b

Program.cs

@@ -1,7 +1,9 @@
 using System.Numerics;
+using System.Reflection;
 using System.Runtime.CompilerServices;
 using Hexa.NET.ImGui;
 using Hexa.NET.ImPlot;
+using HexaGen.Runtime;
 using SDL3_TestingSuite.SDL3;
 
 namespace SDL3_TestingSuite;
@@ -12,169 +14,243 @@ public class Program
     private static bool _imPlotDemoVisible;
     private static bool _fontStuff;
     private static readonly Dictionary<string, List<uint>?> GlyphsByName = new Dictionary<string, List<uint>?>();
-    private static bool _initialized;
+    private static bool _fontStuffInitialized;
+    private static bool _init;
     private static ImFontPtr _font;
     private static float size = 1f;
+    private static SDL3Window _window = null!;
+    private static OpenGLTexture? _imageTexture;
+    private static string? _imageLoadError;
 
     public static void Main()
     {
-        SDL3Window window = new SDL3Window("SDL3 Testing Suite", 100, 100, 1280, 720);
+        string baseDirectory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)!;
-        window.RenderCallback += () =>
+        string osPlatform = typeof(LibraryLoader).GetMethod("GetOSPlatform", BindingFlags.Static | BindingFlags.NonPublic)?.Invoke(null, null) as string ?? "";     // LibraryLoader.GetOSPlatform();
+        string architecture = typeof(LibraryLoader).GetMethod("GetArchitecture", BindingFlags.Static | BindingFlags.NonPublic)?.Invoke(null, null) as string ?? ""; // LibraryLoader.GetArchitecture());
+        LibraryLoader.CustomLoadFolders.AddRange(new string[]
         {
+            Path.Combine(baseDirectory),
+            Path.Combine(baseDirectory, "runtimes", osPlatform, "native"),
+            Path.Combine(baseDirectory, "runtimes", $"{osPlatform}-{architecture}", "debug"), // allows debug builds sideload.
+            Path.Combine(baseDirectory, "runtimes", $"{osPlatform}-{architecture}", "native"),
+        });
+
+        _window = new SDL3Window("SDL3 Testing Suite", 100, 100, 1280, 720);
+        _window.Disposing += DisposeImages;
+        _window.RenderCallback += () =>
+        {
+            if (!_init)
+            {
+                _init = true;
+                LoadImageTexture("");
+            }
+
             ImGuiViewportPtr viewport = ImGui.GetMainViewport();
             ImGui.SetNextWindowPos(viewport.WorkPos);
             ImGui.SetNextWindowSize(viewport.WorkSize);
             ImGui.SetNextWindowViewport(viewport.ID);
 
-            if (ImGui.Begin("MainWindow", ImGuiWindowFlags.NoBackground | ImGuiWindowFlags.MenuBar | ImGuiWindowFlags.NoDocking | ImGuiWindowFlags.NoTitleBar | ImGuiWindowFlags.NoResize | ImGuiWindowFlags.NoMove | ImGuiWindowFlags.NoCollapse | ImGuiWindowFlags.NoBringToFrontOnFocus))
+            ImGui.Begin("MainWindow", ImGuiWindowFlags.NoBackground | ImGuiWindowFlags.MenuBar | ImGuiWindowFlags.NoDocking | ImGuiWindowFlags.NoTitleBar | ImGuiWindowFlags.NoResize | ImGuiWindowFlags.NoMove | ImGuiWindowFlags.NoCollapse | ImGuiWindowFlags.NoBringToFrontOnFocus);
+            if (ImGui.BeginMenuBar())
             {
-                if (ImGui.BeginMenuBar())
+                if (ImGui.BeginMenu("Stuff"))
                 {
-                    if (ImGui.BeginMenu("Stuff"))
+                    if (ImGui.MenuItem("Quit"))
                     {
-                        if (ImGui.MenuItem("Quit"))
+                        _window.ShouldClose = true;
-                        {
-                            window.ShouldClose = true;
-                        }
-
-                        ImGui.EndMenu();
                     }
-                    ImGui.Spacing();
-                    ImGui.MenuItem("Demo Window", "", ref _demoWindowVisible);
-                    ImGui.Spacing();
-                    ImGui.MenuItem("ImPlot Demo Window", "", ref _imPlotDemoVisible);
-                    ImGui.Spacing();
-                    ImGui.MenuItem("Font Stuff", "", ref _fontStuff);
 
-                    ImGui.EndMenuBar();
+                    ImGui.EndMenu();
                 }
+                ImGui.Spacing();
+                ImGui.MenuItem("Demo Window", "", ref _demoWindowVisible);
+                ImGui.Spacing();
+                ImGui.MenuItem("ImPlot Demo Window", "", ref _imPlotDemoVisible);
+                ImGui.Spacing();
+                ImGui.MenuItem("Font Stuff", "", ref _fontStuff);
 
-                ImGui.End();
+                ImGui.EndMenuBar();
             }
+            string hash = "AAAA";
+            bool hasValue = true;
+            string text2 = "";
+
+            if (ImGui.InputTextWithHint($"##{hash}", hasValue ? "" : "Null", ref text2, 99999, ImGuiInputTextFlags.EnterReturnsTrue | ImGuiInputTextFlags.CtrlEnterForNewLine))
+            {
+                
+            }
+            
+            float buttonSize = ImGui.GetFrameHeight();
+
+            float avail = ImGui.GetContentRegionAvail().X;
+            float inputWidth = avail - buttonSize;
+
+            ImGui.PushItemWidth(inputWidth);
+            ImGui.SameLine(0f, 0f);
+
+            if (ImGui.Button($"X##{hash}_clear", new Vector2(buttonSize, buttonSize)))
+            {
+            }
+
+            ImGui.PopItemWidth();
+            
+            
+            ImGui.End();
 
             if (_fontStuff)
             {
                 ImGui.SetNextWindowSize(new Vector2(250, 500), ImGuiCond.FirstUseEver);
-                if (ImGui.Begin("FontStuff", ref _fontStuff))
+                ImGui.Begin("FontStuff", ref _fontStuff);
+
+                ImGui.ShowFontSelector("Font");
+
+                bool change = false;
+                if (ImGui.GetFont() != _font)
                 {
-                    ImGui.ShowFontSelector("Font");
+                    _font = ImGui.GetFont();
+                    change = true;
+                }
 
-                    bool change = false;
+                string fontName = _font.GetDebugNameS();
-                    if (ImGui.GetFont() != _font)
+                fontName = string.IsNullOrEmpty(fontName) ? _font.FontId.ToString() : fontName;
+                if (!_fontStuffInitialized || change)
+                {
+                    if (!GlyphsByName.TryGetValue(fontName, out List<uint>? glyphs))
                     {
-                        _font = ImGui.GetFont();
+                        glyphs = new List<uint>();
-                        change = true;
-                    }
 
