glyphcss

ASCII polygon-mesh renderer for the DOM — projects 3D meshes into a monospace character grid in a single <pre>. No WebGL, no canvas, no per-polygon DOM.

Loads OBJ, glTF, GLB, and MagicaVoxel .vox files. Supports wireframe, solid, and voxel render modes with swappable glyph palettes.

Forked from polycss — the mesh math, parsers (OBJ / glTF / GLB / VOX), scene composition tree, camera math, and input controls carried over intact. The paint backend is rewritten: instead of emitting one CSS-transformed DOM leaf per polygon, the rasteriser walks all polygons, fills a cols × rows character grid, and writes a single string to <pre>.textContent per render.

Installation

# Vanilla / custom elements
npm install glyphcss

# React
npm install @glyphcss/react

# Vue 3
npm install @glyphcss/vue

You can also load glyphcss directly from a CDN. Here is a minimal custom-element scene:

<script type="module" src="https://esm.sh/glyphcss/elements"></script>

<glyph-camera rot-x="65" rot-y="45">
  <glyph-scene>
    <glyph-orbit-controls></glyph-orbit-controls>
    <glyph-mesh src="/cottage.glb"></glyph-mesh>
  </glyph-scene>
</glyph-camera>

Framework Components

React and Vue expose the same component model. <GlyphCamera> owns the viewpoint, <GlyphScene> owns the rasteriser options and lighting, and <GlyphMesh> loads or receives polygon data.

React

import {
  GlyphCamera,
  GlyphScene,
  GlyphOrbitControls,
  GlyphMesh,
} from "@glyphcss/react";

export default function App() {
  return (
    <GlyphCamera rotX={65} rotY={45}>
      <GlyphScene mode="solid" glyphPalette="default">
        <GlyphOrbitControls drag wheel />
        <GlyphMesh src="/gallery/obj/cottage.obj" />
      </GlyphScene>
    </GlyphCamera>
  );
}

Vue

<template>
  <GlyphCamera :rot-x="65" :rot-y="45">
    <GlyphScene mode="solid" glyph-palette="default">
      <GlyphOrbitControls drag wheel />
      <GlyphMesh src="/gallery/obj/cottage.obj" />
    </GlyphScene>
  </GlyphCamera>
</template>

<script setup lang="ts">
import {
  GlyphCamera,
  GlyphScene,
  GlyphOrbitControls,
  GlyphMesh,
} from "@glyphcss/vue";
</script>

Render Modes

Each render pass fills a cols × rows character grid and writes the result as a single string assignment to <pre>.textContent (or innerHTML when color spans are enabled).

Mode	How cells are filled
wireframe	Polygon edges rasterised as ASCII rules; glyph weight scales with edge prominence
solid	Filled polygons; glyph picked from the palette's solid ramp by Lambert-shaded intensity
voxel	Cube-aligned geometry; face normals drive glyph selection

Glyph Palettes

The glyphPalette option selects a named character set used for both wireframe tiers and solid shading ramps. Built-in palettes:

default, ascii, dots, lines, blocks, stars, arrows, braille, runes, math, binary, hex

<GlyphScene mode="wireframe" glyphPalette="braille">
  <GlyphMesh src="/model.glb" />
</GlyphScene>

API Reference

GlyphCamera

GlyphCamera is the ergonomic default — it resolves to GlyphOrthographicCamera. Use GlyphPerspectiveCamera for perspective depth.

Prop	Type	Default	Description
rotX	number	65	Tilt angle in degrees
rotY	number	45	Spin angle in degrees
zoom	number	0.65	Absolute scale: zoom=1 → one world unit = 50 px (BASE_TILE). Not a viewport fraction.
center	[number, number]	[0.5, 0.5]	Projection center in normalized grid coordinates

GlyphPerspectiveCamera adds:

Prop	Type	Default	Description
distance	number	6	Perspective distance in world units. Larger = flatter.
stretch	number	1.0	Extra horizontal scale on top of cellAspect

rotX=65, rotY=45 is the classic isometric-ish viewpoint. Rotation values are in degrees throughout (XYZ Euler) — there are no radians in the public API.

