Sync HUD and enable all paint channels on pipette pick

After a successful pipette pick the painter now enables all four paint
channels (albedo, metallic/smoothness, occlusion, emission) and raises a
Picked event. The HUD subscribes and re-syncs every widget (toggles,
sliders, both colour pickers) to the adopted brush values.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Scripts/MeshPainter.Pick.cs

@@ -1,3 +1,4 @@
+using System;
 using UnityEngine;
 
 public partial class MeshPainter
@@ -18,6 +19,12 @@ public partial class MeshPainter
              "(all alphas set to 1) instead of painting. Held button picks only once.")]
     public bool pipette = false;
 
+    /// <summary>
+    /// Raised after a successful pick, once the brush has adopted the sampled values and all four
+    /// paint-channel flags have been enabled. The in-game HUD listens to re-sync its widgets.
+    /// </summary>
+    public event Action Picked;
+
     private bool _pickHeld; // edge tracking so a held button picks once, not every frame
 
     /// <summary>
@@ -67,5 +74,14 @@ public partial class MeshPainter
         // "Set all alpha values to 1": full-strength adoption across every opacity control.
         metallicSmoothnessOpacity = 1f;
         occlusionOpacity = 1f;
+
+        // Picking a whole material implies repainting all of it, so enable every channel.
+        paintAlbedo = true;
+        paintMetallicSmoothness = true;
+        paintOcclusion = true;
+        paintEmission = true;
+
+        // Let listeners (the in-game HUD) refresh their widgets to the adopted values + flags.
+        Picked?.Invoke();
     }
 }

Assets/Scripts/PaintHud.cs

@@ -112,10 +112,18 @@ public class PaintHud : MonoBehaviour
 
         WirePanel(_panel.transform);
 
+        // Re-sync every widget when the pipette adopts a sampled material (painter -> HUD).
+        if (painter) painter.Picked += SyncFromPainter;
+
         // Set initial visibility (the manager's first SwitchTo may have fired before this Start).
         OnModeChanged(modeManager ? modeManager.ActiveMode : null);
     }
 
+    private void OnDestroy()
+    {
+        if (painter) painter.Picked -= SyncFromPainter;
+    }
+
     private void OnModeChanged(GameMode mode)
     {
         if (_panel) _panel.SetActive(mode is PaintMode);
@@ -204,6 +212,55 @@ public class PaintHud : MonoBehaviour
             MakeDraggable(panel, name);
     }
 
+    /// <summary>
+    /// Pushes the painter's current values back into every widget (painter -> HUD), e.g. after a
+    /// pipette pick changed them outside the UI. No listeners are added here: setting a toggle/slider
+    /// value fires its existing change listener, which keeps the painter, value labels and panel-fade
+    /// alphas in sync; the colour pickers update silently via SetColor (it does not raise Changed).
+    /// </summary>
+    private void SyncFromPainter()
+    {
+        if (!_panel || !painter) return;
+        var panel = _panel.transform;
+
+        SetToggle(panel, ToggleAlbedo, painter.paintAlbedo);
+        SetToggle(panel, ToggleMetallicSmoothness, painter.paintMetallicSmoothness);
+        SetToggle(panel, ToggleOcclusion, painter.paintOcclusion);
+        SetToggle(panel, ToggleEmission, painter.paintEmission);
+        SetToggle(panel, ToggleSpray, painter.spray);
+        SetToggle(panel, TogglePipette, painter.pipette);
+
+        SetPicker(panel, PickerAlbedo, painter.brushColor);
+        SetPicker(panel, PickerEmission, painter.emissionColor);
+
+        SetSlider(panel, SliderMetallic, painter.metallic);
+        SetSlider(panel, SliderSmoothness, painter.smoothness);
+        SetSlider(panel, SliderMetallicSmoothnessAlpha, painter.metallicSmoothnessOpacity);
+        SetSlider(panel, SliderOcclusion, painter.occlusion);
+        SetSlider(panel, SliderOcclusionAlpha, painter.occlusionOpacity);
+        SetSlider(panel, SliderEmissionIntensity, painter.emissionIntensity);
+        SetSlider(panel, SliderBrushSize, painter.brushSize);
+    }
+
+    private static void SetToggle(Transform panel, string name, bool value)
+    {
+        var toggle = Find<Toggle>(panel, name);
+        if (toggle) toggle.isOn = value; // only fires onValueChanged when it actually changes
+    }
+
+    private static void SetSlider(Transform panel, string name, float value)
+    {
+        var cell = FindDeep(panel, name);
+        var slider = cell ? cell.GetComponentInChildren<Slider>() : null;
+        if (slider) slider.value = value; // listener refreshes the value label + painter
+    }
+
+    private static void SetPicker(Transform panel, string name, Color color)
+    {
+        var picker = Find<HsvColorPicker>(panel, name);
+        if (picker) picker.SetColor(color);
+    }
+
     /// <summary>
     /// Attaches (idempotently) a <see cref="DraggablePanel"/> to the whole panel so it can be dragged
     /// from any of its non-interactive surface (header, padding, labels, background); the component