Syntaxus Dogmata

An Insane Developer's Journal

Widgets, Frames and Screens — Oh My!

Lots of activity this week.

I decided to follow through with my plans to remove the Widget class from VertX. As of now, widgets are no more, and sprites are directly interacting with their screens. Unsurprisingly, the transition went smoothly.

One quandary down, two to go!

Next, I’m pushing ahead with the “Window” class I mentioned yesterday. I’m actually calling it a “Frame” class, and I’ve decided I’m going to start out by using the GraphicsDevice.Viewport technique I was speculating about yesterday. It won’t do everything I wanted, but at least it’ll be a very simple way to start out, and it’s a chance to learn about an interesting XNA feature.

Where I’m floundering is what the imposition of the Frame class implies. Much of its functionality will be extracted from the current Screen class, which up until now has been a customizable abstract class. Now that I’m looking at how much functionality frames will replace in the Screen class, I’m starting to think that not only should Screen not be abstract, but possibly a sealed class that treats all of its frames identically. This shifts all the “smart code” from the screen to its frames — a distribution of complexity I see as a good thing. I delight in useful simplicity, after all.

The problem with making Screen a sealed class is that it forces a level of complexity every time you make a new screen. By making Screen abstract, I’m able to encapsulate that complexity in the Screen class’s descendants. That way, it requires only a single “new” statement to transition from one screen to another, rather than constructing all the Frames required, and adding them to the screen one by one from outside the Screen class. If I rob myself of that encapsulation, it shifts the complexity from within the Screen class to exposing it to the rest of the framework — not a good thing!

Come to think of it, the “smart code distribution” perk I mentioned will be spread among the frames in any event. It won’t matter if Screen is a sealed class or not.

That settles it. I think it’s too high a price to pay just to keep things stable the closer you get to the VertXEngine in the class hierarchy. The screens should encapsulate all of their own setup code, which means keeping the Screen base class abstract. See? I knew this dev journal was good for something.

Hey, shut up. I wasn’t talking to you!


Apr 13, 2010 - Posted by | VertX™, Video Games | ,

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