-                    string fontName = _font.GetDebugNameS();
+                        ImFontPtr font = _font;
-                    fontName = string.IsNullOrEmpty(fontName) ? _font.FontId.ToString() : fontName;
+
-                    if (!_initialized || change)
+                        for (uint codepoint = 0; codepoint <= 0x10FFFF; codepoint++)
-                    {
-                        if (!GlyphsByName.TryGetValue(fontName, out List<uint>? glyphs))
                         {
-                            glyphs = new List<uint>();
+                            if (codepoint >= 0xD800 && codepoint <= 0xDFFF)
-
-                            ImFontPtr font = _font;
-
-                            for (uint codepoint = 0; codepoint <= 0x10FFFF; codepoint++)
                             {
-                                if (codepoint >= 0xD800 && codepoint <= 0xDFFF)
+                                continue;
-                                {
-                                    continue;
-                                }
-
-                                if (!font.IsGlyphInFont(codepoint)) continue;
-
-                                glyphs.Add(codepoint);
                             }
 
-                            GlyphsByName[fontName] = glyphs;
+                            if (!font.IsGlyphInFont(codepoint)) continue;
-                            Logger.Log($"Initialized font {fontName} with {glyphs.Count} glyphs");
+
+                            glyphs.Add(codepoint);
                         }
 
-                        _initialized = true;
+                        GlyphsByName[fontName] = glyphs;
+                        Logger.Log($"Initialized font {fontName} with {glyphs.Count} glyphs");
                     }
 
-                    ImGui.PushFont(null, 24);
+                    _fontStuffInitialized = true;
-
-                    if (GlyphsByName.TryGetValue(fontName, out List<uint>? glyphs2))
-                    {
-                        float cursorXStart = ImGui.GetCursorPosX();
-                        float maxWidth = ImGui.GetContentRegionAvail().X;
-
-                        foreach (uint codepoint in glyphs2!)
-                        {
-                            string text = char.ConvertFromUtf32((int)codepoint);
-                            float glyphWidth = ImGui.CalcTextSize(text).X;
-
-                            float cursorX = ImGui.GetCursorPosX();
-                            if (cursorX > cursorXStart && (cursorX + glyphWidth) > (cursorXStart + maxWidth))
-                            {
-                                ImGui.NewLine();
-                            }
-
-                            ImGui.TextUnformatted(text);
-
-                            ImGui.SameLine();
-                        }
-                    }
-
-                    ImGui.PopFont();
-
-                    ImGui.End();
                 }
-            }
 
-            if (ImGui.Begin("Thing"))
+                ImGui.PushFont(null, 24);
-            {
+
-                float time = (float)ImGui.GetTime() * 5;
+                if (GlyphsByName.TryGetValue(fontName, out List<uint>? glyphs2))
-                if (ImPlot.BeginPlot("Moving Rainbow Sine Wave"))
                 {
-                    int count = 200;
+                    float cursorXStart = ImGui.GetCursorPosX();
+                    float maxWidth = ImGui.GetContentRegionAvail().X;
 
-                    float[] xs = new float[2];
+                    foreach (uint codepoint in glyphs2!)
-                    float[] ys = new float[2];
-
-                    for (int i = 0; i < count - 1; i++)
                     {
-                        float x0 = i * 0.1f;
+                        string text = char.ConvertFromUtf32((int)codepoint);
-                        float x1 = (i + 1) * 0.1f;
+                        float glyphWidth = ImGui.CalcTextSize(text).X;
 
-                        float y0 = MathF.Sin(x0 * size + time);
+                        float cursorX = ImGui.GetCursorPosX();
-                        float y1 = MathF.Sin(x1 * size + time);
+                        if (cursorX > cursorXStart && (cursorX + glyphWidth) > (cursorXStart + maxWidth))
+                        {
+                            ImGui.NewLine();
+                        }
 
-                        xs[0] = x0;
+                        ImGui.TextUnformatted(text);
-                        xs[1] = x1;
-
-                        ys[0] = y0;
-                        ys[1] = y1;
-
-                        float t = i / (float)count;
-
-                        float r = 0.5f + 1f * MathF.Sin(6.2831f * (t));
-                        float g = 0.5f + 1f * MathF.Sin(6.2831f * (t + 0.33f));
-                        float b = 0.5f + 1f * MathF.Sin(6.2831f * (t + 0.66f));
-
-
-                        ImPlot.PushStyleColor(ImPlotCol.Line, new Vector4(r, g, b, 1f));
-                        ImPlot.PlotLine("##seg", ref xs[0], ref ys[0], 2);
-                        ImPlot.PopStyleColor();
 
+                        ImGui.SameLine();
                     }
-
-                    ImPlot.EndPlot();
                 }
-                ImGui.SliderFloat("Sine", ref size, 1f, 120f);
 
+                ImGui.PopFont();
                 ImGui.End();
             }
 
-            if (ImGui.Begin("ImageThing"))
+            ImGui.Begin("Thing");
+            float time = (float)ImGui.GetTime() * 5;
+            if (ImPlot.BeginPlot("Moving Rainbow Sine Wave"))
             {
+                int count = 200;
 
