forked from: Sprite3DSet for Alternativa3D v8

import alternativa.engine3d.spriteset.Sprite3DSet;
import alternativa.engine3d.spriteset.util.SpriteGeometryUtil;

A high performance sprite batch renderer in Alternativa3D that you can use to help render old-school sprites, globally axis-locked sprites, z-locked sprites, etc. in batches,
You can use the class to create starfields (star streaks/hyperspace jump), dust, particle systems, etc. The Sprite3DSet Object3D class isn't prescriptive, since the rendering
engine is seperate from the particle/material system itself. Do whatever you wish in your own material/particle system, than pump the raw numeric data into the Sprite3DSet's sprite data arrays.
@author Glenn Ko

[Embed(source = "../../resources/images/test/leaf.png")]
") >= 0);
_specFollowTarget.addChild(_floor);
_template.scene.removeChild(_template.rootControl);
new LEAF().bitmapData;
bitmask 4 (100), to ensure Z position is clamped to Zero floorn!
set normalized tree alignment to bottom ( last 2 parameters for originX,originY 