From 18639412c260c2af1d4268cb3a3209e208276005 Mon Sep 17 00:00:00 2001
From: triethyl <triethylammonium@pm.me>
Date: Sun, 15 Feb 2026 23:37:22 -0500
Subject: changed background

---
 site/themes/sine/static/js/background.js        | 216 +++++++++++++++---------
 site/themes/sine/static/js/old-background.js    |  82 +++++++++
 site/themes/sine/static/js/oldish-background.js |  90 ++++++++++
 3 files changed, 309 insertions(+), 79 deletions(-)
 create mode 100644 site/themes/sine/static/js/old-background.js
 create mode 100644 site/themes/sine/static/js/oldish-background.js

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);
diff --git a/site/themes/sine/static/js/old-background.js b/site/themes/sine/static/js/old-background.js
new file mode 100644
index 0000000..e9b61a2
--- /dev/null
+++ b/site/themes/sine/static/js/old-background.js
@@ -0,0 +1,82 @@
+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);
+  }
+  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);
+  }
+
+  draw();
+});
diff --git a/site/themes/sine/static/js/oldish-background.js b/site/themes/sine/static/js/oldish-background.js
new file mode 100644
index 0000000..3a55a0f
--- /dev/null
+++ b/site/themes/sine/static/js/oldish-background.js
@@ -0,0 +1,90 @@
+document.addEventListener("DOMContentLoaded", () => {
+  const canvas = document.getElementById("background");
+
+  if (canvas.getContext) {
+    const ctx = canvas.getContext("2d");
+
+    // Source - https://stackoverflow.com/a/58673385
+    // Posted by Sanxofon, modified by community. See post 'Timeline' for change history
+    // Retrieved 2026-02-15, License - CC BY-SA 4.0
+    
+    var w = canvas.width; // Canvas width => Frequency is relative to this
+    var h = canvas.height/2; // Canvas height over two => Amplitude: Volume
+    var f=1; // How many cycles per canvas width => Frequency: Tone & Speed
+    // Calculates y position from x
+    function calcSineY(x) {
+      // This is the meat (unles you are vegan)
+      // Note that:
+      // h is the amplitude of the wave
+      // x is the current x value we get every time interval
+      // 2 * PI is the length of one cycle (full circumference)
+      // f/w is the frequency fraction
+      return h - h * Math.sin( x * 2 * Math.PI * (f/w) );
+    }
+    function drawSine(x){
+      ctx.clearRect(0, 0, w, h*2);
+      //draw x axis
+      ctx.beginPath(); // Draw a new path
+      ctx.strokeStyle = "green"; // Pick a color
+      ctx.moveTo(0,h); // Where to start drawing
+      ctx.lineTo(w,h); // Where to draw to
+      ctx.stroke(); // Draw
+      
+      // // draw horizontal line of current amplitude
+      // ctx.beginPath(); // Draw a new path
+      // ctx.moveTo(0,h); // Where to start drawing
+      // ctx.strokeStyle = "gray"; // Pick a color
+      // for(var i=0;i<x;i++){ // Loop from left side to current x
+      //   var y = calcSineY(x); // Calculate y value from x
+      //   ctx.moveTo(i,y); // Where to start drawing
+      //   ctx.lineTo(x,y); // Where to draw to
+      // }
+      // ctx.stroke(); // Draw
+      //
+      // // draw amplitude bar at current point
+      // ctx.beginPath(); // Draw a new path
+      // ctx.strokeStyle = "red"; // Pick a color
+      // for(var i=0;i<x;i++){ // Loop from left side to current x
+      //   var y = calcSineY(x); // Calculate y value from x
+      //   ctx.moveTo(x,h); // Where to start drawing
+      //   ctx.lineTo(x,y); // Where to draw to
+      // }
+      // ctx.stroke(); // Draw
+      //
+      // // draw area below y
+      // ctx.beginPath(); // Draw a new path
+      // ctx.strokeStyle = "orange"; // Pick a color
+      // for(var i=0;i<x;i++){ // Loop from left side to current x
+      //   if(i/3==Math.round(i/3)) { // Draw only one line each 3 pixels
+      //     var y = calcSineY(i); // Calculate y value from x
+      //     ctx.moveTo(i,h); // Where to start drawing
+      //     ctx.lineTo(i,y); // Where to draw to
+      //   }
+      // }
+      // ctx.stroke(); // Draw
+      
+      // draw sin curve point to point until x
+      ctx.beginPath(); // Draw a new path
+      ctx.strokeStyle = "black"; // Pick a color
+      for(var i=0;i<x;i++){ // Loop from left side to current x
+        var y = calcSineY(i); // Calculate y value from x
+        ctx.lineTo(i,y); // Where to draw to
+      }
+      ctx.stroke(); // Draw
+    }
+    // Define initial value of x positiom (leftmost side of cnanvas)
+    var x=0;
+    // Start time interval
+    var interval = setInterval(function(){
+      drawSine(x); // Call draww function every cycle
+      x++; // Increment x by 1
+      // if(x>w){
+      //     x=0; // x cannot be more than canvas with, so back to 0
+      //       f++; // increment frequency for demonstration
+      //   }
+    },10); // Loop every 10 milliseconds
+
+  } else {
+
+  }
+});
-- 
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