<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Test Canvas Game</title>
<style>
body {
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<canvas id="gc">
</canvas>
<script>
//setup
c = document.getElementById("gc");
cc = c.getContext('2d');
c.height = window.innerHeight;
c.width = window.innerWidth;
c.addEventListener('mousemove', function(e) {
p1y = e.clientY - ph / 2;
});
lastTime = Date.now();
deltaTime = 0;
fps = 0;
//gameplay variables
p1y = p2y = 40;
pt = 10;
ph = 100;
bx = by = xv = yv = 500;//just making sure bx and by exist, they'll be reset when the game first starts
bd = 12;
score1 = score2 = 0;
ais = 5;
function reset() {
bx = c.width / 2;
by = c.height / 2;
xv = -xv;
yv = 4;
}
function update() {
//measure timing
now = Date.now();
deltaTime = (now-lastTime)/1000;
lastTime = now;
fps = 1/deltaTime;
//move ball
bx += xv * deltaTime;
by += yv * deltaTime;
if (by < 0 && yv < 0) {
yv = -yv;
}
if (by > c.height && yv > 0) {
yv = -yv;
}
//check collision with sides for scoring
if (bx > c.width) {
if (by > p2y && by < p2y + ph) {
xv = -xv;
dy = by - (p2y + ph / 2);
yv = dy * 10;
} else {
score1++;
reset();
}
}
if (bx < 0) {
if (by > p1y && by < p1y + ph) {
xv = -xv;
dy = by - (p1y + ph / 2);
yv = dy * 10;//.3
} else {
score2++
reset();
}
}
//ai
if (p2y + ph / 2 < by) {
p2y += ais;
} else {
p2y -= ais;
}
//draw background
var gradient=cc.createLinearGradient(0,0,c.width,c.height);
gradient.addColorStop("0","#ff146e");
gradient.addColorStop("1","#145aff");
cc.fillStyle=gradient;
// cc.fillStyle="white";
cc.fillRect(0, 0, c.width, c.height);
//draw paddles
cc.fillStyle = 'cyan';
cc.fillRect(0, p1y, pt, ph);
cc.fillStyle = 'red';
cc.fillRect(c.width - pt, p2y, pt, ph);
//draw ball
cc.fillStyle = 'lightgreen';
cc.fillRect(bx - bd / 2, by - bd / 2, bd, bd);
//draw scores
cc.fillStyle = 'white';
cc.font = '20px Times'
cc.fillText(score1, 100, 100);
cc.fillText(score2, c.width - 100, 100);
//draw framerate
cc.fillText("framerate: " + fps, c.width/2 - 100, 100);
window.requestAnimationFrame(update); //Keep the game running
}
reset() //prepare the game
update() //start the game
</script>
</body>
</html>