/// <summary>
/// Initializes a new instance of the <see cref="BVTree"/> class.
/// </summary>
/// <param name="verts">A set of vertices.</param>
/// <param name="polys">A set of polygons composed of the vertices in <c>verts</c>.</param>
/// <param name="nvp">The maximum number of vertices per polygon.</param>
/// <param name="cellSize">The size of a cell.</param>
/// <param name="cellHeight">The height of a cell.</param>
public BVTree(PolyVertex[] verts, PolyMesh.Polygon[] polys, int nvp, float cellSize, float cellHeight)
{
nodes = new Node[polys.Length * 2];
var items = new List <Node>();
for (int i = 0; i < polys.Length; i++)
{
PolyMesh.Polygon p = polys[i];
Node temp;
temp.Index = i;
temp.Bounds.Min = temp.Bounds.Max = verts[p.Vertices[0]];
for (int j = 1; j < nvp; j++)
{
int vi = p.Vertices[j];
if (vi == PolyMesh.NullId)
{
break;
}
var v = verts[vi];
PolyVertex.ComponentMin(ref temp.Bounds.Min, ref v, out temp.Bounds.Min);
PolyVertex.ComponentMax(ref temp.Bounds.Max, ref v, out temp.Bounds.Max);
}
temp.Bounds.Min.Y = (int)Math.Floor((float)temp.Bounds.Min.Y * cellHeight / cellSize);
temp.Bounds.Max.Y = (int)Math.Ceiling((float)temp.Bounds.Max.Y * cellHeight / cellSize);
items.Add(temp);
}
Subdivide(items, 0, items.Count, 0);
}
/// <summary>
/// Calculates the bounding box for a set of bounding boxes.
/// </summary>
/// <param name="items">The list of all the bounding boxes.</param>
/// <param name="minIndex">The first bounding box in the list to get the extends of.</param>
/// <param name="maxIndex">The last bounding box in the list to get the extends of.</param>
/// <param name="bounds">The extends of all the bounding boxes.</param>
private static void CalcExtends(List <Node> items, int minIndex, int maxIndex, out PolyBounds bounds)
{
bounds = items[minIndex].Bounds;
for (int i = minIndex + 1; i < maxIndex; i++)
{
Node it = items[i];
PolyVertex.ComponentMin(ref it.Bounds.Min, ref bounds.Min, out bounds.Min);
PolyVertex.ComponentMax(ref it.Bounds.Max, ref bounds.Max, out bounds.Max);
}
}