For DATT 1100 - demonstration of "layering"

target_practice_modified.pde

PGraphics target;

void setup() {
  size(500, 400);
  target = createGraphics(width, height);
  target.beginDraw();
  target.background(0);
  target.stroke(255);
  target.fill(255);
  target.ellipse(250, 200, 250, 250);
  target.stroke(255, 0, 0);
  target.fill(255, 0, 0);
  target.ellipse(250, 200, 200, 200);
  target.stroke(0, 0, 255);
  target.fill(0, 0, 255);
  target.ellipse(250, 200, 150, 150);
  target.stroke(255);
  target.fill(255);
  target.ellipse(250, 200, 100, 100);
  target.stroke(255, 0, 0);
  target.fill(255, 0, 0);
  target.ellipse(250, 200, 50, 50);
  target.endDraw();
  noCursor();
}

void draw() {
  image(target, 0, 0);

  if (mousePressed) {
    stroke(0);
    fill(255, 255, 0);
    ellipse(mouseX, mouseY, 10, 10);
  } else {
    stroke(0);
    fill(255);
    ellipse(mouseX, mouseY, 25, 25);
    stroke(0);
    line(mouseX-10, mouseY, mouseX+10, mouseY);
    stroke(0);
    line(mouseX, mouseY-10, mouseX, mouseY+10);
  }
}

void mousePressed() {
  target.beginDraw();
  target.fill(0);
  target.stroke(0);
  target.ellipse(mouseX, mouseY, 10, 10);
  target.endDraw();
}