​

 mirror with some other features experiment

**************************************************/

​

// Always declare variables. Although Javascript

// is very tolerant, it's not a good idea to

// depend on it.

​

let camera; // the camera object

let arraySize; // global to avoid recalculating

// every frame

let previous_frame = []; // the previous frame

​

function setup() {

  createCanvas(400, 400);

  pixelDensity(1);

​

  camera = createCapture(VIDEO);

  camera.size(400, 400);

​

  // Number of pixels is the dimensions of the

  // input device, and each pixel has 4

  // components (red, green, blue, alpha)

  arraySize = camera.width * camera.height * 4;

​

  // Initialize the previous frame to blank

  for (let i = 0; i < arraySize; i++) {

    previous_frame.push = 0;

  }

​

  camera.hide();

}

​

function draw() {

  background(0);

​

  // Get the pixel array from the camera

  camera.loadPixels();

​

  // Get the pixel array from the canvas

  loadPixels();

​

  let curr_r, curr_g, curr_b;

  let prev_r, prev_g, prev_b;

  let diff_r, diff_g, diff_b; // computed differences

​

  // For each pixel in the video frame

  // for (let i = 0; i < arraySize; i += 4) {

​

  for (let y = 0; y < camera.height; y++) {

    for (let x = 0; x < camera.width; x++) {

      // let index = 4 * (x + y * width);

      // flip the x to make software mirror

      let i = 4 * (width - 1 - x + y * width);

      print ("x = " + x + " y = " + y + " i = " + i)

​

      // Extract the red, green, and blue

      // components from both the current

      // and the previous pixel color

      curr_r = camera.pixels[i + 0];

      curr_g = camera.pixels[i + 1];

      curr_b = camera.pixels[i + 2];

​

      prev_r = previous_frame[i + 0];

      prev_g = previous_frame[i + 1];

      prev_b = previous_frame[i + 2];

​

      // And calculate the differences

      diff_r = abs(curr_r - prev_r);

      diff_g = abs(curr_g - prev_g);

      diff_b = abs(curr_b - prev_b);

​

      // Put the difference pixel in the pixels array

      pixels[i + 0] = diff_r;

      pixels[i + 1] = diff_g;

      pixels[i + 2] = diff_b;

​

      let diffs = diff_r + diff_g + diff_b;

      if (diffs > 200) {

        pixels[i + 0] = 255;

        pixels[i + 1] = 255;

        pixels[i + 2] = 255;

      } else {

        pixels[i + 0] = 0;

        pixels[i + 1] = 0;

        pixels[i + 2] = 0;

      }

​

      // The current pixel becomes

      // the previous pixel for the next frame

      previous_frame[i + 0] = curr_r;

      previous_frame[i + 1] = curr_g;

      previous_frame[i + 2] = curr_b;

    }

  }

​

  // Write the pixels array to the canvas

  updatePixels();

}

​

​