static uint BoxAndHalfSpace(H1Box InBox, H1Plane InPlane, ref H1CollisionDetectResult OutResult)
{
if (!H1PrimitiveIntersection.Intersect(InBox, InPlane))
{
return(0);
}
foreach (H1Vector3 BoxVertex in BoxVertices)
{
// calculate transformed box vertex
H1Vector3 TransformedBoxVertex = H1Vector3.Transform(BoxVertex * InBox.HalfSize, InBox.Transform);
// calculate the distance from the plane
float VertexDistance = H1Vector3.Dot(TransformedBoxVertex, InPlane.Normal);
// compare this to the plane's distance
if (VertexDistance <= InPlane.Distance)
{
// create the contact data
H1CollisionContact Contact = new H1CollisionContact();
Contact.ContactPoint = InPlane.Normal;
Contact.ContactPoint *= (VertexDistance - InPlane.Distance);
Contact.ContactPoint += TransformedBoxVertex;
Contact.ContactNormal = InPlane.Normal;
Contact.Penetration = InPlane.Distance - VertexDistance;
OutResult.Contacts.Add(Contact);
}
}
return(Convert.ToUInt32(OutResult.Contacts.Count));
}
public static float TransformToAxis(H1Box InBox, H1Vector3 InAxis)
{
// think of quater-box (halfsize) end point projecting to InAxis
// which gives maximum distance(by math.abs) toward axis from box
return(InBox.HalfSize.X * Math.Abs(H1Vector3.Dot(InAxis, InBox.Transform.Axis0))
+ InBox.HalfSize.Y * Math.Abs(H1Vector3.Dot(InAxis, InBox.Transform.Axis1))
+ InBox.HalfSize.Z * Math.Abs(H1Vector3.Dot(InAxis, InBox.Transform.Axis2)));
}
public static bool Intersect(H1Box InBox, H1Plane InPlane)
{
// work out the projected radius of the box onto the plane direction
float ProjectedRadius = TransformToAxis(InBox, InPlane.Normal);
// work out how far the box is from the origin
H1Vector3 BoxPosition = InBox.Transform.Axis3;
float BoxDistance = H1Vector3.Dot(InPlane.Normal, BoxPosition) - ProjectedRadius;
// check for the intersection
return(BoxDistance <= InPlane.Distance);
}