/// <summary>
/// danger! This works for ContactDemo, but there is one hang up. The call to Math.Abs() should not
/// be needed. It isn't in the orange book text. However, we only get negative numbers from that Dot.
/// </summary>
/// <param name="box"></param>
/// <param name="plane"></param>
/// <param name="data"></param>
/// <returns></returns>
public static int boxAndPlane(Box box, Plane plane, CollisionData data)
{
if (data.contactsLeft <= 0) return 0;
int contacts_found = 0;
// p dot L < l
Vector3[] verts = box.WorldVerts();
foreach (Vector3 vert in verts)
{
//float vertexDist = (float)Math.Abs( (double)Vector3.Dot(plane.Normal, vert));
float vertexDist = Vector3.Dot(-plane.Normal, vert);
if (vertexDist >= plane.Offset + data.tolerance)
{
// the contact point is halfway between the vertex and the plane
// we multiply the direction by half the spearation distance
// and add the vertex location
Contact contact = new Contact();
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnPlane_Corner;
contact.Bodies[0] = box.Body;
contact.Bodies[1] = null;
contact.Point = plane.ClosestPoint(vert);
contact.Normal = plane.Normal;
contact.Penetration = vertexDist - plane.Offset;//TrickyMathHelper.Abs(plane.Offset - vertexDist);
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
contacts_found++;
}
}
return contacts_found;
}
public static int boxAndBoxBetter(Box left, Box right, CollisionData data)
{
Vector3[] leftWorldVerts = left.WorldVerts();
Vector3[] rightWorldVerts = right.WorldVerts();
foreach (Vector3 leftWorldVert in leftWorldVerts)
{
Contact contact = IntersectionTests.checkBoxAndPoint(right, leftWorldVert, data.restitution, data.friction);
if (contact != null)
{
contact.Bodies[1] = left.Body;
data.contacts.Add(contact);
}
}
if (data.contacts.Count > 0)
{
return data.contacts.Count;
}
foreach (Vector3 rightWorldVert in rightWorldVerts)
{
Contact contact = IntersectionTests.checkBoxAndPoint(left, rightWorldVert, data.restitution, data.friction);
if (contact != null)
{
contact.Bodies[1] = right.Body;
data.contacts.Add(contact);
}
}
// If any point/face contacts get precedent over edge/edge
if (data.contacts.Count > 0)
{
return data.contacts.Count;
}
List<Vector3[]> leftEdges = left.WorldEdges();
List<Vector3[]> rightEdges = right.WorldEdges();
foreach (Vector3[] leftEdge in leftEdges)
{
foreach (Vector3[] rightEdge in rightEdges)
{
Contact contact = checkEdgeAndEdge(left, leftEdge[0], leftEdge[1], right, rightEdge[0], rightEdge[1], data.restitution, data.friction);
if (contact != null)
{
data.contacts.Add(contact);
}
}
}
return data.contacts.Count;
}
