Fixed Mod Key Event

[NosicLin]

Describe the bug
About Unity Mod key

To Reproduce
I Have fix unity mod key event bug, add test it ok, The origin code will wend two ModKey event to ImGui。 Eg: ModControl when left and right control not down it only send to false event to imgui. but when only one key press ,it will send down and up event to imgui。

to fixed then bug, I have separate normal key event and mod key event。 and cache the event is it not change。only send event to imgui when it status change。

using ImGuiNET;
using System.Collections.Generic;
using UImGui.Assets;
using UnityEngine;

namespace UImGui.Platform
{
// TODO: Check this feature and remove from here when checked and done.
// Implemented features:
// [x] Platform: Clipboard support.
// [x] Platform: Mouse cursor shape and visibility. Disable with io.ConfigFlags |= ImGuiConfigFlags.NoMouseCursorChange.
// [x] Platform: Keyboard arrays indexed using KeyCode codes, e.g. ImGui.IsKeyPressed(KeyCode.Space).
// [ ] Platform: Gamepad support. Enabled with io.ConfigFlags |= ImGuiConfigFlags.NavEnableGamepad.
// [] Platform: IME support.
// [] Platform: INI settings support.

/// <summary>
/// Platform bindings for ImGui in Unity in charge of: mouse/keyboard/gamepad inputs, cursor shape, timing, windowing.
/// </summary>
internal sealed class InputManagerPlatform : PlatformBase
{

    struct KeyMapInfo
    {
        public KeyCode UnityKeyCode;
        public ImGuiKey ImGuiKeyCode;
        public bool IsDown;
    }

    struct ModKeyMapInfo
    {
        public KeyCode[] UnityKeyCodes;
        public ImGuiKey ImGuiKeyCode;
        public bool IsDown;
    }


    private readonly Event _textInputEvent = new Event();
    private readonly KeyCode[] _keyCodes = (KeyCode[])System.Enum.GetValues(typeof(KeyCode));

    private KeyMapInfo[] _keyMapInfos;
    private ModKeyMapInfo[] _modKeyMapInfos;



    public InputManagerPlatform(CursorShapesAsset cursorShapes, IniSettingsAsset iniSettings) :
        base(cursorShapes, iniSettings)
    { }

    public override bool Initialize(ImGuiIOPtr io, ImGuiPlatformIOPtr pio, UIOConfig config, string platformName)
    {
        base.Initialize(io, pio, config, platformName);

        InitializeKeyMaps();
        return true;
    }

    public void InitializeKeyMaps()
    {
        List<KeyMapInfo> keyMapInfos = new List<KeyMapInfo>();
        foreach (KeyCode keyCode in _keyCodes)
        {
            if (TryMapKeys(keyCode, out ImGuiKey imguiKey))
            {

                keyMapInfos.Add(new KeyMapInfo()
                {
                    UnityKeyCode = keyCode,
                    ImGuiKeyCode = imguiKey

                });
            }
        }
        _keyMapInfos = keyMapInfos.ToArray();


        _modKeyMapInfos = new ModKeyMapInfo[]
        {
            new ModKeyMapInfo()
            {
                UnityKeyCodes =new KeyCode[]{KeyCode.LeftControl,KeyCode.RightControl},
                ImGuiKeyCode= ImGuiKey.ModCtrl,
            },
            new ModKeyMapInfo()
            {
                UnityKeyCodes =new KeyCode[]{KeyCode.LeftShift,KeyCode.RightShift},
                ImGuiKeyCode= ImGuiKey.ModShift,
            },
            new ModKeyMapInfo()
            {
                UnityKeyCodes =new KeyCode[]{KeyCode.LeftAlt,KeyCode.RightAlt},
                ImGuiKeyCode= ImGuiKey.ModAlt,
            },
            new ModKeyMapInfo()
            {
                UnityKeyCodes =new KeyCode[]{KeyCode.LeftWindows,KeyCode.RightWindows},
                ImGuiKeyCode= ImGuiKey.ModSuper
            },
        };


    }


    public override void PrepareFrame(ImGuiIOPtr io, Rect displayRect)
    {
        base.PrepareFrame(io, displayRect);

        UpdateKeyboard(io);

        UpdateMouse(io);
        UpdateCursor(io, ImGui.GetMouseCursor());
    }

    private void UpdateKeyboard(ImGuiIOPtr io)
    {

        // update normal key 
        int keyCodeNu = _keyMapInfos.Length;
        for (int i = 0; i < keyCodeNu; i++)
        {
            ref KeyMapInfo mapInfo = ref _keyMapInfos[i];

            bool isDown = Input.GetKey(mapInfo.UnityKeyCode);
            if (isDown != mapInfo.IsDown)
            {
                mapInfo.IsDown = isDown;
                io.AddKeyEvent(mapInfo.ImGuiKeyCode, isDown);
            }
        }


        //update mod key 
        int modKeyNu = _modKeyMapInfos.Length;
        for (int i = 0; i < modKeyNu; i++)
        {
            ref ModKeyMapInfo modInfo = ref _modKeyMapInfos[i];
            bool isDown = false;
            foreach (var k in modInfo.UnityKeyCodes)
            {
                if (Input.GetKey(k))
                {
                    isDown = true;
                    break;
                }
            }


            if (isDown != modInfo.IsDown)
            {
                modInfo.IsDown = isDown;
                io.AddKeyEvent(modInfo.ImGuiKeyCode, isDown);
            }
        }


