/// <summary>
/// In order to build a BspTree, you have to supply the
/// BspTreeBuilder with index an position arrays that are copies of
/// the originals, so that they can be modified during the build
/// process. The supplied epsilon parameter specifies the absolute
/// tolerance value for coplanar triangles.
/// </summary>
public BspTreeBuilder(int[] triangleVertexIndexArray,
V3d[] vertexPositionArray,
double absoluteEpsilon,
int[] triangleAttributeIndexArray)
: base(null, triangleVertexIndexArray, triangleAttributeIndexArray)
{
m_weightsArray = new WeightedIndex[0][];
m_positionArray = vertexPositionArray;
TriangleCountMul3 = m_triangleVertexIndexArray.Length;
int triangleCount = TriangleCountMul3 / 3;
VertexCount = m_positionArray.Length;
m_absoluteEpsilon = absoluteEpsilon;
m_originalVertexCount = VertexCount;
// simple shuffle-algorithm (imagine the array as a square
// from left->right, top->bottom)
// address the array now top->bottom, left->right
int stride = (int)Fun.Ceiling(Fun.Sqrt(triangleCount + 1.0));
for (int offset = 0; offset < stride; offset++)
{
for (int ti = offset; ti < triangleCount; ti += stride)
{
BspNode.AddTriangle(this, ti * 3, ref m_tree);
}
}
TriangleCountMul3 = m_tree.TriangleCount() * 3;
}
internal BspTree(BspNode tree,
int[] triangleVertexIndexArray,
int[] triangleAttributeIndexArray)
{
m_tree = tree;
m_triangleVertexIndexArray = triangleVertexIndexArray;
m_triangleAttributeIndexArray = triangleAttributeIndexArray;
}
internal static void AddTriangle(
BspTreeBuilder builder, int tiMul3, ref Triangle3d tr, V3d triangleNormal,
ref BspNode node)
{
if (node != null)
{
node.AddTriangle(builder, tiMul3, ref tr, triangleNormal);
}
else
{
node = new BspNode(tiMul3, tr.P0, triangleNormal);
}
}
internal BspNode(int tiMul3, V3d point, V3d normal)
{
m_point = point;
m_normal = normal;
m_zeroList = new List <int>(1)
{
tiMul3
};
m_negativeCount = 0;
m_positiveCount = 0;
m_positiveTree = null;
m_negativeTree = null;
}
internal static void AddTriangle(
BspTreeBuilder builder, int tiMul3, ref BspNode node)
{
Triangle3d tr;
builder.GetTriangleVertexPositions(tiMul3, out tr.P0, out tr.P1, out tr.P2);
V3d e0 = tr.P1 - tr.P0;
V3d e1 = tr.P2 - tr.P0;
V3d n = V3d.Cross(e0, e1);
double len2 = n.LengthSquared;
if (len2 > 0.0)
{
AddTriangle(builder, tiMul3, ref tr,
n * (1.0 / Math.Sqrt(len2)),
ref node);
}
}