-                ImGui.End();
+                float[] xs = new float[2];
+                float[] ys = new float[2];
+
+                for (int i = 0; i < count - 1; i++)
+                {
+                    float x0 = i * 0.1f;
+                    float x1 = (i + 1) * 0.1f;
+
+                    float y0 = MathF.Sin(x0 * size + time);
+                    float y1 = MathF.Sin(x1 * size + time);
+
+                    xs[0] = x0;
+                    xs[1] = x1;
+
+                    ys[0] = y0;
+                    ys[1] = y1;
+
+                    float t = i / (float)count;
+
+                    float r = 0.5f + 1f * MathF.Sin(6.2831f * (t));
+                    float g = 0.5f + 1f * MathF.Sin(6.2831f * (t + 0.33f));
+                    float b = 0.5f + 1f * MathF.Sin(6.2831f * (t + 0.66f));
+
+
+                    ImPlot.PushStyleColor(ImPlotCol.Line, new Vector4(r, g, b, 1f));
+                    ImPlot.PlotLine("##seg", ref xs[0], ref ys[0], 2);
+                    ImPlot.PopStyleColor();
+
+                }
+
+                ImPlot.EndPlot();
             }
-            
+            ImGui.SliderFloat("Sine", ref size, 1f, 120f);
+            ImGui.End();
+
+            bool regen1 = true;
+
+            if (_imageTexture != null)
+            {
+                Vector2 displaySize = ImGui.GetIO().DisplaySize;
+                Vector2 imageSize = new Vector2(_imageTexture.Width, _imageTexture.Height);
+
+                float maxWidth = displaySize.X * 0.5f;
+                float maxHeight = displaySize.Y * 0.5f;
+                float scale = MathF.Min(maxWidth / imageSize.X, maxHeight / imageSize.Y);
+
+                Vector2 scaledSize = imageSize * MathF.Min(scale, 1.0f);
+                Vector2 padding = ImGui.GetStyle().WindowPadding;
+                Vector2 windowSize = new Vector2(scaledSize.X + padding.X * 2, scaledSize.Y + padding.Y * 2 + (ImGui.GetFrameHeight() * 4));
+
+                ImGui.SetNextWindowSize(windowSize, ImGuiCond.Always);
+                ImGui.Begin(_imageTexture.FileName ?? "Image", ref regen1, ImGuiWindowFlags.NoResize | ImGuiWindowFlags.NoScrollbar | ImGuiWindowFlags.NoSavedSettings);
+
+                regen1 = !ImGui.Button("Regen");
+
+                ImGui.Image(_imageTexture.ImGuiTexture, scaledSize);
+
+                string text1 = $"{_imageTexture.Width}x{_imageTexture.Height}";
+                ImGui.TextUnformatted(text1);
+                ImGui.SameLine(ImGui.CalcTextSize(text1).X + padding.X * 2);
+                ImGui.TextUnformatted($"EXT: {(_imageTexture.Extension ?? "Unknown Format")}");
+                ImGui.TextUnformatted($"{(_imageTexture.FilePath ?? "Unknown Path")}");
+            }
+            else
+            {
+                ImGui.Begin("Image", ref regen1, ImGuiWindowFlags.NoResize | ImGuiWindowFlags.NoScrollbar | ImGuiWindowFlags.NoSavedSettings);
+
+                ImGui.TextUnformatted(_imageLoadError ?? "No image loaded.");
+            }
+            ImGui.End();
+            bool regen = !regen1;
+            if (regen)
+            {
+                DisposeImages();
+                LoadImageTexture("");
+            }
+
             if (_demoWindowVisible)
             {
                 ImGui.ShowDemoWindow(ref _demoWindowVisible);
@@ -185,7 +261,30 @@ public class Program
             }
         };
 
-        window.Run();
+        _window.Run();
+    }
+
+    private static void LoadImageTexture(string path)
+    {
+        if (string.IsNullOrEmpty(path)) return;
+
+        try
+        {
+            _imageTexture = OpenGLTexture.FromFile(_window.GL, path);
+            _imageLoadError = null;
+        }
+        catch (Exception e)
+        {
+            DisposeImages();
+            _imageLoadError = e.Message;
+            Logger.Log(e);
+        }
+    }
+
+    private static void DisposeImages()
+    {
+        _imageTexture?.Dispose();
+        _imageTexture = null;
     }
 
     public static class Logger
@@ -195,7 +294,12 @@ public class Program
 
         public static void Log(object? value, [CallerFilePath] string path = "", [CallerMemberName] string caller = "", [CallerLineNumber] int line = 0)
         {
-            Write(value?.ToString(), path, caller, line);
+            if (value == null)
+            {
+                Write("null", path, caller, line);
+                return;
+            }
+            Write(value.ToString(), path, caller, line);
         }
 
         public static void Log(object?[] values, [CallerFilePath] string path = "", [CallerMemberName] string caller = "", [CallerLineNumber] int line = 0)

SDL3 TestingSuite.csproj

@@ -14,10 +14,15 @@
         <!--<PackageReference Include="ImGui.NET" Version="*" />-->
         <PackageReference Include="Hexa.NET.ImGui" Version="2.2.9" />
         <PackageReference Include="Hexa.NET.ImGui.Widgets" Version="1.2.18" />
+        <PackageReference Include="Hexa.NET.ImNodes" Version="2.2.9" />
         <PackageReference Include="Hexa.NET.ImPlot" Version="2.2.9" />
+        <PackageReference Include="Hexa.NET.ImPlot3D" Version="2.2.9" />
+        <PackageReference Include="Hexa.NET.OpenGL4" Version="1.1.0" />
+        <PackageReference Include="Hexa.NET.SDL3.Image" Version="1.0.0" />
         <PackageReference Include="Hexa.NET.Utilities" Version="2.2.12" />
         <PackageReference Include="SDL3-CS" Version="3.2.18" />
         <PackageReference Include="SDL3-CS.Native" Version="3.2.18" />
+        <PackageReference Include="SDL3-CS.Native.Image" Version="3.3.0" />
     </ItemGroup>
 
 </Project>

SDL3/FontFind.cs

@@ -21,7 +21,7 @@ public static class FontFind
 {
     extension(ImGuiIOPtr io)
     {
-        public unsafe ImFontPtr AddFont(string fontPath)
+        public unsafe ImFontPtr AddFont(string fontPath, bool merge = false)
         {
             try
             {
@@ -29,13 +29,14 @@ public static class FontFind
                 FileInfo info = new FileInfo(fontPath);
                 if (!info.Exists || info.Length <= 0) return null;
 
-                FontMetrics metrics = ReadFontMetrics(fontPath);
+                FontMetrics metrics = ReadFontMetricsSafe(fontPath);
                 float size = GetRecommendedPixelSize(metrics);
 
                 ImFontConfigPtr config = ImGui.ImFontConfig();
-                config.FontLoaderFlags |= (uint)ImGuiFreeTypeLoaderFlags.LoadColor;
+                config.FontLoaderFlags |= (uint)ImGuiFreeTypeLoaderFlags.LoadColor | (uint)ImGuiFreeTypeLoaderFlags.Bitmap;
+                config.MergeMode = merge;
                 ImFontPtr font = io.Fonts.AddFontFromFileTTF(fontPath, size, config);
-                Program.Logger.Log("Added font: " + Path.GetFileName(fontPath));
+                Program.Logger.Log($"{(merge ? "Merged" : "Added")} font: " + Path.GetFileName(fontPath));
                 return font;
             }
             catch (Exception e)
@@ -71,6 +72,21 @@ public static class FontFind
             return flag;
         }
     }
+    
+    public static FontMetrics ReadFontMetricsSafe(string fontPath)
+    {
+        try
+        {
+            return ReadFontMetrics(fontPath);
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine("Font parsing failed: " + fontPath);
+            Console.WriteLine(ex.ToString());
+
+            return new FontMetrics();
+        }
+    }
 
     public static FontMetrics ReadFontMetrics(string fontPath)
     {

SDL3/ImGuiSDL3Renderer.cs

@@ -1,377 +1,682 @@
 using System.Diagnostics;
 using System.Numerics;
-using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using Hexa.NET.ImGui;
-using SDL3;
+using Hexa.NET.OpenGL;
 
 namespace SDL3_TestingSuite.SDL3;
 
