HTML Canvas Animation Fountain

Description

HTML Canvas Animation Fountain

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<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Fountain</title>
  </head>//from   w w  w .j a v  a  2s.c o m
  <body>
    <canvas id="canvas" width="400" height="400"></canvas>
    <script>
class Ball {
  constructor() {
    this.x = 0;
    this.y = 0;
    this.radius = 2;
    this.vx = 0;
    this.vy = 0;
    this.rotation = 0;
    this.scaleX = 1;
    this.scaleY = 1;
    this.color = 'blue';
    this.lineWidth = 1;
  }

  draw(context) {
    context.save();
    context.translate(this.x, this.y);
    context.rotate(this.rotation);
    context.scale(this.scaleX, this.scaleY);
    
    context.lineWidth = this.lineWidth;
    context.fillStyle = this.color;
    context.beginPath();
    //x, y, radius, start_angle, end_angle, anti-clockwise
    context.arc(0, 0, this.radius, 0, Math.PI * 2, true);
    context.closePath();
    context.fill();
    if (this.lineWidth > 0) {
      context.stroke();
    }
    context.restore();
  }
}
    window.onload = function () {
      var canvas = document.getElementById('canvas'),
          context = canvas.getContext('2d'),
          balls = [],
          numBalls = 80,
          gravity = 0.5;

      for (var ball, i = 0; i < numBalls; i++) {
        ball = new Ball();
        ball.x  = canvas.width / 2;
        ball.y  = canvas.height;
        ball.vx = Math.random() * 2 - 1;
        ball.vy = Math.random() * -10 - 10;
        balls.push(ball);
      }

      function draw (ball) {
        ball.vy += gravity;
        ball.x += ball.vx;
        ball.y += ball.vy;
        if (ball.x - ball.radius > canvas.width ||
            ball.x + ball.radius < 0 ||
            ball.y - ball.radius > canvas.height ||
            ball.y + ball.radius < 0) {
          ball.x = canvas.width / 2;
          ball.y = canvas.height;
          ball.vx = Math.random() * 2 - 1;
          ball.vy = Math.random() * -10 - 10;
        }
        ball.draw(context);
      }

      (function drawFrame () {
        window.requestAnimationFrame(drawFrame, canvas);
        context.clearRect(0, 0, canvas.width, canvas.height);

        balls.forEach(draw);
      }());
    };
    </script>
  </body>
</html>



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