Is it possible to make the 'stars' 'twinkle' all over the screen when the mouseX position moves instead of the spotlight that I have going on right now? This is my sketch so far:

int[][] fire;

// Flame colors
color[] palette;
float angle;
int[] calc1,calc2,calc3,calc4,calc5;

PGraphics pg;


int numCircles  = 500;
Circle[] circles = new Circle[numCircles];

void setup(){
  size(1440, 800, P2D);
  noFill();
   smooth();
   for (int i=0; i<numCircles; i++){
     circles[i] = new Circle(random(width),random(height));
   }
 
  // Create buffered image for 3d cube
  pg = createGraphics(width, height, P3D);

  calc1 = new int[width];
  calc3 = new int[width];
  calc4 = new int[width];
  calc2 = new int[height];
  calc5 = new int[height];

  colorMode(HSB);

  fire = new int[width][height];
  palette = new color[250];

  // Generate the palette
  for(int x = 0; x < palette.length; x++) {
    //Hue 0 to 85: red to yellow
    //Saturation is maximum: 255
    //Lightness is 0..255 for x=0..128, and 255 for x=128..255
    palette[x] = color(x/3, 255, constrain(x*3, 5, 255));
  }
 
  // this speeds up the effect by 10fps
  for (int x = 0; x < width; x++) {
    calc1[x] = x % width;
    calc3[x] = (x - 1 + width) % width;
    calc4[x] = (x + 1) % width;
  }
 
  for(int y = 0; y < height; y++) {
    calc2[y] = (y + 1) % height;
    calc5[y] = (y + 2) % height;
  }
 

void draw() {
 

  angle = angle + 0.05;

  // draw cube
  pg.beginDraw();
  pg.translate(width >> 1, height >> 1);
  pg.rotateX(sin(angle/2));
  pg.rotateY(cos(angle/2));
  pg.background(0);
  pg.stroke(128);
  pg.scale(mouseY/4);
  pg.noFill();
  pg.box(4);
  pg.endDraw();

  loadPixels();

  int counter = 0;
  // Do the fire calculations for every pixel, from top to bottom
  for (int y = 0; y < height; y++) {
    for(int x = 0; x < width; x++) {
    

      fire[x][y] =
          ((fire[calc3[x]][calc2[y]]
          + fire[calc1[x]][calc2[y]]
          + fire[calc4[x]][calc2[y]]
          + fire[calc1[x]][calc5[y]]) << 5) / 129;

      // Output everything to screen using our palette colors
      pixels[counter] = palette[fire[x][y]];

      // Extract the red value using right shift and bit mask
      // equivalent of red(pg.pixels[x+y*w])
      if ((pg.pixels[counter++] >> 16 & 0xFF) == 128) {
        // Only map 3D cube 'lit' pixels onto fire array needed for next frame
        fire[x][y] = 128;
      }
    }
  }
  updatePixels();
}
 if(keyPressed) {
    if (key == 'a' || key == 'A') {
      fill(0x90880000);
      rect(random(height),random(width),random(height),random(width));
    }
    if (key == 'b' || key == 'B') {
     fill(0x90000066);
     rect(random(width),random(height),random(width),random(height));
    }
    if (key == 'c' || key == 'C') {
      fill(0x90005500);
      rect(random(height),random(width),random(height),random(width));
    }
    if (key == 'd' || key == 'D') {
      fill(0x90330066);
      rect(random(width),random(height),random(width),random(height));
    }
    if (key == 'e' || key == 'E') {
      fill(0x90777777);
      rect(random(height),random(width),random(height),random(width));
    }
 }

for (int i=0; i<numCircles; i++) {
    circles[i].display(); // display all the circles
  }
}

class Circle {
  float x,y; // location
  float dim; // dimension
  color c; // color
 
  Circle(float x, float y) {
    this.x = x;
    this.y = y;
    dim = random(5);
    c = color(random(55));
  }
 
  void display() {
    float distance = dist(x,y,mouseX,mouseY); // distance between circle and mouse
    if (distance < 355) { // if distance is smaller than 255
      fill(355-distance);
    } else { // if distance is bigger than 255
      fill(c);
    }
    ellipse(x,y,dim,dim); // a circle at position xy
  }
}