        // Text input.
        while (Event.PopEvent(_textInputEvent))
        {
            if (_textInputEvent.rawType == EventType.KeyDown &&
                _textInputEvent.character != 0 && _textInputEvent.character != '\n')
            {
                Input.imeCompositionMode = IMECompositionMode.On;
                io.AddInputCharacter(_textInputEvent.character);
            }
        }
    }

    private static void UpdateMouse(ImGuiIOPtr io)
    {
        Vector2 mousePosition = Utils.ScreenToImGui(Input.mousePosition);
        io.AddMousePosEvent(mousePosition.x, mousePosition.y);
        io.AddMouseButtonEvent(0, Input.GetMouseButton(0));
        io.AddMouseButtonEvent(1, Input.GetMouseButton(1));
        io.AddMouseButtonEvent(2, Input.GetMouseButton(2));
        io.AddMouseWheelEvent(Input.mouseScrollDelta.x, Input.mouseScrollDelta.y);
    }

    private static bool TryMapKeys(KeyCode key, out ImGuiKey imguikey)
    {
        static ImGuiKey KeyToImGuiKeyShortcut(KeyCode keyToConvert, KeyCode startKey1, ImGuiKey startKey2)
        {
            int changeFromStart1 = (int)keyToConvert - (int)startKey1;
            return startKey2 + changeFromStart1;
        }

        imguikey = key switch
        {
            >= KeyCode.F1 and <= KeyCode.F12 => KeyToImGuiKeyShortcut(key, KeyCode.F1, ImGuiKey.F1),
            >= KeyCode.Keypad0 and <= KeyCode.Keypad9 => KeyToImGuiKeyShortcut(key, KeyCode.Keypad0, ImGuiKey.Keypad0),
            >= KeyCode.A and <= KeyCode.Z => KeyToImGuiKeyShortcut(key, KeyCode.A, ImGuiKey.A),
            >= KeyCode.Alpha0 and <= KeyCode.Alpha9 => KeyToImGuiKeyShortcut(key, KeyCode.Alpha0, ImGuiKey._0),
            // BUG: mod keys make everything slow. 
            /*
            KeyCode.LeftShift or KeyCode.RightShift => ImGuiKey.ModShift,
            KeyCode.LeftControl or KeyCode.RightControl => ImGuiKey.ModCtrl,
            KeyCode.LeftAlt or KeyCode.RightAlt => ImGuiKey.ModAlt,
            KeyCode.LeftWindows or KeyCode.RightWindows => ImGuiKey.ModSuper,
            */

            KeyCode.LeftShift => ImGuiKey.LeftShift,
            KeyCode.RightShift => ImGuiKey.RightShift,
            KeyCode.LeftControl => ImGuiKey.LeftCtrl,
            KeyCode.RightControl => ImGuiKey.RightCtrl,
            KeyCode.LeftAlt => ImGuiKey.LeftAlt,
            KeyCode.RightAlt => ImGuiKey.RightAlt,
            KeyCode.LeftWindows => ImGuiKey.LeftSuper,
            KeyCode.RightWindows => ImGuiKey.RightSuper,


            KeyCode.Menu => ImGuiKey.Menu,
            KeyCode.UpArrow => ImGuiKey.UpArrow,
            KeyCode.DownArrow => ImGuiKey.DownArrow,
            KeyCode.LeftArrow => ImGuiKey.LeftArrow,
            KeyCode.RightArrow => ImGuiKey.RightArrow,
            KeyCode.Return => ImGuiKey.Enter,
            KeyCode.Escape => ImGuiKey.Escape,
            KeyCode.Space => ImGuiKey.Space,
            KeyCode.Tab => ImGuiKey.Tab,
            KeyCode.Backspace => ImGuiKey.Backspace,
            KeyCode.Insert => ImGuiKey.Insert,
            KeyCode.Delete => ImGuiKey.Delete,
            KeyCode.PageUp => ImGuiKey.PageUp,
            KeyCode.PageDown => ImGuiKey.PageDown,
            KeyCode.Home => ImGuiKey.Home,
            KeyCode.End => ImGuiKey.End,
            KeyCode.CapsLock => ImGuiKey.CapsLock,
            KeyCode.ScrollLock => ImGuiKey.ScrollLock,
            KeyCode.Print => ImGuiKey.PrintScreen,
            KeyCode.Pause => ImGuiKey.Pause,
            KeyCode.Numlock => ImGuiKey.NumLock,
            KeyCode.KeypadDivide => ImGuiKey.KeypadDivide,
            KeyCode.KeypadMultiply => ImGuiKey.KeypadMultiply,
            KeyCode.KeypadMinus => ImGuiKey.KeypadSubtract,
            KeyCode.KeypadPlus => ImGuiKey.KeypadAdd,
            KeyCode.KeypadPeriod => ImGuiKey.KeypadDecimal,
            KeyCode.KeypadEnter => ImGuiKey.KeypadEnter,
            KeyCode.KeypadEquals => ImGuiKey.KeypadEqual,
            KeyCode.Tilde => ImGuiKey.GraveAccent,
            KeyCode.Minus => ImGuiKey.Minus,
            KeyCode.Plus => ImGuiKey.Equal,
            KeyCode.LeftBracket => ImGuiKey.LeftBracket,
            KeyCode.RightBracket => ImGuiKey.RightBracket,
            KeyCode.Semicolon => ImGuiKey.Semicolon,
            KeyCode.Quote => ImGuiKey.Apostrophe,
            KeyCode.Comma => ImGuiKey.Comma,
            KeyCode.Period => ImGuiKey.Period,
            KeyCode.Slash => ImGuiKey.Slash,
            KeyCode.Backslash => ImGuiKey.Backslash,
            _ => ImGuiKey.None
        };

        return imguikey != ImGuiKey.None;
    }
}

}