#define b2_maxTOIContacts			32
-
-/// A velocity threshold for elastic collisions. Any collision with a relative linear
-/// velocity below this threshold will be treated as inelastic.
-#define b2_velocityThreshold		1.0f
-
-/// The maximum linear position correction used when solving constraints. This helps to
-/// prevent overshoot.
-#define b2_maxLinearCorrection		0.2f
-
-/// The maximum angular position correction used when solving constraints. This helps to
-/// prevent overshoot.
-#define b2_maxAngularCorrection		(8.0f / 180.0f * b2_pi)
-
-/// The maximum linear velocity of a body. This limit is very large and is used
-/// to prevent numerical problems. You shouldn't need to adjust this.
-#define b2_maxTranslation			2.0f
-#define b2_maxTranslationSquared	(b2_maxTranslation * b2_maxTranslation)
-
-/// The maximum angular velocity of a body. This limit is very large and is used
-/// to prevent numerical problems. You shouldn't need to adjust this.
-#define b2_maxRotation				(0.5f * b2_pi)
-#define b2_maxRotationSquared		(b2_maxRotation * b2_maxRotation)
-
-/// This scale factor controls how fast overlap is resolved. Ideally this would be 1 so
-/// that overlap is removed in one time step. However using values close to 1 often lead
-/// to overshoot.
-#define b2_baumgarte				0.2f
-#define b2_toiBaumgarte				0.75f
-
-
-// Sleep
-
-/// The time that a body must be still before it will go to sleep.
-#define b2_timeToSleep				0.5f
-
-/// A body cannot sleep if its linear velocity is above this tolerance.
-#define b2_linearSleepTolerance		0.01f
-
-/// A body cannot sleep if its angular velocity is above this tolerance.
-#define b2_angularSleepTolerance	(2.0f / 180.0f * b2_pi)
+	/// For legacy compatibility
+	uintptr_t pointer;
+};
 
 // Memory Allocation
 
+/// Default allocation functions
+B2_API void* b2Alloc_Default(int32 size);
+B2_API void b2Free_Default(void* mem);
+
 /// Implement this function to use your own memory allocator.
-void* b2Alloc(int32 size);
+inline void* b2Alloc(int32 size)
+{
+	return b2Alloc_Default(size);
+}
 
 /// If you implement b2Alloc, you should also implement this function.
-void b2Free(void* mem);
-
-/// Logging function.
-void b2Log(const char* string, ...);
-
-/// Dump to a file. Only one dump file allowed at a time.
-void b2OpenDump(const char* fileName);
-void b2Dump(const char* string, ...);
-void b2CloseDump();
-
-/// Version numbering scheme.
-/// See http://en.wikipedia.org/wiki/Software_versioning
-struct b2Version
+inline void b2Free(void* mem)
 {
-	int32 major;		///< significant changes
-	int32 minor;		///< incremental changes
-	int32 revision;		///< bug fixes
-};
+	b2Free_Default(mem);
+}
 
-/// Current version.
-extern b2Version b2_version;
+/// Default logging function
+B2_API void b2Log_Default(const char* string, va_list args);
+
+/// Implement this to use your own logging.
+inline void b2Log(const char* string, ...)
+{
+	va_list args;
+	va_start(args, string);
+	b2Log_Default(string, args);
+	va_end(args);
+}
+
+#endif // B2_USER_SETTINGS
+
+void loveAssert(bool test, const char* teststr);
+
+#define b2Assert(A) loveAssert((A), #A)
+
+namespace love {
+	namespace physics {
+		namespace box2d {
+			struct bodyudata;
+			struct fixtureudata;
+			struct jointudata;
+		}
+	}
+}
+
+#define b2BodyUserData love::physics::box2d::bodyudata*
+#define b2FixtureUserData love::physics::box2d::fixtureudata*
+#define b2JointUserData love::physics::box2d::jointudata*
+
+#include "b2_common.h"
 
 #endif

src/libraries/box2d/b2_shape.h

@@ -23,13 +23,14 @@
 #ifndef B2_SHAPE_H
 #define B2_SHAPE_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 #include "b2_collision.h"
 
 class b2BlockAllocator;
 
 /// This holds the mass data computed for a shape.
-struct b2MassData
+struct B2_API b2MassData
 {
 	/// The mass of the shape, usually in kilograms.
 	float mass;
@@ -44,10 +45,10 @@ struct b2MassData
 /// A shape is used for collision detection. You can create a shape however you like.
 /// Shapes used for simulation in b2World are created automatically when a b2Fixture
 /// is created. Shapes may encapsulate a one or more child shapes.
-class b2Shape
+class B2_API b2Shape
 {
 public:
-	
+
 	enum Type
 	{
 		e_circle = 0,

src/libraries/box2d/b2_stack_allocator.h

@@ -23,12 +23,13 @@
 #ifndef B2_STACK_ALLOCATOR_H
 #define B2_STACK_ALLOCATOR_H
 
+#include "b2_api.h"
 #include "b2_settings.h"
 
 const int32 b2_stackSize = 100 * 1024;	// 100k
 const int32 b2_maxStackEntries = 32;
 
-struct b2StackEntry
+struct B2_API b2StackEntry
 {
 	char* data;
 	int32 size;
@@ -38,7 +39,7 @@ struct b2StackEntry
 // This is a stack allocator used for fast per step allocations.
 // You must nest allocate/free pairs. The code will assert
 // if you try to interleave multiple allocate/free pairs.
-class b2StackAllocator
+class B2_API b2StackAllocator
 {
 public:
 	b2StackAllocator();

src/libraries/box2d/b2_time_of_impact.h

@@ -23,11 +23,12 @@
 #ifndef B2_TIME_OF_IMPACT_H
 #define B2_TIME_OF_IMPACT_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 #include "b2_distance.h"
 