-/// <summary>
-/// Implementation of ImGui for SDL3 Renderer backend.
-/// https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_sdlrenderer3.h
-/// </summary>
 public unsafe static class ImGuiSDL3Renderer
 {
     public class RendererData
     {
-        public nint Renderer; // Main viewport's renderer
+        public GL Gl = null!;
-        public ImVector<SDL.FColor> ColorBuffer;
+        
+        public uint GlVersion;                // e.g. 320 for GL 3.2
+        public string GlslVersionString = ""; // e.g. "#version 330 core\n"
+        public bool GlProfileIsES2;
+        public bool GlProfileIsES3;
+        public bool GlProfileIsCompat;
+        public int GlProfileMask;
+        public int MaxTextureSize;
 
-        // Render State
+        public uint ShaderHandle;
-        public SDL.ScaleMode CurrentScaleMode;
+        public int AttribLocationTex;
+        public int AttribLocationProjMtx;
+        public uint AttribLocationVtxPos;
+        public uint AttribLocationVtxUV;
+        public uint AttribLocationVtxColor;
+        public uint VboHandle;
+        public uint ElementsHandle;
+
+        public bool HasPolygonMode;
+        public bool HasBindSampler;
+        public bool HasClipOrigin;
+
+        public uint[] TexSamplers = new uint[2]; // [0]=linear, [1]=nearest
+
+        public bool UseTexParameterToSetSampler;
+        public int NextSampler; // GL_LINEAR or GL_NEAREST
     }
 
-    private struct BackupSDLRendererState
+    public static RendererData? GetRendererData() => ImGui.GetCurrentContext().Handle != null ? ImGuiUserData<RendererData>.Get(ImGui.GetIO().BackendRendererUserData) : null;
+
+    public static bool Init(GL gl, string? glslVersion = null)
     {
-        public SDL.Rect Viewport;
-        public bool ClipEnabled;
-        public SDL.Rect ClipRect;
-    }
-
-    public static RendererData GetRendererData() => ImGui.GetCurrentContext().Handle != null ? ImGuiUserData<RendererData>.Get(ImGui.GetIO().BackendRendererUserData)! : null!;
-
-    public static SDL3Window? Parent;
-
-    public static bool Init(nint renderer, SDL3Window? parentWindow = null)
-    {
-        Parent = parentWindow;
         ImGuiIOPtr io = ImGui.GetIO();
+        Debug.Assert(io.BackendRendererUserData == null, "Already initialised a renderer backend!");
 
-        RendererData bd = new RendererData();
+        RendererData bd = new RendererData { Gl = gl };
         io.BackendRendererUserData = ImGuiUserData<RendererData>.Store(bd);
-        io.BackendRendererName = (byte*)Marshal.StringToHGlobalAnsi("NepImGuiSDL3Renderer");
+        io.BackendRendererName = (byte*)Marshal.StringToHGlobalAnsi("imgui_impl_opengl3_cs");
-        io.BackendFlags |= ImGuiBackendFlags.RendererHasVtxOffset; // We can honor the ImDrawCmd.VtxOffset field, allowing for large meshes.
-        io.BackendFlags |= ImGuiBackendFlags.RendererHasTextures;  // We can honor ImGuiPlatformIO.Textures[] requests during render.
-        io.BackendFlags |= ImGuiBackendFlags.RendererHasViewports;
 
-        bd.Renderer = renderer;
+        string? glVersionStr = Marshal.PtrToStringAnsi((nint)gl.GetString(GLStringName.Version));
+
+        if (glVersionStr != null && glVersionStr.StartsWith("OpenGL ES 2", StringComparison.Ordinal))
+        {
+            bd.GlVersion = 200;
+            bd.GlProfileIsES2 = true;
+        }
+        else
+        {
+            gl.GetIntegerv(GLGetPName.MajorVersion, out int major);
+            gl.GetIntegerv(GLGetPName.MinorVersion, out int minor);
+            if (major == 0 && minor == 0 && glVersionStr != null)
+            {
+                string[] parts = glVersionStr.Split('.');
+                if (parts.Length >= 2)
+                {
+                    int.TryParse(parts[0], out major);
+                    int.TryParse(new string(parts[1].TakeWhile(char.IsDigit).ToArray()), out minor);
+                }
+            }
+
+            bd.GlVersion = (uint)(major * 100 + minor * 10);
+
+            if (glVersionStr != null && glVersionStr.StartsWith("OpenGL ES 3", StringComparison.Ordinal))
+                bd.GlProfileIsES3 = true;
+
+            gl.GetIntegerv(GLGetPName.MaxTextureSize, out bd.MaxTextureSize);
+
+            if (!bd.GlProfileIsES3 && bd.GlVersion >= 320)
+            {
+                gl.GetIntegerv(GLGetPName.ContextProfileMask, out bd.GlProfileMask);
+
+            }
+        }
+
+        if (bd.GlVersion >= 320)
+            io.BackendFlags |= ImGuiBackendFlags.RendererHasVtxOffset; // large meshes
+        io.BackendFlags |= ImGuiBackendFlags.RendererHasTextures;      // dynamic font atlas
+        io.BackendFlags |= ImGuiBackendFlags.RendererHasViewports;     // multi-viewport
 
         ImGuiPlatformIOPtr platformIO = ImGui.GetPlatformIO();
-        platformIO.RendererCreateWindow = DelegateStorage.RendererCreateWindowDelegate.GetPtrForDelegate();
+        platformIO.RendererTextureMaxWidth = bd.MaxTextureSize;
-        platformIO.RendererDestroyWindow = DelegateStorage.RendererDestroyWindowDelegate.GetPtrForDelegate();
+        platformIO.RendererTextureMaxHeight = bd.MaxTextureSize;
-        platformIO.RendererRenderWindow = DelegateStorage.RendererRenderWindowDelegate.GetPtrForDelegate();
+
-        platformIO.RendererSwapBuffers = DelegateStorage.RendererSwapBuffersDelegate.GetPtrForDelegate();
+        if (glslVersion == null)
+        {
+            if (bd.GlProfileIsES2) glslVersion = "#version 100";
+            else if (bd.GlProfileIsES3) glslVersion = "#version 300 es";
+            else if (OperatingSystem.IsMacOS()) glslVersion = "#version 150";
+            else glslVersion = "#version 130";
+        }
+        bd.GlslVersionString = glslVersion + "\n";
+
+        bd.HasPolygonMode = !bd.GlProfileIsES2 && !bd.GlProfileIsES3;
+        bd.HasBindSampler = bd.GlVersion >= 330 || bd.GlProfileIsES3;
+        bd.HasClipOrigin = bd.GlVersion >= 450;
+
+        if (!bd.HasClipOrigin && !bd.GlProfileIsES2 && !bd.GlProfileIsES3)
+        {
+            gl.GetIntegerv(GLGetPName.NumExtensions, out int numExt);
+            for (uint i = 0; i < numExt; i++)
+            {
+                string? ext = Marshal.PtrToStringAnsi((nint)gl.GetStringi(GLStringName.Extensions, i));
+                if (ext == "GL_ARB_clip_control")
+                {
+                    bd.HasClipOrigin = true;
+                    break;
+                }
+            }
+        }
+
+        InitMultiViewportSupport();
 
         return true;
     }
 
     public static void Dispose()
     {
+        RendererData? bd = GetRendererData();
+        Debug.Assert(bd != null, "No renderer backend to shut down, or already shut down?");
+
         ImGuiIOPtr io = ImGui.GetIO();
-        ImGuiPlatformIOPtr platformIO = ImGui.GetPlatformIO();
+
+        ShutdownMultiViewportSupport();
+        DestroyDeviceObjects();
 
         if (io.BackendRendererName != null)
-        {
             Marshal.FreeHGlobal((nint)io.BackendRendererName);
-        }
 
