let rows = 400;

​

let current;

let previous;

​

let damping = 0.9;

​

function setup() {

    createCanvas(400, 400);

    current = Create2DArray(rows);

    previous = Create2DArray(rows);

    for (let i = 0; i < cols; i++) {

        for (let j = 0; j < rows; j++) {

            current[i][j] = 100;

            previous[i][j] = 100;

        }

    }

}

​

function draw() {

    background(0);

    loadPixels();

​

    for (let i = 1; i < cols - 1; i++) {

        for (let j = 1; j < rows - 1; j++) {

            current[i][j] = (previous[i - 1][j] +

                    previous[i + 1][j] +

                    previous[i][j - 1] +

                    previous[i][j + 1]) / 2 -

                current[i][j];

​

            let index = i + j * cols;

            pixels[index] = color(current[i][j]);

        }

    }

​

    updatePixels();

    let temp = previous;

    previous = current;

    current = temp;

}

​

​

function Create2DArray(rows) {

  var arr = [];

​

  for (var i=0;i<rows;i++) {

     arr[i] = [];

  }

​

  return arr;

}