 /// Input parameters for b2TimeOfImpact
-struct b2TOIInput
+struct B2_API b2TOIInput
 {
 	b2DistanceProxy proxyA;
 	b2DistanceProxy proxyB;
@@ -37,7 +38,7 @@ struct b2TOIInput
 };
 
 /// Output parameters for b2TimeOfImpact.
-struct b2TOIOutput
+struct B2_API b2TOIOutput
 {
 	enum State
 	{
@@ -57,6 +58,6 @@ struct b2TOIOutput
 /// non-tunneling collisions. If you change the time interval, you should call this function
 /// again.
 /// Note: use b2Distance to compute the contact point and normal at the time of impact.
-void b2TimeOfImpact(b2TOIOutput* output, const b2TOIInput* input);
+B2_API void b2TimeOfImpact(b2TOIOutput* output, const b2TOIInput* input);
 
 #endif

src/libraries/box2d/b2_time_step.h

@@ -22,10 +22,11 @@
 #ifndef B2_TIME_STEP_H
 #define B2_TIME_STEP_H
 
+#include "b2_api.h"
 #include "b2_math.h"
 
 /// Profiling data. Times are in milliseconds.
-struct b2Profile
+struct B2_API b2Profile
 {
 	float step;
 	float collide;
@@ -38,7 +39,7 @@ struct b2Profile
 };
 
 /// This is an internal structure.
-struct b2TimeStep
+struct B2_API b2TimeStep
 {
 	float dt;			// time step
 	float inv_dt;		// inverse time step (0 if dt == 0).
@@ -49,21 +50,21 @@ struct b2TimeStep
 };
 
 /// This is an internal structure.
-struct b2Position
+struct B2_API b2Position
 {
 	b2Vec2 c;
 	float a;
 };
 
 /// This is an internal structure.
-struct b2Velocity
+struct B2_API b2Velocity
 {
 	b2Vec2 v;
 	float w;
 };
 
 /// Solver Data
-struct b2SolverData
+struct B2_API b2SolverData
 {
 	b2TimeStep step;
 	b2Position* positions;

src/libraries/box2d/b2_timer.h

@@ -23,11 +23,12 @@
 #ifndef B2_TIMER_H
 #define B2_TIMER_H
 
+#include "b2_api.h"
 #include "b2_settings.h"
 
 /// Timer for profiling. This has platform specific code and may
 /// not work on every platform.
-class b2Timer
+class B2_API b2Timer
 {
 public:
 

src/libraries/box2d/b2_types.h

@@ -0,0 +1,33 @@
+// MIT License
+
+// Copyright (c) 2020 Erin Catto
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#ifndef B2_TYPES_H
+#define B2_TYPES_H
+
+typedef signed char	int8;
+typedef signed short int16;
+typedef signed int int32;
+typedef unsigned char uint8;
+typedef unsigned short uint16;
+typedef unsigned int uint32;
+
+#endif

src/libraries/box2d/b2_weld_joint.h

@@ -23,12 +23,13 @@
 #ifndef B2_WELD_JOINT_H
 #define B2_WELD_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Weld joint definition. You need to specify local anchor points
 /// where they are attached and the relative body angle. The position
 /// of the anchor points is important for computing the reaction torque.
-struct b2WeldJointDef : public b2JointDef
+struct B2_API b2WeldJointDef : public b2JointDef
 {
 	b2WeldJointDef()
 	{
@@ -54,7 +55,7 @@ struct b2WeldJointDef : public b2JointDef
 
 	/// The bodyB angle minus bodyA angle in the reference state (radians).
 	float referenceAngle;
-	
+
 	/// The rotational stiffness in N*m
 	/// Disable softness with a value of 0
 	float stiffness;
@@ -65,7 +66,7 @@ struct b2WeldJointDef : public b2JointDef
 
 /// A weld joint essentially glues two bodies together. A weld joint may
 /// distort somewhat because the island constraint solver is approximate.
-class b2WeldJoint : public b2Joint
+class B2_API b2WeldJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;

src/libraries/box2d/b2_wheel_joint.h

@@ -23,6 +23,7 @@
 #ifndef B2_WHEEL_JOINT_H
 #define B2_WHEEL_JOINT_H
 
+#include "b2_api.h"
 #include "b2_joint.h"
 
 /// Wheel joint definition. This requires defining a line of
@@ -31,7 +32,7 @@
 /// can violate the constraint slightly. The joint translation is zero
 /// when the local anchor points coincide in world space. Using local
 /// anchors and a local axis helps when saving and loading a game.
-struct b2WheelJointDef : public b2JointDef
+struct B2_API b2WheelJointDef : public b2JointDef
 {
 	b2WheelJointDef()
 	{
@@ -91,7 +92,7 @@ struct b2WheelJointDef : public b2JointDef
 /// along an axis fixed in bodyA and rotation in the plane. In other words, it is a point to
 /// line constraint with a rotational motor and a linear spring/damper. The spring/damper is
 /// initialized upon creation. This joint is designed for vehicle suspensions.
-class b2WheelJoint : public b2Joint
+class B2_API b2WheelJoint : public b2Joint
 {
 public:
 	b2Vec2 GetAnchorA() const override;

src/libraries/box2d/b2_world.h

@@ -23,6 +23,7 @@
 #ifndef B2_WORLD_H
 #define B2_WORLD_H
 
+#include "b2_api.h"
 #include "b2_block_allocator.h"
 #include "b2_contact_manager.h"
 #include "b2_math.h"
@@ -42,7 +43,7 @@ class b2Joint;
 /// The world class manages all physics entities, dynamic simulation,
 /// and asynchronous queries. The world also contains efficient memory
 /// management facilities.
-class b2World
+class B2_API b2World
 {
 public:
 	/// Construct a world object.
@@ -58,7 +59,7 @@ public:
 
