Improved Matrix Mapper Code

matrix-mapper.epe

// Improved Matrix Mapper Code
function (pixelCount) {
  width = 16    // width of LED panel
  angle = 90   // rotation in degrees: 0, 90, 180, 270
  flip = true   // does the rendering need to be flipped?
  
  height = width/pixelCount
  
  map = []
  for (i = 0; i < pixelCount; i++) {
    y = Math.floor(i / width)
    x = i % width
    x = y % 2 == 1 ? width - 1 - x : x //zigzag
    map.push([x, y])
  }
  
  if (flip) {
    for (i = 0; i < map.length; i++) {
      map[i][0] = (width - 1) - map[i][0]; // mirror X
    }
  }

    // helper: apply 90°-step rotation
  function rotate90(x, y, angle) {
    if (angle === 90)   return [y,        width - 1 - x]
    if (angle === 180)  return [width - 1 - x, height - 1 - y]
    if (angle === 270)  return [height - 1 - y, x]
    return [x, y] // 0° or default
  }

  // apply rotation of angle
  for (i = 0; i < map.length; i++) {
    p = rotate90(map[i][0], map[i][1], angle)
    map[i][0] = p[0]
    map[i][1] = p[1]
  }
  
  return map
}