PGraphics result;

public void settings() {
  size(512, 512, P2D);
}

public void setup() {

  result = createGraphics(512, 512, P2D);
  result.beginDraw();
  result.endDraw();
}

public void draw() {

  // a white background...
  background(255);
  // just became black...
  result.clear();
}