colision detection with Triangular meshes

[amrishkum]

hi

I am trying to detect collision between two triangular surface meshes. I could use static triangular meshes as collision shapes and then tried to detect collision between them . Is this the correct way to do ?

Is there any problem in the code below?

The code what I am using for detecting collision between triangular mesh is

Code: Select all

//Adding triangular meshes to the collision shapes
trimeshShape = new btBvhTriangleMeshShape(m_indexVertexArrays,useQuantizedAabbCompression);

m_collisionShapes.push_back(trimeshShape);

btCollisionWorld* collisionWorld = 0;
if (m_collisionShapes.size() >1)
{
for (int index =1; index < m_collisionShapes.size(); index++)
{

m_collisionConfiguration = new btDefaultCollisionConfiguration();
m_dispatcher = new btCollisionDispatcher(m_collisionConfiguration);
btVector3 worldMin(-1000,-1000,-1000);
btVector3 worldMax(1000,1000,1000);
m_broadphase = new btAxisSweep3(worldMin,worldMax);
collisionWorld = new btCollisionWorld(m_dispatcher,m_broadphase,m_collisionConfiguration);

btCollisionAlgorithm* algo = collisionWorld->getDispatcher()->findAlgorithm(&objects[0],&objects[index]);
btManifoldResult contactPointResult(&objects[0],&objects[index]);
algo->processCollision(&objects[0],&objects[index],collisionWorld->getDispatchInfo(),&contactPointResult);

btManifoldArray manifoldArray;
algo->getAllContactManifolds(manifoldArray);

int numManifolds = manifoldArray.size();
int numContacts =0;
bool bCheckCollision = false;
for (int i=0;i<numManifolds;i++)
{
btPersistentManifold* contactManifold = manifoldArray;
numContacts = contactManifold->getNumContacts();
if (numContacts >0)
{
bCheckCollision = true;
break;
}

}

if (bCheckCollision == true)
{
return 1;
}
}

}


Thanks

[amrishkum]

Hi

I have two stationary triangular meshes and I am trying to detect collision between them. When I used above method, the method fails and it doesn't get results. I tried to even use btGImpactMeshShape and also used m_dynamicsWorld. But I am not getting correct results.

The meshes are stationary. When they meshes intersect, I need to know whether they collided or not.

I am also uploading the code file.

Please let me know if somebody has some suggestions.

[amrishkum]

I did write a simple code to detect collision between two triangles and this doesn't work too. Does any one has suggestion what is wrong in code as two triangles two intersect.

The number of contacts is zero which should not be the case. Can someone tell what I doing wrong? Please help............

Code: Select all

btTriangleMesh* trimesh = new btTriangleMesh(true,false);

trimesh->addTriangle(btVector3(0,0,0), btVector3(100,0,0), btVector3(0,0,100));


btCollisionShape * trimeshShape = new btBvhTriangleMeshShape(trimesh,true,true);


objects[0].setCollisionShape(trimeshShape);

btTriangleMesh *trimesh1 = new btTriangleMesh(true,false);

trimesh1->addTriangle(btVector3(0,100,0), btVector3(100,-50,50), btVector3(0,0,0));


btCollisionShape * trimeshShape1 = new btBvhTriangleMeshShape(trimesh1,true,true);

objects[1].setCollisionShape(trimeshShape1);

m_collisionConfiguration = new btDefaultCollisionConfiguration();

m_dispatcher = new btCollisionDispatcher(m_collisionConfiguration);

btVector3 worldMin(-1000,-1000,-1000);
btVector3 worldMax(1000,1000,1000);
m_broadphase = new btAxisSweep3(worldMin,worldMax);

collisionWorld = new btCollisionWorld(m_dispatcher,m_broadphase,m_collisionConfiguration);

collisionWorld->addCollisionObject(&objects[0]);
collisionWorld->addCollisionObject(&objects[1]);
collisionWorld->performDiscreteCollisionDetection();
int num_manifolds = collisionWorld->getDispatcher()->getNumManifolds();
for (int i=0;i<num_manifolds;i++)
{
btPersistentManifold* contactManifold = collisionWorld->getDispatcher()->getManifoldByIndexInternal(i);
int numContacts = contactManifold->getNumContacts();
}

[amrishkum]

Can anyone help me? Please help...I need it urgently. I am also attaching the image of colliding triangles..

tritricol.jpg