A constraint that makes it look at a source object.
See: https://github.com/vrm-c/vrm-specification/tree/master/specification/VRMC_node_constraint-1.0_beta#roll-constraint
The object being constrained by the source.
The object constrains the destination.
The weight of the constraint.
The aim axis of the constraint.
Set initial state of the constraint.
Update and apply the constraint.
A constraint that makes it look at a source object.
See: https://github.com/vrm-c/vrm-specification/tree/master/specification/VRMC_node_constraint-1.0_beta#roll-constraint