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(BoxShape &box1, BoxShape &box2, float dt, Contact *pxContacts, size_t numMaxContacts)
{
dt;
Point2f xAxis [4];
float fDepth[4];
xAxis[0] = box1.GetDir(0);
if (!IntervalIntersect(xAxis[0], box1, box2, fDepth[0])) return 0;
xAxis[1] = box1.GetDir(1);
if (!IntervalIntersect(xAxis[1], box1, box2, fDepth[1])) return 0;
xAxis[2] = box2.GetDir(0);
if (!IntervalIntersect(xAxis[2], box1, box2, fDepth[2])) return 0;
xAxis[3] = box2.GetDir(1);
if (!IntervalIntersect(xAxis[3], box1, box2, fDepth[3])) return 0;
float dcoll;
Point2f Ncoll;
if (!FindCollisionPlane(xAxis, fDepth, Ncoll, dcoll)) return 0;
Point2f D = box1.body.getPosition() - box2.body.getPosition();
if (D * Ncoll < 0.0f)
Ncoll *= -1.0f;
Point2f xPoints0[4];
Point2f xPoints1[4];
size_t numPoints0;
size_t numPoints1;
numPoints0 = box1.FindSupportPoints( Ncoll, xPoints0);
numPoints1 = box2.FindSupportPoints(-Ncoll, xPoints1);
if (!ConvertSupportPointsToContacts(box1, box2, Ncoll, xPoints0, numPoints0, xPoints1, numPoints1, pxContacts, numMaxContacts))
return 0;
return numMaxContacts;
}