Add the EventListener class

src/engine/CollisionWorld.cpp

@@ -34,6 +34,7 @@ using namespace std;
 // Constructor
 CollisionWorld::CollisionWorld()
                : mCollisionDetection(this, mMemoryAllocator), mCurrentBodyID(0) {
+
 }
 
 // Destructor

src/engine/CollisionWorld.h

@@ -39,6 +39,7 @@
 #include "../constraint/Joint.h"
 #include "../constraint/ContactPoint.h"
 #include "../memory/MemoryAllocator.h"
+#include "EventListener.h"
 
 /// Namespace reactphysics3d
 namespace reactphysics3d {
@@ -91,7 +92,8 @@ class CollisionWorld {
         virtual void notifyRemovedOverlappingPair(const BroadPhasePair* removedPair);
 
         /// Notify the world about a new narrow-phase contact
-        virtual void notifyNewContact(const BroadPhasePair* pair, const ContactPointInfo* contactInfo);
+        virtual void notifyNewContact(const BroadPhasePair* pair,
+                                      const ContactPointInfo* contactInfo);
 
         /// Update the overlapping pair
         virtual void updateOverlappingPair(const BroadPhasePair* pair);

src/engine/DynamicsWorld.cpp

@@ -48,7 +48,7 @@ DynamicsWorld::DynamicsWorld(const Vector3 &gravity, decimal timeStep = DEFAULT_
                 mIslands(NULL), mNbBodiesCapacity(0),
                 mSleepLinearVelocity(DEFAULT_SLEEP_LINEAR_VELOCITY),
                 mSleepAngularVelocity(DEFAULT_SLEEP_ANGULAR_VELOCITY),
-                mTimeBeforeSleep(DEFAULT_TIME_BEFORE_SLEEP) {
+                mTimeBeforeSleep(DEFAULT_TIME_BEFORE_SLEEP), mEventListener(NULL) {
 
 }
 
@@ -147,11 +147,11 @@ void DynamicsWorld::update() {
 
         // Update the AABBs of the bodies
         updateRigidBodiesAABB();
-
-        // Reset the external force and torque applied to the bodies
-        resetBodiesForceAndTorque();
     }
 
+    // Reset the external force and torque applied to the bodies
+    resetBodiesForceAndTorque();
+
     // Compute and set the interpolation factor to all the bodies
     setInterpolationFactorToAllBodies();
 }
@@ -968,6 +968,13 @@ void DynamicsWorld::notifyNewContact(const BroadPhasePair* broadPhasePair,
     OverlappingPair* overlappingPair = mOverlappingPairs.find(indexPair)->second;
     assert(overlappingPair != NULL);
 
+    // If it is the first contact since the pair are overlapping
+    if (overlappingPair->getNbContactPoints() == 0) {
+
+        // Trigger a callback event
+        if (mEventListener != NULL) mEventListener->beginContact(*contactInfo);
+    }
+
     // Add the contact to the contact cache of the corresponding overlapping pair
     overlappingPair->addContact(contact);
 
@@ -978,6 +985,9 @@ void DynamicsWorld::notifyNewContact(const BroadPhasePair* broadPhasePair,
     // of the two bodies involved in the contact
     addContactManifoldToBody(overlappingPair->getContactManifold(), overlappingPair->mBody1,
                              overlappingPair->mBody2);
+
+    // Trigger a callback event for the new contact
+    if (mEventListener != NULL) mEventListener->newContact(*contactInfo);
 }
 
 // Enable/Disable the sleeping technique

src/engine/DynamicsWorld.h

@@ -130,6 +130,9 @@ class DynamicsWorld : public CollisionWorld {
         /// becomes smaller than the sleep velocity.
         decimal mTimeBeforeSleep;
 
+        /// Pointer to an event listener object
+        EventListener* mEventListener;
+
         // -------------------- Methods -------------------- //
 
         /// Private copy-constructor
@@ -305,6 +308,9 @@ public :
         /// Set the time a body is required to stay still before sleeping
         void setTimeBeforeSleep(decimal timeBeforeSleep);
 
+        /// Set an event listener object to receive events callbacks.
+        void setEventListener(EventListener* eventListener);
+
         // TODO : REMOVE THIS
         Island** getIslands() { return mIslands;}
 
@@ -490,6 +496,13 @@ inline void DynamicsWorld::setTimeBeforeSleep(decimal timeBeforeSleep) {
     mTimeBeforeSleep = timeBeforeSleep;
 }
 
+// Set an event listener object to receive events callbacks.
+/// If you use NULL as an argument, the events callbacks will be disabled.
+inline void DynamicsWorld::setEventListener(EventListener* eventListener) {
+    mEventListener = eventListener;
+}
+
+
 }
 
 #endif

src/engine/EventListener.h

@@ -0,0 +1,62 @@
+/********************************************************************************
+* ReactPhysics3D physics library, http://code.google.com/p/reactphysics3d/      *
+* Copyright (c) 2010-2013 Daniel Chappuis                                       *
+*********************************************************************************
+*                                                                               *
+* This software is provided 'as-is', without any express or implied warranty.   *
+* In no event will the authors be held liable for any damages arising from the  *
+* use of this software.                                                         *
+*                                                                               *
+* Permission is granted to anyone to use this software for any purpose,         *
+* including commercial applications, and to alter it and redistribute it        *
+* freely, subject to the following restrictions:                                *
+*                                                                               *
+* 1. The origin of this software must not be misrepresented; you must not claim *
+*    that you wrote the original software. If you use this software in a        *
+*    product, an acknowledgment in the product documentation would be           *
+*    appreciated but is not required.                                           *
+*                                                                               *
+* 2. Altered source versions must be plainly marked as such, and must not be    *
+*    misrepresented as being the original software.                             *
+*                                                                               *
+* 3. This notice may not be removed or altered from any source distribution.    *
+*                                                                               *
+********************************************************************************/
+
+#ifndef REACTPHYSICS3D_EVENT_LISTENER_H
+#define REACTPHYSICS3D_EVENT_LISTENER_H
+
+// Libraries
+#include "../constraint/ContactPoint.h"
+
+namespace reactphysics3d {
+
+// Class EventListener
+/**
+ * This class can be used to receive event callbacks from the physics engine.
+ * In order to receive callbacks, you need to create a new class that inherits from
+ * this one and you must override the methods you need. Then, you need to register your
+ * new event listener class to the physics world using the DynamicsWorld::setEventListener()
+ * method.
+ */
+class EventListener {
+
+    public :
+
+        /// Constructor
+        EventListener() {}
+
+        /// Destructor
+        virtual ~EventListener() {}
+
+        /// Called when a new contact point is found between two bodies that were separated before
+        virtual void beginContact(const ContactPointInfo& contact) {}
+
+        /// Called when a new contact point is found between two bodies
+        virtual void newContact(const ContactPointInfo& contact) {}
+
+};
+
+}
+
+#endif

src/reactphysics3d.h

@@ -42,6 +42,7 @@
 #include "engine/DynamicsWorld.h"
 #include "engine/CollisionWorld.h"
 #include "engine/Material.h"
+#include "engine/EventListener.h"
 #include "collision/shapes/CollisionShape.h"
 #include "collision/shapes/BoxShape.h"
 #include "collision/shapes/SphereShape.h"