bevy_rich_text3d

Mesh based raster rich text implementation for bevy.

Overview

This crate is similar to bevy_text but aims to be more user friendly and powerful.

Unlike bevy_text, this crate renders text as a Mesh and an Image atlas. This not only works with StandardMaterial but also can be empowered by user defined shaders.

We render each glyph as a separate quad, meaning in shaders, we can easily manipulate individual glyphs for different effects. Additionally we support exporting specific values like glyph count, glyph position or user defined magic numbers via the uv1 field.

Getting Started

Add plugins:

app.insert_resource(Text3dPluginSettings {
        default_atlas_dimension: (512, 512),
        scale_factor: 2.,
    })
    .add_plugins(Text3dPlugin)

Spawn a Text3d.

commands.spawn(
    Text3d::new("Hello, World!"),
    // Mesh2d also works
    Mesh3d::default(),
    MeshMaterial3d(materials.add(
        StandardMaterial {
            base_color_texture: Some(TextAtlas::DEFAULT_IMAGE.clone()),
            alpha_mode: AlphaMode::Blend,
            ..Default::default()
        }
    ))
)

Rich Text

Rich text can be created from a string using the Text3d::parse function. We support a simple syntax like {style:value} which is equivalent to <style>value</style> in html, and {value}, which acts as a dynamic value that can be fetched from the world.

See documentation on Text3d::parse for up-to-date syntax.

Tech Stack

• cosmic_text

Cosmic text is used for layout, this portion is shared with bevy_text.

• zeno

Used for tesselation, this is the same render engine as bevy_text, cosmic_text and swash. We use this crate directly since we do not use swash.

• bevy

Bevy's asset system functions as an alternative to swash.

Glyph Atlas

We store rendered glyphs inside a texture atlas in the component TextAtlasHandle. If you did not create a new one, all glyphs will be cached inside the same default texture, and you can use the convenient TextAtlas::DEFAULT_IMAGE as the image in your materials.

However, if you need more control over where your glyphs are stored, you can manually create a TextAtlas and Image alongside your Text3d, they can be managed the same way as other assets.

FAQ

• How do I add fonts?

Add fonts to Res<CosmicFontSystem>::db_mut(), see cosmic_text's documentation for details.

• Some characters are missing when text changes

You must add TouchTextMaterialPlugin to get around a change detection issue in bevy. This is a band-aid solution intended to be removed later as we wait for a fix upstream.