Guidebook CSharp 03 UI

Hub entries, HUD rows, and UIToolkit panels — the one-call wiring plus the three IL2CPP companions. Layers: GregUILayerManager (Background < HUD < Panel < Dialog < Overlay < Tooltip < Notification); Hub in Dialog, your panels in Panel, key bar in HUD.

Hub + HUD (one call each)

GregMenuBinding.BindToggle("shift_helper_cs.main", ToggleMain, () => _isOpen);
GregMenuBinding.Report("shift_helper_cs.main", _isOpen);   // keep Hub truthful
GregMenuRegistry.RegisterOpener("shift_helper_cs.main", OpenMain);
GregMenuRegistry.RegisterCloser("shift_helper_cs.main", CloseMain);
GregMenuRegistry.RegisterMenu("shift_helper_cs.main", new GregMenuOptions
{
    LockCamera = true, LockMovement = true, LockInteract = true,
    ShowCursor = true, PanelWidth = 420f,
});
GregHudRegistry.Register("shift_helper_cs", "H", "ShiftHelper (H)");

The F1 Hub (GregModHub) groups GregModRegistry.All() by mod.Menus[] vs GregMenuRegistry.Snapshot() and renders honest buttons (Close only iff HasCloser). Settings jump: GregSettingsHub.FindTabForMenu(menuId, owner)->ShowTab().

Panels: the canonical recipe

OnGUI is stripped in IL2CPP — always GregPanelBuilder:

GregPanelBuilder.Create("ShiftHelper")
    .SetSize(500, 600)
    .Build()
    .AddHeadline("ShiftHelper")
    .AddLabel($"Broken servers: {broken}")
    .AddButton("Repair all", () => { RepairAll(); GregMenuBinding.Report("shift_helper_cs.main", _isOpen); })
    .AddToggle("Auto-repair", autoRepair, v => autoRepair = v)
    .AddSlider("Interval", 10, 300, interval, v => interval = (int)v)
    .AddSpacer(8).AddSeparator()
    .Show();   // .Hide() / .Toggle() / .Destroy()

Three mandatory companions (see docs/modding/ui-panels.md):

1. Clicks: Button.RegisterCallback<ClickEvent> and the per-frame worldBound fallback (GregClickRouter.RouteClicks, 500 ms dedup, Screen.height - y flip) — there is no EventSystem.
2. Fonts: GregFontLoader.DefaultUGUIFont (null-tolerant; Toolkit default renders invisible otherwise).
3. Input lock: GregMenuRegistry.SetOpen(menuId, open) drives GregInputLock (cursor, PlayerManager movement/look flags, PlayerInput.actions); ignore toggles while Pause/Escape/Options canvases are open.

Extras: GregPanel.GetOrCreate / RebuildContent / TickAll (0.28 s slide-in, right-docked, draggable), GregUIStack, theme, tooltips, GregNotificationManager, settings tabs via GregSettingsHub.RegisterTab (MelonPreferences-backed).

Exercises

1. Open/close your panel from hotkey and Hub; confirm Close appears (closer registered).
2. Click every control at two resolutions; confirm font visibility and cursor restore.
3. Add a Settings tab and reach it from the Hub’s Settings button.

Checkpoint

• Panel + Hub + HUD wired; clicks work without EventSystem; input locks only while open.

Next: Guidebook CSharp 04 Patches — Harmony the safe way.