public unsafe static OrientedBox Create(byte *positions, int vertexCount, int stride)
{
OrientedBox box = new OrientedBox();
var minValues = new Vector3(float.MaxValue, float.MaxValue, float.MaxValue);
var maxValues = new Vector3(float.MinValue, float.MinValue, float.MinValue);
//Compute Covariance Matrix
Matrix c = Matrix.CorrelationMatrix(positions, vertexCount, stride);
Vector3[] eigenVectors;
Vector3 eigenValues;
eigenVectors = Matrix.ComputeEigenVectors(c, 1.0e-10f, out eigenValues);
var r = eigenVectors[0];
var s = eigenVectors[1];
var T = eigenVectors[2];
Vector3 t;
for (int i = 0; i < vertexCount; i++)
{
Vector3 *pter = (Vector3 *)(positions + i * stride);
t = new Vector3(Vector3.Dot(*pter, r), Vector3.Dot(*pter, s), Vector3.Dot(*pter, T));
minValues = Vector3.Min(minValues, t);
maxValues = Vector3.Max(maxValues, t);
}
t = 0.5f * (minValues + maxValues);
box.extends = 0.5f * (maxValues - minValues);
box.center = t.X * r + t.Y * s + t.Z * T;
box.rotation = new Matrix(r, s, T, new Vector3());
box.Update(Matrix.Identity);
return(box);
}
public static OrientedBox Create(IEnumerable <Vector3> positions)
{
OrientedBox box = new OrientedBox();
var minValues = new Vector3(float.MaxValue, float.MaxValue, float.MaxValue);
var maxValues = new Vector3(float.MinValue, float.MinValue, float.MinValue);
//Compute Covariance Matrix
Matrix c = Matrix.CorrelationMatrix(positions);
Vector3[] eigenVectors;
Vector3 eigenValues;
eigenVectors = Matrix.ComputeEigenVectors(c, 1.0e-10f, out eigenValues);
var r = eigenVectors[0];
var s = eigenVectors[1];
var T = eigenVectors[2];
Vector3 t;
foreach (var v in positions)
{
t = new Vector3(Vector3.Dot(v, r), Vector3.Dot(v, s), Vector3.Dot(v, T));
minValues = Vector3.Min(minValues, t);
maxValues = Vector3.Max(maxValues, t);
}
t = 0.5f * (minValues + maxValues);
box.extends = 0.5f * (maxValues - minValues);
box.center = t.X * r + t.Y * s + t.Z * T;
box.rotation = new Matrix(r, s, T, new Vector3());
box.Update(Matrix.Identity);
return(box);
}
