vector101/cross.html at main · sathonay/vector101 · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Cross product viewer</title>
</head>
<body>
<canvas id="canva"></canvas>
<script src="utils.js"></script>
<script>
	let vecA = {
		x1: canva.width / 2,
		y1: canva.height / 2,
		x2: canva.width / 2,
		y2: canva.height / 2 - 100,
		color: "blue"
	};

	let vecB = {
		x1: canva.width / 2,
		y1: canva.height / 2,
		x2: canva.width / 2 + 100,
		y2: canva.height / 2,
		color: "red"
	};

	function drawInfos() {
		ctx.font = "1.5rem serif";
		var yoffset = 0;
		ctx.fillText("Drag left click: move blue vector direction",
			0,
			(yoffset += 25)
		);
		ctx.fillText("Drag right click: move blue vector direction",
			0,
			(yoffset += 25)
		);
		ctx.fillText("CTRL + Drag left click: both vector origine",
			0,
			(yoffset += 25)
		);
		var yoffset = 0;
		var va = vector(vecA);
		var vb = vector(vecB);
		ctx.fillText("blue vec: x: " + va.x + " y: " + -va.y,
			canva.width / 2,
			canva.height / 2  + (yoffset += 25)
		);
		ctx.fillText("red vec: x: " + vb.x + " y: " + -vb.y,
			canva.width / 2,
			canva.height / 2  + (yoffset += 25)
		);
		ctx.fillText("cross product: " + cross(va, vb),
			canva.width / 2,
			canva.height / 2  + (yoffset += 25)
		);
	}

	function render() {
		clearCanva();
		drawVector(vecA);
		drawVector(vecB);
		drawInfos();
	}

	window.addEventListener("resize", (event) => {
		fullScreenCanva();
		render();
	})

	window.addEventListener("load", (event) => {
		fullScreenCanva();
		render();
	});

	canva.addEventListener('contextmenu', (event) => {
		event.preventDefault()
		render();
	});

	canva.addEventListener("mouseup", (event) => {
		render();
	})

	canva.addEventListener("mousemove", (event) => {
		if (event.ctrlKey && event.buttons == 1) {
			vecA.x1 = event.clientX;
			vecA.y1 = event.clientY;
			vecB.x1 = event.clientX;
			vecB.y1 = event.clientY;
		}
		if (!event.ctrlKey && event.buttons == 1) {
			vecA.x2 = event.clientX;
			vecA.y2 = event.clientY;
		}
		if (!event.ctrlKey && event.buttons == 2) {
			vecB.x2 = event.clientX;
			vecB.y2 = event.clientY;
		}
		render();
	});
</script>
</body>
</html>