         ImGuiUserData<RendererData>.Free(io.BackendRendererUserData);
         io.BackendRendererName = null;
         io.BackendRendererUserData = null;
         io.BackendFlags &= ~(ImGuiBackendFlags.RendererHasVtxOffset | ImGuiBackendFlags.RendererHasTextures | ImGuiBackendFlags.RendererHasViewports);
-        platformIO.RendererTextureMaxWidth = 0;
-        platformIO.RendererTextureMaxHeight = 0;
-        platformIO.RendererRenderState = null;
-    }
-
-    public static void SetupRenderState(nint renderer)
-    {
-        // Clear out any viewports and cliprect set by the user
-        // FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
-        SDL.SetRenderViewport(renderer, nint.Zero);
-        SDL.SetRenderClipRect(renderer, nint.Zero);
     }
 
     public static void NewFrame()
     {
-        RendererData bd = GetRendererData();
+        RendererData? bd = GetRendererData();
-        Debug.Assert(bd != null, "Context or backend not initialized! Did you call ImGuiSDL3Renderer.Init()?");
+        Debug.Assert(bd != null, "Context or backend not initialised! Did you call ImGuiOpenGL3Renderer.Init()?");
+
+        if (bd.ShaderHandle == 0)
+        {
+            bool ok = CreateDeviceObjects();
+            Debug.Assert(ok, "ImGuiOpenGL3Renderer.CreateDeviceObjects() failed!");
+        }
     }
 
-    public static void RenderDrawData(ImDrawDataPtr drawData, nint renderer)
+    public static void RenderDrawData(ImDrawDataPtr drawData)
     {
-        // Skip if no data to render
+        if (drawData.Handle == null) return;
-        if (drawData.Handle == null || drawData.CmdListsCount == 0)
-            return;
 
-        SDL.GetRenderScale(renderer, out float renderScaleX, out float renderScaleY);
+        int fbWidth = (int)(drawData.DisplaySize.X * drawData.FramebufferScale.X);
-        Vector2 renderScale = new Vector2(renderScaleX == 1.0f ? drawData.FramebufferScale.X : 1.0f, renderScaleY == 1.0f ? drawData.FramebufferScale.Y : 1.0f);
+        int fbHeight = (int)(drawData.DisplaySize.Y * drawData.FramebufferScale.Y);
+        if (fbWidth <= 0 || fbHeight <= 0) return;
 
-        int fbWidth = (int)(drawData.DisplaySize.X * renderScale.X);
+        RendererData bd = GetRendererData()!;
-        int fbHeight = (int)(drawData.DisplaySize.Y * renderScale.Y);
+        GL gl = bd.Gl;
-        if (fbWidth <= 0 || fbHeight <= 0)
-            return;
 
-        for (int i = 0; i < drawData.Textures.Size; i++)
+        if (drawData.Textures.Size > 0)
         {
-            ImTextureDataPtr texture = drawData.Textures[i];
+            for (int i = 0; i < drawData.Textures.Size; i++)
-            if (texture.Handle != null)
             {
-                UpdateTexture(texture, renderer);
+                ImTextureDataPtr tex = drawData.Textures[i];
+                if (tex.Status != ImTextureStatus.Ok)
+                    UpdateTexture(tex);
             }
         }
 
-        // Backup SDL renderer state
+        gl.GetIntegerv(GLGetPName.ActiveTexture, out int lastActiveTexture);
-        BackupSDLRendererState old = new BackupSDLRendererState
+        gl.ActiveTexture(GLTextureUnit.Texture0);
+        gl.GetIntegerv(GLGetPName.CurrentProgram, out int lastProgram);
+        gl.GetIntegerv(GLGetPName.TextureBinding2D, out int lastTexture);
+        gl.GetIntegerv(GLGetPName.SamplerBinding, out int lastSampler);
+        gl.GetIntegerv(GLGetPName.ArrayBufferBinding, out int lastArrayBuffer);
+        gl.GetIntegerv(GLGetPName.VertexArrayBinding, out int lastVertexArray);
+        int[] lastPolygonMode = new int[2];
+        if (bd.HasPolygonMode) gl.GetIntegerv(GLGetPName.PolygonMode, lastPolygonMode);
+        int[] lastViewport = new int[4];
+        gl.GetIntegerv(GLGetPName.Viewport, lastViewport);
+        int[] lastScissorBox = new int[4];
+        gl.GetIntegerv(GLGetPName.ScissorBox, lastScissorBox);
+
+        gl.GetIntegerv(GLGetPName.BlendSrcRgb, out int lastBlendSrcRgb);
+        gl.GetIntegerv(GLGetPName.BlendDstRgb, out int lastBlendDstRgb);
+        gl.GetIntegerv(GLGetPName.BlendSrcAlpha, out int lastBlendSrcAlpha);
+        gl.GetIntegerv(GLGetPName.BlendDstAlpha, out int lastBlendDstAlpha);
+        gl.GetIntegerv(GLGetPName.BlendEquationRgb, out int lastBlendEqRgb);
+        gl.GetIntegerv(GLGetPName.BlendEquationAlpha, out int lastBlendEqAlpha);
+
+        bool lastBlend = gl.IsEnabled(GLEnableCap.Blend);
+        bool lastCullFace = gl.IsEnabled(GLEnableCap.CullFace);
+        bool lastDepthTest = gl.IsEnabled(GLEnableCap.DepthTest);
+        bool lastStencilTest = gl.IsEnabled(GLEnableCap.StencilTest);
+        bool lastScissorTest = gl.IsEnabled(GLEnableCap.ScissorTest);
+        bool lastPrimRestart = bd.GlVersion >= 310 && !bd.GlProfileIsES3 && gl.IsEnabled(GLEnableCap.PrimitiveRestart);
+
+        uint vao = 0;
+        gl.GenVertexArrays(1, ref vao);
+        SetupRenderState(drawData, fbWidth, fbHeight, vao);
+
+        Vector2 clipOff = drawData.DisplayPos;
+        Vector2 clipScale = drawData.FramebufferScale;
+
+        for (int listIdx = 0; listIdx < drawData.CmdListsCount; listIdx++)
         {
-            ClipEnabled = SDL.RenderClipEnabled(renderer)
+            ImDrawListPtr drawList = drawData.CmdLists[listIdx];
-        };
-        SDL.GetRenderViewport(renderer, out old.Viewport);
-        SDL.GetRenderClipRect(renderer, out old.ClipRect);
 
