void testApp::drawNollSinusoids()
{
    float amplitude = 30.0;
    float phase = PI;
 
    output.setColor(0x333333);
    output.setLineWidth(1.0);
    output.noFill();
    for (int i = 0; i < 90; i++) {
        float period = 30 / PI;
        float offsetY =  15 + i * 5.8;
        output.beginShape();
 
        for (int x = 0; x < windowWidth; x++) {
            float y = sin(x / period + phase);
 
            output.curveVertex(x, amplitude * y + amplitude + offsetY);
            period += 0.031;
        }
        output.endShape();
    }
}

int paddleWidth = 100;
int ballSize = 20;
// all the following deal with center of object
int compPos, userPos;
int ballX, ballY, ballDX, ballDY;
float multiplier = 1.0; // speed up ball
 
void setup() {
  size(400,400);
  frameRate(30);
  noStroke();
 
  resetGame();
}
 
void resetGame() {
  multiplier = 1.0;
  compPos = (height - paddleWidth) / 2;
  userPos = compPos;
  ballX = (width - ballSize) / 2;
  ballY = (height - ballSize) / 2;
  ballDX = 0;
  ballDY = 0;
}
 
void draw() {
  background(#333333);
  fill(#f0f0f0);
 
  // update ball position
  ballX += ballDX * multiplier;
  ballY += ballDY * multiplier;
  multiplier += 0.003;
 
  // check for collision
  // computer side
  if (ballX - ballSize / 2 < 10) {
    if (abs(ballY - compPos)  width - 10) {
    if (abs(ballY - userPos) <= paddleWidth / 2) {
      ballDX = -ballDX;
      ballX = height - 10 - ballSize / 2;
      ballDY += (ballY - userPos) / 5;
    } else {
      resetGame();
    }
  }
  // top
  if (ballY - ballSize / 2  height) {
    ballDY = -ballDY;
    ballY = height - ballSize / 2;
  }
 
  // update user position
  userPos = mouseY;
  if (userPos  height - paddleWidth / 2)
    userPos = height - paddleWidth / 2;
 
  // update computer position
  float compDY = (ballY - compPos);
  if (compDY > 10)
    compDY = 10;
  compPos += compDY;
  if (compPos  height - paddleWidth / 2)
    compPos = height - paddleWidth / 2;
 
  // draw computer paddle
  rect(0, compPos - paddleWidth / 2, 10, paddleWidth);
  // draw user paddle
  rect(width - 10, userPos - paddleWidth / 2, 10, paddleWidth);
 
  // draw ball
  ellipse(ballX, ballY, ballSize, ballSize);
}
 
void mousePressed() {
  if (ballDX == 0 && ballDY == 0) {
    ballDX = 5;
    ballDY = 2;
  }
}