<?php

// Set up game parameters
$paddleWidth = 10;
$paddleHeight = 100;
$ballSize = 10;

// Create canvas
$canvasWidth = 400;
$canvasHeight = 200;
echo "<canvas id='pong' width='$canvasWidth' height='$canvasHeight'></canvas>";

// Paddle positions
$paddle1Y = $canvasHeight/2 - $paddleHeight/2; 
$paddle2Y = $canvasHeight/2 - $paddleHeight/2;

// Ball position
$ballX = $canvasWidth/2;
$ballY = $canvasHeight/2;
$ballSpeedX = 5;
$ballSpeedY = 3;

// Main game loop
while (true) {

  // Move ball
  $ballX += $ballSpeedX;
  $ballY += $ballSpeedY;

  // Bounce off top and bottom
  if ($ballY <= 0 || $ballY >= $canvasHeight) {
    $ballSpeedY = -$ballSpeedY; 
  }

  // Draw scene
  echo "<script>
    var ctx = document.getElementById('pong').getContext('2d');
    ctx.clearRect(0, 0, $canvasWidth, $canvasHeight);
    ctx.fillStyle = 'white';
    
    // Draw ball
    ctx.beginPath();
    ctx.arc($ballX, $ballY, $ballSize, 0, 2 * Math.PI); 
    ctx.fill();

    // Draw paddles
    ctx.fillRect(0, $paddle1Y, $paddleWidth, $paddleHeight);
    ctx.fillRect($canvasWidth - $paddleWidth, $paddle2Y, $paddleWidth, $paddleHeight);
  </script>";

  usleep(10000); // Sleep for 10ms
}

?>