Add correlation marker modes

www/views/goniometer_rtw.js

@@ -24,6 +24,7 @@ const BASE_ZOOM = 1.0;
 const BASE_GONIO_SCALE = (BASE_TARGET / ALIGN_PEAK) * Math.pow(10, -BASE_HEADROOM_DB / 20) * BASE_ZOOM;
 const AGC_TARGET_DB = linearToDb(ALIGN_PEAK);
 const CORR_SILENCE_THRESHOLD_DEFAULT = -75;
+const CORR_HOLD_MS = 4000;
 const MAX_TRAIL_FRAMES = 48;
 
 function computePanelSlotWidth(canvasWidth, slotCount = METER_SLOTS, slotGap = 12) {
@@ -48,6 +49,10 @@ export function init() {
     staticLayerCanvas: null,
     staticLayerCtx: null,
     staticLayerKey: '',
+    corrNegativeMarkerMode: 'memory',
+    corrHoldPeak: 0,
+    corrHoldUntil: 0,
+    corrResetToken: 0,
   };
 }
 
@@ -99,9 +104,16 @@ export async function render(env, state) {
   // Correlation is measured continuously in the audio DSP. Do not add a
   // second, frame-rate-dependent browser integration here.
   const corrVisual = Number.isFinite(audio?.correlation) ? clamp1(audio.correlation) : 0;
-  const corrNegativePeak = Number.isFinite(audio?.correlationNegativePeak)
+  const corrMemoryPeak = Number.isFinite(audio?.correlationNegativePeak)
     ? clamp1(audio.correlationNegativePeak)
     : 0;
+  const corrNegativeMarker = resolveCorrelationNegativeMarker(
+    state,
+    CONFIG,
+    corrVisual,
+    corrMemoryPeak,
+    frameNow,
+  );
   drawCorrelationBar(
     g,
     layout.plot.x + layout.plot.w / 2,
@@ -109,7 +121,7 @@ export async function render(env, state) {
     Math.round(Math.min(layout.scope.w * 0.75, layout.plot.w - 50)),
     18,
     corrVisual,
-    corrNegativePeak,
+    corrNegativeMarker,
   );
 
   if (slots.length) {
@@ -123,6 +135,34 @@ export async function render(env, state) {
   }
 }
 
+export function resolveCorrelationNegativeMarker(state, CONFIG = {}, current = 0, memoryPeak = 0, nowMs = 0) {
+  const requestedMode = String(CONFIG.CORR_NEGATIVE_MARKER_MODE || 'memory').toLowerCase();
+  const mode = ['memory', 'hold', 'off'].includes(requestedMode) ? requestedMode : 'memory';
+  const resetToken = Math.max(0, Math.floor(Number(CONFIG.CORR_RESET_TOKEN) || 0));
+
+  if (state.corrResetToken !== resetToken || state.corrNegativeMarkerMode !== mode) {
+    state.corrResetToken = resetToken;
+    state.corrNegativeMarkerMode = mode;
+    state.corrHoldPeak = 0;
+    state.corrHoldUntil = 0;
+  }
+
+  if (mode === 'off') return 0;
+  if (mode === 'memory') return Math.max(-1, Math.min(1, Number(memoryPeak) || 0));
+
+  const now = Number.isFinite(nowMs) ? nowMs : 0;
+  const currentNegative = Math.min(0, Math.max(-1, Math.min(1, Number(current) || 0)));
+  const holdActive = Number.isFinite(state.corrHoldUntil) && now < state.corrHoldUntil;
+  if (!holdActive) {
+    state.corrHoldPeak = currentNegative;
+    state.corrHoldUntil = currentNegative < -0.001 ? now + CORR_HOLD_MS : 0;
+  } else if (currentNegative < state.corrHoldPeak) {
+    state.corrHoldPeak = currentNegative;
+    state.corrHoldUntil = now + CORR_HOLD_MS;
+  }
+  return Number.isFinite(state.corrHoldPeak) ? state.corrHoldPeak : 0;
+}
+
 function drawStaticLayer(g, state, rect, layout, CONFIG, slotCount) {
   const layer = ensureStaticLayer(state, rect, layout, CONFIG, slotCount);
   if (!layer) {