MOZ_text: Text extension for glTF

This is an extension for glTF to support text objects.

The aim is not to save the mesh but only metadata about the content, font and text properties, so it is in the final application the decision of how to interpret and render it.

Currently only threejs is implemeted, temporarily modifying the GLTFLoader while the support for plugins is not officially merged.

The ultimate goal would be to have a perfect match between Blender (or other 3d package) and the render engine, but given the multiple differences of how text is handled in all the steps, this is far from being perfect right now. Instead of that, this project aims to a very practical approach: to have a useful tool that we can use today for simple use cases.

For comparisons between Blender and threejs scenes, try the test scene and compare it with the blender scenes

Workflow and usage

This is meant to be used as follows:

1. Install Add-on

   In Blender, install the io_scene_gltf2_moz_text add-on (Edit > Preferences > Add-ons > "Install..."), and turn on the add-on checkbox (see diagram below, 1).

2. Add texts

   Add and edit all the texts object in your scene (shift+a > "Text"). There is a MOZ_text panel at the bottom of the text properties (see diagram below, 2).

3. Export

   Export the scene (or selected objects) to glTF (File > Export > glTF 2.0), and find the extension general options at the end of the glTF options (see diagram below, 3).

4. Add font files

   Add the neccesary font files in your project folders. Use the same relative path as the one specified in the previous step.

5. Load glTF

   Use the custom GLTFLoader provided to load the glTF in threejs.

Extension parameters

Inside the glTF, the extension is added to a node as "MOZ_text", with these parameters:

"extensions" : {
    "MOZ_text" : {
        "index" : 1,
        "type" : "sdf | texture | geometry",
        "color" : [1.0, 0.98, 1.0, 1.0],
        "alignX" : "left",
        "alignY" : "top",
        "value" : "Lorem\nIpsun",
        "fontName" : "Impact",
        "fontFile" : "fonts/Impact.ttf",
        "size" : 2,
        "maxWidth" : 0,
        "overflow" : "NONE",
        "letterSpacing" : 0,
        "lineSpacing" : 0.56,
        "dimensions" : [9.7, 2.5],
        "extrude" : 0.63,
        "extrudeResolution" : 2,
        "bevel" : 0.039,
        "bevelOffset" : -0.019,
        "bevelResolution" : 1
    }
}

How to run examples

If you want to run https://mixedreality.mozilla.org/MOZ_text locally:

1. clone repo
2. cd MOZ_text/test
3. npm install
4. npm run start
5. open localhost:8080

Blender parameters support

In Blender, the MOZ_text panel under the text properties allows to specify how the text should be rendered in the application. Current possible values are SDF, Texture or Geometry.

Currently only these text parameters are exported:

Depending on type, some parameters are ignored. For example, bevel and extrude parameters are only used if text type is geometry.