public Contact Build(PayloadBuilder builder)
{
if (!string.IsNullOrEmpty(jointName))
{
int jointIndex = builder.GetJointIndexForName(jointName);
AffineTransform jointTransform = builder.GetJointTransformCharacterSpace(jointIndex);
if (!Missing.equalEps(Missing.zero, normal, 1e-4f))
{
AffineTransform rootTransform = builder.GetRootTransform();
float3 forward = Missing.zaxis(rootTransform.q);
// Rotate trajectory forward axis such that it coincides with
// the desired normal vector for this contact.
quaternion q = Missing.forRotation(forward, normal);
// Construct world space rotation, i.e. a rotation that
// rotates the cardinal coordinate frame into the contact frame.
quaternion qw = math.mul(q, rootTransform.q);
// Inverse transform 'qw' w.r.t. the root transform, i.e. we
// can reconstruct the world space contact transform by
// concatenating the trajectory and contact transform.
quaternion ql = math.mul(Missing.conjugate(rootTransform.q), qw);
float3 t = jointTransform.t;
return(new Contact
{
transform = new AffineTransform(t, ql)
});
}
}
return(Contact.Default);
}