* Draw a text (wireframe) using a LOGO / TURTLE type language with very small code

 * see my other related sketchs

 *

 * jump table is optimized out by using the result of the jump table directly from an array

 * this is smallest and will work great on platforms such as x86 (because jumping can cost quite a lot on instructions size)

 * on x86 the stack can be used to push the commands and pop every iteration for example

 */

​

let lineLength = 64

let index = 0

​

function computeStartPosition() {

  // compute start drawing position given as a precomputed index (a single instruction on x86)

  let x = width / 2 - lineLength * 5 / 2 + lineLength

  let y = height / 2 + lineLength / 2

  // fix the pixels to the grid

  x = Math.floor(x)

  y = Math.floor(y)

​

  index = (x + y * width) * 4

  // 

}

​

function setup() {

  createCanvas(512, 512);

  background(0);

  computeStartPosition()

  drawOnce()

}

​

function drawOnce() {

  let commands = [-width, -1, width, 1, 0, -width, 1, 0, 1, width - 1, 1]

  loadPixels()

  for (let l = 0; l < commands.length; l += 1) {

    let r = commands[l]

​

    let c = abs(r) << 8

    for (let i = 0; i < lineLength; i += 1) {

      pixels[index + 0] = c

      pixels[index + 1] = c

      pixels[index + 2] = c

​

      if (r == 0) {

        index += 4

      } else {

        index += r * 4

      }

    }

  }

  updatePixels() 

}

​

function draw() {

​

}