Get Collisions - Ogre Addon Forums

JohnBoyManbullet

29-07-2011 04:07:38

Im so glad i have what your looking for, this will be so easy to implement





	const unsigned int numManifolds = dispatcher->getNumManifolds();



	



	// Go through every manifold.

	for (unsigned int i=0; i < numManifolds; i++)

	{



   // Get current manifold.

   btPersistentManifold* contactManifold = dispatcher->getManifoldByIndexInternal(i); 

   

   // Get collisionpair.

   obA =

      static_cast<btCollisionObject*>(contactManifold->getBody0());

   btCollisionObject* obB =

      static_cast<btCollisionObject*>(contactManifold->getBody1());



 //   raycallback.addSingleResult(obA,true);

   // Check if the two colliding objects are the boxes.

 

   if ( (body3 == obA && body4 == obB)

      || (body4 == obA && body3 == obB) )    // is the ground touching the unit

   {

  

   StepUpRay(evt);

  // StepDownRay( );

 

   }

   // Refresh contact points.

   contactManifold->refreshContactPoints(obA->getWorldTransform(), obB->getWorldTransform());

   

   // Get number of contact points of these two objects.

   const unsigned int numContacts = contactManifold->getNumContacts();

   

   // Go through every contact point.

   for (unsigned int j = 0;j < numContacts; j++)

   {

   // Get current manifold point.

   btManifoldPoint& pt = contactManifold->getContactPoint(j);



   // Get positions.

   btVector3 ptA = pt.getPositionWorldOnA();

   btVector3 ptB = pt.getPositionWorldOnB();



   // Transform to ogre.

   Vector3 aPoint = Vector3(ptA.x(), ptA.y(), ptA.z());

   Vector3 bPoint = Vector3(ptB.x(), ptB.y(), ptB.z());



   // Your code here if need to check the collision by contact points.

   }

}

Cookiezzz

29-07-2011 13:30:16

Thanks very much,
but is there a way with OgreBullet?

cookiezzz

JohnBoyManbullet

29-07-2011 22:16:30

Thats bullet with ogre, this forum should be called just bullet.

Cookiezzz

30-07-2011 16:04:35

Ok,
i tried your code. Just one question :
What is StepUpRay(evt);?

JohnBoyManbullet

30-07-2011 23:21:33

its nothing relevant.

Cookiezzz

02-08-2011 17:11:00

Hi again,
it works so far, but the Ogre Object and the collision don't match. Any Ideas?





			Ogre::AxisAlignedBox boundingB = Player.Entity->getBoundingBox();

             size = boundingB.getSize(); 

			 size *= (Player.node->getScale()); // only the half needed

			 size /= 2;

             size *= 0.96f;   // Bullet margin is a bit bigger so we need a smaller size

             // after that create the Bullet shape with the calculated size

			 OgreBulletCollisions::BoxCollisionShape *sceneBoxShape = new OgreBulletCollisions::BoxCollisionShape(size);

			 Player.Body = new OgreBulletDynamics::RigidBody("PlayerPhys" ,mWorld);

			 Player.Body->setShape(   Player.node,sceneBoxShape,    

                              0.0f,         // dynamic body restitution

                               0.0f,0.1f,         // dynamic body friction

							   Ogre::Vector3(0,0,0),      // starting position of the box

							   Ogre::Quaternion(1,0,0,0));// orientation of the box

			 Player.Body->setPosition(0,900,0);

			 Player.Body->setKinematicObject(true);

			 Player.Body->showDebugShape(true);





			 

			 boundingB = Floor.Entity->getBoundingBox();

			 size = boundingB.getSize(); 

			 size *= (Floor.node->getScale());

			 size /=2;// only the half needed

             size *= 0.96f;   // Bullet margin is a bit bigger so we need a smaller size

             // after that create the Bullet shape with the calculated size

			 Floor.Shape = new OgreBulletCollisions::BoxCollisionShape(size);

			 Floor.Body = new OgreBulletDynamics::RigidBody("FloorPhys" ,mWorld);

			 Floor.Body->setStaticShape(Floor.Shape,0.1f,0.0f,Ogre::Vector3(0,0,0));

JohnBoyManbullet

04-08-2011 11:27:45

I think i know whats wrong. You need to use motion states. I always have and heard you always wana move yer shapes with motion states. http://bulletphysics.org/mediawiki-1.5. ... tionStates . Add the shape to yer motion state, then compare the motion state to the collision object. That what i do and it works like a charm.

Cookiezzz

05-08-2011 11:04:22

i use OgreBUllet and i think it uses motionstates.

Cookiezzz

05-08-2011 18:35:27

OK,

when there is one collision there is no more

.
And the collisionshapes have a wrong figure

JohnBoyManbullet

05-08-2011 22:59:49

k well i havent gone too far into it my self. at least you have learned how the contact manafolds work. Here, this is the bullet wikis explanations with variations on what i showd you. http://www.bulletphysics.org/mediawiki- ... d_Triggers