How To Interface Joystick Module with Arduino

/*
  Joystick and Processing
  modified on 21 Jul 2019
  by Saeed Hosseini @ Electropeak
  
Home

  Thanks to http://learningprocessing.com/examples/
*/
import processing.serial.*; 
Serial myPort;
int VRx;
int VRy; 
int but;
String val;
int maxImages = 5;
int imageIndex = 0;
int i = 1;
PImage[] img = new PImage[maxImages]; 
PImage image;
void setup() {
  size(512, 512);
  myPort = new Serial(this, "COM5", 9600);
  myPort.bufferUntil('\n'); 
  background(0);
}
void draw() {
  game();
}
void serialEvent( Serial myPort) 
{
  // read the data until the newline n appears
  val = myPort.readStringUntil('\n');
  if (val != null)
  {
    val = trim(val);

    // break up the decimal and new line reading
    int[] vals = int(splitTokens(val, ","));
    // we assign to variables
    VRx = vals[0];
    VRy = vals[1] ;
    but = vals[2];
  }
}
void game() {
  img[i] = loadImage( "p" + i + ".jpg" );
  image = img[i];
  loadPixels();
  img[i].loadPixels();
  for (int x = 0; x < image.width; x++ ) {
    for (int y = 0; y <image.height; y++ ) {

      // Calculate the 1D pixel location
      int loc = x + y*image.width;

      // Get the R,G,B values from image
      float r = red  (image.pixels[loc]);
      float g = green(image.pixels[loc]);
      float b = blue (image.pixels[loc]);

      // Calculate an amount to change brightness
      // based on proximity to the mouse
      float distance = dist(x, y, VRy, VRx);

      // The closer the pixel is to the mouse, the lower the value of "distance" 
      // We want closer pixels to be brighter, however, so we invert the value using map()
      // Pixels with a distance of 50 (or greater) have a brightness of 0.0 (or negative which is equivalent to 0 here)
      // Pixels with a distance of 0 have a brightness of 1.0.
      float adjustBrightness = map(distance, 0, 50, 1, 0);
      r *= adjustBrightness;
      g *= adjustBrightness;
      b *= adjustBrightness;

      // Constrain RGB to between 0-255
      r = constrain(r, 0, 255);
      g = constrain(g, 0, 255);
      b = constrain(b, 0, 255);

      // Make a new color and set pixel in the window
      color c = color(r, g, b);
      pixels[loc] = c;

      if (but == 1) i++;
      if (i>4) i = 1;
    }
  }

  updatePixels();
}