GlyphScene

Must be placed inside a camera component.

Prop	Type	Default	Description
mode	"wireframe" | "solid" | "voxel"	"solid"	Render mode
glyphPalette	string	"default"	Named glyph character set
useColors	boolean	true	Emit <span> color elements inside the <pre>
cols	number	80	Character grid width
rows	number	24	Character grid height
cellAspect	number	2.0	Cell height / width ratio
directionalLight	GlyphDirectionalLight	{ direction: [-0.5,-0.7,-0.5], intensity: 1 }	Key light
ambientLight	GlyphAmbientLight	{ intensity: 0.4 }	Fill light
smoothShading	boolean	false	Gouraud shading — interpolates Lambert intensity across vertices. Off by default (faceted ASCII look is intentional).
creaseAngle	number	60	Degrees — edges sharper than this stay flat even with smoothShading on
autoSize	boolean	false	Auto-measure the host element and adapt cols/rows to fill it via ResizeObserver
shadow	GlyphShadowOptions	undefined	Enable shadow mapping (see Shadows section)

GlyphMesh

Prop	Type	Default	Description
polygons	Polygon[]	—	Pre-parsed geometry. Takes precedence over src and geometry.
src	string	—	URL of an OBJ, glTF, GLB, or VOX file (custom elements and <glyph-mesh> only; use loadMesh imperatively in React/Vue)
geometry	GlyphGeometryName	—	Built-in geometry shortcut (e.g. "sphere", "cube")
size	number	1	Uniform size passed to resolveGeometry
color	string	—	Fill color passed to resolveGeometry
position	Vec3	—	World-space translation
rotation	Vec3	—	XYZ Euler rotation in degrees
scale	number | Vec3	—	Uniform or per-axis scale
castShadow	boolean	false	This mesh casts shadows onto receiveShadow surfaces
receiveShadow	boolean	false	This mesh receives (displays) shadows

A mesh that is both castShadow and receiveShadow self-shadows.

GlyphGround

Convenience ground plane — a horizontal planePolygons registered as a mesh.

Prop	Type	Default	Description
size	number	5	Half-extent in world units
color	string	"#444444"	Fill color
position	Vec3	[0, -0.5, 0]	World-space position
castShadow	boolean	false
receiveShadow	boolean	true	Ground planes are the primary shadow receivers

Controls

Component	Behaviour
GlyphOrbitControls	Drag orbit, shift-drag pan, wheel zoom, optional auto-rotate
GlyphMapControls	Pan-first map-style input
GlyphFirstPersonControls	Keyboard and pointer-look navigation

Props accepted by all controls: drag, wheel, touch.

Hotspots

GlyphHotspot is a 3D anchor that produces an absolutely-positioned DOM overlay tracking a world-space point. The rasteriser projects the at coordinate to a grid cell; glyphcss positions a <div> over that cell. Children are portalled inside that div.

<GlyphHotspot id="label-a" at={[0, 2, 0]}>
  <span className="label">Summit</span>
</GlyphHotspot>

Prop	Type	Description
id	string	Stable identifier
at	Vec3	World-space anchor
size	[number, number]	Hitbox size in character cells. Default [1, 1].

Polygon Data Model

Each polygon describes one renderable face:

import type { Polygon } from "@glyphcss/core";

const polygons: Polygon[] = [
  {
    vertices: [[0, 0, 0], [1, 0, 0], [0, 1, 0]],
    color: "#f97316",
  },
  {
    vertices: [[0, 0, 0], [1, 0, 0], [1, 1, 0], [0, 1, 0]],
    color: "#3b82f6",
  },
];

Polygons can also carry UV coordinates and TextureTriangle data for texture-mapped meshes (loaded via OBJ/MTL or glTF).

