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66 lines
1.4 KiB
66 lines
1.4 KiB
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8" />
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<title>MDN Breakout</title>
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<style>
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* { padding: 0; margin: 0; }
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canvas { background: #eee; display: block; margin: 0 auto; }
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</style>
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</head>
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<body>
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<canvas id="myCanvas" width="480" height="320"></canvas>
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<script>
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(function() {
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var canvas = document.getElementById("myCanvas");
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var ctx = canvas.getContext("2d");
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var ballRadius = 10;
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var ballColor = '#0095DD';
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var x = canvas.width/2;
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var y = canvas.height-30;
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var dx = 2;
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var dy = -2;
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function randInt(min, max) {
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min = Math.ceil(min);
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max = Math.floor(max);
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return Math.floor(Math.random() * (max - min)) + min;
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}
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function randColor() {
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return 'rgba(' + ([
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randInt(0, 255),
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randInt(0, 255),
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randInt(0, 255)
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].map(function(elem, i) { return '' + elem; }).join(',')) + ', 1.0)'
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}
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function drawBall() {
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ctx.beginPath();
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ctx.arc(x, y, ballRadius, 0, Math.PI*2);
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ctx.fillStyle = ballColor;
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ctx.fill();
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ctx.closePath();
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}
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function draw() {
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ctx.clearRect(0, 0, canvas.width, canvas.height);
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drawBall();
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x += dx;
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y += dy;
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if(y + dy > canvas.height-ballRadius || y + dy < ballRadius) {
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dy = -dy;
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ballColor = randColor();
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}
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if(x + dx > canvas.width-ballRadius || x + dx < ballRadius) {
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dx = -dx;
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ballColor = randColor();
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}
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}
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setInterval(draw, 10);
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})();
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</script>
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</body>
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</html>
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