First version of freqscope

src/AudioVisualisation.ts

@@ -122,11 +122,11 @@ export interface OscilloscopeConfig {
   thickness: number;
   fftSize: number; // multiples of 256
   orientation: "horizontal" | "vertical";
-  is3D: boolean;
+  mode: "3D" | "scope" | "freqscope";
   size: number;
 }
 
-let lastZeroCrossingType: string | null = null;  // 'negToPos' or 'posToNeg'
+let lastZeroCrossingType: string | null = null; // 'negToPos' or 'posToNeg'
 
 /**
  * Initializes and runs an oscilloscope using an AnalyzerNode.
@@ -140,12 +140,47 @@ export const runOscilloscope = (
   let config = app.osc;
   let analyzer = getAnalyser(config.fftSize);
   let dataArray = new Float32Array(analyzer.frequencyBinCount);
+  let freqDataArray = new Uint8Array(analyzer.frequencyBinCount);
   const canvasCtx = canvas.getContext("2d")!;
   const WIDTH = canvas.width;
   const HEIGHT = canvas.height;
   let lastDrawTime = 0;
   let frameInterval = 1000 / 30;
 
+  function drawFrequencyScope() {
+    analyzer.getByteFrequencyData(freqDataArray);
+    canvasCtx.clearRect(0, 0, WIDTH, HEIGHT);
+
+    // Ensure the number of bars does not exceed the frequency data length
+    const numBars = freqDataArray.length;
+    const barWidth = WIDTH / numBars;
+    let barHeight;
+    let x = 0;
+
+    for (let i = 0; i < numBars; i++) {
+      // Calculate index in the frequency data array using logarithmic scale
+      const logIndex = Math.floor(
+        Math.pow(i / numBars, 2) * freqDataArray.length
+      );
+      barHeight = Math.floor(
+        freqDataArray[logIndex] * ((HEIGHT / 256) * app.osc.size)
+      );
+
+      // Color configuration
+      if (app.osc.color === "random") {
+        canvasCtx.fillStyle = `hsl(${Math.random() * 360}, 100%, 50%)`;
+      } else {
+        const gradient = canvasCtx.createLinearGradient(0, 0, WIDTH / 2, 0);
+        gradient.addColorStop(0, app.osc.color || `rgb(255, 255, 255)`);
+        gradient.addColorStop(1, `rgb(${barHeight + 50},50,50)`);
+        canvasCtx.fillStyle = gradient;
+      }
+
+      canvasCtx.fillRect(x, (HEIGHT - barHeight) / 2, barWidth + 1, barHeight);
+
+      x += barWidth;
+    }
+  }
 
   function draw() {
     const currentTime = Date.now();
@@ -166,8 +201,7 @@ export const runOscilloscope = (
     }
 
     analyzer.getFloatTimeDomainData(dataArray);
-    canvasCtx.globalCompositeOperation = 'source-over';
-
+    canvasCtx.globalCompositeOperation = "source-over";
 
     canvasCtx.fillStyle = "rgba(0, 0, 0, 0)";
     canvasCtx.fillRect(0, 0, WIDTH, HEIGHT);
@@ -184,23 +218,26 @@ export const runOscilloscope = (
     } else {
       canvasCtx.strokeStyle = app.osc.color;
     }
-    const remainingRefreshTime = app.clock.time_position.pulse % app.osc.refresh;
-    const opacityRatio = 1 - (remainingRefreshTime / app.osc.refresh);
+    const remainingRefreshTime =
+      app.clock.time_position.pulse % app.osc.refresh;
+    const opacityRatio = 1 - remainingRefreshTime / app.osc.refresh;
     canvasCtx.globalAlpha = opacityRatio;
     canvasCtx.beginPath();
 
-
     let startIndex = 0;
     for (let i = 1; i < dataArray.length; ++i) {
       let currentType = null;
       if (dataArray[i] >= 0 && dataArray[i - 1] < 0) {
-        currentType = 'negToPos';
+        currentType = "negToPos";
       } else if (dataArray[i] < 0 && dataArray[i - 1] >= 0) {
-        currentType = 'posToNeg';
+        currentType = "posToNeg";
       }
 
       if (currentType) {
-        if (lastZeroCrossingType === null || currentType === lastZeroCrossingType) {
+        if (
+          lastZeroCrossingType === null ||
+          currentType === lastZeroCrossingType
+        ) {
           startIndex = i;
           lastZeroCrossingType = currentType;
           break;
@@ -208,14 +245,18 @@ export const runOscilloscope = (
       }
     }
 
