In Java (Swing), say I've got a 2D game where I have various types of entities on
the screen, such as a player, bad guys, powerups, etc. When
the player moves across
the screen, in order
to do efficient checking of what is in
the immediate vicinity of
the player, I would think I'd want indexed access
to the things that are near
the character based on their position.
For example, if player 'P' steps onto element 'E' in
the following example...
| | | | | |
| | | |P| |
| | |E| | |
| | | | | |
... would be
to do something like:
if(player.getPosition().x == entity.getPosition().x &&
entity.getPosition.y == thing.getPosition().y)
{
//do something
}
And thats fine, but that implies that
the entities hold their positions, and therefor if I had MANY entities on
the screen I would have
to loop through all possible entities available and check each ones position against
the player position. This seems really inefficient especially if you start getting tons of entities.
So, I would suspect I'd want some sort of map like
Map<Point, Entity> map = new HashMap<Point, Entity>();
And store my point information there, so that I could access these entities in constant time.
The only problem with that approach is that, if I want
to move an entity
to a different point on
the screen, I'd have
to search through
the values of
the HashMap for
the entity I want
to move (inefficient since I dont know its Point position ahead of time), and then once I've found it remove it from
the HashMap, and re-insert it with
the new position information.
Any suggestions or advice on what sort of data structure / storage format I ought
to be using here in order
to have efficient access
to Entities based on their position, as well as Position's based on
the Entity?
