42 lines
		
	
	
		
			673 B
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			42 lines
		
	
	
		
			673 B
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
let canvas = document.querySelector("#canvas");
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let ctx = canvas.getContext("2d");
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let width = canvas.width;
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let height = canvas.height;
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let x = 0;
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let y = 0;
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let forwards = true;
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function drawCircle(x, y) {
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  ctx.fillStyle = "rgb(0, 128, 255)";
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  ctx.beginPath();
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  ctx.arc(x, y, 10, 0, Math.PI * 2, false);
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  ctx.fill();
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}
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function update() {
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 if (forwards === true) {
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  x += 1;
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  y = 10
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}
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 else{
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  x -= 1;
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  y = 10
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 }
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 if (x >= 300){
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  forwards = false;
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 }
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 if (x <= 0){
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  forwards = true
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 }
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// y += 1; 
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// x %= width;
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// y %= height;
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}
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function draw() {
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     ctx.clearRect(0, 0, width, height);
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     drawCircle(x, y);
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}
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setInterval(() => {
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update();
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draw();
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}, 1); |