How do I ......?! collision problem

The situation:

one mesh, one coll object, ...!!
and a car with 4 wheels and a body (can drive in each direction, so there is no front or back)
gravity is set

All this code works, collision works, gravity works,....

The problem:

int collisionCounter=0;
The car rides on the floor, IF the car hits the wall I want collisionCounter++
How can I do this in my situation?

you can use the faceID when creating the TreeCollision background object. then inside the contactCallback (userProcess function), you can check which faceID is causing the collision. if it is the wall, you can increment your counter.

great!
But everything is one mesh. (wall+floor+doors=mylevel.mesh)


bool optimalisatieTreeCollision = false;
Entity* level1Entity = mSceneMgr->createEntity("Level1", "level1.mesh");
SceneNode* level1SceneNode = mSceneMgr->getRootSceneNode()->createChildSceneNode("Level1");
level1SceneNode->attachObject(level1Entity)
OgreNewt::Collision* level1Col = new OgreNewt::CollisionPrimitives::TreeCollision(m_World, level1SceneNode, optimalisatieTreeCollision);
level1Col->setUserID(???);
OgreNewt::Body* level1Body = new OgreNewt::Body( m_World, level1Col );
delete level1Col;
level1Body->attachToNode( level1SceneNode );

So I will need multiple userIDs in one TreeCol

no, not the "userID", but the "faceID". OgreNewt sets the "faceID" for each face in the collision to the index of the submesh in the mesh. So, the faceID in the treecollision is different for each material assigned to the mesh's faces.

the way you get the ID is to get the submesh index for the submesh using the material you want. so for example, if you have a big level with some "ice" areas, you probably have an "ice" material assigned to those faces. if you know that submesh #3 of your big mesh are the faces with that material, the faceID (that you get in contactProcess()) will also be "3".

thx walaber for the help. looks like what I need!
But I'm still having problems with collisionCallbacks
difficult for me to create those callbacks.

I'll give it another shot tomorrow

you can use the faceID when creating the TreeCollision background object. then inside the contactCallback (userProcess function), you can check which faceID is causing the collision. if it is the wall, you can increment your counter.

Can you give me more info on how to use the faceID?

I can only give 1 materialID to the treecol object instead of several for each material.





Entity* level1Entity = mSceneMgr->createEntity("Level1", "level1.mesh");
SceneNode* level1SceneNode = mSceneMgr->getRootSceneNode()->createChildSceneNode("Level1");
level1SceneNode->attachObject(level1Entity);

OgreNewt::Collision* level1Col = new OgreNewt::CollisionPrimitives::TreeCollision(m_World, level1SceneNode, optimalisatieTreeCollision);
OgreNewt::Body* level1Body = new OgreNewt::Body(m_World, level1Col);
delete level1Col;
level1Body->attachToNode(level1SceneNode);

level1Body->setMaterialGroupID(matIDLevel);


the callback (with unfortunately always the same id for the m_body1)


void BotsingCallback::userProcess()
{
int id0 = m_body0->getMaterialGroupID()->getID();
int id1 = m_body1->getMaterialGroupID()->getID();
...


In newton, each point can have it's own ID, good for different terrains and such, snow, dirt, etc...

Unsure how to add those in OgreNewt however...

level1Entity->getSubEntity(6)->setMaterialName("plinten");

this is close to what I need, is there not some kind of method level1Entity->getSubEntity(6)->setMaterialGroupID(..) (THIS DOES NOT EXIST )

the TreeCollision creator in OgreNewt assigns an ID == to the submech number.

so inside your callback, when you check the "faceID" of the collision, if it is on a face from mesh->getSubMesh(0), the returned value will be 0.

if it is from mesh->getSubMesh(5), the returned value will be 5.

the TreeCollision creator in OgreNewt assigns an ID == to the submech number.

so inside your callback, when you check the "faceID" of the collision, if it is on a face from mesh->getSubMesh(0), the returned value will be 0.

if it is from mesh->getSubMesh(5), the returned value will be 5.

I understand!
But my callback gives me always the same id! not the id of the submesh


Entity* level1Entity = mSceneMgr->createEntity("Level1", "level1.mesh");
SceneNode* level1SceneNode = mSceneMgr->getRootSceneNode()->createChildSceneNode("Level1");
level1SceneNode->attachObject(level1Entity);

OgreNewt::Collision* level1Col = new OgreNewt::CollisionPrimitives::TreeCollision(m_World, level1SceneNode, optimalisatieTreeCollision);
OgreNewt::Body* level1Body = new OgreNewt::Body(m_World, level1Col);
delete level1Col;
level1Body->attachToNode(level1SceneNode);

//voor wrijving & botsingen
matIDLevel = new OgreNewt::MaterialID( m_World );
level1Body->setMaterialGroupID(matIDLevel); // !!!!!!!!!!!!!!!!!!!

matPairLevelRolstoelBody = new OgreNewt::MaterialPair( m_World, matIDobject, matIDLevel ); // !!!!!!!!!!!!!!

// callback
botsingCallback = new BotsingCallback();
matPairLevelRolstoelBody->setContactCallback( botsingCallback );

in your callback, you need to use getContactFaceAttribute() to get the ID of the face currently colliding.

thxxxxxxxxx!!! that's it

please walaber, have a look at http://www.ogre3d.org/phpBB2addons/viewtopic.php?t=1066

desperate on that one :/