Update 3/31/12 I created a new, more complete game using this plugin:
http://mathbattlegame.appspot.com/static/PhyFPS/index.html
I submitted it to the HB Games contest:
http://www.hbgames.org/forums/viewtopic.php?f=293&t=76413
Update: Now you can shoot "bullets" by pressing 'Q'.
I also added the download to both the plugin and the demo at:
https://sites.google.com/site/jptarqu/downloads
The name of the download is copperlicht-c2-plugin-v-0.9.zip.
Please note that to run the sample capx, you will need to export it to your web server (either local server like IIS express, apache, etc. or to a external server). The reason behind this, is that copperlicht will try to load the external file containing the level made in Coppercube. I could not find a way of embedding that files and the texture files needed by that file in C2's debug server. I personally use IIS express to test the demo in my computer.
Another thing to note is that there is a lot of trial and error trying to match the coordinates between copperlicht and C2. For example, for the walls, I used coppercube to design the 3D level and "measured" the units there and put the objects in the same place in C2's layout.
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I am working on a plugin that would allow you to present your C2 levels as 3D levels in copperlicht. Here is a demo so far:
http://mathbattlegame.appspot.com/static/copperlicht/tutorial2/index.html
I synchronize the positions and rotations between C2 and copperlicht, so copperlicht is just a "screen" for C2's logic. In the demo you see that you actually move and rotate the C2 sprite, and copperlicht is just being told to imitate the pos and rotation. This will allow you to use all the nice things from C2 and show them in 3D.
I will work on the plugin more and put a link to a capx and the plugin files.
Note: this plugin and the demo require WebGL because of Copperlicht(tested in Chrome).