int x=200;
int y=200;
int r =30;
boolean dentro = false;
void setup(){
  size(400,400);
  ellipseMode(RADIUS);
}
void mousePressed(){
  dentro = dist(mouseX, mouseY, x, y) <= r;
}
void mouseDragger(){
  if (dentro){
    int dx = mouseX-pmouseX;
    int dy = mouseY-pmouseY;
    x+=dx;
    y+=dy;
  }
}
void draw(){
 ellipse (x,y,r,r);
}-----------
class Bola{
    int x;
  int y;
Bola(int a, int b){
  this.x=a;
  this.y=b;
  ellipse (a,b,10,10);
}
boolean dentro(int cX, int cY){
return( dist(cX, cY, this.x, this.y) <= 10);
}
void desenha(){
ellipse (this.x,this.y,10,10);
}
}

Bola b[] = new Bola[2];
int sel =-1;
void setup(){
  size(400,400);
  ellipseMode(RADIUS);
  b[0] = new Bola(30,30);
  b[1] = new Bola(100,100);
}
void mousePressed(){
  for(int i=0; i<b.length;i++){
  if(b[i].dentro(mouseX,mouseY)){
    sel =i;
    break;
  }
  }
  if(sel==-1){
  b= (Bola[]) append(b, new Bola(mouseX,mouseY));
  }
}
void mouseDragged(){
    if(sel!=-1){
    int dx = mouseX-pmouseX;
    int dy = mouseY-pmouseY;
    b[sel].x+=dx;
    b[sel].y+=dy;
    }
}
void draw(){
  for(int i =0;i<b.length;i++){
  background(125);
  b[i].desenha();
}
}