 	/// Register a contact filter to provide specific control over collision.
 	/// Otherwise the default filter is used (b2_defaultFilter). The listener is
-	/// owned by you and must remain in scope. 
+	/// owned by you and must remain in scope.
 	void SetContactFilter(b2ContactFilter* filter);
 
 	/// Register a contact event listener. The listener is owned by you and must
@@ -185,7 +186,7 @@ public:
 
 	/// Change the global gravity vector.
 	void SetGravity(const b2Vec2& gravity);
-	
+
 	/// Get the global gravity vector.
 	b2Vec2 GetGravity() const;
 

src/libraries/box2d/b2_world_callbacks.h

@@ -23,6 +23,7 @@
 #ifndef B2_WORLD_CALLBACKS_H
 #define B2_WORLD_CALLBACKS_H
 
+#include "b2_api.h"
 #include "b2_settings.h"
 
 struct b2Vec2;
@@ -37,7 +38,7 @@ struct b2Manifold;
 /// Joints and fixtures are destroyed when their associated
 /// body is destroyed. Implement this listener so that you
 /// may nullify references to these joints and shapes.
-class b2DestructionListener
+class B2_API b2DestructionListener
 {
 public:
 	virtual ~b2DestructionListener() {}
@@ -53,7 +54,7 @@ public:
 
 /// Implement this class to provide collision filtering. In other words, you can implement
 /// this class if you want finer control over contact creation.
-class b2ContactFilter
+class B2_API b2ContactFilter
 {
 public:
 	virtual ~b2ContactFilter() {}
@@ -66,7 +67,7 @@ public:
 /// Contact impulses for reporting. Impulses are used instead of forces because
 /// sub-step forces may approach infinity for rigid body collisions. These
 /// match up one-to-one with the contact points in b2Manifold.
-struct b2ContactImpulse
+struct B2_API b2ContactImpulse
 {
 	float normalImpulses[b2_maxManifoldPoints];
 	float tangentImpulses[b2_maxManifoldPoints];
@@ -82,7 +83,7 @@ struct b2ContactImpulse
 /// You should strive to make your callbacks efficient because there may be
 /// many callbacks per time step.
 /// @warning You cannot create/destroy Box2D entities inside these callbacks.
-class b2ContactListener
+class B2_API b2ContactListener
 {
 public:
 	virtual ~b2ContactListener() {}
@@ -124,7 +125,7 @@ public:
 
 /// Callback class for AABB queries.
 /// See b2World::Query
-class b2QueryCallback
+class B2_API b2QueryCallback
 {
 public:
 	virtual ~b2QueryCallback() {}
@@ -136,7 +137,7 @@ public:
 
 /// Callback class for ray casts.
 /// See b2World::RayCast
-class b2RayCastCallback
+class B2_API b2RayCastCallback
 {
 public:
 	virtual ~b2RayCastCallback() {}

src/libraries/box2d/collision/b2_distance.cpp

@@ -27,7 +27,7 @@
 #include "box2d/b2_polygon_shape.h"
 
 // GJK using Voronoi regions (Christer Ericson) and Barycentric coordinates.
-int32 b2_gjkCalls, b2_gjkIters, b2_gjkMaxIters;
+B2_API int32 b2_gjkCalls, b2_gjkIters, b2_gjkMaxIters;
 
 void b2DistanceProxy::Set(const b2Shape* shape, int32 index)
 {

src/libraries/box2d/collision/b2_dynamic_tree.cpp

@@ -41,8 +41,6 @@ b2DynamicTree::b2DynamicTree()
 	m_nodes[m_nodeCapacity-1].height = -1;
 	m_freeList = 0;
 
-	m_path = 0;
-
 	m_insertionCount = 0;
 }
 

src/libraries/box2d/collision/b2_time_of_impact.cpp

@@ -29,9 +29,9 @@
 
 #include <stdio.h>
 
-float b2_toiTime, b2_toiMaxTime;
-int32 b2_toiCalls, b2_toiIters, b2_toiMaxIters;
-int32 b2_toiRootIters, b2_toiMaxRootIters;
+B2_API float b2_toiTime, b2_toiMaxTime;
+B2_API int32 b2_toiCalls, b2_toiIters, b2_toiMaxIters;
+B2_API int32 b2_toiRootIters, b2_toiMaxRootIters;
 
 //
 struct b2SeparationFunction

src/libraries/box2d/common/b2_settings.cpp

@@ -27,28 +27,23 @@
 #include <stdarg.h>
 #include <stdlib.h>
 
-#include "common/Exception.h"
-
 b2Version b2_version = {2, 4, 0};
 
 // Memory allocators. Modify these to use your own allocator.
-void* b2Alloc(int32 size)
+void* b2Alloc_Default(int32 size)
 {
 	return malloc(size);
 }
 
