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Text in the world

· 3 min read
Dragos
Balaur

The widget layer already shaped text properly: bidi, Arabic joining, CJK breaks, the project's font chain. None of it reached the scene, because the atlas wrote straight into an egui texture. Now it owns its pixels, and a label in a panel and a sign in a scene come from one bitmap.

Text in the world, one row per thing it does

What landed​

  • text2d and text3d. One component for both passes, with the keys a label takes plus pixels_per_unit to size it like a sprite. In 3D: billboard, double_sided, depth_test, alpha_cut.
  • Outline and shadow. The same quads offset and tinted, each layer a thousandth of a unit in front of the last: coplanar, the depth test picks between them at random.
  • Markup in the world. [b], [i], [color=…], [wave]. A block is one mesh per colour, so a coloured word keeps its colour.
  • Bitmap fonts. An AngelCode .fnt ships a pixel face as drawn. No shaping, one glyph per character, and its page goes in the same atlas.
  • Immediate calls. render.draw_text and draw_text_2d for one frame, like a debug line. The Rig tool names bones in the viewport with them.
  • render.text_size, and double-click a text node to edit it in place.

A promise the code was not keeping​

text_size said it measured against the project's fonts and never a system face. It did not: the chain ends with whatever the machine has, so an uncovered character measured differently on macOS than on Linux. A width written into state is in the digest.

Measuring now sees the project's faces and the bundled ones only; drawing keeps the system's. The same leak reached the glyph mesher, which is worse: a kind = "text" mesh has colliders fitted to it, so the host's fonts were in the simulation.

  • Crisp at any distance. A block is rasterised at the size it covers on screen, quantised to buckets 8.7% apart, so walking towards a sign re-shapes it a few times rather than magnifying a bitmap. Browsers bucket the same way; geometric rather than linear, because a camera's distance spans orders of magnitude.
  • Emoji. A colour face per platform joins the fallback chain; the atlas already took colour bitmaps.

What is not done​

Distance fields. Buckets mean a glyph is scaled by up to 8.7%, so it is fractionally soft or sharp where an SDF would be exact. That is the trade PLAN-text called the cheaper first answer, and it is waiting for a scene that asks.

Text in the world is the manual page. examples/text is a tour: press Play on its card in Examples.