Variables and binds

A click tells you where the mouse was at that instant. To walk there over the next second you have to keep it somewhere, and that somewhere is a variable.

Make one from the field that needs it

Open the Aim frame, click its Start cell and add Set Value. Click the card’s name to open its panel: every field there has a small +, Create and bind a new variable. Use it on Target, name it target, type Vector2.

Creating target as a Vector2 from the field that needs it.

One click creates the variable, binds the field to it and lists it in the sidebar. On a field that receives a value the button is shorter still, Create a variable named after this output, and it asks nothing. The other way round, New Variable on the Props tab, is there for when you are planning ahead, but the moment you need a variable is usually the moment you are looking at the field that wants it.

Right-click a variable’s row in Props for its type, its default and Is Export, which puts it in Godot’s own inspector: see Properties.

The five things a field can hold

A chip on a card is just the literal case of something with five settings. In the card’s panel, each field has a row of small buttons that switch between them:

Source	How	When
Literal	Type it into the chip	A fixed number, a colour, a piece of text
Bind	The circle button	Read a variable, a property of the node, or a built-in value
Expression	The calculator button	A one-off bit of maths the actions do not cover
Inline action	The action button, or the input pin on the card	Feed the field with another action’s result
Wire	Drag from an output dot to an input pin	Reuse a value a step above already produced

A field holds one source at a time: picking a new one drops the old.

The inline action row has a rule of its own: only pure producers are offered, actions that just compute a value, with no branches and no body. That is why Random Float can go inside a field and Wait cannot, and a Wait you need the result of goes in the chain, storing into a variable the field then binds to.

The source buttons on a field, from literal to inline action.

Bind the value

Still on the Set Value, set Value with the bind button, then Mouse Position.

Binding Value to the built-in Mouse Position.

The bind list is longer than “your variables”. At the top are built-in values, Self, Node path…, Mouse Position, Screen Size, Delta, Random Float, Key pressed… and more, which cost no action at all to read. Under them come your variables, filtered to the types that fit the field, and then the properties of the node itself, whatever the class you extended exposes: position and modulate on a Sprite2D, plus velocity on a CharacterBody2D.

Node fields already point at Self

A field that wants a node starts on Self, the node the script is on. Change it only when you mean another node, and then Node path… gives you a picker of the real nodes in your scene.

Some fields are where a value lands rather than where it comes from, like the Target you just filled: those take a bind and nothing else, because randf() = 5 is not a thing you can write. They read not set until you give them one, so an unfinished step is visible instead of silently doing nothing.

Leave Aim

Click the Aim entry’s Start cell again, or the Add action node after the step, and add Transition, pointing its To branch at Walk and naming it going there.

Transition sending Aim to Walk, named going there.

Fill Walk

On Walk’s Every Frame cell, two steps:

1. Lerp Toward, with Target bound to the node’s position, To bound to the target variable, and Weight 0.1.
2. Is Near, with A bound to position, B bound to target and Distance 8. Point its Yes cell at Idle and name the transition arrived.

Lerp Toward and Is Near on Walk, with Yes going back to Idle.

Easing never lands

A lerp only keeps getting closer, forever, so something has to decide that close enough is arrived. Any time you use a Lerp Toward, an Is Near belongs next to it.

Play it

Compile and play. The sprite slides to wherever you click, and you can click again mid-slide to change its mind, because the click check is on the parent and keeps running under all of it.

The sprite sliding to each click, redirected mid-slide.

That is a playable thing, built out of six ideas. The next two pages are about not repeating yourself.