/// <summary>
/// Generar OBB a partir de AABB
/// </summary>
/// <param name="aabb">BoundingBox</param>
/// <returns>OBB generado</returns>
public static TgcBoundingOrientedBox computeFromAABB(TgcBoundingAxisAlignBox aabb)
{
return(computeFromAABB(aabb.toStruct()).toClass());
}
/// <summary>
/// Calcular OBB a partir de un conjunto de puntos.
/// Prueba todas las orientaciones entre initValues y endValues, saltando de angulo en cada intervalo segun step
/// Continua recursivamente hasta llegar a un step menor a 0.01f
/// </summary>
/// <returns></returns>
private static OBBStruct computeFromPointsRecursive(TGCVector3[] points, TGCVector3 initValues, TGCVector3 endValues,
float step)
{
var minObb = new OBBStruct();
var minVolume = float.MaxValue;
var minInitValues = TGCVector3.Empty;
var minEndValues = TGCVector3.Empty;
var transformedPoints = new TGCVector3[points.Length];
float x, y, z;
x = initValues.X;
while (x <= endValues.X)
{
y = initValues.Y;
var rotX = FastMath.ToRad(x);
while (y <= endValues.Y)
{
z = initValues.Z;
var rotY = FastMath.ToRad(y);
while (z <= endValues.Z)
{
//Matriz de rotacion
var rotZ = FastMath.ToRad(z);
var rotM = TGCMatrix.RotationYawPitchRoll(rotY, rotX, rotZ);
TGCVector3[] orientation =
{
new TGCVector3(rotM.M11, rotM.M12, rotM.M13),
new TGCVector3(rotM.M21, rotM.M22, rotM.M23),
new TGCVector3(rotM.M31, rotM.M32, rotM.M33)
};
//Transformar todos los puntos a OBB-space
for (var i = 0; i < transformedPoints.Length; i++)
{
transformedPoints[i].X = TGCVector3.Dot(points[i], orientation[0]);
transformedPoints[i].Y = TGCVector3.Dot(points[i], orientation[1]);
transformedPoints[i].Z = TGCVector3.Dot(points[i], orientation[2]);
}
//Obtener el AABB de todos los puntos transformados
var aabb = TgcBoundingAxisAlignBox.computeFromPoints(transformedPoints);
//Calcular volumen del AABB
var extents = aabb.calculateAxisRadius();
extents = TGCVector3.Abs(extents);
var volume = extents.X * 2 * extents.Y * 2 * extents.Z * 2;
//Buscar menor volumen
if (volume < minVolume)
{
minVolume = volume;
minInitValues = new TGCVector3(x, y, z);
minEndValues = new TGCVector3(x + step, y + step, z + step);
//Volver centro del AABB a World-space
var center = aabb.calculateBoxCenter();
center = center.X * orientation[0] + center.Y * orientation[1] + center.Z * orientation[2];
//Crear OBB
minObb.center = center;
minObb.extents = extents;
minObb.orientation = orientation;
}
z += step;
}
y += step;
}
x += step;
}
//Recursividad en mejor intervalo encontrado
if (step > 0.01f)
{
minObb = computeFromPointsRecursive(points, minInitValues, minEndValues, step / 10f);
}
return(minObb);
}
