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feat(ui): AcDream.UI.ImGui backend — Hexa.NET.ImGui + Silk.NET input bridge

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Second piece of Phase D.2a: the ImGui-specific backend that implements
AcDream.UI.Abstractions' IPanelRenderer / IPanelHost. No GameWindow
hookup yet — compiles standalone for clean review before integration.

Packages:
  * Hexa.NET.ImGui 2.2.9 (auto-generated from cimgui 1.92.2b)
  * Hexa.NET.ImGui.Backends 1.0.18 (consolidated — OpenGL3 is here)
  * Silk.NET.Input 2.23.0 + Silk.NET.OpenGL 2.23.0 (matches AcDream.App)

Files:

  ImGuiBootstrapper.cs
    One-shot static Initialize(glslVersion) / Shutdown() pair. Creates
    the ImGui context, applies dark style, enables NavEnableKeyboard,
    and boots ImGuiImplOpenGL3. Re-init is a no-op.

  SilkInputBridge.cs
    Event-driven Silk.NET -> ImGui IO bridge. Subscribes on construction;
    Dispose() unsubscribes. Covers:
      - KeyDown/Up -> ImGui.AddKeyEvent with modifier latching
        (Ctrl/Shift/Alt/Super routed via both ModXxx flags AND named
        key events so both IsKeyPressed checks and ImGui shortcut
        matching work)
      - KeyChar -> AddInputCharacter for text fields
      - MouseMove -> AddMousePosEvent
      - MouseDown/Up -> AddMouseButtonEvent (L=0, R=1, M=2)
      - Scroll -> AddMouseWheelEvent (both axes)
    Silk.NET.Input.Key -> ImGuiKey map covers WASD, arrows, modifiers,
    letters, digits, function keys. Unmapped keys silently ignored.
    BeginFrame(displaySize, dt) sets IO.DisplaySize + IO.DeltaTime.

  ImGuiPanelRenderer.cs
    IPanelRenderer impl — one-line wrappers on ImGui.Begin/End,
    TextUnformatted, SameLine, Separator, ProgressBar. The ONLY place
    Hexa.NET.ImGui types appear outside bootstrap/input plumbing. Panels
    still never import ImGui.

  ImGuiPanelHost.cs
    IPanelHost impl. Dictionary keyed by IPanel.Id for idempotent
    Register. RenderAll iterates visible panels and calls their Render.
    Does NOT call ImGui.NewFrame / ImGui.Render — ownership belongs to
    the caller (GameWindow) so GL state is explicit. Diagnostic `Count`
    property.

No behavior change yet; next commit wires this into GameWindow behind
ACDREAM_DEVTOOLS=1 and ships the first visible VitalsPanel.
This commit is contained in:
Erik 2026-04-25 00:29:09 +02:00
parent fc03fa377b
commit a7dbce3474
6 changed files with 361 additions and 0 deletions
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src/AcDream.UI.ImGui/ImGuiBootstrapper.cs Normal file
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using Hexa.NET.ImGui;
using Hexa.NET.ImGui.Backends.OpenGL3;
namespace AcDream.UI.ImGui;
/// <summary>
/// One-shot ImGui setup / teardown for the devtools overlay. Called from
/// <c>GameWindow</c> when <c>ACDREAM_DEVTOOLS=1</c>. Hides the cimgui
/// context + OpenGL3 renderer-impl lifecycles behind two static methods
/// so the calling code stays clean.
///
/// <para>
/// Intentionally <b>not</b> an <c>IDisposable</c> singleton — the host
/// window owns the one call to <see cref="Shutdown"/> at application
/// exit. Re-initialisation mid-session is not supported.
/// </para>
/// </summary>
public static class ImGuiBootstrapper
{
private static bool _initialized;
/// <summary>
/// Create an ImGui context, apply the dark style + enable keyboard
/// navigation, and bootstrap the OpenGL3 renderer backend. The GL
/// context owned by Silk.NET must be current on the calling thread.
/// </summary>
/// <param name="glslVersion">
/// GLSL version directive for the ImGui-internal shader.
/// <c>"#version 330"</c> matches acdream's existing shaders and is
/// the safest default for the OpenGL 4.3 core profile we ship.
/// </param>
public static void Initialize(string glslVersion = "#version 330")
{
if (_initialized) return;
Hexa.NET.ImGui.ImGui.CreateContext();
Hexa.NET.ImGui.ImGui.StyleColorsDark();
var io = Hexa.NET.ImGui.ImGui.GetIO();
io.ConfigFlags |= ImGuiConfigFlags.NavEnableKeyboard;
// DO NOT enable NavEnableGamepad — we don't wire a gamepad backend.
// DO NOT enable DockingEnable / ViewportsEnable — out of scope for D.2a.
ImGuiImplOpenGL3.Init(glslVersion);
_initialized = true;
}
/// <summary>Tear down the OpenGL3 renderer + destroy the ImGui context.</summary>
public static void Shutdown()
{
if (!_initialized) return;
ImGuiImplOpenGL3.Shutdown();
Hexa.NET.ImGui.ImGui.DestroyContext();
_initialized = false;
}
/// <summary>True after <see cref="Initialize"/> has run successfully.</summary>
public static bool IsInitialized => _initialized;
}