104 lines
2.4 KiB
JavaScript
104 lines
2.4 KiB
JavaScript
const canvas = document.getElementById("myCanvas");
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const ctx = canvas.getContext("2d");
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let centerX, centerY;
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function setCanvasSize() {
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canvas.width = window.innerWidth;
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canvas.height = window.innerHeight;
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centerX = canvas.width / 2;
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centerY = canvas.height / 2;
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}
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setCanvasSize();
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window.addEventListener("resize", setCanvasSize);
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const degPerSec = 0.0000015;
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const maxTime = 99999999;
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let startingRotation = 0.5;
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let currentFrame = 0;
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let fps = 0;
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let fpsCounter = 0;
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let lastTime = 0;
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function render(timestamp) {
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if (!startTime) startTime = timestamp;
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const elapsedTime = timestamp - startTime;
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clearCanvas();
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drawSpiral(startingRotation + degPerSec * elapsedTime);
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if (elapsedTime < maxTime) {
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requestAnimationFrame(render);
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}
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displayFPS(timestamp);
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}
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let startTime = null;
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requestAnimationFrame(render);
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function clearCanvas() {
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ctx.clearRect(0, 0, canvas.width, 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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function drawSpiral(angle) {
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const startColor = [45, 129, 252];
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const endColor = [252, 3, 98];
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const distanceMultiplier = 5;
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const maxIterations = 200;
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let cX = centerX;
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let cY = centerY;
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for (let n = 0; n < maxIterations; n++) {
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ctx.beginPath();
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ctx.moveTo(cX, cY);
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const nColor = lerpRGB(startColor, endColor, Math.cos(rad(n / 2)));
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const nAngle = n * angle + Math.sin(angle * (n - angle * 100) * 2);
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const radius = distanceMultiplier * n;
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const xCoord = radius * Math.cos(nAngle) + centerX;
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const yCoord = radius * Math.sin(nAngle) + centerY;
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ctx.lineTo(xCoord, yCoord);
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cX = xCoord;
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cY = yCoord;
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// ctx.arc(xCoord, yCoord, 8, 0, 2 * Math.PI);
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ctx.strokeStyle = colourToText(nColor);
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ctx.lineWidth = 5;
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ctx.lineCap = "round";
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ctx.stroke();
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}
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}
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function rad(degrees) {
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return degrees * (Math.PI / 180);
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}
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function lerpRGB(a, b, t) {
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const result = [0, 0, 0];
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for (let i = 0; i < 3; i++) {
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result[i] = (1 - t) * a[i] + t * b[i];
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}
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return result;
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}
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function displayFPS(timestamp) {
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// Calculate FPS
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fpsCounter++;
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if (timestamp > lastTime + 1000) {
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fps = Math.round((fpsCounter * 1000) / (timestamp - lastTime));
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fpsCounter = 0;
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lastTime = timestamp;
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}
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// Display FPS
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ctx.fillStyle = "white";
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ctx.font = "16px Arial";
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ctx.fillText(`FPS: ${fps}`, 10, 30);
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}
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function colourToText(colour) {
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return `rgb(${colour[0]}, ${colour[1]}, ${colour[2]})`;
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}
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