1 files changed, 137 insertions, 79 deletions
diff --git a/site/themes/sine/static/js/background.js b/site/themes/sine/static/js/background.js
index e9b61a2..174820a 100644
--- a/site/themes/sine/static/js/background.js
+++ b/site/themes/sine/static/js/background.js
@@ -1,82 +1,140 @@
-document.addEventListener("DOMContentLoaded", () => {
-  const canvas = document.getElementById("background");
-  if (!canvas) return;
-  const ctx = canvas.getContext("2d");
-
-  // Grab config from the embedded <script>
-  const configEl = document.getElementById("background-config");
-  const config = configEl ? JSON.parse(configEl.textContent) : {};
-
-  // Use config values with defaults as fallback
-  const spacing    = config.spacing    ?? 24;
-  const maxRadius  = config.maxRadius  ?? 8;
-  const baseOffset = config.baseOffset ?? 120;
-  const freq       = config.freq       ?? 0.008;
-  const speed      = config.speed      ?? 0.02;
-
-  const baseAmp    = config.baseAmp    ?? 100;
-  const env1Freq   = config.envelope1Freq ?? 0.002;
-  const env1Amp    = config.envelope1Amp  ?? 120;
-  const env2Freq   = config.envelope2Freq ?? 0.0005;
-  const env2Amp    = config.envelope2Amp  ?? 200;
-
-  let t = parseFloat(localStorage.getItem("waveProgress")) || 0;
-  let widthCss = window.innerWidth;
-  let heightCss = window.innerHeight;
-  let pixelRatio = window.devicePixelRatio || 1;
-
-  function resize() {
-    widthCss = window.innerWidth;
-    heightCss = window.innerHeight;
-    pixelRatio = window.devicePixelRatio || 1;
-
-    canvas.width = Math.floor(widthCss * pixelRatio);
-    canvas.height = Math.floor(heightCss * pixelRatio);
-    canvas.style.width = widthCss + "px";
-    canvas.style.height = heightCss + "px";
-    ctx.setTransform(pixelRatio, 0, 0, pixelRatio, 0, 0);
+const canvas = document.getElementById("background");
+const ctx = canvas.getContext("2d");
+
+// Resize Handling
+
+function resizeCanvas() {
+  canvas.width = window.innerWidth;
+  canvas.height = window.innerHeight;
+}
+
+resizeCanvas();
+window.addEventListener("resize", resizeCanvas);
+
+// Custom Math Functions
+
+function customFunction(x, t, c) {
+  const centerY = c.height / 2;
+
+  return centerY + (30 + 10 * Math.sin(0.05 * t)) *
+    Math.sin(0.006 * x - 0.4 * t) +
+    20 * Math.sin(0.011 * x - 0.25 * t + 2);
+}
+
+function customFunctionTwo(x, t, c) {
+  const centerY = c.height / 2;
+
+  return centerY + (
+    40 * Math.sin(0.005 * x - 0.6 * t) +
+    25 * Math.sin(0.009 * x - 0.35 * t + 2) +
+    15 * Math.sin(0.015 * x - 0.2 * t + 5)
+  );
+}
+
+// Math Function Drawing Engine
+
+// Get time from localstorage if it exists
+let time = parseFloat(localStorage.getItem("time")) || 0;
+
+function drawFunction(fn, color) {
+
+  ctx.beginPath();
+
+  // Start at left edge
+  ctx.moveTo(0, fn(0, time, canvas));
+
+  // Plot function across entire width
+  for (let x = 0; x < canvas.width; x++) {
+    const y = fn(x, time, canvas);
+    ctx.lineTo(x, y);
+  }
+
+  ctx.strokeStyle = color;
+  ctx.lineWidth = 2;
+  ctx.stroke();
+}
+
+// Starfield Drawing Engine
+
+function makeStarfield(width, height, count, seed = 1) {
+  function rng() {
