/// <summary>
/// Update the contact manifold and touching status.
/// Note: do not assume the fixture AABBs are overlapping or are valid.
/// </summary>
/// <param name="wake">Whether we should wake the bodies due to touching changing.</param>
/// <returns>What current status of the contact is (e.g. start touching, end touching, etc.)</returns>
internal ContactStatus Update(IPhysicsManager physicsManager, out bool wake)
{
PhysicsComponent bodyA = FixtureA !.Body;
PhysicsComponent bodyB = FixtureB !.Body;
var oldManifold = Manifold;
// Re-enable this contact.
Enabled = true;
bool touching;
var wasTouching = IsTouching;
wake = false;
var sensor = !(FixtureA.Hard && FixtureB.Hard);
var bodyATransform = physicsManager.GetTransform(bodyA);
var bodyBTransform = physicsManager.GetTransform(bodyB);
// Is this contact a sensor?
if (sensor)
{
IPhysShape shapeA = FixtureA.Shape;
IPhysShape shapeB = FixtureB.Shape;
touching = _manifoldManager.TestOverlap(shapeA, ChildIndexA, shapeB, ChildIndexB, bodyATransform, bodyBTransform);
// Sensors don't generate manifolds.
Manifold.PointCount = 0;
}
else
{
Evaluate(ref Manifold, bodyATransform, bodyBTransform);
touching = Manifold.PointCount > 0;
// Match old contact ids to new contact ids and copy the
// stored impulses to warm start the solver.
for (var i = 0; i < Manifold.PointCount; ++i)
{
var mp2 = Manifold.Points[i];
mp2.NormalImpulse = 0.0f;
mp2.TangentImpulse = 0.0f;
var id2 = mp2.Id;
for (var j = 0; j < oldManifold.PointCount; ++j)
{
var mp1 = oldManifold.Points[j];
if (mp1.Id.Key == id2.Key)
{
mp2.NormalImpulse = mp1.NormalImpulse;
mp2.TangentImpulse = mp1.TangentImpulse;
break;
}
}
Manifold.Points[i] = mp2;
}
if (touching != wasTouching)
{
wake = true;
}
}
IsTouching = touching;
var status = ContactStatus.NoContact;
if (!wasTouching)
{
if (touching)
{
status = ContactStatus.StartTouching;
}
}
else
{
if (!touching)
{
status = ContactStatus.EndTouching;
}
}
#if DEBUG
if (!sensor)
{
_debugPhysics.HandlePreSolve(this, oldManifold);
}
#endif
return(status);
}