-
-    if (app.osc.is3D) {
+    if (app.osc.mode === "freqscope") {
+      drawFrequencyScope();
+    } else if (app.osc.mode === "3D") {
       for (let i = startIndex; i < dataArray.length; i += 2) {
         const x = (dataArray[i] * WIDTH * app.osc.size) / 2 + WIDTH / 4;
         const y = (dataArray[i + 1] * HEIGHT * app.osc.size) / 2 + HEIGHT / 4;
         i === startIndex ? canvasCtx.moveTo(x, y) : canvasCtx.lineTo(x, y);
       }
-    } else if (app.osc.orientation === "horizontal") {
+    } else if (
+      app.osc.mode === "scope" &&
+      app.osc.orientation === "horizontal"
+    ) {
       const sliceWidth = (WIDTH * 1.0) / dataArray.length;
       const yOffset = HEIGHT / 4;
       let x = 0;
@@ -226,7 +267,7 @@ export const runOscilloscope = (
         x += sliceWidth;
       }
       canvasCtx.lineTo(WIDTH, yOffset);
-    } else {
+    } else if (app.osc.mode === "scope" && app.osc.orientation === "vertical") {
       const sliceHeight = (HEIGHT * 1.0) / dataArray.length;
       const xOffset = WIDTH / 4;
       let y = 0;
@@ -243,6 +284,5 @@ export const runOscilloscope = (
     canvasCtx.globalAlpha = 1.0;
   }
 
-
   draw();
 };

src/documentation/oscilloscope.ts

@@ -8,21 +8,42 @@ export const oscilloscope = (application: Editor): string => {
 You can turn on the oscilloscope to generate interesting visuals or to inspect audio. Use the <ic>scope()</ic> function to turn it on and off. The oscilloscope is off by default.
 
 ${makeExample(
-    "Oscilloscope configuration",
-    `
+  "Oscilloscope configuration",
+  `
 scope({
     enabled: true, // off by default
     color: "#fdba74", // any valid CSS color or "random"
     thickness: 4, // stroke thickness
     fftSize: 256, // multiples of 128
     orientation: "horizontal", // "vertical" or "horizontal"
-    is3D: false, // 3D oscilloscope
+    mode: "scope" | "3D" | "freqscope", // scope mode
     size: 1, // size of the oscilloscope
     refresh: 1 // refresh rate (in pulses)
 })
   `,
-    true
-  )}
+  true
+)}
+
+${makeExample(
+  "Demo with multiple scope mode",
+  `
+rhythm(.5, [4,5].dur(4*3, 4*1), 8)::sound('fhardkick').out()
+beat(0.25)::sound('square').freq([
+  [250, 250/2, 250/4].pick(),
+  [250, 250/2, 250/4].beat() / 2 * 4,
+  ])
+  .fmi([1,2,3,4].bar()).fmh(fill()? 0 : 4)
+  .lpf(100+usine(1/4)*1200).lpad(4, 0, .5)
+  .room(0.5).size(8).vib(0.5).vibmod(0.125)
+  .ad(0, .125).out()
+beat(2)::sound('fsoftsnare').shape(0.5).out()
+scope({enabled: true, thickness: 8,
+  mode: ['freqscope', 'scope', '3D'].beat(),
+  color: ['purple', 'green', 'random'].beat(), 
+  size: 0.5, fftSize: 2048}) 
+    `,
+  true
+)}
 
 Note that these values can be patterned as well! You can transform the oscilloscope into its own light show if you want. The picture is not stable anyway so you won't have much use of it for precision work :)
 

src/main.ts

@@ -76,7 +76,7 @@ export class Editor {
     refresh: 1,
     fftSize: 1024,
     orientation: "horizontal",
-    is3D: false,
+    mode: "scope",
     size: 1,
   };