Assetspreview

Models, materials, graphics settings and sounds, and how Motoko code refers to them.

Assets live in the directories listed in asset_roots. Each asset file has a .meta.yaml file beside it that gives it a permanent id and the name your code uses.

Asset metadata#

format_version: 1
uuid: 11111111-0000-4000-8000-000000000003
address: material/blue
importer: copy
importer_version: 1
kind: material
binding: blue

moxzi-game init-assets . creates missing metadata files with kind: bytes and a binding taken from the file name. Edit them, then commit them with the assets. To move or rename an asset, move its .meta.yaml file with it; the id and binding stay the same.

Using assets in Motoko#

The build generates a module, mo:game-assets/Assets, from the metadata:

// Generated by Moxzi. Edit source metadata, not this file.
import Asset "mo:moxzi/Asset";
module {
  public let asset_blue : Asset.Material = #material("11111111-0000-4000-8000-000000000003");
  public let asset_controls : Asset.Ui = #ui("11111111-0000-4000-8000-000000000005");
  public let asset_cube : Asset.Model = #model("11111111-0000-4000-8000-000000000001");
  public let asset_graphics : Asset.Bytes = #bytes("11111111-0000-4000-8000-000000000006");
  public let asset_grey : Asset.Material = #material("11111111-0000-4000-8000-000000000004");
  public let asset_ground : Asset.Model = #model("11111111-0000-4000-8000-000000000002");
  public let asset_sound_click : Asset.Audio = #audio("11111111-0000-4000-8000-000000000007");
  public let material_blue : Nat32 = 1;
  public let material_grey : Nat32 = 2;
  public let mesh_cube : Nat32 = 1;
  public let mesh_ground : Nat32 = 2;
};

Using a name that doesn't exist is a compile error. Two assets can't share a binding.

Models#

A model is a primitive shape in YAML, or a .glb file.

version: 1
primitive:
  shape: cuboid
  size: [1, 1, 1]

.glb files are supported with limits: one mesh, transforms already applied, no textures, skins or animations.

Materials#

version: 1
base_color_linear: [0.05, 0.3, 0.9, 1]
metallic: 0.1
roughness: 0.5
emissive_linear: [0.0, 0.0, 0.0]

Colours are linear, not sRGB. To convert an sRGB value c between 0 and 1, use ((c + 0.055) / 1.055) ^ 2.4 (or c / 12.92 for values below 0.04).

Graphics settings#

version: 1
bloom: false
shadows: true

Give this file kind: bytes and address: settings/graphics. To let players turn effects down, add a button with local: reduced_effects (see Controls).

The scene#

The scene is built in Motoko from mo:moxzi/Render:

moxzi_snapshot returns the whole scene with Render.snapshot. Each tick, return only the changes, built from Render.empty:

Between ticks, the player interpolates entity positions, so movement looks smooth at any frame rate.

Sounds#

Sounds are WAV files with kind: audio:

Return sounds from moxzi_advance in the audio field, created with Audio.play. See Writing a game. Sounds are presentation only: they aren't saved, and they're skipped if they arrive more than half a second late.

To let players change the volume, return audio_gain = ?g (0 to 1) in your replies, as Pong does.

Limitations#