Snippet: Function checking if an object is within radius of another.

InRadius.as

/**
 * 	Check to see if an object is within radius of another.
 * @param	x1 	object1 
 * @param	y1	object1
 * @param	x2	object2
 * @param	y2	object2
 * @param	radius	Size of the radius, which is usually
 * @return	returns true if object2 is within radius of object 1
 * @example	if (InRadius(player.x,player.y,enemy.x,enemy.y,100)) trace ("enemy within a 100 pixel radius of player");
 */
public function InRadius(x1:Number, y1:Number, x2:Number, y2:Number,radius:Number):Boolean
{
	var magnitude:Number = radius * radius
	if ((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1) <= magnitude) return true;
	else return false;
}