-void b2Free(void* mem)
+void b2Free_Default(void* mem)
 {
 	free(mem);
 }
 
 // You can modify this to use your logging facility.
-void b2Log(const char* string, ...)
+void b2Log_Default(const char* string, va_list args)
 {
-	va_list args;
-	va_start(args, string);
 	vprintf(string, args);
-	va_end(args);
 }
 
 FILE* b2_dumpFile = nullptr;
@@ -77,9 +72,3 @@ void b2CloseDump()
 	fclose(b2_dumpFile);
 	b2_dumpFile = nullptr;
 }
-
-void loveAssert(bool test, const char* teststr)
-{
-	if (!test)
-		throw love::Exception("Box2D assertion failed: %s", teststr);
-}

src/libraries/box2d/dynamics/b2_body.cpp

@@ -434,6 +434,9 @@ void b2Body::SetTransform(const b2Vec2& position, float angle)
 	{
 		f->Synchronize(broadPhase, m_xf, m_xf);
 	}
+
+	// Check for new contacts the next step
+	m_world->m_newContacts = true;
 }
 
 void b2Body::SynchronizeFixtures()

src/libraries/box2d/dynamics/b2_contact.cpp

@@ -156,6 +156,7 @@ b2Contact::b2Contact(b2Fixture* fA, int32 indexA, b2Fixture* fB, int32 indexB)
 
 	m_friction = b2MixFriction(m_fixtureA->m_friction, m_fixtureB->m_friction);
 	m_restitution = b2MixRestitution(m_fixtureA->m_restitution, m_fixtureB->m_restitution);
+	m_restitutionThreshold = b2MixRestitutionThreshold(m_fixtureA->m_restitutionThreshold, m_fixtureB->m_restitutionThreshold);
 
 	m_tangentSpeed = 0.0f;
 }

src/libraries/box2d/dynamics/b2_contact_solver.cpp

@@ -31,7 +31,7 @@
 // Solver debugging is normally disabled because the block solver sometimes has to deal with a poorly conditioned effective mass matrix.
 #define B2_DEBUG_SOLVER 0
 
-bool g_blockSolve = true;
+B2_API bool g_blockSolve = true;
 
 struct b2ContactPositionConstraint
 {
@@ -80,6 +80,7 @@ b2ContactSolver::b2ContactSolver(b2ContactSolverDef* def)
 		b2ContactVelocityConstraint* vc = m_velocityConstraints + i;
 		vc->friction = contact->m_friction;
 		vc->restitution = contact->m_restitution;
+		vc->threshold = contact->m_restitutionThreshold;
 		vc->tangentSpeed = contact->m_tangentSpeed;
 		vc->indexA = bodyA->m_islandIndex;
 		vc->indexB = bodyB->m_islandIndex;
@@ -213,7 +214,7 @@ void b2ContactSolver::InitializeVelocityConstraints()
 			// Setup a velocity bias for restitution.
 			vcp->velocityBias = 0.0f;
 			float vRel = b2Dot(vc->normal, vB + b2Cross(wB, vcp->rB) - vA - b2Cross(wA, vcp->rA));
-			if (vRel < -b2_velocityThreshold)
+			if (vRel < -vc->threshold)
 			{
 				vcp->velocityBias = -vc->restitution * vRel;
 			}

src/libraries/box2d/dynamics/b2_contact_solver.h

@@ -55,6 +55,7 @@ struct b2ContactVelocityConstraint
 	float invIA, invIB;
 	float friction;
 	float restitution;
+	float threshold;
 	float tangentSpeed;
 	int32 pointCount;
 	int32 contactIndex;

src/libraries/box2d/dynamics/b2_distance_joint.cpp

@@ -21,6 +21,7 @@
 // SOFTWARE.
 
 #include "box2d/b2_body.h"
+#include "box2d/b2_draw.h"
 #include "box2d/b2_distance_joint.h"
 #include "box2d/b2_time_step.h"
 
@@ -48,7 +49,9 @@ void b2DistanceJointDef::Initialize(b2Body* b1, b2Body* b2,
 	localAnchorA = bodyA->GetLocalPoint(anchor1);
 	localAnchorB = bodyB->GetLocalPoint(anchor2);
 	b2Vec2 d = anchor2 - anchor1;
-	length = d.Length();
+	length = b2Max(d.Length(), b2_linearSlop);
+	minLength = length;
+	maxLength = length;
 }
 
 b2DistanceJoint::b2DistanceJoint(const b2DistanceJointDef* def)
@@ -56,13 +59,18 @@ b2DistanceJoint::b2DistanceJoint(const b2DistanceJointDef* def)
 {
 	m_localAnchorA = def->localAnchorA;
 	m_localAnchorB = def->localAnchorB;
-	m_length = def->length;
+	m_length = b2Max(def->length, b2_linearSlop);
+	m_minLength = b2Max(def->minLength, b2_linearSlop);
+	m_maxLength = b2Max(def->maxLength, m_minLength);
 	m_stiffness = def->stiffness;
 	m_damping = def->damping;
 
-	m_impulse = 0.0f;
 	m_gamma = 0.0f;
 	m_bias = 0.0f;
+	m_impulse = 0.0f;
+	m_lowerImpulse = 0.0f;
+	m_upperImpulse = 0.0f;
+	m_currentLength = 0.0f;
 }
 
 void b2DistanceJoint::InitVelocityConstraints(const b2SolverData& data)
@@ -93,23 +101,29 @@ void b2DistanceJoint::InitVelocityConstraints(const b2SolverData& data)
 	m_u = cB + m_rB - cA - m_rA;
 
