/// <summary>
/// Aligns the rigid bodies by correcting their orienation
/// This should be called after the simulation step
/// </summary>
private void AlignBones()
{
// orient the bodies accordingly
for (var i = this.BoneInset; i < this.simulatedTransforms.Count - this.BoneInset; i++)
{
if (!this.simulatedTransforms[i].Dynamic)
{
continue;
}
var a = this.simulatedTransforms[i - 1].Position;
var b = this.simulatedTransforms[i + 1].Position;
// this is the upVector computed for each bone of the rest pose
var transform = this.restPoseSpace * this.restPoseTransforms[i]; // todo: direction of multiply?
var y = SimdExtensions.CreateQuaternion(transform).Act(new SCNVector3(0f, 1f, 0f));
var x = SCNVector3.Normalize(b - a);
var z = SCNVector3.Normalize(SCNVector3.Cross(x, y));
y = SCNVector3.Normalize(SCNVector3.Cross(z, x));
var rot = new OpenTK.Matrix3(x.X, y.X, z.X, x.Y, y.Y, z.Y, x.Z, y.Z, z.Z);
this.simulatedTransforms[i].Orientation = new SCNQuaternion(rot.ToQuaternion());
}
}
/// <summary>
/// Returns the interpolated transform at a given length (l from 0.0 to totalLength)
/// </summary>
public SCNMatrix4 Transform(float l)
{
var position = this.Position(l);
var x = this.Tangent(l);
var y = SCNVector3.Normalize(this.UpVector);
var z = SCNVector3.Normalize(SCNVector3.Cross(x, y));
y = SCNVector3.Normalize(SCNVector3.Cross(z, x));
var rot = new OpenTK.Matrix3(x.X, y.X, z.X, x.Y, y.Y, z.Y, x.Z, y.Z, z.Z);
var matrix = SCNMatrix4.Rotate(rot.ToQuaternion());
return(matrix.SetTranslation((OpenTK.Vector3)position));
}