-        // Set up render state
+            int vtxSize = drawList.VtxBuffer.Size * sizeof(ImDrawVert);
-        SetupRenderState(renderer);
+            int idxSize = drawList.IdxBuffer.Size * sizeof(ushort);
 
-        // Set render state in platform IO
+            gl.BufferData(GLBufferTargetARB.ArrayBuffer, vtxSize, drawList.VtxBuffer.Data, GLBufferUsageARB.StreamDraw);
-        ImGuiPlatformIOPtr platformIo = ImGui.GetPlatformIO();
+            gl.BufferData(GLBufferTargetARB.ElementArrayBuffer, idxSize, drawList.IdxBuffer.Data, GLBufferUsageARB.StreamDraw);
-        platformIo.RendererRenderState = (void*)renderer;
 
-        Vector2 clipOffset = drawData.DisplayPos;
+            for (int cmdIdx = 0; cmdIdx < drawList.CmdBuffer.Size; cmdIdx++)
-
-        // Render command lists
-        for (int n = 0; n < drawData.CmdListsCount; n++)
-        {
-            ImDrawListPtr drawList = drawData.CmdLists[n];
-
-            for (int cmdIndex = 0; cmdIndex < drawList.CmdBuffer.Size; cmdIndex++)
             {
-                ImDrawCmd cmd = drawList.CmdBuffer[cmdIndex];
+                ImDrawCmd cmd = drawList.CmdBuffer[cmdIdx];
 
                 if (cmd.UserCallback != null)
                 {
-                    if (cmd.UserCallback == DelegateStorage.DrawCallbackResetRenderStateDelegate.GetPtrForDelegate())
+
+                    nint cbPtr = (nint)cmd.UserCallback;
+                    if (cbPtr == (nint)DelegateStorage.DrawCallbackResetRenderStateDelegate.GetPtrForDelegate())
                     {
-                        SetupRenderState(renderer);
+                        SetupRenderState(drawData, fbWidth, fbHeight, vao);
+                    }
+                    else if (cbPtr == (nint)DelegateStorage.DrawCallbackSetSamplerLinearDelegate.GetPtrForDelegate())
+                    {
+                        ApplySamplerLinear(bd);
+                    }
+                    else if (cbPtr == (nint)DelegateStorage.DrawCallbackSetSamplerNearestDelegate.GetPtrForDelegate())
+                    {
+                        ApplySamplerNearest(bd);
                     }
                     else
                     {
-                        // this is cursed af and idk if it even works :)
+                        ImDrawCmdPtr cmdPtr = new ImDrawCmdPtr { Handle = &cmd };
-                        ImDrawCmdPtr cmdPtr = new ImDrawCmdPtr
-                        {
-                            Handle = (ImDrawCmd*)Unsafe.AsPointer(ref cmd)
-                        };
                         ((delegate* unmanaged[Cdecl]<ImDrawListPtr, ImDrawCmdPtr, void>)cmd.UserCallback)(drawList, cmdPtr);
                     }
+                    continue;
+                }
+
+                float clipMinX = (cmd.ClipRect.X - clipOff.X) * clipScale.X;
+                float clipMinY = (cmd.ClipRect.Y - clipOff.Y) * clipScale.Y;
+                float clipMaxX = (cmd.ClipRect.Z - clipOff.X) * clipScale.X;
+                float clipMaxY = (cmd.ClipRect.W - clipOff.Y) * clipScale.Y;
+                if (clipMaxX <= clipMinX || clipMaxY <= clipMinY) continue;
+
+                gl.Scissor((int)clipMinX, fbHeight - (int)clipMaxY, (int)(clipMaxX - clipMinX), (int)(clipMaxY - clipMinY));
+
+                gl.BindTexture(GLTextureTarget.Texture2D, (uint)(nint)cmd.GetTexID());
+
+                if (!bd.HasBindSampler && bd.UseTexParameterToSetSampler)
+                {
+                    gl.TexParameterf(GLTextureTarget.Texture2D, GLTextureParameterName.MinFilter, bd.NextSampler);
+                    gl.TexParameterf(GLTextureTarget.Texture2D, GLTextureParameterName.MagFilter, bd.NextSampler);
+                }
+
+                if (bd.GlVersion >= 320)
+                {
+                    gl.DrawElementsBaseVertex(GLPrimitiveType.Triangles, (int)cmd.ElemCount, GLDrawElementsType.UnsignedShort, (void*)(cmd.IdxOffset * sizeof(ushort)), (int)cmd.VtxOffset);
                 }
                 else
                 {
-                    // Apply clipping rectangle
+                    gl.DrawElements(GLPrimitiveType.Triangles, (int)cmd.ElemCount, GLDrawElementsType.UnsignedShort, (void*)(cmd.IdxOffset * sizeof(ushort)));
-                    Vector4 clipRect = cmd.ClipRect;
-                    Vector2 clipMin = new Vector2((clipRect.X - clipOffset.X) * renderScale.X, (clipRect.Y - clipOffset.Y) * renderScale.Y);
-                    Vector2 clipMax = new Vector2((clipRect.Z - clipOffset.X) * renderScale.X, (clipRect.W - clipOffset.Y) * renderScale.Y);
-
-                    clipMin.X = Math.Max(0, clipMin.X);
-                    clipMin.Y = Math.Max(0, clipMin.Y);
-                    clipMax.X = Math.Min(fbWidth, clipMax.X);
-                    clipMax.Y = Math.Min(fbHeight, clipMax.Y);
-                    if (clipMax.X <= clipMin.X || clipMax.Y <= clipMin.Y)
-                        continue;
-
-                    SDL.Rect r = new SDL.Rect
-                    {
-                        X = (int)clipMin.X,
-                        Y = (int)clipMin.Y,
-                        W = (int)(clipMax.X - clipMin.X),
-                        H = (int)(clipMax.Y - clipMin.Y)
-                    };
-                    SDL.SetRenderClipRect(renderer, r);
-
-                    // Convert ImGui vertices to SDL vertices
-                    uint indexOffset = cmd.IdxOffset;
-                    uint vertexOffset = cmd.VtxOffset;
-                    uint elemCount = cmd.ElemCount;
-
-                    SDL.Vertex[] vertices = new SDL.Vertex[elemCount];
-                    int[] indices = new int[elemCount];
-
-                    for (int i = 0; i < elemCount; i++)
-                    {
-                        ushort idx = drawList.IdxBuffer[(int)indexOffset + i];
-                        int vertIdx = (int)(vertexOffset + idx);
-
-                        ImDrawVert srcVert = drawList.VtxBuffer[vertIdx];
-
-                        uint col = srcVert.Col;
-
-                        byte colR = (byte)((col >> 0) & 0xFF);
-                        byte colG = (byte)((col >> 8) & 0xFF);
-                        byte colB = (byte)((col >> 16) & 0xFF);
-                        byte colA = (byte)((col >> 24) & 0xFF);
-
-                        vertices[i] = new SDL.Vertex
-                        {
-                            Position = new SDL.FPoint
-                            {
-                                X = (srcVert.Pos.X - clipOffset.X) * renderScale.X,
-                                Y = (srcVert.Pos.Y - clipOffset.Y) * renderScale.Y
-                            },
-                            Color = new SDL.FColor
-                            {
-                                R = colR / 255f,
-                                G = colG / 255f,
-                                B = colB / 255f,
-                                A = colA / 255f
-                            },
-                            TexCoord = new SDL.FPoint
-                            {
-                                X = srcVert.Uv.X,
-                                Y = srcVert.Uv.Y
-                            }
-                        };
-
-                        indices[i] = i;
-                    }
-
-                    // Get texture
-                    ImTextureID texId = cmd.GetTexID();
-                    if (!SDL.RenderGeometry(renderer, texId, vertices, vertices.Length, indices, indices.Length))
-                    {
-                        Program.Logger.Log($"Failed to render ImGui draw command: {SDL.GetError()}");
-                    }
                 }
             }
         }
 
