Godot for Unity Developers Levi D. Smith @GaTechGrad Knoxville Game Design July 2017 

Background • How is it pronouced? • Waiting for Godot • Another Ludum Dare controversy 

Why Use It? • Free, no "pro" version required for number of sales • MIT licensed, open source, you can view the code or even contribute • Runs on many "open" operating systems • No splash screen • If you like Python (GDScript) over C#/Javascript, faster code editor • It's the "cool" thing to do right now • More stable than Unity? – Infinte loops just crash the game, not the entire editor. – By now Unity should be able to easily break out of infinte loops 

Installing • Highly recommend getting the version from Steam – Also free • Building yourself isn’t simple 

Comparisons with Unity • GameObject > Nodes • Nodes are hierarchical • No components - Can be confusing, collider, rigid body • Inspector - same, ordered from lowest subclass to highest • Spatial is the base 3D Node -Transform like GameObject, with position, rotation, and scale • Only one script can be attached to an object, must have filename • void Start() > func _ready() • void Update() > func _process(delta): – must call set_process(true) in _ready()! • Time.deltaTime > delta • Phyton style language for scripting (at least it has visual tabs) 

Comparisons with Unity (continued) • Project Assets tab > FileSystem – Assets (sound effects, fonts, meshes, textures) have to be manually imported, unlike Blender • Scenes are same as Unity scenes – Camera, directional light • Prefabs don't exist – Make new scene – Instantiate scene and add it to a node – Instantiate(gameObject, Vector3) > preload("res://path/scene.tscn").instance() • Application.load_level > Switching scenes is a hassle – Problems happen when having two Nodes with the same name in two different scenes • Internally, they get named differently • Game view > Click camera and press preview (can't update in real time) 

Comparisons with Unity (continued) • AudioSource > StreamPlayer (music), SamplePlayer (Sounds) • "Play mode" is limited, can't view changes in scene • GameObject.Find > get_node("/root/path") – check has_node("/root/path") first • No need to call GetComponent() to get a script variable on a Node • No data types, use str(variable), float(variable), etc to convert • Build settings > Export • Project Settings, Input > Project Settings > Input Map – Input.GetButtonDown("FIRE1") > Input.is_action_pressed("FIRE1") • Particle system is limited (no fade over time) but sufficient 

Annoyances • Intellisense isn't that great, usually doesn't detect methods on Node type • Spinning thing every time screen is painted • Limitations on moving in 3D view (no right click + ASWD FPS controls) – Middle Mouse - rotate – Ctrl + Middle Mouse - zoom – Shift + Middle Mouse - translate • Ambient light in 3D view doesn't apply to actual game 

What It Doesn’t Have • Animation import is limited • No direct Blender import – Must be exported to OBJ or Collada first – Collada must be imported as a scene • Limited Asset Store • No PlayMaker equivalent • Tutorials seemed to be focused on 2D games 

What It Does Have • Signals, actions that can be applied to the selected Node – Autofills script • Simple 2D, 3D, and Script views – Better than waiting on Visual Studio / MonoDevelop to load • Docs – http://docs.godotengine.org/en/stable/ – Not many examples • Use "pass" for a method with no code