Traits

Trait is a concept in Iron which means a piece of logic code that is attached to object(s) or scene(s).

There are 4 different types of traits:

  1. Haxe Trait: Haxe text-based scripting trait that can be used to write game-play logic in.

  2. Logic Nodes Trait: Visual scripting trait for writing game-play logic in. It is similar to UE4's Blueprints.

  3. Canvas Trait: Trait for UI, it is Zui's canvas under the hood. And it uses Armory2D as WYSIWYG editor.

  4. WebAssembly (WASM): WebAssembly can also be used as scripting trait, It can be written in Rust/C/C++ and than complied to WASM to use it in Armory (WASM will only work with Krom target). WASM is very useful when it comes to plugins, you can use Libraries made in Rust/C/C++ and compile it to WASM and then use it in Armory and Kha. Two examples that are used in ArmorPaint: Texture-synthesis(Rust), Chips(C).

Haxe

Create a cube, name it Haxe and place it wherever you want. Select it and go to Scene - Armory Scene Trait.

  1. Click +, select Haxe and click OK, Haxe trait placeholder should appear.
  2. Click New Script and name the script of your choice, just make sure the first letter is capital (HaxeScript for me).
  3. Finally hit Edit Script, your system default IDE should now open up with the project.
// In HaxeScript.hx
package arm;

//Imports
import iron.object.Object;
import iron.math.Vec4;
import iron.Scene;

class HaxeScript extends iron.Trait {
    // Initialise haxeCube as Object
    var haxeCube:Object;

    public function new() {
        super();
        //NotifyOnInit function get executed when the 'trait' is initiated.
        notifyOnInit(function() {
            //Get haxeCube Object from active Scene.
            haxeCube = Scene.active.getChild("Haxe");
        });

        //NotifyOnUpdate function get executed every frame.
        notifyOnUpdate(function() {
            //Rotate haxeCube with Vec4(x, y, z) and speed.
            haxeCube.transform.rotate(new Vec4(0.0, 0.0, 1.0), 0.01);
        });
    }
}

Now, if you were to play it, you should see Haxe cube rotating!.

Logic Node

Create a cube, name it Nodes and place it wherever you want. Select it and go to Scene - Armory Scene Trait.

  1. Click +, select Nodes and click OK, Nodes trait placeholder should appear.
  2. Change your editor type to Logic Node Editor and click +New.
  3. A node tree should be created, you can rename it by editing the text field (LogicNodes for me).
  4. Go back to Scene - Armory Scene trait, select the logic nodes place holder and click Tree, select LogicNodes in dropdown.

and now add following nodes (Shift + A):

Some Image

  1. On Update: It is triggered every tick.
  2. Rotate object on axis, speed is set directly in vector.

Now if you play it, Nodes cube should start spinning.

Wasm

Create a cube, name it Wasm and place it wherever you want. Select it and go to Scene - Armory Scene Trait.

  1. Click +, select Wasm and click OK, Wasm trait placeholder should appear.
  2. Click New Module, and it should re-direct you to WebAssembly Studio, select Empty Rust Project (you can select c/c++ too) and click Create.
  3. Enter Rust/C/C++ code and click Build and there should be main.wasm in out folder, right-click and download it.
  4. Put outputted main.wasm in Bundled folder (create one, if there is none).
  5. Go back to Scene - Armory Scene Trait, select previously created Wasm placeholder, click Refresh and select main in Module dropdown.
// Rust example of rotating cube
// main.rs
extern {
    fn notify_on_update(f: extern fn() -> ()) -> ();
    fn get_object(name: *const i8) -> i32;
    fn set_transform(object: i32, x: f32, y: f32, z: f32, rx: f32, ry: f32, rz: f32, sx: f32, sy: f32, sz: f32) -> ();
}

#[no_mangle]
pub extern "C" fn update() -> () {
    unsafe {
        let name = std::ffi::CString::new("Wasm").unwrap();
        let object = get_object(name.as_ptr());
        static mut rot: f32 = 0.1;
        rot += 0.01;
        set_transform(object, 0.0, 0.0, 0.0, 0.0, 0.0, rot, 0.5, 0.5, 0.5);
    }
}

#[no_mangle]
pub extern "C" fn main() -> i32 {
    unsafe {
        notify_on_update(update);
    }
    return 0;
}

Now if you play it then you should have spinny rusty wasm cube.

Canvas

  1. Click +, select UI and click OK, Canvas trait placeholder should appear.
  2. Click New Canvas and enter the name and click Edit Canvas.
  3. Add Text element and set text as Hello World from Canvas! and save it.

If you play it now, you should see Hello World from Canvas.

Check Canvas tutorial for more!

You should finally get this:

🎉 There we go! We covered the basics of Traits! 🎉

If anything goes wrong, don't forget to check source code