feat: more matrix stream examples

test/pixelstream/shared-frame-utils.js

@@ -0,0 +1,89 @@
+const SERPENTINE_WIRING = true;
+
+function clamp(value, min, max) {
+  return Math.max(min, Math.min(max, value));
+}
+
+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 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 samplePalette(paletteStops, 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 toIndex(col, row, width, serpentine = SERPENTINE_WIRING) {
+  if (!serpentine || row % 2 === 0) {
+    return row * width + col;
+  }
+  return row * width + (width - 1 - col);
+}
+
+function createFrame(width, height, fill = '000000') {
+  return new Array(width * height).fill(fill);
+}
+
+function frameToPayload(frame) {
+  return 'RAW:' + frame.join('');
+}
+
+function fadeFrame(frame, factor) {
+  for (let index = 0; index < frame.length; ++index) {
+    const hex = frame[index];
+    const r = parseInt(hex.slice(0, 2), 16) * factor;
+    const g = parseInt(hex.slice(2, 4), 16) * factor;
+    const b = parseInt(hex.slice(4, 6), 16) * factor;
+    frame[index] = toHex(r) + toHex(g) + toHex(b);
+  }
+}
+
+module.exports = {
+  SERPENTINE_WIRING,
+  clamp,
+  hexToRgb,
+  rgbToHex,
+  lerpRgb,
+  samplePalette,
+  toIndex,
+  createFrame,
+  frameToPayload,
+  fadeFrame,
+};
+