72 lines
1.9 KiB
HTML
72 lines
1.9 KiB
HTML
<!DOCTYPE html>
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<html>
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<!-- ahhh -->
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<body style="margin: 0; overflow: hidden">
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<canvas
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id="myCanvas"
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width="10"
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height="10"
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style="display: block; box-sizing: border-box"
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>
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Your browser does not support the HTML5 canvas tag.</canvas
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>
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<script>
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let c = document.getElementById("myCanvas");
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let ctx = c.getContext("2d");
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ctx.canvas.width = window.innerWidth;
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ctx.canvas.height = window.innerHeight;
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let deg_per_sec = 30;
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let time = 120;
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let fps = 60;
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centerX = ctx.canvas.width / 2;
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centerY = ctx.canvas.height / 2;
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rotation = 0; //was = j = angle
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currentFrame = 0; //was = i
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function render() {
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if (currentFrame < time / (1 / fps)) {
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setTimeout(() => {
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render();
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render_clear();
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DrawPolygon(4, 300, rotation, "red");
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}, 1000 / fps);
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rotation += deg_per_sec / fps; // was = j = angle, now = rotation
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currentFrame += 1; // was = i
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}
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}
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render();
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function DrawPolygon(sides, width, rotation, colour) {
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ctx.beginPath();
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ctx.moveTo(
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centerX + width * Math.cos((rotation * Math.PI) / 180),
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centerY + width * Math.sin((rotation * Math.PI) / 180)
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);
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for (var i = 1; i <= sides; i += 1) {
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ctx.lineTo(
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centerX + width * Math.cos( (i * 2 * Math.PI) / sides + (rotation * Math.PI) / 180 ),
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centerY + width * Math.sin( (i * 2 * Math.PI) / sides + (rotation * Math.PI) / 180 )
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);
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}
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ctx.strokeStyle = colour;
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ctx.lineWidth = 1;
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ctx.stroke();
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}
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function render_clear() {
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ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
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ctx.fillStyle = "black";
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ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height);
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}
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</script>
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</body>
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</html>
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