From 76c97155ceff296978be04c48b3f9b3ec2a232ab Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Benjamin=20B=C3=A4dorf?= <hello@benjaminbaedorf.eu>
Date: Fri, 7 Jun 2019 20:07:24 +0200
Subject: [PATCH] Pitched random location bars

---
 src/index.js      | 73 +++++++++++++++++++++++++++--------------------
 webpack.config.js |  7 +----
 2 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/src/index.js b/src/index.js
index 3dbd84d..bd48cca 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,15 +1,7 @@
 import p5 from 'p5';
 import './index.scss';
 
-const VOLUME_THRESHOLD = 0;
-const FFT_SIZE = 1024;
-
-function getColorValue(volume) {
-  const normalizedVolume = volume * VOLUME_NORMALIZATION;
-  const color = Math.floor(normalizedVolume);
-  const opacity = (normalizedVolume > VOLUME_MAX ? normalizedVolume : VOLUME_MAX) / 100;
-  return `rgba(${color}, ${color}, ${color}, ${opacity})`;
-}
+const FFT_SIZE = 256;
 
 function getRMS(spectrum) {
   let rms = 0;
@@ -21,8 +13,14 @@ function getRMS(spectrum) {
   return rms;
 }
 
-function getWidth(volume) {
-  return volume * VOLUME_NORMALIZATION;
+function getPitch(spectrum) {
+  let cg = 0;
+  let weight = 0;
+  for (let i = 0; i < spectrum.length; i++) {
+    cg += spectrum[i] * i;
+    weight += spectrum[i]; 
+  }
+  return Math.floor(cg / weight);
 }
 
 function getRandomX() {
@@ -38,28 +36,34 @@ async function main() {
   const audioCtx = new AudioContext();
   const microphone = await navigator.mediaDevices.getUserMedia({ audio: true });
   const analyser = new AnalyserNode(audioCtx);
-
-  let fresh = false;
-  let spectrum = [];
-  let volume = 0;
   analyser.smoothingTimeConstant = 0.2;
   analyser.fftSize = FFT_SIZE;
 
-  const audioProcessor = audioCtx.createScriptProcessor(FFT_SIZE*2, 1, 1);
+  let fresh = false;
+  let spectrum = [];
+  let pitch = 0;
+  let volume = 0;
+  let volumeThreshold = 0;
+  let bars = [];
+
+  const audioProcessor = audioCtx.createScriptProcessor(FFT_SIZE * 2, 1, 1);
   audioProcessor.onaudioprocess = () => {
     fresh = true;
     // bitcount returns array which is half the FFT_SIZE
     spectrum = new Uint8Array(analyser.frequencyBinCount);
 
     // getByteFrequencyData returns amplitude for each bin
-    // analyser.getByteFrequencyData(spectrum);
+    analyser.getByteFrequencyData(spectrum);
     // getByteTimeDomainData gets volumes over the sample time
     // analyser.getByteTimeDomainData(self.spectrum);
+    
+    spectrum.reverse();
 
-    volume = getRMS(spectrum);
+    const currentVolume = getRMS(spectrum);
     // get peak - a hack when our volumes are low
-    if (volume > VOLUME_THRESHOLD) VOLUME_THRESHOLD = volume;
-    volume = self.vol;
+    if (currentVolume > volumeThreshold) volumeThreshold = currentVolume;
+    volume = currentVolume;
+    pitch = getPitch(spectrum, volume, volumeThreshold);
   }
 
   const input = audioCtx.createMediaStreamSource(microphone);
@@ -67,30 +71,37 @@ async function main() {
   analyser.connect(audioProcessor);
   // audioProcessor.connect(audioCtx.destination);
 
-
   const instance = new p5(( sketch ) => {
     sketch.setup = () => {
       sketch.createCanvas(window.innerWidth, window.innerHeight);
+      sketch.colorMode(sketch.HSL, 255);
     };
 
-    function drawBar(bar) {
-      sketch.fill(getColorValue(bar.volume));
-      sketch.rect(bar.x, 0, getWidth(bar.volume), window.innerHeight);
-    }
-
-    let bars = [];
-
     sketch.draw = () => {
       if (!fresh) {
         return;
       }
 
       fresh = false;
+      sketch.background(sketch.color(0, 0, 0));
 
-      sketch.background(0);
-
-      for (const pitch of spectrum) {
+      bars.push({
+        x: getRandomX(),
+        volume,
+        pitch,
+        age: 1,
+      });
+      const newBars = [];
+      for (const bar of bars) {
+        sketch.fill(sketch.color(0, (bar.volume / volumeThreshold) * 255, 255));
+        sketch.rect(bar.x, 0, bar.age * bar.volume * 2, window.innerHeight);
+        bar.age /= 2;
+        if (bar.age > 0.1) {
+          newBars.push(bar);
+        }
       }
+
+      bars = newBars;
     };
   });
 }
diff --git a/webpack.config.js b/webpack.config.js
index a5e91ba..5fc1667 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -14,12 +14,7 @@ module.exports = {
         use: [
           { loader: "style-loader" },
           { loader: "css-loader" },
-          {
-            loader: "sass-loader",
-            options: {
-              includePaths: ["absolute/path/a", "absolute/path/b"],
-            },
-          },
+          { loader: "sass-loader" },
         ],
       },
     ],