Canvas rendering issues / Text Transition rendering issues

[Daniel Zwolenski]

One of the goals of Richard's Tower Defender game is to test/showcase
rendering performance and smoothness. The game is still very very ugly and
basic but we have added some transitions and also included a Canvas
background and we are starting to see some serious rendering issues.

Richard probably hasn't a chance to look at these much yet so he may have
more insight but it would be interesting to hear comments from others on
what may be causing these issues (e.g. code in our end or code in the JFX
end) and how to deal with them.

There is an executable JAR of the (still very ugly game) at:
https://bytebucket.org/rbair/fx-games/wiki/release/defender-jfx.jar

All the code is at: https://bitbucket.org/rbair/fx-games/src (I can narrow
down further to areas of interest if you need it - just ask).

When the game first loads we show an animated 'introduction' screen that
has some basic Text transitions on it. This has some issues:

   - The first title text is very jittery as it zooms in
   - The tag line that fades in does a noticeable, sudden jump at the end
   from what looks like a bolder font to a thin one (or anti-aliased or
   something).
   - The spinning text has a similar combination of the previous two issues

We have also added a Canvas as a background for the game in the 'grass'
level (the 'brick' level uses a Pane as a background) and it has resulted
in all sorts of odd problems. The canvas level has some pretty serious
issues:

   - Towers (nodes) have some z-order issues when being placed before
   animations start
   - Bad Guys (nodes) rendering outside of their parents clip bound's and
   then tend to leave a tail behind them (i.e. the back-buffer is not cleared
   or something)
   - Lots of flickering of Bad Guys when they are animating (again looks
   like z-order issues)
   - Putting an overlayed light box with a translucent glass pane (click
   the 'New Game' button) causes all sorts of extreme, weird flickering and
   clipping problems

Note that this could all be related to how we're using regions or something
like that but even so it's pretty bad that we can make this happen even if
we wanted to. The 'bricks' level uses a pane as it's background and works a
treat with pretty much the exact same code.

Cheers,
Dan