feat: more matrix stream examples

test/pixelstream/lava-lamp.js

@@ -1,11 +1,17 @@
 const dgram = require('dgram');
 
+const {
+  clamp,
+  hexToRgb,
+  samplePalette: samplePaletteFromStops,
+  toIndex,
+} = require('./shared-frame-utils');
+
 const DEFAULT_PORT = 4210;
 const DEFAULT_WIDTH = 16;
 const DEFAULT_HEIGHT = 16;
 const DEFAULT_INTERVAL_MS = 60;
 const DEFAULT_BLOB_COUNT = 6;
-const SERPENTINE_WIRING = true;
 const BASE_BLOB_SPEED = 0.18;
 const PHASE_SPEED_MIN = 0.6;
 const PHASE_SPEED_MAX = 1.2;
@@ -123,8 +129,8 @@ function generateFrame() {
   for (let row = 0; row < height; ++row) {
     for (let col = 0; col < width; ++col) {
       const energy = calculateEnergyAt(col, row);
-      const color = samplePalette(energy);
-      frame[toIndex(col, row)] = color;
+      const color = samplePaletteFromStops(paletteStops, energy);
+      frame[toIndex(col, row, width)] = color;
     }
   }
 
@@ -151,62 +157,6 @@ function getBlobRadius(blob) {
   return blob.minRadius + (blob.maxRadius - blob.minRadius) * oscillation;
 }
 
-function toIndex(col, row) {
-  if (!SERPENTINE_WIRING || row % 2 === 0) {
-    return row * width + col;
-  }
-  return row * width + (width - 1 - col);
-}
-
-function samplePalette(value) {
-  const clampedValue = clamp(value, 0, 1);
-
-  for (let index = 0; index < paletteStops.length - 1; ++index) {
-    const left = paletteStops[index];
-    const right = paletteStops[index + 1];
-    if (clampedValue <= right.stop) {
-      const span = right.stop - left.stop || 1;
-      const t = clamp((clampedValue - left.stop) / span, 0, 1);
-      const interpolatedColor = lerpRgb(left.color, right.color, t);
-      return rgbToHex(interpolatedColor);
-    }
-  }
-
-  return rgbToHex(paletteStops[paletteStops.length - 1].color);
-}
-
-function lerpRgb(lhs, rhs, t) {
-  return {
-    r: Math.round(lhs.r + (rhs.r - lhs.r) * t),
-    g: Math.round(lhs.g + (rhs.g - lhs.g) * t),
-    b: Math.round(lhs.b + (rhs.b - lhs.b) * t),
-  };
-}
-
-function hexToRgb(hex) {
-  const normalizedHex = hex.trim().toLowerCase();
-  const value = normalizedHex.startsWith('#') ? normalizedHex.slice(1) : normalizedHex;
-  return {
-    r: parseInt(value.slice(0, 2), 16),
-    g: parseInt(value.slice(2, 4), 16),
-    b: parseInt(value.slice(4, 6), 16),
-  };
-}
-
-function rgbToHex(rgb) {
-  return toHex(rgb.r) + toHex(rgb.g) + toHex(rgb.b);
-}
-
-function toHex(value) {
-  const boundedValue = clamp(Math.round(value), 0, 255);
-  const hex = boundedValue.toString(16);
-  return hex.length === 1 ? '0' + hex : hex;
-}
-
-function clamp(value, min, max) {
-  return Math.max(min, Math.min(max, value));
-}
-
 function sendFrame() {
   const payload = generateFrame();
   const message = Buffer.from(payload, 'utf8');