/// <summary>
/// Override to compute rotations unconstrained as a rotation about the gravity vector, Y-axis.
/// </summary>
/// <returns>True on success.</returns>
/// <remarks>
/// It takes at least 3 non-collinear points to imply a rotation.
/// If there are fewer than that, this reverts back to the behavior of
/// computing a rotation which pitches to align points but doesn't introduce roll.
/// </remarks>
protected override bool ComputeRotations()
{
bool haveNonZero = false;
for (int i = 0; i < actives.Count; ++i)
{
for (int j = i + 1; j < actives.Count; ++j)
{
for (int k = j + 1; k < actives.Count; ++k)
{
WeightedRotation wrotNew = ComputeRotation(actives[i].orientable, actives[j].orientable, actives[k].orientable);
if (wrotNew.weight > 0)
{
haveNonZero = true;
WeightedRotation wrot = actives[i];
wrot = AverageRotation(wrot, wrotNew);
actives[i] = wrot;
wrot = actives[j];
wrot = AverageRotation(wrot, wrotNew);
actives[j] = wrot;
wrot = actives[k];
wrot = AverageRotation(wrot, wrotNew);
actives[k] = wrot;
}
}
}
}
if (!haveNonZero)
{
// This can happen if there aren't enough points, or they are all collinear.
return(base.ComputeRotations());
}
return(true);
}
/// <summary>
/// Compute a new weighted rotation representing the two input weighted rotations.
/// </summary>
/// <param name="accum">The accumulator rotation.</param>
/// <param name="add">The rotation to add in.</param>
/// <returns>A new aggregate weighted rotation.</returns>
private WeightedRotation AverageRotation(WeightedRotation accum, WeightedRotation add)
{
float interp = add.weight / (accum.weight + add.weight);
Quaternion combinedRot = Quaternion.Slerp(accum.rotation, add.rotation, interp);
combinedRot.Normalize();
float combinedWeight = accum.weight + add.weight;
return(new WeightedRotation()
{
orientable = accum.orientable,
rotation = combinedRot,
weight = combinedWeight
});
}
/// <summary>
/// Compute rotations by pairs, weighting by distance and averaging for each orientable.
/// </summary>
/// <returns></returns>
private bool ComputeRotations()
{
for (int i = 0; i < actives.Count; ++i)
{
for (int j = i + 1; j < actives.Count; ++j)
{
WeightedRotation wrotNew = ComputeRotation(actives[i].orientable, actives[j].orientable);
WeightedRotation wrot = actives[i];
wrot = AverageRotation(wrot, wrotNew);
actives[i] = wrot;
wrot = actives[j];
wrot = AverageRotation(wrot, wrotNew);
actives[j] = wrot;
}
}
return(true);
}
