A clip that blends between its children by a run-time value, for example a set of aim poses blended by the angle to the target, or a walk and a run blended by speed.
Each child has a value (ParametricPairData.mValue). Every frame the Updater
supplies the current value, and the clip blends the two children whose values are on
either side of it. The weight is linear between the two. A value outside the range of
the list plays the first or the last child alone.
The children do not play as clips of their own. The parametric clip samples both at the same fraction of their length, so children of different lengths stay in step. The length of the parametric clip is the blend of the two children's lengths with the same weight, so it changes as the value changes.
The result plays on this clip's own track, with this clip's own mask.
Bool = false Turns on the clip's own events. When false, which is the default, the events in
this clip's mEventDataMap never fire, and only the events of the children fire.
When true, this clip's events fire as well.
Of the two children that are blended, only the events of the one with the larger weight fire.
The source of the blend value: any parametric updater.
The client reads it when the clip starts and then every frame, and uses the value
as it is. A bool updater gives 1 or 0.
The updater class also decides how the rotations of the two children are blended. For the updaters that return an angle or a direction, the client uses a spherical interpolation. For the others it uses a linear one along the shortest path.
The children and their values, see ParametricPairData.
The list must be in ascending order of mValue. The client does not sort it, and it
looks for the first pair of neighbours that the value lies between. With one entry,
that child plays alone.