Pass polygons directly to a GlyphScene (imperative API) or a GlyphMesh component:

<GlyphCamera rotX={65} rotY={45}>
  <GlyphScene>
    <GlyphMesh polygons={polygons} />
  </GlyphScene>
</GlyphCamera>

Shadows

Shadows are opt-in. Enable them by setting shadow on <GlyphScene>, then flag individual meshes with castShadow and/or receiveShadow. glyphcss uses a shadow-map technique — renders depth from the light direction, then compares per cell — rather than an analytic projection.

<GlyphScene
  shadow={{ color: "#000000", opacity: 0.35, lift: 0.05, maxExtend: 2000 }}
>
  <GlyphMesh src="/tree.glb" castShadow />
  <GlyphGround receiveShadow />
</GlyphScene>

Option	Type	Default	Description
shadow.color	string	"#000000"	Shadow tint hex color
shadow.opacity	number	0.25	Darkness 0–1 toward color
shadow.lift	number	0.05	Depth bias — prevents self-shadow acne on flat lit surfaces
shadow.maxExtend	number	2000	Half-extent of the light-space projection volume

Loading Mesh Files

Use loadMesh() from @glyphcss/core to parse supported formats imperatively:

import {
  createGlyphScene,
  createGlyphOrthographicCamera,
  loadMesh,
} from "glyphcss";

const host = document.getElementById("scene")!;
const camera = createGlyphOrthographicCamera({ rotX: 65, rotY: 45 });
const scene = createGlyphScene(host, { camera });

const mesh = await loadMesh("/gallery/obj/cottage.obj");
scene.add(mesh.polygons);

In custom element HTML, set the src attribute directly — <glyph-mesh> fetches and parses the file automatically:

<glyph-mesh src="/model.glb"></glyph-mesh>
<glyph-mesh src="/model.obj"></glyph-mesh>
<glyph-mesh src="/model.vox"></glyph-mesh>

In React and Vue, use loadMesh (from @glyphcss/react or @glyphcss/vue) and pass the parsed polygons to <GlyphMesh>:

const { polygons } = await loadMesh("/model.glb");
<GlyphMesh polygons={polygons} />

Supported formats:

• OBJ + MTL, including map_Kd textures and UV coordinates
• glTF / GLB, including embedded images and TEXCOORD_0
• MagicaVoxel .vox, with face-culling and default or custom palettes

Performance

glyphcss renders through a single <pre> element. The performance envelope is shaped by two things: the number of polygons walked per render and the size of the character grid written to the DOM.

Rendering is change-driven, not a fixed loop: a render is scheduled only when the camera or scene state actually changes, and multiple changes in the same tick are coalesced into a single pass. A static, un-interacted scene performs zero redraws. (Continuous animation — auto-rotate, inertia — does write every frame, but each frame is a genuinely different image.)

On every render pass:

1. All mounted meshes are walked in scene order.
2. Polygon vertices are transformed through the camera matrix to 2D projected positions.
3. A cols × rows character grid is filled: polygons are depth-tested, each cell picks a glyph from the active palette.
4. All cells are joined and written to <pre>.textContent (or .innerHTML for color mode) exactly once.

There are no per-polygon DOM elements and no CSS matrix3d. Hotspot overlays update via a single el.style.left/top assignment per hotspot per render — not a DOM rebuild.

autoSize uses a ResizeObserver to re-fit the grid whenever the host element resizes, keeping the character density constant regardless of viewport size.

Packages

Package	npm name	Description
@glyphcss/core	@glyphcss/core	Pure math: Vec3, Polygon, scene, camera, mesh ops, parsers. Zero browser globals.
glyphcss	glyphcss	ASCII rasteriser + vanilla custom elements + imperative createGlyphScene API.
@glyphcss/react	@glyphcss/react	React components, hooks, and controls.
@glyphcss/vue	@glyphcss/vue	Vue 3 mirror of the React package.

License

MIT.