Shared Material

AwaySheet.as

package 
{
	import away3d.core.base.SubMesh;
	import away3d.entities.Mesh;
	import away3d.materials.TextureMaterial;
	import away3d.textures.Texture2DBase;
	import flash.geom.Rectangle;
	import starling.textures.Texture;
	import starling.textures.TextureAtlas;
	
	/**
	 * ...
	 */
	public class AwaySheet 
	{
		protected var _material:TextureMaterial;
		private var _baseSheet:TextureAtlas;
		
		public function AwaySheet(atlas:TextureAtlas) 
		{
			_baseSheet = atlas;
			
			createAwayTexture(_baseSheet.texture);
		}
		
		private function createAwayTexture(tex:Texture):void 
		{
			var sharedTex:SharedTexture = new SharedTexture(tex);
			_material = new TextureMaterial(sharedTex, true, false, false);
			_material.animateUVs = true; // this has to be on for UV manipulation to work
			_material.alphaBlending = true;
		}
		
		public function get atlas():TextureAtlas { return _baseSheet; }
		public function get awayTexture():Texture2DBase { return _material.texture; }
		public function get sharedMaterial():TextureMaterial { return _material; }
	
		public function setupUV(mesh:Mesh, name:String):void 
		{
			if(mesh == null)
				throw new ArgumentError("submesh cannot be null");
			
			var regionRc:Rectangle = _baseSheet.getRegion(name);
			if(regionRc == null)
				throw new ArgumentError("given region does not exist: " + name);
				
			var submesh:SubMesh = mesh.subMeshes[0];

			var w:Number = _baseSheet.texture.width;
			var h:Number = _baseSheet.texture.height;
			
			submesh.offsetU = regionRc.x / w;
			submesh.offsetV = regionRc.y / h;
			submesh.scaleU  = regionRc.width / w;
			submesh.scaleV  = regionRc.height / h;
		}
 	
	}

}

SharedTexture.as

package
{
	import away3d.textures.Texture2DBase;
	import flash.display3D.textures.TextureBase;
	import starling.textures.Texture;
	
	/**
	 * ...
	 */
	public class SharedTexture extends Texture2DBase 
	{
		private var refTexture:Texture;
		
		public function SharedTexture(tex:Texture) 
		{
			super();
			refTexture = tex;
		}
		
		override protected function uploadContent(texture:TextureBase):void
		{
			// Leave empty
		}
		
		override protected function createTexture(context:Context3D):TextureBase
		{
			var baseTex:TextureBase = refTexture.base;
			return baseTex;
		}
		
	}

}