Function updateMaskingTriDebug

js/main.js:1943–1977

(e)

    exclThresholdSlider.value = bucketThreshold;
    exclThresholdVal.value = bucketThreshold;
    _lastHoverTriIdx = -1;
  });

  exclClearBtn.addEventListener('click', () => {
    if (paintTree) paintTree.clearLayer(_activeSlot());
    refreshExclusionOverlay();
  });

  // Clicking a mask-mode button pre-selects the fill tool so painting can
  // start without an extra click (an already-active brush is kept). Only the
  // buttons do this — programmatic setSelectionMode() calls (project load,
  // session restore) must not activate a paint tool.
  exclModeExcludeBtn.addEventListener('click', () => {
    maskModeChosen = true;
    setSelectionMode(false);   // early-returns if already exclude…
    updateMaskModeButtons();   // …so refresh the highlight explicitly
    if (!exclusionTool) setExclusionTool('bucket');
  });
  exclModeIncludeBtn.addEventListener('click', () => {
    maskModeChosen = true;
    setSelectionMode(true);
    updateMaskModeButtons();
    if (!exclusionTool) setExclusionTool('bucket');
  });

  // ── Canvas mouse events for exclusion painting ────────────────────────────
  canvas.addEventListener('mousedown', (e) => {
    if (!currentGeometry || e.button !== 0) return;

    // Rotation gizmo takes priority
    if (isGizmoDragging()) return;

    // Place on Face mode
    if (placeOnFaceActive) {
      e.preventDefault();
      handlePlaceOnFaceClick(e);
      return;
    }