The Average Life of Gynlorf

It seems as if Conway’s Defense has reached a landmark of one thousand lines! I wonder if it will get to 2000.

Today I feel like talking about how I implemented input management into Conway’s Defense, and I think it’s pretty nifty.

The first thing I decided to do is create a class with a Dictionary called Bindings, which I used to store bindings for keys. This way the user can change the keys to whatever he wants, without requiring a huge amount of extra code. I also added variables for the current Keyboard State and the previous one, which we use for checking the state of the key. Finally, I created an enum representing the possible states of the keys.

//Throw in your using statements here...

namespace InputManagement
{
	public class InputManagement : GameComponent
	{
		private KeyboardState CurrentFrame;
		private KeyboardState LastFrame;
		private Dictionary<string, string> Bindings;

		public InputManagement(Game1 game) : base(game)
		{
			CurrentFrame = Keyboard.GetState();
			LastFrame = CurrentFrame;
		}
	}

	public enum KeyStates
	{
		None,
		Pressed,
		Held,
		Released
	}
}

Now that our variables have been created, I created an override function for Update(), to change the Keyboard states. I also added a function called InitDefaultControls(); to store the default controls into the dictionary. It is also a good idea to have a CheckBinding() method for our game to use to easily find out the state of a binding.

public void InitDefaultControls()
{
	Bindings = new Dictionary<string, string>();
	Bindings.Add("Left", "Left");
	Bindings.Add("Right", "Right");
	Bindings.Add("Jump", "Up");
	Bindings.Add("Duck", "Down");
}

public KeyStates CheckBinding(string binding)
{
	if(Bindings.ContainsKey(binding))
	{
		string value = Bindings[binding];
		bool Lks = LastFrame.IsKeyDown((Keys)Enum.Parse(typeof(Keys), value, true)); //Set the Last keystate bool to check if the key was pressed. We convert the string for the binding to a Keys enum value.
		bool Tks = CurrentFrame.IsKeyDown((Keys)Enum.Parse(typeof(Keys), value, true));
		if(!Lks && !Tks) { return KeyStates.None; }
		else if(Lks && Tks) { return KeyStates.Held; }
		else if(Lks) { return KeyStates.Released; }
		else { return KeyStates.Pressed;}
	}
	return KeyStates.None; //We will return none if the binding does not exist. You could make an error state if you want, but we'll just use KeyStates.None
}

public override void Update(GameTime gameTime)
{
	base.Update(gameTime);

	LastFrame = CurrentFrame;
	CurrentFrame = Keyboard.GetState();
}

To implement the class, you simply have to add a reference to this class, create an instance of InputManagement and add it to the Components list in your Game class. Once you’ve done that, you can at any time call the CheckBinding() method of your InputManagement instance and grab the KeyStates value.

That’s really all you need. If you want to expand on the concept, you could add another function to return true if the binding is at the specified KeyStates value. You can also modify the code to use GamePad button states. You could even go so far as to add a class that stores the button type and use that instead of the second string for the Dictionary. This way, you could have it store both GamePad values and JoyStick values. You also might want to return a float for analog sticks, instead of a enum value, too.

I finally removed the malware that some jerk put on my website >:|

Now, I can get back to blogging! >_>