bool Circle::CircleCircleIntersect( Circle *a, Circle *b, Vector2 *pointAOut, Vector2 *pointBOut ){
Vector2 *d = b->m_pos->Sub( a->m_pos );
float centerDist = d->get_m_Len();
if( centerDist > a->m_radius + b->m_radius ){
// separated
pointAOut = pointBOut = 0;
return false;
} else {
// partial intersection
float r0Sqr = a->m_radius*a->m_radius;
float newCenterDist = ( r0Sqr-b->m_radius*b->m_radius+centerDist*centerDist )/( 2*centerDist );
float sqr = r0Sqr-newCenterDist*newCenterDist;
if( sqr <= 0.0 ){
// containment
pointAOut = pointBOut = 0;
return false;
}
Vector2 *P2 = a->m_pos->Add( d->MulScalar( newCenterDist/centerDist ) );
float radius = sqrt( sqr );
Vector2 *perp = b->m_pos->Sub( a->m_pos )->get_m_Perp()->get_m_Unit();
Vector2 *temp_a = P2->Add(perp->MulScalar(radius)); //TESTME
Vector2 *temp_b = P2->Sub(perp->MulScalar(radius));
pointAOut->m_x = temp_a->m_x;
pointAOut->m_y = temp_a->m_y;
pointBOut->m_x = temp_b->m_x;
pointBOut->m_y = temp_b->m_y;
return true;
}
}
PointAndDistanceContainer *Circle::ClosestPointAndDistOnEdge( Vector2 *p ){
Vector2 *d = p->Sub(m_pos);
float distCenter = d->get_m_Len();
float penetration = distCenter - m_radius;
if( distCenter == 0 ){
return new PointAndDistanceContainer( m_pos->Add(new Vector2( m_radius, 0 )), -m_radius );
}
// generate point on edge
Vector2 *pow = d->MulScalar(m_radius/distCenter)->AddTo(m_pos);
return new PointAndDistanceContainer(pow, penetration);
}