Note: This package is experimental and subject to change. Use at your own discretion.

The gltext package offers a simple set of text rendering utilities for OpenGL programs. It deals with TrueType and Bitmap (raster) fonts. Text can be rendered in various directions (Left-to-right, right-to-left and top-to-bottom). This allows for correct display of text for various languages.

The package supports the full set of unicode characters, provided the loaded font does as well.

• Have a look at Valve's 'Signed Distance Field` techniques to render sharp font textures are different zoom levels.

  • SIGGRAPH2007_AlphaTestedMagnification.pdf
  • Youtube video

  More links to info in the youtube video description. An alternative might be a port of GLyphy

• Determining the height of truetype glyphs is not entirely accurate. It is unclear at this point how to get to this information reliably. Specifically the parts in LoadTruetype at truetype.go#L54+. The vertical glyph bounds computed by freetype-go are not correct for certain fonts. Right now we manually offset the value by added 4 to the height. This is an unreliable hack and should be fixed.
• freetype-go does not expose AdvanceHeight for vertically rendered fonts. This may mean that the Advance size for top-to-bottom fonts is incorrect.

go get code.google.com/p/freetype-go

go get github.com/go-gl/gltext

Refer to go-gl/examples/gltext for usage examples.

Copyright 2012 The go-gl Authors. All rights reserved. Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.