void setup()
{
  size(displayWidth, displayHeight, P2D);
}

void draw()
{
  loadPixels();
  for(int iY = 0; iY < displayHeight; ++iY)
  {
    for(int iX = 0; iX < displayWidth; ++iX)
    {
      final int iIndex = (iX + iY * displayWidth);
      pixels[iIndex] = color(random(256), random(256), random(256));
    }
  }
  updatePixels();
}