A Little Netwire Theory
So as you can probably figure out by looking around on my blog, I'm working quite a bit in Netwire recently. I put one of my posts, netwire-pong... Pong in Netwire (duh) on /r/haskell. I presented some qualms I had with the Netwire library. In response some people gave me some advice regarding the organization of Netwire applications. I've been pondering their responses for a couple of days, and I think I'm ready to publish something on it.
netwire-pong as Reference
Abstraction. Seriously. When writing my netwire-pong game, I wasn't thinking about this. I was trying to get things working, without really thinking about how I should get them working. That bit me in the bum later on, as is mentioned in the article. In hind-sight, now clear thanks to the people over on reddit, I shouldn't be passing around so much information. The ball, to perform collision and scoring required:
The render size.
The left paddle.
The right paddle.
I'm passing everything my ball could collide with. Every single thing. In this case, it's only three, but in a large application, that's a lot more. Think of a game with hundreds of entities. Do I want to pass them all to something that might collide with them? Of course not. Thanks to comments from /u/mstrlu and others, I realized the better way is to just tell the ball when it has collided. Even handling the scoring (which is just returning a value telling the game if it should increment either of the scores) could be done externally relative to the ball.
This is a simple case, but defines a precedent for future use. Pass on and return the minimal amount of information you need to. Thereby making the Wires modular and easily composable.
Going Onward
As mentioned in my previous post I'm beginning work on a project named netwire-vinyl. While it's primarily an exploration of modern OpenGL through vinyl-gl, it also serves as an application of this minimalist technique. vinyl-gl definitely is not going to be a fully fledged game, but hopefully it will be complex enough to really demonstrate the power of both vinyl-gl and Netwire.