public static bool sphereAndHalfSpace(
SphereRigid sphere,
CollisionPlane plane,
ref CollisionData data
)
{
// Make sure we have contacts
if (data.contactsLeft <= 0)
{
return(false);
}
// Cache the sphere position
Vector3 position = sphere.PositionCenterEngine;
// Find the distance from the plane
float ballDistance =
Vector3.Dot(plane.Direction, position) -
sphere.Radius - plane.Offset;
if (ballDistance >= 0)
{
return(false);
}
Contact c = new Contact();
c.ContactNormal = plane.Direction;
c.Penetration = -ballDistance;
c.ContactPoint =
position - plane.Direction * (ballDistance + sphere.Radius);
c.SetBodyData(sphere, null,
data.friction, data.restitution);
c.ContactToWorld.M11 = plane.Direction.X;
c.ContactToWorld.M12 = -plane.Direction.Y;
c.ContactToWorld.M21 = plane.Direction.Y;
c.ContactToWorld.M22 = plane.Direction.X;
data.contacts.Add(c);
sphere.SetCanSleep(true);
data.addContacts(1);
return(true);
}
public static bool sphereAndSphere(
SphereRigid one,
SphereRigid two,
ref CollisionData data
)
{
// Cache the sphere positions
Vector3 positionOne = one.PositionCenterEngine;
Vector3 positionTwo = two.PositionCenterEngine;
// Find the vector between the objects
Vector3 midline = positionOne - positionTwo;
float size = midline.Length();
// See if it is large enough.
if (size <= 0.0f || size >= one.Radius + two.Radius)
{
return(false);
}
// We manually create the normal, because we have the
// size to hand.
Vector3 normal = midline * (((float)1.0) / size);
Contact c = new Contact();
c.ContactNormal = normal;
c.ContactPoint = positionTwo + midline * (float)0.5;
c.Penetration = (one.Radius + two.Radius - size);
c.SetBodyData(one, two,
data.friction, data.restitution);
c.ContactToWorld.M11 = normal.X;
c.ContactToWorld.M12 = -normal.Y;
c.ContactToWorld.M21 = normal.Y;
c.ContactToWorld.M22 = normal.X;
data.contacts.Add(c);
one.SetCanSleep(true);
two.SetCanSleep(true);
data.addContacts(1);
return(true);
}