public void AppendIntoList(FastLinkedList <T> list)
{
if (list == null)
{
return;
}
if (list._First == null)
{
return;
}
if (_First == null)
{
_First = list._First;
_Last = list._Last;
}
else
{
Node temp = _Last;
_Last.Next = list._First;
_Last.Next.Previous = _Last;
_Last = list._Last;
if (_Last.Previous == null)
{
_Last.Previous = temp;
}
}
length = list.length + length;
}
/**
* Remove the triangles in @triangles that are completely inside the geometry contained
* by this BSPTree instance. Triangles that are partially inside the geometry are clipped
* against it.
*
* If @clipLessThan is false, the operation is reversed and triangles portions outside the geometry
* of this BSPTree instance are removed.
*/
public void ClipOutTriangles(FastLinkedList <Triangle> triangles, bool clipLessThan = true, IList <Triangle> discarded = null)
{
// ensure the root node exists
if (root == null)
{
return;
}
// call the private, recursive version of ClipOutTriangles
ClipOutTriangles(root, triangles, clipLessThan, discarded);
}
public void CopyInto(IList <T> copy)
{
if (copy == null)
{
return;
}
FastLinkedList <T> .Node current = First;
while (current != null)
{
copy.Add(current.Value);
current = current.Next;
}
}
/**
* Rescursive version of AddTriangles. This method partitions the triangles
* in @triangles using @node's split plane, and then recursively calls itself
* with the resulting greater-than and less-than lists.
*/
private void AddTriangles(Node node, FastLinkedList <Triangle> triangles)
{
if (triangles == null)
{
return;
}
if (node == null)
{
return;
}
// get a reference to the list of triangles that are co-planar with
// @node's split plane
FastLinkedList <Triangle> nodeTriangles = node.GetTriangleList();
FastLinkedList <Triangle> lessThan = new FastLinkedList <Triangle>();
FastLinkedList <Triangle> greaterThan = new FastLinkedList <Triangle>();
// iterate through each triangle in @triangles and classify/partition each according
// @node's split plane. co-planar triangles go into @nodeTriangles, triangles on the front
// side go into @greaterThan, traingles on the back side go into @lessThan.
triangles.Iterate((Triangle tri) => {
Partitioner.Orientation orient = Partitioner.SliceTriangle(tri, node.SplitPlane, lessThan, greaterThan, nodeTriangles, nodeTriangles);
});
// release clear memory occupied by @triangles
triangles.Clear();
// recurse on the back side of @node's split plane
if (lessThan.First != null)
{
if (node.LessThan == null)
{
node.LessThan = Node.Create(lessThan.First.Value.OrientationPlane);
}
AddTriangles(node.LessThan, lessThan);
}
// recurse on the front side of @node's split plane
if (greaterThan.First != null)
{
if (node.GreaterThan == null)
{
node.GreaterThan = Node.Create(greaterThan.First.Value.OrientationPlane);
}
AddTriangles(node.GreaterThan, greaterThan);
}
}
/**
* Invert this Node instances's split plane and triangles.
*/
public void Invert()
{
FastLinkedList <Triangle> .Node current = triangles.First;
while (current != null)
{
current.Value.Invert();
current = current.Next;
}
SplitPlane.Invert();
Node tempList = LessThan;
LessThan = GreaterThan;
GreaterThan = tempList;
}
/**
* Add the triangles from @triangles into this BSPTree instance.
*/
public void AddTriangles(List <Triangle> triangles)
{
if (triangles == null || triangles.Count <= 0)
{
return;
}
// ensure the root node exists
if (root == null)
{
root = Node.Create(triangles[0].OrientationPlane);
}
// convert @triangles to a FastLinkedList structure.
FastLinkedList <Triangle> linkedTriangles = new FastLinkedList <Triangle>();
linkedTriangles.CopyFrom(triangles);
// call the private, recursive version of AddTriangles
AddTriangles(root, linkedTriangles);
}
private Node()
{
LessThan = null;
GreaterThan = null;
triangles = new FastLinkedList <Triangle>();
}
/**
* Recursive version of ClipOutTriangles. This method partitions the triangles
* in @triangles using @node's split plane, and then recursively calls itself
* with the resulting greater-than and less-than lists. If the recursion reaches a
* point where triangles in @triangles are on the back side of @node's split plane,
* but this instance of BSPTree contains no geometry on that side (node.LessThan == null),
* then the triangles placed in @lessThan are deleted from @triangles. This removes
* the portions of triangles in @triangles that lie inside the geometry of this BSPTree
* instance.
*
* If @clippLessThan is false, then we perform the reverse of the above oepration.
* Triangles placed in @greaterThan than are removed when node.GreaterThan == null.
* In that case the portions of triangles in @triangles that lie outside the geometry
* of this BSPTree instance are removed.
*/
private void ClipOutTriangles(Node node, FastLinkedList <Triangle> triangles, bool clipLessThan = true, IList <Triangle> discarded = null)
{
if (triangles == null || triangles.First == null)
{
return;
}
if (node == null)
{
return;
}
FastLinkedList <Triangle> lessThan = new FastLinkedList <Triangle>();
FastLinkedList <Triangle> greaterThan = new FastLinkedList <Triangle>();
// iterate through each triangle in @triangles and classify/partition each according
// @node's split plane. triangles on the front side go into @greaterThan, triangles
// on the back side go into @lessThan. co-planar triangles whose normal matches that of
// @node's split plane go into @greaterThan; the rest go into @lessThan.
triangles.Iterate((Triangle tri) => {
Partitioner.Orientation orient = Partitioner.SliceTriangle(tri, node.SplitPlane, lessThan, greaterThan, lessThan, greaterThan, true);
});
// release memory used by @triangles
triangles.Clear();
// recurse on the back side of @node's split plane if this BSPTree contains
// geometry on that side. if it does not, and we want to clip out triangles
// inside this BSPTree's geometry (@clipLessThan == true), then we clear out @lessThan.
if (node.LessThan != null)
{
ClipOutTriangles(node.LessThan, lessThan, clipLessThan, discarded);
}
else if (clipLessThan)
{
if (discarded != null)
{
lessThan.CopyInto(discarded);
}
lessThan.Clear();
}
// recurse on the front side of @node's split plane if this BSPTree contains
// geometry on that side. if it does not, and we want to clip out triangles
// outside this BSPTree's geometry (@clipLessThan == false), then we clear out @greaterThan.
if (node.GreaterThan != null)
{
ClipOutTriangles(node.GreaterThan, greaterThan, clipLessThan, discarded);
}
else if (!clipLessThan)
{
if (discarded != null)
{
greaterThan.CopyInto(discarded);
}
greaterThan.Clear();
}
// rebuild @triangles with the properly clipped triangles
triangles.AppendIntoList(lessThan);
triangles.AppendIntoList(greaterThan);
}