Getting Started with Vuo — Part 5: Examining a Vuo composition that counts
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Getting Started with Vuo — Part 5: Examining a Vuo composition that counts

August 26, 2019

Let’s take a look at another simple composition
and learn a little more about how the parts and pieces of Vuo work. This is a composition
that counts. When I press Run, it produces this: a blank window with numbers counting
in the center. Let’s slowly walk through what’s happening, and as we go through it, we’ll
define a few more elements in the Vuo Editor. We know that information in Vuo flows from
the left of a node to the right of a node, from input to output, and that all information
flows in one direction, downstream from output ports to input ports. So in looking at this
composition, we can see that everything originates here, at the “Fired” port of “Fire Periodically.” This node is quite similar to the “Fire on
Start” node, except that it fires an event at a steady rate, and we get to set that rate
here at the “Seconds” port. It’s currently firing an event out of the “Fired” port every
one second. Every one second, an event will travel down
the cable to the “Increment” port of the “Count” node. We’ll take a look at our documentation
for “Count” and we see that it keeps track of a count that can be incremented or decremented.
We can count up or down. It’s important to note that this node has the ability to keep
track. It has memory. Meaning that our composition is currently counting and I can temporarily
disconnect our cable of events, stopping our count, then I can reconnect our cable and
it will pick up right where it left off. A node that has memory is called a stateful
node and this is revealed by the thick border along the bottom. Notice that “Make Text Layer”
doesn’t have a border, and is therefore stateless, and stateless nodes don’t have memory. We’re
always going to get the get the exact same result from “Make Text Layer” unless we manually
adjust the input ports, or feed new information in with a cable, which is happening here. Looking back at the “Count” node, we also
see a triangular symbol after each input port. This is called a port action symbol. Whenever
you see one of these, it means that this port will affect the node in a way that’s special
or different. In the case of the “Count” node, sending an
event through any port would affect the output differently. The “Increment” port would cause
the count to increase, the “Decrement” port would cause the count to decrease, and the
“Set Count” port would cause the count to be reset to zero. [Actually, it would be set
to the port’s value, which is zero here.] Compare this to the “Make Text Layer” node.
No matter which port you send an event into, “Make Text Layer” will produce the exact same
layer. The only way to get something different is to input additional data, which we’re about
to get to. So the “Count” node is currently receiving
an event every one second to its “Increment” port and in turn is outputting an event every
one second that is carrying the latest number as its data. Before our count enters the “Text” port of
“Make Text Layers” in enters a Type Converter, which reveals that our count is being outputted
as a real number, which computers read differently than readable text, and that Vuo is automatically
converting it to text. There’s nothing special you need to do to create one, if I disconnect
the cable it will disappear, and when I connect the cable, Vuo will automatically create it. Vuo processes many different types of data,
and sometimes you will need to get an extra node involved. If you find yourself trying
to progress between two types of data, and can’t find what you’re looking for, try typing
“convert” into the Node Library, and here you’ll see of significant list of nodes to
help you do so. Now, our number, in this font, at this position
on the window is being rendered as a text layer and being sent outward here. That layer
is flowing down to “Render Layers to Window,” which is rendering our singular layer onto
our window. Great. To learn more about Vuo by building this composition, check out our
next tutorial.

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