Dragging, dropping, and sliding

If you're writing a game for a platform that has either touch or mouse support, then offering the ability for players to drag, drop, and slide elements around the screen can be a surprisingly compelling motivation to play in and of itself.

Getting ready

This recipe requires a selection of 100 by 100 pixel images to form both the background areas and the foreground draggable items. In my example, I created a blank, white texture named "block" for the background and a series of simple, white-lettered textures for the draggable item textures, as shown in the following illustration:

How to do it...

To start dragging and dropping items in your own games:

1. 1. Begin by adding a new class to hold the state of what has been dropped onto the board and where:

   class Map
   {
   private Dictionary<Point, Icon> iconByPosition =
   new Dictionary<Point, Icon>();
   public bool TryGetIcon(Point position, out Icon icon)
   {
   return iconByPosition.TryGetValue(position, out icon);
   ...