/*
 * @name Brightness
 * @arialabel Astronaut rendered in black and white is covered with a black screen. The user’s mouse acts as a flashlight and parts of the image are illuminated as the user’s mouse travels over
 * @description This program adjusts the brightness of a part of the image by calculating the distance of each pixel to the mouse.
 * <br><br><span class="small"><em>This example is ported from the <a href="https://processing.org/examples/brightness.html">Brightness example</a>
 * on the Processing website</em></span>
 */
// This program adjusts the brightness
// of a part of the image by
// calculating the distance of
// each pixel to the mouse.
let img;
// preload() runs once, before setup()
// loadImage() needs to occur here instead of setup()
// preload() makes sure image is loaded before anything else occurs
function preload() {
  // load the original image
  // img = loadImage('assets/rover_wide.jpg');
  img = loadImage('../../../../p5js-website-legacy-examples/assets/rover_wide.jpg');
}
// setup() runs after preload, once()
function setup() {
  // createCanvas(710, 400);
  createCanvas(windowWidth, windowHeight);
  pixelDensity(1);
  frameRate(30);
}

function draw() {
  image(img, 0, 0);
  // Only need to load the pixels[] array once, because we're only
  // manipulating pixels[] inside draw(), not drawing shapes.
  loadPixels();
  // We must also call loadPixels() on the PImage since we are going to read its pixels.
  img.loadPixels();
  for (let x = 0; x < img.width; x++) {
    for (let y = 0; y < img.height; y++) {
      // Calculate the 1D location from a 2D grid
      let loc = (x + y * img.width) * 4;
      // Get the R,G,B values from image
      let r, g, b;
      r = img.pixels[loc];
      // g = img.pixels[loc+1];
      // b = img.pixels[loc+2];
      // Calculate an amount to change brightness based on proximity to the mouse
      // The closer the pixel is to the mouse, the lower the value of "distance"
      let maxdist = 50; //dist(0,0,width,height);
      let d = dist(x, y, mouseX, mouseY);
      let adjustbrightness = (255 * (maxdist - d)) / maxdist;
      r += adjustbrightness;
      // g += adjustbrightness;
      // b += adjustbrightness;
      // Constrain RGB to make sure they are within 0-255 color range
      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
      let pixloc = (y * width + x) * 4;
      pixels[pixloc] = r;
      pixels[pixloc + 1] = r;
      pixels[pixloc + 2] = r;
      pixels[pixloc + 3] = 255; // Always have to set alpha
    }
  }
  updatePixels();
}