 	// Handle singularity.
-	float length = m_u.Length();
-	if (length > b2_linearSlop)
+	m_currentLength = m_u.Length();
+	if (m_currentLength > b2_linearSlop)
 	{
-		m_u *= 1.0f / length;
+		m_u *= 1.0f / m_currentLength;
 	}
 	else
 	{
 		m_u.Set(0.0f, 0.0f);
+		m_mass = 0.0f;
+		m_impulse = 0.0f;
+		m_lowerImpulse = 0.0f;
+		m_upperImpulse = 0.0f;
 	}
 
 	float crAu = b2Cross(m_rA, m_u);
 	float crBu = b2Cross(m_rB, m_u);
 	float invMass = m_invMassA + m_invIA * crAu * crAu + m_invMassB + m_invIB * crBu * crBu;
+	m_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
 
-	if (m_stiffness > 0.0f)
+	if (m_stiffness > 0.0f && m_minLength < m_maxLength)
 	{
-		float C = length - m_length;
+		// soft
+		float C = m_currentLength - m_length;
 
 		float d = m_damping;
 		float k = m_stiffness;
@@ -117,27 +131,31 @@ void b2DistanceJoint::InitVelocityConstraints(const b2SolverData& data)
 		// magic formulas
 		float h = data.step.dt;
 
-		// gamma = 1 / (h * (d + h * k)), the extra factor of h in the denominator is since the lambda is an impulse, not a force
+		// gamma = 1 / (h * (d + h * k))
+		// the extra factor of h in the denominator is since the lambda is an impulse, not a force
 		m_gamma = h * (d + h * k);
 		m_gamma = m_gamma != 0.0f ? 1.0f / m_gamma : 0.0f;
 		m_bias = C * h * k * m_gamma;
 
 		invMass += m_gamma;
-		m_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
+		m_softMass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
 	}
 	else
 	{
+		// rigid
 		m_gamma = 0.0f;
 		m_bias = 0.0f;
-		m_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
+		m_softMass = m_mass;
 	}
 
 	if (data.step.warmStarting)
 	{
 		// Scale the impulse to support a variable time step.
 		m_impulse *= data.step.dtRatio;
+		m_lowerImpulse *= data.step.dtRatio;
+		m_upperImpulse *= data.step.dtRatio;
 
-		b2Vec2 P = m_impulse * m_u;
+		b2Vec2 P = (m_impulse + m_lowerImpulse - m_upperImpulse) * m_u;
 		vA -= m_invMassA * P;
 		wA -= m_invIA * b2Cross(m_rA, P);
 		vB += m_invMassB * P;
@@ -161,19 +179,85 @@ void b2DistanceJoint::SolveVelocityConstraints(const b2SolverData& data)
 	b2Vec2 vB = data.velocities[m_indexB].v;
 	float wB = data.velocities[m_indexB].w;
 
-	// Cdot = dot(u, v + cross(w, r))
-	b2Vec2 vpA = vA + b2Cross(wA, m_rA);
-	b2Vec2 vpB = vB + b2Cross(wB, m_rB);
-	float Cdot = b2Dot(m_u, vpB - vpA);
+	if (m_minLength < m_maxLength)
+	{
+		if (m_stiffness > 0.0f)
+		{
+			// Cdot = dot(u, v + cross(w, r))
+			b2Vec2 vpA = vA + b2Cross(wA, m_rA);
+			b2Vec2 vpB = vB + b2Cross(wB, m_rB);
+			float Cdot = b2Dot(m_u, vpB - vpA);
 
-	float impulse = -m_mass * (Cdot + m_bias + m_gamma * m_impulse);
-	m_impulse += impulse;
+			float impulse = -m_softMass * (Cdot + m_bias + m_gamma * m_impulse);
+			m_impulse += impulse;
 
-	b2Vec2 P = impulse * m_u;
-	vA -= m_invMassA * P;
-	wA -= m_invIA * b2Cross(m_rA, P);
-	vB += m_invMassB * P;
-	wB += m_invIB * b2Cross(m_rB, P);
+			b2Vec2 P = impulse * m_u;
+			vA -= m_invMassA * P;
+			wA -= m_invIA * b2Cross(m_rA, P);
+			vB += m_invMassB * P;
+			wB += m_invIB * b2Cross(m_rB, P);
+		}
+
+		// lower
+		{
+			float C = m_currentLength - m_minLength;
+			float bias = b2Max(0.0f, C) * data.step.inv_dt;
+
+			b2Vec2 vpA = vA + b2Cross(wA, m_rA);
+			b2Vec2 vpB = vB + b2Cross(wB, m_rB);
+			float Cdot = b2Dot(m_u, vpB - vpA);
+
+			float impulse = -m_mass * (Cdot + bias);
+			float oldImpulse = m_lowerImpulse;
+			m_lowerImpulse = b2Max(0.0f, m_lowerImpulse + impulse);
+			impulse = m_lowerImpulse - oldImpulse;
+			b2Vec2 P = impulse * m_u;
+
+			vA -= m_invMassA * P;
+			wA -= m_invIA * b2Cross(m_rA, P);
+			vB += m_invMassB * P;
+			wB += m_invIB * b2Cross(m_rB, P);
+		}
+
+		// upper
+		{
+			float C = m_maxLength - m_currentLength;
+			float bias = b2Max(0.0f, C) * data.step.inv_dt;
+
+			b2Vec2 vpA = vA + b2Cross(wA, m_rA);
+			b2Vec2 vpB = vB + b2Cross(wB, m_rB);
+			float Cdot = b2Dot(m_u, vpA - vpB);
+
+			float impulse = -m_mass * (Cdot + bias);
+			float oldImpulse = m_upperImpulse;
+			m_upperImpulse = b2Max(0.0f, m_upperImpulse + impulse);
+			impulse = m_upperImpulse - oldImpulse;
+			b2Vec2 P = -impulse * m_u;
+
+			vA -= m_invMassA * P;
+			wA -= m_invIA * b2Cross(m_rA, P);
+			vB += m_invMassB * P;
+			wB += m_invIB * b2Cross(m_rB, P);
+		}
+	}
+	else
+	{
+		// Equal limits
+
+		// Cdot = dot(u, v + cross(w, r))
+		b2Vec2 vpA = vA + b2Cross(wA, m_rA);
+		b2Vec2 vpB = vB + b2Cross(wB, m_rB);
+		float Cdot = b2Dot(m_u, vpB - vpA);
+
+		float impulse = -m_mass * Cdot;
+		m_impulse += impulse;
+
+		b2Vec2 P = impulse * m_u;
+		vA -= m_invMassA * P;
+		wA -= m_invIA * b2Cross(m_rA, P);
+		vB += m_invMassB * P;
+		wB += m_invIB * b2Cross(m_rB, P);
+	}
 
