size_t collide(CircleShape &circle, BoxShape &box, float dt, Contact *pxContacts, size_t numMaxContacts)
{
dt, pxContacts, numMaxContacts;
const Point2f &p1 = circle.body.getPosition();
const Point2f &p2 = box.body.getPosition();
// work in the box's coordinate system
const Point2f kDiff = p1 - p2;
// compute squared distance and closest point on box
float fSqrDistance = 0.0f, fDelta;
Point2f kClosest(kDiff * box.GetDir(0), kDiff * box.GetDir(1));
const Point2f &extents = box.GetExtents();
if (kClosest.x < -extents.x)
{
fDelta = kClosest.x + extents.x;
fSqrDistance += fDelta*fDelta;
kClosest.x = -extents.x;
}
else if (kClosest.x > extents.x)
{
fDelta = kClosest.x - extents.x;
fSqrDistance += fDelta*fDelta;
kClosest.x = extents.x;
}
if (kClosest.y < -extents.y)
{
fDelta = kClosest.y + extents.y;
fSqrDistance += fDelta*fDelta;
kClosest.y = -extents.y;
}
else if (kClosest.y > extents.y)
{
fDelta = kClosest.y - extents.y;
fSqrDistance += fDelta*fDelta;
kClosest.y = extents.y;
}
if (fSqrDistance > circle.GetRadius() * circle.GetRadius())
{
return 0;
}
Point2f d = p2 + kClosest - p1;
d.Normalize();
pxContacts[0] = Contact(p1 + d * circle.GetRadius(), p2 + kClosest, &circle.body, &box.body);
return 1;
}
size_t collide(CircleShape &circle1, CircleShape &circle2, float dt, Contact *pxContacts, size_t numMaxContacts)
{
dt, numMaxContacts;
float rR = circle1.GetRadius() + circle2.GetRadius();
const Point2f &p1 = circle1.body.getPosition();
const Point2f &p2 = circle2.body.getPosition();
Point2f d = p2 - p1;
float len = d.Length();
if (len > rR)
{
return 0;
}
d.Normalize();
pxContacts[0] = Contact(p1 + d * circle1.GetRadius(), p1 + d * (len - circle1.GetRadius()), &circle1.body, &circle2.body);
return 1;
}
