If this library helps you out consider buying me a coffee!

Why

After surveying the landscape of graph frameworks for Unity for the past few years and trying to use them I found myself always painting myself into corners, having to work in constrained ways and/or just not liking the API setup around building graph based tools.

I've also come to love Odin Inspector and the power it brings to writing editor tools.

So here we are - this is our love letter to Odin by marrying it with a graph framework that gets out of your way and hopefully makes it trivial to build new graph based tools ontop.

Features

• Strong interface based design - Graphs and Nodes can be POCO's (Plain Old CLR Object - IE Classes)
  • Allows for c# code to generate graph data programmatically
• Built ontop of Unity
  • Uses Unity's Serializer to reduce outside dependencies (leverages the new SerializeReference features)
  • Uses UI toolkit (UIElements) to support the future of Editor UI's
• Natively supports Odin Inspector inside the Graph Editor Window
• Complete control over flow/execution - Allows for writing any kind of graph, statemachine, behaviour, flow, etc
• Batteries Included - Base classes for Graph, Node, Port and Flow to get up and working quickly
  • Also includes standard nodes and graph types that could be shared from graph tool to graph tool

Quickstart

To write a new custom node quickly you inherit from the base Node class and define your ports.

using RedOwl.Sleipnir.Engine;

[Node]
public class AddNode : Node
{
    [FlowIn(nameof(OnEnter))] public FlowPort Enter;
    [FlowOut] public FlowPort Exit;

    [ValueIn] public ValuePort<float> Left;
    [ValueIn] public ValuePort<float> Right;

    [ValueOut] public ValuePort<float> Output;

    protected IFlowPort OnEnter(IFlow flow)
    {
        Output.Value = Left.Value + Right.Value;
        return Exit;
    }
}

The above is a simple definition of a node that performs an "add" math operation on the "left" and "right" value in ports and pushs the result to the value out port.

To then make use of this new node you navigate to your Project Browser in Unity right click and then Create -> Red Owl -> Graph

This creates a scriptable object asset in your project that can serialize graph data using unity's serializer. From there you double click the asset to open the Graph Editor window.

From there you can press spacebar and a node search window will open - navigate to your new node and that will place an instance in your graph. You should beable to create a graph like the following image.

The follow graph will perform an addition on the 2 float values and log the result to the console.

Cheers! (For more examples dig into the codebase at ./Engine/Nodes)

Creating Graphs via C

private static void CreateSampleGraph()
{
    var graph = new Graph();

    var startNode = graph.Add(new StartNode {NodePosition = new Vector2(128, 0)});
    var logNode1 = graph.Add(new LogNode {NodePosition = new Vector2(0, 100)});
    var logNode2 = graph.Add(new LogNode {NodePosition = new Vector2(200, 100)});
    var floatNode1 = graph.Add(new FloatValueNode(10) {NodePosition = new Vector2(-200, 0)});
    var floatNode2 = graph.Add(new FloatValueNode(100) {NodePosition = new Vector2(-200, 200)});
    var floatNode3 = graph.Add(new FloatValueNode(5) {NodePosition = new Vector2(-200, 400)});

    // Flow
    graph.Connect(startNode.Start, logNode1.Enter);
    graph.Connect(startNode.Start, logNode2.Enter);

    // Values
    graph.Connect(floatNode1.Value, logNode1.Message);
    graph.Connect(floatNode2.Value, logNode2.Message);

    GraphAsset.Save(graph, "Generated", "Resources/Graphs");
}

Installing

In Package Manager click Add package from git URL and use the following:

https://github.com/red-owl-games/Sleipnir.git

Things to checkout

https://github.com/buunguyen/fasterflect http://introspectingcode.blogspot.com/2011/06/dynamically-compile-code-at-runtime.html