Hello all! In just a few days (I will finish the code over the holidays)
I'm going to be submitting a bit of code to Robert to evaluate for
inclusion into OSG proper. It is a continuation of his experimentation
with a new text interface called TextNode.
TextNode diverges a great deal from what you might be used to with Text
and Text3D objects, but in the end the transition (if Robert accepts
it :)) will be worth it. The API has been cleaned up, internal data is
much easier to get at, and the rendering and layout backends have become
pluggable.
Before I finish up the last bits so that a first beta version can be
submitted and people can begin experimenting with it, I'd like to
solicit some input.
1) I'm dropping all support for the FFP. I mean, c'mon. It makes the
code substantially harder to maintain and understand. If this causes the
code to be rejected (or perhaps results in Text and Text3D staying
around for a bit longer to support FFP), then so be it. :) In lieu of
this, however, I'd like some opinions on which version of GLSL I should
target and how well that version is currently supported by OSG.
2) TextNode (3D) glyph support is working quite well; it wasn't hard,
since most of the code was already there in the backend. Each glyph is
cached based on its Style and Font, put into a PAT, and then finally all
of the text is squished into a top-level MatrixTransform. I continue to
use the setAlignment() and setAxisAlignment() API, but obviously you're
free to do whatever you like. How does this sound to everyone?
3) TextNode (2D) is still going to require a bit of work at the time of
the first submission. In the new API, osg::Geometry objects are
constructed using quads textured with the 2D glyphs and, again, packaged
into a top-level MatrixTransform. A remaining (serious) question is how
to do drop-shadows and outlines?
4) As some of you may know, I am also the author of osgCairo and
osgPango. Both of these nodekits came to be as I was working on
osgWidget, which--combined with getting sick--seriously sidetracked that
project. :) (I haven't forgot about osgWidget though--hang in there!)
This isn't an attempt to plug that software, but rather me posing a
question I've asked before:
4.a) The 2D quality provided by osgPango simply cannot be
matched by anything any of us could do by hand. This is
partly due to osgPango's massive user base and its main
developers, but it is also due to the fact that the Glyph
rasterizer is Cairo. Now, I won't be so bold as to ask OSG
to accept osgPango (yet :)), but what I would like to do is
provide a way for Cairo to do the glyph rasterization instead of
doing it manually with Freetype. This is the approach osgPango
takes, and it lets osgPango provide a very powerful glyph
"effect" API. Let me elaborate below...
In current 2D OSG, you request a string of text. Each
character is iterated over and the backend calls FT_Load_Char
to render each glyph at a particular resolution, at which
point that glyph is put into a texture atlas to be reused
later.
If we supported Cairo as a rasterizing backend, we would instead
be given the glyph information for each character as a vector
path and would have the freedom to do whatever Cairo's drawing
API allows with it. In the most basic case, this would be a
simple fill() operation, but as you can see from the osgPango
screenshots: http://www.jeremymoles.com/osgPango , a lot of
interesting things can be done when you have a vectorized
path of a glyph. :)
Don't misunderstand me though: osgPango isn't going anywhere! The layout
support alone provided by osgPango is incredible, and it is able to
provide additional information to the rasterizer for higher quality
fonts (it also supports more than just Freetype; Atsui and the Windows
font backend, for example). It also understands just about every
language and locale out there, so text is always positioned properly.
But I would like to at least like to pose the idea of using Cairo as the
rasterizer, or at least providing a plugin (since it is the freetype
plugin in the osgPlugins directory that actually is responsible for
building the glyph atlas) to do this.
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I TRULY feel like if we can get this UI stuff under control (which is
why I started working on osgWidget, osgCairo, osgPango) we can
absolutely establish OSG as the premiere OpenGL toolkit. Hopefully I can
make enough strides in this area in my freetime so that one day I can do
it FULL TIME for a living. :) If anyone is familiar with Scaleform (and
if you've played any games made in the last 5 years, you can't have
missed it), something of that visual quality and style is what I
envision for OSG one day (minus the Flash absurdity)...
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