Array 2D.

Array 2D.

Demonstrates the syntax for creating a two-dimensional (2D) array. Values in a 2D array are accessed through two index values. 2D arrays are useful for storing images. In this example, each dot is colored in relation to its distance from the center of the image.

float[][] distances;
float maxDistance;
int spacer;

void setup() {
  size(640, 360);
  maxDistance = dist(width/2, height/2, width, height);
  distances = new float[width][height];
  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      float distance = dist(width/2, height/2, x, y);
      distances[x][y] = distance/maxDistance * 255;
  spacer = 10;
  noLoop();  // Run once and stop

void draw() {
  // This embedded loop skips over values in the arrays based on
  // the spacer variable, so there are more values in the array
  // than are drawn here. Change the value of the spacer variable
  // to change the density of the points
  for (int y = 0; y < height; y += spacer) {
    for (int x = 0; x < width; x += spacer) {
      point(x + spacer/2, y + spacer/2);

Functions Used


Sets the color used to draw lines and borders around shapes

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Defines the dimension of the display window width and height in units of pixels

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Draws a point, a coordinate in space at the dimension of one pixel

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The setup() function is run once, when the program starts

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Sets the width of the stroke used for lines, points, and the border around shapes

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Stops Processing from continuously executing the code within draw()

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Called directly after setup(), the draw() function continuously executes the lines of code contained inside its block until the program is stopped or noLoop() is called

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The background() function sets the color used for the background of the Processing window

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Calculates the distance between two points

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