+    seed |= 0;
+    seed = seed + 0x6D2B79F5 | 0;
+    let t = Math.imul(seed ^ seed >>> 15, 1 | seed);
+    t ^= t + Math.imul(t ^ t >>> 7, 61 | t);
+    return ((t ^ t >>> 14) >>> 0) / 4294967296;
+  }
+
+  const stars = [];
+
+  for (let i = 0; i < count; i++) {
+    stars.push({
+      x: rng() * width,
+      y: rng() * height,
+      size: rng() * 1.5 + 0.3,
+      base: 0.5 + rng() * 0.3,
+      phase: rng() * Math.PI * 2,
+      speed: 0.5 + rng() * 2.0
+    });
+  }
+
+  return stars;
+}
+
+function drawStars(ctx, stars, time, color) {
+  ctx.fillStyle = color;
+
+  for (const s of stars) {
+    const twinkle = Math.sin(time * s.speed + s.phase) * 0.5 + 0.5;
+    const alpha = s.base + twinkle * 0.5;
+
+    ctx.globalAlpha = alpha;
+    ctx.fillRect(s.x, s.y, s.size, s.size);
   }
-  window.addEventListener("resize", resize);
-  resize();
-
-  function draw() {
-    const styles = getComputedStyle(document.documentElement);
-    const fg = styles.getPropertyValue("--fg").trim();
-
-    ctx.clearRect(0, 0, widthCss, heightCss);
-    ctx.fillStyle = fg;
-
-    for (let x = 0; x <= widthCss + spacing; x += spacing) {
-      // envelope: controls crest variance
-      const envelope =
-        baseAmp
-        + Math.sin(x * env1Freq + t * 0.1) * env1Amp
-        + Math.sin(x * env2Freq + t * 0.05) * env2Amp;
-
-      const waveY = heightCss - (Math.sin(x * freq + t) * envelope + baseOffset);
-      // const waveY = Math.max(heightCss - 50, heightCss - (Math.sin(x * freq + t) * envelope + baseOffset));
-
-      for (let y = heightCss; y >= 0; y -= spacing) {
-        const dist = Math.max(0, y - waveY);
-        const radius = Math.min(maxRadius, dist / 40);
-        if (radius > 0.2) {
-          ctx.beginPath();
-          // ctx.arc(x + spacing / 2, y - spacing / 2, radius, 0, Math.PI * 2);
-          ctx.fillRect(
-            x + spacing / 2 - radius,
-            y - spacing / 2 - radius,
-            radius * 2,
-            radius * 2
-          );
-          ctx.fill();
-        }
-      }
-    }
-
-    t += speed;
-    localStorage.setItem("waveProgress", t);
-    requestAnimationFrame(draw);
+
+  ctx.globalAlpha = 1;
+}
+
+// Animation Loop
+
+let animationId = null;
+let lastTime = 0;
+
+const stars = makeStarfield(canvas.width, canvas.height, 600, 42);
+
+function animate(timestamp) {
+  animationId = requestAnimationFrame(animate);
+
+  // First frame setup
+  if (!lastTime) {
+    lastTime = timestamp;
   }
 
-  draw();
-});
+  // Time difference in seconds
+  const delta = (timestamp - lastTime) / 1000;
+  lastTime = timestamp;
+
+  // Advance time
+  time += delta;
+
+  // save time in localstorage
+  localStorage.setItem("time", time);
+
+  // Get colors
+  const styles = getComputedStyle(document.documentElement);
+  const fgColor = styles.getPropertyValue("--fg").trim();
+
+  // Clear the canvas
+  ctx.clearRect(0, 0, canvas.width, canvas.height);
+
+  // Draw Stars
+  drawStars(ctx, stars, time, fgColor);
+
+  // Draw first custom function
+  drawFunction(customFunction, fgColor);
+
+  // draw second custom function
+  drawFunction(customFunctionTwo, fgColor);
+}
+
+animate(0);