 	data.velocities[m_indexA].v = vA;
 	data.velocities[m_indexA].w = wA;
@@ -183,12 +267,6 @@ void b2DistanceJoint::SolveVelocityConstraints(const b2SolverData& data)
 
 bool b2DistanceJoint::SolvePositionConstraints(const b2SolverData& data)
 {
-	if (m_stiffness > 0.0f)
-	{
-		// There is no position correction for soft distance constraints.
-		return true;
-	}
-
 	b2Vec2 cA = data.positions[m_indexA].c;
 	float aA = data.positions[m_indexA].a;
 	b2Vec2 cB = data.positions[m_indexB].c;
@@ -201,8 +279,23 @@ bool b2DistanceJoint::SolvePositionConstraints(const b2SolverData& data)
 	b2Vec2 u = cB + rB - cA - rA;
 
 	float length = u.Normalize();
-	float C = length - m_length;
-	C = b2Clamp(C, -b2_maxLinearCorrection, b2_maxLinearCorrection);
+	float C;
+	if (m_minLength == m_maxLength)
+	{
+		C = length - m_minLength;
+	}
+	else if (length < m_minLength)
+	{
+		C = length - m_minLength;
+	}
+	else if (m_maxLength < length)
+	{
+		C = length - m_maxLength;
+	}
+	else
+	{
+		return true;
+	}
 
 	float impulse = -m_mass * C;
 	b2Vec2 P = impulse * u;
@@ -232,7 +325,7 @@ b2Vec2 b2DistanceJoint::GetAnchorB() const
 
 b2Vec2 b2DistanceJoint::GetReactionForce(float inv_dt) const
 {
-	b2Vec2 F = (inv_dt * m_impulse) * m_u;
+	b2Vec2 F = inv_dt * (m_impulse + m_lowerImpulse - m_upperImpulse) * m_u;
 	return F;
 }
 
@@ -242,6 +335,36 @@ float b2DistanceJoint::GetReactionTorque(float inv_dt) const
 	return 0.0f;
 }
 
+float b2DistanceJoint::SetLength(float length)
+{
+	m_impulse = 0.0f;
+	m_length = b2Max(b2_linearSlop, length);
+	return m_length;
+}
+
+float b2DistanceJoint::SetMinLength(float minLength)
+{
+	m_lowerImpulse = 0.0f;
+	m_minLength = b2Clamp(minLength, b2_linearSlop, m_maxLength);
+	return m_minLength;
+}
+
+float b2DistanceJoint::SetMaxLength(float maxLength)
+{
+	m_upperImpulse = 0.0f;
+	m_maxLength = b2Max(maxLength, m_minLength);
+	return m_maxLength;
+}
+
+float b2DistanceJoint::GetCurrentLength() const
+{
+	b2Vec2 pA = m_bodyA->GetWorldPoint(m_localAnchorA);
+	b2Vec2 pB = m_bodyB->GetWorldPoint(m_localAnchorB);
+	b2Vec2 d = pB - pA;
+	float length = d.Length();
+	return length;
+}
+
 void b2DistanceJoint::Dump()
 {
 	int32 indexA = m_bodyA->m_islandIndex;
@@ -254,7 +377,45 @@ void b2DistanceJoint::Dump()
 	b2Dump("  jd.localAnchorA.Set(%.9g, %.9g);\n", m_localAnchorA.x, m_localAnchorA.y);
 	b2Dump("  jd.localAnchorB.Set(%.9g, %.9g);\n", m_localAnchorB.x, m_localAnchorB.y);
 	b2Dump("  jd.length = %.9g;\n", m_length);
+	b2Dump("  jd.minLength = %.9g;\n", m_minLength);
+	b2Dump("  jd.maxLength = %.9g;\n", m_maxLength);
 	b2Dump("  jd.stiffness = %.9g;\n", m_stiffness);
 	b2Dump("  jd.damping = %.9g;\n", m_damping);
 	b2Dump("  joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
 }
+
+void b2DistanceJoint::Draw(b2Draw* draw) const
+{
+	const b2Transform& xfA = m_bodyA->GetTransform();
+	const b2Transform& xfB = m_bodyB->GetTransform();
+	b2Vec2 pA = b2Mul(xfA, m_localAnchorA);
+	b2Vec2 pB = b2Mul(xfB, m_localAnchorB);
+
+	b2Vec2 axis = pB - pA;
+	float length = axis.Normalize();
+
+	b2Color c1(0.7f, 0.7f, 0.7f);
+	b2Color c2(0.3f, 0.9f, 0.3f);
+	b2Color c3(0.9f, 0.3f, 0.3f);
+	b2Color c4(0.4f, 0.4f, 0.4f);
+
+	draw->DrawSegment(pA, pB, c4);
+	
+	b2Vec2 pRest = pA + m_length * axis;
+	draw->DrawPoint(pRest, 8.0f, c1);
+
+	if (m_minLength != m_maxLength)
+	{
+		if (m_minLength > b2_linearSlop)
+		{
+			b2Vec2 pMin = pA + m_minLength * axis;
+			draw->DrawPoint(pMin, 4.0f, c2);
+		}
+
+		if (m_maxLength < FLT_MAX)
+		{
+			b2Vec2 pMax = pA + m_maxLength * axis;
+			draw->DrawPoint(pMax, 4.0f, c3);
+		}
+	}
+}

