jit.gl.text2d On jit.gl.videoplane

On Jun 2, 2006, at 4:01 AM, darcysays wrote:

> Im trying to overlay some text on a gl video plane, but what
> results is the text within small boxes.
> I think there must be a simple way to solve this, but suggestions
> from the past lists dont work or I might be missing something.

Your problem is as follows: in automatic mode there is currently no
way to enforce the sequence of object rendering. In your patch your
text is rendered first, and then the videoplane. This obscures the
text in the absence of depth testing (default off for jit.gl.text2d).

If depth_enable is *on*, however, then the videoplane will not render
anywhere the text is closer to the camera (for the entire
quadrilateral which has been rendered for each glyph, as the depth
buffer is written to based on the geometry, not the glyph's alpha
channel).

The correct way to do this in the current version of Jitter is to
disable automatic mode and then explicitly render the text last,
without depth testing. Example is below.

In the next version of Jitter there are two new attributes which
would be of use in these types of scenarios:

- @layer : in automatic mode object rendering order is
sorted from low to high based on layer number, default 0. (note:
objects in the same layer are not guaranteed any specific rendering
order)
- @depth_clear : before rendering object, clear the depth
buffer (useful for having 3D layers which need depth testing internal
to rendering it's geometry--e.g. a sphere--but wish to override the
depth buffer for all previously rendered objects)

jit.gl.render drawclients message also has a new optional layer
number argument for only drawing objects in a specifc layer.

Coming soon to a theater near you (no please don't ask for dates).

-Joshua