CollisionEvents& PhysicsEngine::getCollisionEvents() {
const uint32_t CONTINUE_EVENT_FILTER_FREQUENCY = 10;
_collisionEvents.clear();
// scan known contacts and trigger events
ContactMap::iterator contactItr = _contactMap.begin();
while (contactItr != _contactMap.end()) {
ContactInfo& contact = contactItr->second;
ContactEventType type = contact.computeType(_numContactFrames);
if(type != CONTACT_EVENT_TYPE_CONTINUE || _numSubsteps % CONTINUE_EVENT_FILTER_FREQUENCY == 0) {
ObjectMotionState* motionStateA = static_cast<ObjectMotionState*>(contactItr->first._a);
ObjectMotionState* motionStateB = static_cast<ObjectMotionState*>(contactItr->first._b);
glm::vec3 velocityChange = (motionStateA ? motionStateA->getObjectLinearVelocityChange() : glm::vec3(0.0f)) +
(motionStateB ? motionStateB->getObjectLinearVelocityChange() : glm::vec3(0.0f));
if (motionStateA && motionStateA->getType() == MOTIONSTATE_TYPE_ENTITY) {
QUuid idA = motionStateA->getObjectID();
QUuid idB;
if (motionStateB && motionStateB->getType() == MOTIONSTATE_TYPE_ENTITY) {
idB = motionStateB->getObjectID();
}
glm::vec3 position = bulletToGLM(contact.getPositionWorldOnB()) + _originOffset;
glm::vec3 penetration = bulletToGLM(contact.distance * contact.normalWorldOnB);
_collisionEvents.push_back(Collision(type, idA, idB, position, penetration, velocityChange));
} else if (motionStateB && motionStateB->getType() == MOTIONSTATE_TYPE_ENTITY) {
QUuid idB = motionStateB->getObjectID();
glm::vec3 position = bulletToGLM(contact.getPositionWorldOnA()) + _originOffset;
// NOTE: we're flipping the order of A and B (so that the first objectID is never NULL)
// hence we must negate the penetration.
glm::vec3 penetration = - bulletToGLM(contact.distance * contact.normalWorldOnB);
_collisionEvents.push_back(Collision(type, idB, QUuid(), position, penetration, velocityChange));
}
}
if (type == CONTACT_EVENT_TYPE_END) {
ContactMap::iterator iterToDelete = contactItr;
++contactItr;
_contactMap.erase(iterToDelete);
} else {
++contactItr;
}
}
return _collisionEvents;
}
