let HIGH = 500;

let n = 4;  // number of used reference points

let PGRID, CLOUDS, DISTA, ALPHA;

let i, x, y;

​

function setup() {

  createCanvas(WIDE, HIGH);

​

  // Create some reference Points

  PGRID = new Array(2, n);

  PGRID[0] = new Array(2);

  PGRID[1] = new Array(n);

  for (i = 0; i < 10; i++){

    PGRID[0][i] = floor(random(50,WIDE-50));

    PGRID[1][i] = floor(random(50,HIGH-50));

  }

  // Fill the Sky (CLOUDS) with R/G value dependent on n reference Points

  CLOUDS = new Array(WIDE / 5, HIGH / 5);

  for (x = 0; x < WIDE / 5; x++) {

    CLOUDS[x] = new Array(WIDE / 5);

    for (y = 0; y < HIGH / 5; y++) {

      DISTA = 0;

      for (i = 0; i < n; i++) {

        DISTA = DISTA + dist(x*5,y*5,PGRID[0][i],PGRID[1][i]);

        ALPHA = map(DISTA/i - 100,0,800,255,0);

        CLOUDS[x][y] = ALPHA;

      }

    }

  }

}

​

// Draw the Sky with Clouds (CLOUDS)

function draw() {

background(150,200,250);  noStroke();

  for (x = 0; x < WIDE / 5; x++) {

    for (y = 0; y < HIGH / 5; y++) {

      fill(CLOUDS[x][y], CLOUDS[x][y], CLOUDS[x][y], CLOUDS[x][y]);

      square(x * 5, y * 5, 5);

    }

  }

​

  noLoop;

}