src/libraries/box2d/dynamics/b2_fixture.cpp

@@ -33,7 +33,6 @@
 
 b2Fixture::b2Fixture()
 {
-	m_userData = nullptr;
 	m_body = nullptr;
 	m_next = nullptr;
 	m_proxies = nullptr;
@@ -47,6 +46,7 @@ void b2Fixture::Create(b2BlockAllocator* allocator, b2Body* body, const b2Fixtur
 	m_userData = def->userData;
 	m_friction = def->friction;
 	m_restitution = def->restitution;
+	m_restitutionThreshold = def->restitutionThreshold;
 
 	m_body = body;
 	m_next = nullptr;
@@ -235,6 +235,7 @@ void b2Fixture::Dump(int32 bodyIndex)
 	b2Dump("    b2FixtureDef fd;\n");
 	b2Dump("    fd.friction = %.9g;\n", m_friction);
 	b2Dump("    fd.restitution = %.9g;\n", m_restitution);
+	b2Dump("    fd.restitutionThreshold = %.9g;\n", m_restitutionThreshold);
 	b2Dump("    fd.density = %.9g;\n", m_density);
 	b2Dump("    fd.isSensor = bool(%d);\n", m_isSensor);
 	b2Dump("    fd.filter.categoryBits = uint16(%d);\n", m_filter.categoryBits);

src/libraries/box2d/dynamics/b2_gear_joint.cpp

@@ -64,6 +64,9 @@ b2GearJoint::b2GearJoint(const b2GearJointDef* def)
 	m_bodyC = m_joint1->GetBodyA();
 	m_bodyA = m_joint1->GetBodyB();
 
+	// Body B on joint1 must be dynamic
+	b2Assert(m_bodyA->m_type == b2_dynamicBody);
+
 	// Get geometry of joint1
 	b2Transform xfA = m_bodyA->m_xf;
 	float aA = m_bodyA->m_sweep.a;
@@ -96,6 +99,9 @@ b2GearJoint::b2GearJoint(const b2GearJointDef* def)
 	m_bodyD = m_joint2->GetBodyA();
 	m_bodyB = m_joint2->GetBodyB();
 
+	// Body B on joint2 must be dynamic
+	b2Assert(m_bodyB->m_type == b2_dynamicBody);
+
 	// Get geometry of joint2
 	b2Transform xfB = m_bodyB->m_xf;
 	float aB = m_bodyB->m_sweep.a;

src/libraries/box2d/dynamics/b2_joint.cpp

@@ -31,7 +31,6 @@
 #include "box2d/b2_prismatic_joint.h"
 #include "box2d/b2_pulley_joint.h"
 #include "box2d/b2_revolute_joint.h"
-#include "box2d/b2_rope_joint.h"
 #include "box2d/b2_weld_joint.h"
 #include "box2d/b2_wheel_joint.h"
 #include "box2d/b2_world.h"
@@ -157,13 +156,6 @@ b2Joint* b2Joint::Create(const b2JointDef* def, b2BlockAllocator* allocator)
 		}
 		break;
 
-	case e_ropeJoint:
-		{
-			void* mem = allocator->Allocate(sizeof(b2RopeJoint));
-			joint = new (mem) b2RopeJoint(static_cast<const b2RopeJointDef*>(def));
-		}
-		break;
-
 	case e_motorJoint:
 		{
 			void* mem = allocator->Allocate(sizeof(b2MotorJoint));
@@ -220,10 +212,6 @@ void b2Joint::Destroy(b2Joint* joint, b2BlockAllocator* allocator)
 		allocator->Free(joint, sizeof(b2FrictionJoint));
 		break;
 
-	case e_ropeJoint:
-		allocator->Free(joint, sizeof(b2RopeJoint));
-		break;
-
 	case e_motorJoint:
 		allocator->Free(joint, sizeof(b2MotorJoint));
 		break;

src/libraries/box2d/dynamics/b2_prismatic_joint.cpp

@@ -462,7 +462,7 @@ b2Vec2 b2PrismaticJoint::GetAnchorB() const
 
 b2Vec2 b2PrismaticJoint::GetReactionForce(float inv_dt) const
 {
-	return inv_dt * (m_impulse.x * m_perp + (m_motorImpulse + m_lowerImpulse + m_upperImpulse) * m_axis);
+	return inv_dt * (m_impulse.x * m_perp + (m_motorImpulse + m_lowerImpulse - m_upperImpulse) * m_axis);
 }
 
 float b2PrismaticJoint::GetReactionTorque(float inv_dt) const
@@ -607,7 +607,6 @@ void b2PrismaticJoint::Dump()
 	b2Dump("  joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
 }
 
