9.5.2

1090 • CHAPTER 22
XPRESSO EDITOR • 1091
History Level denes which one of the stored states the node outputs. To set the History Level, either
pass the value to the node’s History Level port or, if the port is unconnected, enter the value directly
into the Attribute manager. If you set History Level to a higher value than History Depth, the node
outputs the oldest stored state.
 If History Depth is set to 1, the value that arrives at the input is passed directly
to the output regardless of the History Level setting.
 If History Depth is set to 2, the node outputs the current state (if History Level
is set to 0) or the previous state (if History Level is set to 1 or higher).
 If History Depth is set to 3, the node outputs the current state (if History Level
is set to 0), the previous state (if History Level is set to 1) or the next previous
state (if History Level is set to 2 or higher).
Different rules apply when using nodes such as the Object node, since these nodes are themselves
able to output a previous state. In such cases, a History Level of 0 retrieves the previous state instead
of the current state.
MonoFlop
The MonoFlop node in this example is enabled every nine frames. The MonoFlop node then remains
active for 0.2 seconds before becoming inactive again.
The MonoFlop node is a Boolean switch with a built-in time delay. Once triggered, the node counts
down a specied number of frames. The node outputs a Bool value of True while it is counting down.
In the Attribute manager, choose the desired countdown mode:
Normal
The countdown beings once the Trigger port’s value changes from 1 to 0. In other words, nothing
happens when the node is enabled. Only once the node is disabled will the clock start ticking.
OneShot
The node starts counting down as soon as the value 1 arrives at the Trigger port.