bool IsColliding(const Collider &collider_a, const Collider &collider_b, Contacts &contacts)
{
// quick check with the individual collider AABBs for a quick out
if (!collider_a.aabb.Overlap(collider_b.aabb))
return false;
// our simplex for this collision test
Simplex simplex;
// Set initial search direction to the difference of centers
Vector2 d = Vector2(1, -1);//Vector2(collider_b.root_trans.PositionWC() - collider_a.root_trans.PositionWC());
// get the first minkowski difference point
simplex.Add(Support(collider_a, collider_b, d));
// negate the support point, giving us a vector in the direction of the origin
d = -simplex.A().vert;
int count = 0;
// start looping
while (count < 100)
{
// add a new point to the simplex because we haven't terminated yet
simplex.Add(Support(collider_a, collider_b, d));
// see if the simplex is on the correct side of the origin
if (Vector2::OppositeDirection(simplex.A().vert, d))
{
// if the point added last was not past the origin in the direction of d
// then the Minkowski Sum cannot possibly contain the origin since
// the last point added is on the edge of the Minkowski Difference
return false;
}
else
{
// oterwise we need to determine if the origin is in the current simplex
// this function will set the next search direction for us if it fails.
if (simplex.ContainsOrigin(d))
{
// if it does then we know there is a collision
// handle the collision with the EPA algorithm
EPAHandle(collider_a, collider_b, simplex, contacts);
// find the incident edge.
if (contacts.size())
{
auto &it = contacts.back();
it.info.e.edge_a = collider_a.FindIndex(it.normal);
it.info.e.edge_b = collider_b.FindIndex(-it.normal);
}
return true;
}
}
++count;
}
return false;
}
