package greenfoot.collision;

import greenfoot.Actor;
import greenfoot.ActorVisitor;




| A collision query to check for actors within a certain range of a certain
| point
|
| @author Davin McCall
|
public class InRangeQuery
implements CollisionQuery{    
   

| x-coordinate of the center of the circle. In pixels.
|
private int x;
   
   

| y-coordinate of the center of the circle. In pixels.
|
private int y;
   
   

| radius of the circle. In pixels.
|
private int r;

   
   


| Initialise with the given circle. Units are in pixels!
|
public void init(int x, int y, int r)
   {        
      this.x = x;
       
      this.y = y;
       
      this.r = r;     
      }

   
   


| Return true if the distance from some point on the actor to the center of
| the circle, is less than or equal to the radius of the circle.
|
public boolean checkCollision(Actor actor)
   {
      int actorX = ActorVisitor.toPixel(actor, ActorVisitor.getX(actor));
      int actorY = ActorVisitor.toPixel(actor, ActorVisitor.getY(actor));   
        
       
      int dx = actorX - x;
       
      int dy = actorY - y;
      int dist = (int) Math.sqrt(dx * dx + dy * dy);

      return (dist) <= r;     
      } 
   }