-        // Reset render state
+        gl.DeleteVertexArray(vao);
-        platformIo.RendererRenderState = null;
 
-        // Restore renderer state
+        if (lastProgram == 0 || gl.IsProgram((uint)lastProgram))
-        SDL.SetRenderViewport(renderer, old.Viewport);
+            gl.UseProgram((uint)lastProgram);
-        SDL.SetRenderClipRect(renderer, old.ClipEnabled ? old.ClipRect : new SDL.Rect());
+        gl.BindTexture(GLTextureTarget.Texture2D, (uint)lastTexture);
+        if (bd.HasBindSampler) gl.BindSampler(0, (uint)lastSampler);
+        gl.ActiveTexture((GLTextureUnit)lastActiveTexture);
+        gl.BindVertexArray((uint)lastVertexArray);
+        gl.BindBuffer(GLBufferTargetARB.ArrayBuffer, (uint)lastArrayBuffer);
+        gl.BlendEquationSeparate((GLBlendEquationModeEXT)lastBlendEqRgb, (GLBlendEquationModeEXT)lastBlendEqAlpha);
+        gl.BlendFuncSeparate((GLBlendingFactor)lastBlendSrcRgb, (GLBlendingFactor)lastBlendDstRgb, (GLBlendingFactor)lastBlendSrcAlpha, (GLBlendingFactor)lastBlendDstAlpha);
+
+        SetCap(gl, GLEnableCap.Blend, lastBlend);
+        SetCap(gl, GLEnableCap.CullFace, lastCullFace);
+        SetCap(gl, GLEnableCap.DepthTest, lastDepthTest);
+        SetCap(gl, GLEnableCap.StencilTest, lastStencilTest);
+        SetCap(gl, GLEnableCap.ScissorTest, lastScissorTest);
+        if (bd.GlVersion >= 310 && !bd.GlProfileIsES3)
+            SetCap(gl, GLEnableCap.PrimitiveRestart, lastPrimRestart);
+
+        if (bd.HasPolygonMode)
+        {
+            if (bd.GlVersion <= 310 || bd.GlProfileIsCompat)
+            {
+                gl.PolygonMode(GLTriangleFace.Front, (GLPolygonMode)lastPolygonMode[0]);
+                gl.PolygonMode(GLTriangleFace.Back, (GLPolygonMode)lastPolygonMode[1]);
+            }
+            else
+            {
+                gl.PolygonMode(GLTriangleFace.FrontAndBack, (GLPolygonMode)lastPolygonMode[0]);
+            }
+        }
+
+        gl.Viewport(lastViewport[0], lastViewport[1], lastViewport[2], lastViewport[3]);
+        gl.Scissor(lastScissorBox[0], lastScissorBox[1], lastScissorBox[2], lastScissorBox[3]);
     }
 
-    private static void UpdateTexture(ImTextureDataPtr tex, nint renderer)
+
+    private static void SetupRenderState(ImDrawDataPtr drawData, int fbWidth, int fbHeight, uint vao)
     {
+        RendererData bd = GetRendererData()!;
+        GL gl = bd.Gl;
+
+        gl.Enable(GLEnableCap.Blend);
+        gl.BlendEquation(GLBlendEquationModeEXT.FuncAdd);
+        gl.BlendFuncSeparate(GLBlendingFactor.SrcAlpha, GLBlendingFactor.OneMinusSrcAlpha, GLBlendingFactor.One, GLBlendingFactor.OneMinusSrcAlpha);
+        gl.Disable(GLEnableCap.CullFace);
+        gl.Disable(GLEnableCap.DepthTest);
+        gl.Disable(GLEnableCap.StencilTest);
+        gl.Enable(GLEnableCap.ScissorTest);
+
+        if (bd.GlVersion >= 310 && !bd.GlProfileIsES3)
+            gl.Disable(GLEnableCap.PrimitiveRestart);
+
+        if (bd.HasPolygonMode)
+            gl.PolygonMode(GLTriangleFace.FrontAndBack, GLPolygonMode.Fill);
+
+        gl.Viewport(0, 0, fbWidth, fbHeight);
+
+        float L = drawData.DisplayPos.X;
+        float R = drawData.DisplayPos.X + drawData.DisplaySize.X;
+        float T = drawData.DisplayPos.Y;
+        float B = drawData.DisplayPos.Y + drawData.DisplaySize.Y;
+
+        if (bd.HasClipOrigin)
+        {
+            gl.GetIntegerv(GLGetPName.ClipPlane0, out int clipOrigin);
+            if (clipOrigin == (int)GLEnum.UpperLeft)
+            {
+                (T, B) = (B, T);
+            }
+        }
+
+        float[] ortho =
+        {
+            2.0f / (R - L), 0.0f, 0.0f, 0.0f,
+            0.0f, 2.0f / (T - B), 0.0f, 0.0f,
+            0.0f, 0.0f, -1.0f, 0.0f,
+            (R + L) / (L - R), (T + B) / (B - T), 0.0f, 1.0f
+        };
+
+        gl.UseProgram(bd.ShaderHandle);
+        gl.Uniform1f(bd.AttribLocationTex, 0);
+        gl.UniformMatrix4fv(bd.AttribLocationProjMtx, 1, false, ortho);
+
+        if (bd.HasBindSampler)
+            gl.BindSampler(0, bd.TexSamplers[0]); // linear
+
+        gl.BindVertexArray(vao);
+        gl.BindBuffer(GLBufferTargetARB.ArrayBuffer, bd.VboHandle);
+        gl.BindBuffer(GLBufferTargetARB.ElementArrayBuffer, bd.ElementsHandle);
+
+        gl.EnableVertexAttribArray(bd.AttribLocationVtxPos);
+        gl.VertexAttribPointer(bd.AttribLocationVtxPos, 2, GLVertexAttribPointerType.Float, false, sizeof(ImDrawVert), (void*)0);
+
+        gl.EnableVertexAttribArray(bd.AttribLocationVtxUV);
+        gl.VertexAttribPointer(bd.AttribLocationVtxUV, 2, GLVertexAttribPointerType.Float, false, sizeof(ImDrawVert), (void*)8);
+
+        gl.EnableVertexAttribArray(bd.AttribLocationVtxColor);
+        gl.VertexAttribPointer(bd.AttribLocationVtxColor, 4, GLVertexAttribPointerType.UnsignedByte, true, sizeof(ImDrawVert), (void*)16);
+    }
+
+
+    public static void UpdateTexture(ImTextureDataPtr tex)
+    {
+        RendererData bd = GetRendererData()!;
+        GL gl = bd.Gl;
+
         if (tex.Status == ImTextureStatus.WantDestroy)
         {
             if (tex.TexID != ImTextureID.Null)
-                SDL.DestroyTexture(tex.TexID);
+            {
-
+                uint glId = (uint)(nint)tex.TexID;
+                gl.DeleteTexture(glId);
+            }
             tex.SetTexID(ImTextureID.Null);
             tex.SetStatus(ImTextureStatus.Destroyed);
             return;
         }
 
