Some features (texture protocol)

[unfilet]

I propose to create an interface for objects using Mesh.

public interface IRGBAProtocol
{
   void setColor(Color color);
    Color getColor();
    float getOpacity();
   void setOpacity(float opacity);
}

[unikronsoftware]

Any particular reason?
The mesh class is a unity class. This will have to be implemented on everything in tk2d, and a lot of things (tile map chunks) don't even have any behaviour attached to them.

[unfilet]

Class tk2dTextMesh and tk2dBaseSprite have common property Color.
I tried write action for fade in/out, but could not make it universal.

[unikronsoftware]

Well thats the only common thing between them though. text also has a color2, which would be counter intuitive as that would need to change too. It does get a bit messy...

[unfilet]

The bottom line is that all objects that use texture, support for this protocol. And for textmesh think there will be enough opacity.
You used a cocos2d? Their action system helps to solve a lot of problems. And to somehow use them as needed basis for such protocols.