Hi,

 

As always, there are lots of ways to do this,

 

The easiest and most flexible way I find is to make an object of the entity you want to have multiple copies of, in this case a ring. Then create an array of them and use a loop to step through each one updating it.

 

An example will make this clear, see below:

 

int MAXRINGS = 100;
int[] a = new int[MAXRINGS];
int num_rings = 1;
Ring[] myRing;
void setup()
{
  size(200, 200);
  stroke(255);
  frameRate(25);
  smooth();
  strokeWeight(5);
  myRing = new Ring[MAXRINGS];
  // Initial Ring
   myRing[0]  = new Ring(width/2, height/2);
}

void draw(){
  background(0);
  fill(0);
  noFill();
  for(int current=0; current < num_rings; current++) {
   myRing[current].update();
  }
}

 

void mousePressed() {
  if (num_rings < MAXRINGS)
   myRing[num_rings]  = new Ring(mouseX, mouseY);
   num_rings = num_rings + 1;
}

 

class Ring {
  float radius, xpos, ypos;
  Ring(float x, float y)
  {
    radius = 0;
    xpos = x;
    ypos = y;
  }
  void update() {
     radius++;
     if (radius > width)
       radius = 0;
     ellipse(xpos,ypos, radius,radius);
  }
}

 

 

If you want each ring just to start in the middle rather than at the mouseX and mouseY positions, then just change the MousePressed code to:

 

void mousePressed() {
  if (num_rings < MAXRINGS)
   myRing[num_rings]  = new Ring( width/2, height/2);
   num_rings = num_rings + 1;
}

 

Hope this is helpful.

 

Kind Regards

 

Kevin.