I'm pretty new to programming so forgive my ignorance on what should be a fairly simple task.
I have 8 static elipses arranged in a circle.
I would like their brightness adjusted according to mouse proximity. I can't work out the maths for this.
have searched the site for answers but haven't found anything. Any help/pointers to examples greatly appreciated.

Thanks


 int a = 128;
 int b = 128;
 int c = 128;
 int d = 128;
 int e = 128;
 int f = 128;
 int g = 128;
 int h = 128;


void setup(){
 size(640, 640);
 smooth();
 background(0);
 noStroke();
}

void draw() {
 fill(a);
 ellipse(320,120, 64, 64);
 fill(b);
 ellipse(461,179, 64, 64);
 fill(c);
 ellipse(520,320, 64, 64);
 fill(d);
 ellipse(461,461, 64, 64);
 fill(e);
 ellipse(320,520, 64, 64);
 fill(f);
 ellipse(179,461, 64, 64);
 fill(g);
 ellipse(120,320, 64, 64);  
 fill(h);
 ellipse(179,179, 64, 64);  
}