stage3D based drawTiles implementation (ALPHA)

After much confusion and frustration, I now have a working implementation of drawTiles that can use stage3D when published for flash 11.2+.

To use this class, you need to make a couple of changes - it's not a 'turnkey' solution - there are a couple of difference, due to the way stage3D works. The first thing is that you need to use the com.asliceofcrazypie.TilesheetStage3D class instead of the nme.display.Tilesheet class (for other platforms, it behaves identically to a standard tilesheet). Secondly (and most significantly), stage3D content is rendered underneath the standard display list, rather than it's depth being controlled with the graphics object as it is with the standard drawTiles implementation. The graphics object simply gets ignored. Whilst it is possible to render stage3D graphics into a bitmapData, which could then be drawn into the standard display list, the performance of this is catastrophically bad, and makes the whole thing pointless.

It also required the 'starling' library, which is available on haxelib (it was that or port the AGALMiniAssembler myself.)

Also, you will need to call the init method on the tilesheet object after instantiating it, which has one required method, stage - this must be a reference to the stage object. I'd recommend leaving stage3DLevel on 0, and antiAliasLevel currently gets ignored.

Next, you need to class the static method TilesheetStage3D.clear() to clear the graphics (clearing the graphics object does nothing to the stage3D content), and call the static method TilesheetStage3D.render() once you're ready to render the graphics to screen. Bear in mind that both these methods apply to ALL tilesheets, and only need to be called once to update all tilesheets. Here's a simple example:

#if flash11
TilesheetStage3D.clear();
#end

//put all drawTiles calls

#if flash11
TilesheetStage3D.render();
#end

As it says in the title, this is very much an alpha release. It's not been heavily tested, and I know it doesn't properly handle various errors, including the loss of the context3D when the user's machine goes to screensaver. Also, I've never done any 3D programming before, so it's possible that this is a pretty poor implementation (I don't know what's fast, what's slow, etc).

If anyone has any comments/advice, etc please let me know.