Nodes, pins and execution flow

A graph is a set of nodes joined by wires. Execution starts at an event node and follows the wires from its output pin, one node at a time, until it runs out of wire.

The three kinds of node

• Events (pink) have no input pin. They are where execution begins: on scene start, every frame, on an overlap, on a key press.
• Actions have one input and one output. They do something and pass control on — set a variable, play a sound, spawn something.
• Branches have two or more outputs. If continues from true or false; loops continue from body once per iteration and then done.

It all happens in one frame

Unless a node explicitly waits — Delay is the only one that does — the entire chain from an event runs to completion inside a single frame. A loop with 10,000 iterations runs 10,000 times before the screen updates again. This is why loops carry an iteration limit.

Self and other

Nodes that act on an entity have a target: self, other, player, or a specific entity.

• self — the entity the event happened to.
• other — in an overlap or collision, the thing it hit.
• Inside a For Each body, self is the current item.