Fix insufficient ImDrawList implementation

Dalamud/Interface/Internal/ImGuiDrawListFixProvider.cs

@@ -0,0 +1,124 @@
+using System.Diagnostics;
+using System.Linq;
+using System.Numerics;
+
+using Dalamud.Hooking;
+
+using ImGuiNET;
+
+namespace Dalamud.Interface.Internal;
+
+/// <summary>
+/// Fixes ImDrawList not correctly dealing with the current texture for that draw list not in tune with the global
+/// state. Currently, ImDrawList::AddPolyLine and ImDrawList::AddRectFilled are affected.
+///
+/// * The implementation for AddRectFilled is entirely replaced with the hook below.
+/// * The implementation for AddPolyLine is wrapped with Push/PopTextureID.
+/// 
+/// TODO:
+/// * imgui_draw.cpp:1433 ImDrawList::AddRectFilled
+///   The if block needs a PushTextureID(_Data->TexIdCommon)/PopTextureID() block,
+///   if _Data->TexIdCommon != _CmdHeader.TextureId.
+/// * imgui_draw.cpp:729 ImDrawList::AddPolyLine
+///   The if block always needs to call PushTextureID if the abovementioned condition is not met.
+///   Change push_texture_id to only have one condition.
+/// </summary>
+[ServiceManager.EarlyLoadedService]
+internal sealed unsafe class ImGuiDrawListFixProvider : IServiceType, IDisposable
+{
+    private const int CImGuiImDrawListAddPolyLineOffset = 0x589B0;
+    private const int CImGuiImDrawListAddRectFilled = 0x59FD0;
+    private const int CImGuiImDrawListSharedDataTexIdCommonOffset = 0;
+
+    private readonly Hook<ImDrawListAddPolyLine> hookImDrawListAddPolyline;
+    private readonly Hook<ImDrawListAddRectFilled> hookImDrawListAddRectFilled;
+
+    [ServiceManager.ServiceConstructor]
+    private ImGuiDrawListFixProvider(InterfaceManager.InterfaceManagerWithScene imws)
+    {
+        // Force cimgui.dll to be loaded.
+        _ = ImGui.GetCurrentContext();
+        var cimgui = Process.GetCurrentProcess().Modules.Cast<ProcessModule>()
+                            .First(x => x.ModuleName == "cimgui.dll")
+                            .BaseAddress;
+
+        this.hookImDrawListAddPolyline = Hook<ImDrawListAddPolyLine>.FromAddress(
+            cimgui + CImGuiImDrawListAddPolyLineOffset,
+            this.ImDrawListAddPolylineDetour);
+        this.hookImDrawListAddRectFilled = Hook<ImDrawListAddRectFilled>.FromAddress(
+            cimgui + CImGuiImDrawListAddRectFilled,
+            this.ImDrawListAddRectFilledDetour);
+        this.hookImDrawListAddPolyline.Enable();
+        this.hookImDrawListAddRectFilled.Enable();
+    }
+
+    private delegate void ImDrawListAddPolyLine(
+        ImDrawListPtr drawListPtr,
+        ref Vector2 points,
+        int pointsCount,
+        uint color,
+        ImDrawFlags flags,
+        float thickness);
+
+    private delegate void ImDrawListAddRectFilled(
+        ImDrawListPtr drawListPtr,
+        ref Vector2 min,
+        ref Vector2 max,
+        uint col,
+        float rounding,
+        ImDrawFlags flags);
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        this.hookImDrawListAddPolyline.Dispose();
+        this.hookImDrawListAddRectFilled.Dispose();
+    }
+
+    private void ImDrawListAddRectFilledDetour(
+        ImDrawListPtr drawListPtr,
+        ref Vector2 min,
+        ref Vector2 max,
+        uint col,
+        float rounding,
+        ImDrawFlags flags)
+    {
+        if (rounding < 0 || (flags & ImDrawFlags.RoundCornersMask) == ImDrawFlags.RoundCornersMask)
+        {
+            var texIdCommon = *(nint*)(drawListPtr._Data + CImGuiImDrawListSharedDataTexIdCommonOffset);
+            var pushTextureId = texIdCommon != drawListPtr._CmdHeader.TextureId;
+            if (pushTextureId)
+                drawListPtr.PushTextureID(texIdCommon);
+
+            drawListPtr.PrimReserve(6, 4);
+            drawListPtr.PrimRect(min, max, col);
+
+            if (pushTextureId)
+                drawListPtr.PopTextureID();
+        }
+        else
+        {
+            drawListPtr.PathRect(min, max, rounding, flags);
+            drawListPtr.PathFillConvex(col);
+        }
+    }
+
+    private void ImDrawListAddPolylineDetour(
+        ImDrawListPtr drawListPtr,
+        ref Vector2 points,
+        int pointsCount,
+        uint color,
+        ImDrawFlags flags,
+        float thickness)
+    {
+        var texIdCommon = *(nint*)(drawListPtr._Data + CImGuiImDrawListSharedDataTexIdCommonOffset);
+        var pushTextureId = texIdCommon != drawListPtr._CmdHeader.TextureId;
+        if (pushTextureId)
+            drawListPtr.PushTextureID(texIdCommon);
+        
+        this.hookImDrawListAddPolyline.Original(drawListPtr, ref points, pointsCount, color, flags, thickness);
+
+        if (pushTextureId)
+            drawListPtr.PopTextureID();
+    }
+}