Skip to content

Latest commit

 

History

History
72 lines (46 loc) · 2.87 KB

sdf.md

File metadata and controls

72 lines (46 loc) · 2.87 KB
Raw

Signed Distance Field Rendering

You can use Signed Distance Fields (SDF) or Multi-Channel SDF for sharper edges on text scaling.

Tools

You will need to use a separate tool to generate signed distance field images and BMFont files. Examples of such tools:

SDF Shader

See the test-3d.js for a full example.

This module exports shaders/sdf for convenience. It uses standard derivatives extension for anti-aliasing if available, otherwise falls back to gl_FragCoord.w.

Options:

  • opacity the opacity, default 1.0
  • color the color to tint the text, default 0xffffff
  • alphaTest the alpha test value, defaults to 0.0001
  • precision the fragment shader precision, default 'highp'

Note: RawShaderMaterial is required in order to support a wide range of ThreeJS versions.

var Shader = require('three-bmfont-text/shaders/sdf')

var material = new THREE.RawShaderMaterial(Shader({
  map: fontAtlas,
  side: THREE.DoubleSide,
  transparent: true,
  color: 'rgb(230, 230, 230)'
}))

There is also shaders/basic which acts like a typical THREE.MeshBasicMaterial, but using a raw shader. This is useful when you want a consistent interface for manipulating color/texture/etc.

MSDF Shader

See the test-msdf.js for a full example.

A more recent technique by Viktor Chlumský known as Multi-Channel Signed Distance Fields (MSDF) may produce sharper results than typical SDF.

To generate MSDF atlases with the BMFont spec, there is an experimental/work-in-progress tool here:

https://github.com/Jam3/msdf-bmfont

Clone the repo and follow the instructions to generate an atlas from your own TTF file.

Or, if you are feeling more ambitious, you can use the underlying msdfgen binary to build MSDF tiles from a TTF file. You will need to assemble the tiles into a texture atlas and generate a new BMFont file to get it working with three-bmfont-text.

To use the files with three-bmfont-text, you can require the msdf shader much like the above SDF shader:

var MSDFShader = require('three-bmfont-text/shaders/msdf')

var material = new THREE.RawShaderMaterial(MSDFShader({
  map: fontAtlas,
  side: THREE.DoubleSide,
  transparent: true,
  color: 'rgb(230, 230, 230)'
}))

The test folder also includes Roboto-msdf.json and Roboto-msdf.png for testing.

MSDF and its tooling is still new and immature, so please post any issues or suggestions you may have.