Collisions Tutorial is Outdated

[johnrowlay]

I'm trying to determine whether two particular objects are in collision with each other. In the tutorial on your webpage (http://dart.readthedocs.io/en/release-6.0/tutorials/collisions/#lesson-3c-compute-collisions), it suggests to do the following:

dart::collision::CollisionDetector* detector = mWorld->getConstraintSolver()->getCollisionDetector();
detector->detectCollision(true, true);

bool collision = false;
size_t collisionCount = detector->getNumContacts();
for(size_t i = 0; i < collisionCount; ++i)
{
    const dart::collision::Contact& contact = detector->getContact(i);
    if(contact.bodyNode1.lock()->getSkeleton() == object || contact.bodyNode2.lock()->getSkeleton() == object)
    {
        collision = true;
        break;
    }
}

This seems fairly straighforward to me. You loop through all the detected contacts, and check whether the skeletons associated with these contacts are the two skeletons which you are looking for.

However, in the latest version of the code, this tutorial actually does things differently:

auto collisionEngine = mWorld->getConstraintSolver()->getCollisionDetector();
auto collisionGroup = mWorld->getConstraintSolver()->getCollisionGroup();
auto newGroup = collisionEngine->createCollisionGroup(newDomino.get());

dart::collision::CollisionOption option;
dart::collision::CollisionResult result;
bool dominoCollision = collisionGroup->collide(newGroup.get(), option, &result);

This is much less easy to follow. I don't really understand what a CollisionGroup is, nor how to tell whether two particular objects have collided. However, there doesn't seem to be any documentation on this, because the only tutorial on collisions uses an outdated version of the code.

Please could somebody explain how I can achieve this, or update the tutorial to reflect the new code?

Thanks!

[jturner65]

This solution to this tutorial also throws a segmentation fault on windows since it uses make_shared to instance shared ptrs to classes containing vectorizable constructs vs using Eigen::make_aligned_shared. This is similar to #513

[stale]

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