/** This function is called at each internal bullet timestep. It is used
* here to do the collision handling: using the contact manifolds after a
* physics time step might miss some collisions (when more than one internal
* time step was done, and the collision is added and removed). So this
* function stores all collisions in a list, which is then handled after the
* actual physics timestep. This list only stores a collision if it's not
* already in the list, so a collisions which is reported more than once is
* nevertheless only handled once.
* The list of collision
* Parameters: see bullet documentation for details.
*/
btScalar Physics::solveGroup(btCollisionObject** bodies, int numBodies,
btPersistentManifold** manifold,int numManifolds,
btTypedConstraint** constraints,
int numConstraints,
const btContactSolverInfo& info,
btIDebugDraw* debugDrawer,
btStackAlloc* stackAlloc,
btDispatcher* dispatcher)
{
btScalar returnValue=
btSequentialImpulseConstraintSolver::solveGroup(bodies, numBodies,
manifold, numManifolds,
constraints,
numConstraints, info,
debugDrawer,
stackAlloc,
dispatcher);
int currentNumManifolds = m_dispatcher->getNumManifolds();
// We can't explode a rocket in a loop, since a rocket might collide with
// more than one object, and/or more than once with each object (if there
// is more than one collision point). So keep a list of rockets that will
// be exploded after the collisions
for(int i=0; i<currentNumManifolds; i++)
{
btPersistentManifold* contact_manifold =
m_dynamics_world->getDispatcher()->getManifoldByIndexInternal(i);
const btCollisionObject* objA =
static_cast<const btCollisionObject*>(contact_manifold->getBody0());
const btCollisionObject* objB =
static_cast<const btCollisionObject*>(contact_manifold->getBody1());
unsigned int num_contacts = contact_manifold->getNumContacts();
if(!num_contacts) continue; // no real collision
const UserPointer *upA = (UserPointer*)(objA->getUserPointer());
const UserPointer *upB = (UserPointer*)(objB->getUserPointer());
if(!upA || !upB) continue;
// 1) object A is a track
// =======================
if(upA->is(UserPointer::UP_TRACK))
{
if(upB->is(UserPointer::UP_FLYABLE)) // 1.1 projectile hits track
m_all_collisions.push_back(
upB, contact_manifold->getContactPoint(0).m_localPointB,
upA, contact_manifold->getContactPoint(0).m_localPointA);
else if(upB->is(UserPointer::UP_KART))
{
AbstractKart *kart=upB->getPointerKart();
int n = contact_manifold->getContactPoint(0).m_index0;
const Material *m
= n>=0 ? upA->getPointerTriangleMesh()->getMaterial(n)
: NULL;
// I assume that the normal needs to be flipped in this case,
// but I can't verify this since it appears that bullet
// always has the kart as object A, not B.
const btVector3 &normal = -contact_manifold->getContactPoint(0)
.m_normalWorldOnB;
kart->crashed(m, normal);
}
else if(upB->is(UserPointer::UP_PHYSICAL_OBJECT))
{
int n = contact_manifold->getContactPoint(0).m_index1;
const Material *m
= n>=0 ? upA->getPointerTriangleMesh()->getMaterial(n)
: NULL;
const btVector3 &normal = contact_manifold->getContactPoint(0)
.m_normalWorldOnB;
upB->getPointerPhysicalObject()->hit(m, normal);
}
}
// 2) object a is a kart
// =====================
else if(upA->is(UserPointer::UP_KART))
{
if(upB->is(UserPointer::UP_TRACK))
{
AbstractKart *kart = upA->getPointerKart();
int n = contact_manifold->getContactPoint(0).m_index1;
const Material *m
= n>=0 ? upB->getPointerTriangleMesh()->getMaterial(n)
: NULL;
const btVector3 &normal = contact_manifold->getContactPoint(0)
.m_normalWorldOnB;
kart->crashed(m, normal); // Kart hit track
}
else if(upB->is(UserPointer::UP_FLYABLE))
// 2.1 projectile hits kart
m_all_collisions.push_back(
upB, contact_manifold->getContactPoint(0).m_localPointB,
upA, contact_manifold->getContactPoint(0).m_localPointA);
else if(upB->is(UserPointer::UP_KART))
// 2.2 kart hits kart
m_all_collisions.push_back(
upA, contact_manifold->getContactPoint(0).m_localPointA,
upB, contact_manifold->getContactPoint(0).m_localPointB);
else if(upB->is(UserPointer::UP_PHYSICAL_OBJECT))
// 2.3 kart hits physical object
m_all_collisions.push_back(
upB, contact_manifold->getContactPoint(0).m_localPointB,
upA, contact_manifold->getContactPoint(0).m_localPointA);
else if(upB->is(UserPointer::UP_ANIMATION))
m_all_collisions.push_back(
upB, contact_manifold->getContactPoint(0).m_localPointB,
upA, contact_manifold->getContactPoint(0).m_localPointA);
}
// 3) object is a projectile
// =========================
else if(upA->is(UserPointer::UP_FLYABLE))
{
// 3.1) projectile hits track
// 3.2) projectile hits projectile
// 3.3) projectile hits physical object
// 3.4) projectile hits kart
if(upB->is(UserPointer::UP_TRACK ) ||
upB->is(UserPointer::UP_FLYABLE ) ||
upB->is(UserPointer::UP_PHYSICAL_OBJECT) ||
upB->is(UserPointer::UP_KART ) )
{
m_all_collisions.push_back(
upA, contact_manifold->getContactPoint(0).m_localPointA,
upB, contact_manifold->getContactPoint(0).m_localPointB);
}
}
// Object is a physical object
// ===========================
else if(upA->is(UserPointer::UP_PHYSICAL_OBJECT))
{
if(upB->is(UserPointer::UP_FLYABLE))
m_all_collisions.push_back(
upB, contact_manifold->getContactPoint(0).m_localPointB,
upA, contact_manifold->getContactPoint(0).m_localPointA);
else if(upB->is(UserPointer::UP_KART))
m_all_collisions.push_back(
upA, contact_manifold->getContactPoint(0).m_localPointA,
upB, contact_manifold->getContactPoint(0).m_localPointB);
else if(upB->is(UserPointer::UP_TRACK))
{
int n = contact_manifold->getContactPoint(0).m_index1;
const Material *m
= n>=0 ? upB->getPointerTriangleMesh()->getMaterial(n)
: NULL;
const btVector3 &normal = contact_manifold->getContactPoint(0)
.m_normalWorldOnB;
upA->getPointerPhysicalObject()->hit(m, normal);
}
}
else if (upA->is(UserPointer::UP_ANIMATION))
{
if(upB->is(UserPointer::UP_KART))
m_all_collisions.push_back(
upA, contact_manifold->getContactPoint(0).m_localPointA,
upB, contact_manifold->getContactPoint(0).m_localPointB);
}
else
assert("Unknown user pointer"); // 4) Should never happen
} // for i<numManifolds
return returnValue;
} // solveGroup
