libgdx判断actor与circle是否重叠

实质是检测矩形与circle是否重叠

基本函数，判断点是否在circle中

     public static boolean IsInside( float x, float y, Circle circle ){
         float disX = x - circle.x;
         float disY = y - circle.y;
         return disX*disX + disY*disY <= circle.radius*circle.radius;
     }

再判断矩形4个点是否在其中，有一个在即重叠

     public static boolean IsOverlap( Actor actor, Circle circle ){
         float x = actor.getX(), y = actor.getY(), w = actor.getWidth(), h = actor.getHeight();

         return IsInside(x,y,circle) || IsInside(x+w,y,circle) || IsInside(x,y+h,circle) || IsInside(x+w,y+h,circle);
     }