Demonstration Faking Non-Double-Buffered Animation

flicker.pde

float x = 200;
float y = 150;
float r = 24;

float dx = 16;
float dy = 8;


void setup() {
  size(400, 300);
  pixelDensity(2);
  frameRate(24);
  // noLoop();
  background(0);
}

void keyPressed() {
  if (key == ' ') redraw();
  if (key == 's') loop();
}

void mousePressed() {
  redraw(); 
}

void draw() {
  
  if (frameCount % 2 == 0) {
    background(0);
  } else {
    fill(255);
    stroke(255);
    circle(x, y, r*2);

    x += dx;
    y += dy;
    if (x < r || x > width - r) dx *= -1;
    if (y < r || y > height - r) dy *= -1;
  }
}