-///
 void b2PrismaticJoint::Draw(b2Draw* draw) const
 {
 	const b2Transform& xfA = m_bodyA->GetTransform();

src/libraries/box2d/dynamics/b2_revolute_joint.cpp

@@ -338,7 +338,7 @@ b2Vec2 b2RevoluteJoint::GetReactionForce(float inv_dt) const
 
 float b2RevoluteJoint::GetReactionTorque(float inv_dt) const
 {
-	return inv_dt * (m_lowerImpulse + m_upperImpulse);
+	return inv_dt * (m_motorImpulse + m_lowerImpulse - m_upperImpulse);
 }
 
 float b2RevoluteJoint::GetJointAngle() const

src/libraries/box2d/dynamics/b2_wheel_joint.cpp

@@ -455,7 +455,7 @@ b2Vec2 b2WheelJoint::GetAnchorB() const
 
 b2Vec2 b2WheelJoint::GetReactionForce(float inv_dt) const
 {
-	return inv_dt * (m_impulse * m_ay + m_springImpulse * m_ax);
+	return inv_dt * (m_impulse * m_ay + (m_springImpulse + m_lowerImpulse - m_upperImpulse) * m_ax);
 }
 
 float b2WheelJoint::GetReactionTorque(float inv_dt) const

src/libraries/box2d/rope/b2_rope.cpp

@@ -306,6 +306,10 @@ void b2Rope::Step(float dt, int32 iterations, const b2Vec2& position)
 		{
 			SolveBend_PBD_Height();
 		}
+		else if (m_tuning.bendingModel == b2_pbdTriangleBendingModel)
+		{
+			SolveBend_PBD_Triangle();
+		}
 
 		if (m_tuning.stretchingModel == b2_pbdStretchingModel)
 		{
@@ -750,6 +754,42 @@ void b2Rope::SolveBend_PBD_Height()
 	}
 }
 
+// M. Kelager: A Triangle Bending Constraint Model for PBD
+void b2Rope::SolveBend_PBD_Triangle()
+{
+	const float stiffness = m_tuning.bendStiffness;
+
+	for (int32 i = 0; i < m_bendCount; ++i)
+	{
+		const b2RopeBend& c = m_bendConstraints[i];
+
+		b2Vec2 b0 = m_ps[c.i1];
+		b2Vec2 v = m_ps[c.i2];
+		b2Vec2 b1 = m_ps[c.i3];
+
+		float wb0 = c.invMass1;
+		float wv = c.invMass2;
+		float wb1 = c.invMass3;
+
+		float W = wb0 + wb1 + 2.0f * wv;
+		float invW = stiffness / W;
+
+		b2Vec2 d = v - (1.0f / 3.0f) * (b0 + v + b1);
+
+		b2Vec2 db0 = 2.0f * wb0 * invW * d;
+		b2Vec2 dv = -4.0f * wv * invW * d;
+		b2Vec2 db1 = 2.0f * wb1 * invW * d;
+
+		b0 += db0;
+		v += dv;
+		b1 += db1;
+
+		m_ps[c.i1] = b0;
+		m_ps[c.i2] = v;
+		m_ps[c.i3] = b1;
+	}
+}
+
 void b2Rope::Draw(b2Draw* draw) const
 {
 	b2Color c(0.4f, 0.5f, 0.7f);

src/modules/physics/box2d/Body.cpp

@@ -45,7 +45,7 @@ Body::Body(World *world, b2Vec2 p, Body::Type type)
 	udata->ref = nullptr;
 	b2BodyDef def;
 	def.position = Physics::scaleDown(p);
-	def.userData = (void *) udata;
+	def.userData = udata;
 	body = world->world->CreateBody(&def);
 	// Box2D body holds a reference to the love Body.
 	this->retain();
@@ -529,7 +529,7 @@ int Body::setUserData(lua_State *L)
 	if (udata == nullptr)
 	{
 		udata = new bodyudata();
-		body->SetUserData((void *) udata);
+		body->SetUserData(udata);
 	}
 
 	if(!udata->ref)

src/modules/physics/box2d/Fixture.cpp

@@ -45,7 +45,7 @@ Fixture::Fixture(Body *body, Shape *shape, float density)
 	udata->ref = nullptr;
 	b2FixtureDef def;
 	def.shape = shape->shape;
-	def.userData = (void *)udata;
+	def.userData = udata;
 	def.density = density;
 	fixture = body->body->CreateFixture(&def);
 	this->retain();
@@ -262,7 +262,7 @@ int Fixture::setUserData(lua_State *L)
 	if (udata == nullptr)
 	{
 		udata = new fixtureudata();
-		fixture->SetUserData((void *) udata);
+		fixture->SetUserData(udata);
 	}
 
 	if(!udata->ref)

src/modules/physics/box2d/Joint.cpp

@@ -202,7 +202,7 @@ int Joint::setUserData(lua_State *L)
 	if (udata == nullptr)
 	{
 		udata = new jointudata();
-		joint->SetUserData((void *) udata);
+		joint->SetUserData(udata);
 	}
 
 	if(!udata->ref)