I just pushed a new feature into the git repository: BlendModes! It works just like you're used to from Flash:
var image:Image = new Image(texture);
image.blendMode = BlendMode.MULTIPLY;
The following BlendModes are available:
BlendMode.NONE; // see below
BlendMode.AUTO; // inherit blend mode from parent (default)
BlendMode.NORMAL; // the standard mode, like it was in previous Starling versions
The 4 at the bottom should work as expected. BlendMode.AUTO is the default, and it means that the blendmode is inherited from a parent, that is:
When you set a sprite to "sprite.blendMode = BlendMode.SCREEN", and all its children are using "BlendMode.AUTO" (they do by default), then those children will be rendered with SCREEN. That should be rather intuitive.
BlendMode.NONE deactivates all Stage3D alpha blending, which is great for performance, especially for huge images in the background that don't need an alpha channel.
As a proof, here is how the Starling benchmark works on the iPad (in full resolution), when you change the BlendMode of the displayed objects:
-> with blending: 130 objects / 30 fps
-> with BlendMode.NONE: 760 objects / 30 fps (!)
It would be great if some of you could play around with the BlendModes, and tell me if they work as expected! I must admit I never used them much in Flash, so I'd be grateful for any feedback of people who use them regularly.