Slick2d | Entity collision detection

Question

The problem:

I know this has been asked for many times, but I didnt find any good answers.
So I have got some entities for my game, now what is the best way

Answer 1

The classic way to do this is to have a Shape boundingBox associated with each Entity and then use Slick2d's "intersects" method on the shapes:

http://www.slick2d.org/javadoc/org/newdawn/slick/geom/Shape.html#intersects(org.newdawn.slick.geom.Shape)

I believe there is a way to do per-pixel checks on sprites but the bounding box method is more efficient if you don't need pixel-level accuracy.

Some code:

In your Entity abstract class add:

private Shape boundingBox;

public Shape getBoundingBox() {
  return this.boundingBox;
}

Then your intersects method is:

public boolean intersects(Entity entity) {
    if (this.getBoundingBox() == null) {
        return false;
    }
    return this.getBoundingBox().intersects(entity.getBoundingBox());
}

Then you need to set up a bounding box for each Entity that you want to check for collisions.