Simple Gravity with a Bounce
<!doctype html> <html lang="en"> <head> <script type="text/javascript"> window.addEventListener('load', eventWindowLoaded, false); function eventWindowLoaded() {//w ww . j a v a2s. c o m canvasApp(); } function canvasApp() { function drawScreen () { context.fillStyle = '#EEEEEE'; context.fillRect(0, 0, theCanvas.width, theCanvas.height); //Box context.strokeStyle = '#000000'; context.strokeRect(1, 1, theCanvas.width-2, theCanvas.height-2); ball.velocityy += gravity; if ((ball.y + ball.radius) > theCanvas.height) { ball.velocityy = -(ball.velocityy) } ball.y += ball.velocityy; ball.x += ball.velocityx; context.fillStyle = "#000000"; context.beginPath(); context.arc(ball.x,ball.y,ball.radius,0,Math.PI*2,true); context.closePath(); context.fill(); } let speed = 5; let gravity = .1; let angle = 295; let radians = angle * Math.PI/ 180; let radius = 15; let vx = Math.cos(radians) * speed; let vy = Math.sin(radians) * speed; theCanvas = document.getElementById('canvasOne'); context = theCanvas.getContext('2d'); let p1 = {x:20,y:theCanvas.height-radius}; let ball = {x:p1.x, y:p1.y, velocityx: vx, velocityy:vy, radius:radius}; function gameLoop() { window.setTimeout(gameLoop, 20); drawScreen() } gameLoop(); } </script> </head> <body> <div style="position: absolute; top: 50px; left: 50px;"> <canvas id="canvasOne" width="500" height="500"> Your browser does not support the HTML 5 Canvas. </canvas> </div> </body> </html>