-        bool needsCreate = tex.TexID == ImTextureID.Null || SDL.GetRendererFromTexture(tex.TexID) != renderer;
+        gl.PixelStoref(GLPixelStoreParameter.UnpackRowLength, 0);
-        if (tex.Status == ImTextureStatus.WantCreate || needsCreate)
+        gl.PixelStoref(GLPixelStoreParameter.UnpackAlignment, 1);
+
+        if (tex.Status == ImTextureStatus.WantCreate)
         {
-            if (tex.TexID != ImTextureID.Null)
+            Debug.Assert(tex.Format == ImTextureFormat.Rgba32);
-                SDL.DestroyTexture(tex.TexID);
 
-            // Create texture on the renderer that is actually drawing this viewport.
+            gl.GetIntegerv(GLGetPName.TextureBinding2D, out int lastTex);
-            // SDL textures are renderer-owned and cannot be shared across renderer instances.
+            uint glTexId = 0;
-            nint sdlTexture = SDL.CreateTexture(renderer, SDL.PixelFormat.ABGR8888, SDL.TextureAccess.Static, tex.Width, tex.Height);
+            gl.GenTextures(1, ref glTexId);
-            SDL.UpdateTexture(sdlTexture, nint.Zero, (nint)tex.GetPixels(), tex.GetPitch());
+            gl.BindTexture(GLTextureTarget.Texture2D, glTexId);
-            SDL.SetTextureBlendMode(sdlTexture, SDL.BlendMode.Blend);
+            gl.TexParameterf(GLTextureTarget.Texture2D, GLTextureParameterName.MinFilter, (int)GLEnum.Linear);
-            SDL.SetTextureScaleMode(sdlTexture, SDL.ScaleMode.Linear);
+            gl.TexParameterf(GLTextureTarget.Texture2D, GLTextureParameterName.MagFilter, (int)GLEnum.Linear);
+            gl.TexParameterf(GLTextureTarget.Texture2D, GLTextureParameterName.WrapS, (int)GLEnum.ClampToEdge);
+            gl.TexParameterf(GLTextureTarget.Texture2D, GLTextureParameterName.WrapT, (int)GLEnum.ClampToEdge);
+            gl.TexImage2D(GLTextureTarget.Texture2D, 0, GLInternalFormat.Rgba, tex.Width, tex.Height, 0, GLPixelFormat.Rgba, GLPixelType.UnsignedByte, tex.GetPixels());
 
-            tex.SetTexID(sdlTexture);
+            tex.SetTexID((nint)glTexId);
             tex.SetStatus(ImTextureStatus.Ok);
+            gl.BindTexture(GLTextureTarget.Texture2D, (uint)lastTex);
             return;
         }
 
         if (tex.Status == ImTextureStatus.WantUpdates)
         {
-            // Update selected blocks. We only ever write to textures regions which have never been used before!
+            gl.GetIntegerv(GLGetPName.TextureBinding2D, out int lastTex);
-            // This backend choose to use tex.Updates[] but you can use tex.UpdateRect to upload a single region.
+            uint glTexId = (uint)(nint)tex.TexID;
-            nint sdlTexture = tex.TexID;
+            gl.BindTexture(GLTextureTarget.Texture2D, glTexId);
+
             for (int i = 0; i < tex.Updates.Size; i++)
             {
                 ImTextureRect r = tex.Updates[i];
-                SDL.Rect sdlR = new SDL.Rect { X = r.X, Y = r.Y, W = r.W, H = r.H };
+                gl.PixelStoref(GLPixelStoreParameter.UnpackRowLength, tex.Width);
-                SDL.UpdateTexture(sdlTexture, sdlR, (nint)tex.GetPixelsAt(r.X, r.Y), tex.GetPitch());
+                gl.TexSubImage2D(GLTextureTarget.Texture2D, 0, r.X, r.Y, r.W, r.H, GLPixelFormat.Rgba, GLPixelType.UnsignedByte, tex.GetPixelsAt(r.X, r.Y));
             }
+            gl.PixelStoref(GLPixelStoreParameter.UnpackRowLength, 0);
+
             tex.SetStatus(ImTextureStatus.Ok);
+            gl.BindTexture(GLTextureTarget.Texture2D, (uint)lastTex);
         }
     }
 
-    public static void CreateDeviceObjects() { }
+
+    public static bool CreateDeviceObjects()
+    {
+        RendererData bd = GetRendererData()!;
+        GL gl = bd.Gl;
+
+        gl.GetIntegerv(GLGetPName.TextureBinding2D, out int lastTexture);
+        gl.GetIntegerv(GLGetPName.ArrayBufferBinding, out int lastArrayBuffer);
+        gl.GetIntegerv(GLGetPName.VertexArrayBinding, out int lastVertexArray);
+
+        int glslVersion = 130;
+        {
+            string vstr = bd.GlslVersionString.TrimStart().TrimStart('#');
+            if (vstr.StartsWith("version "))
+                int.TryParse(vstr["version ".Length..].Split(' ')[0], out glslVersion);
+        }
+
+        const string vertSrc120 = "uniform mat4 ProjMtx;\n" + "attribute vec2 Position;\n" + "attribute vec2 UV;\n" + "attribute vec4 Color;\n" + "varying vec2 Frag_UV;\n" + "varying vec4 Frag_Color;\n" + "void main() {\n" + "    Frag_UV    = UV;\n" + "    Frag_Color = Color;\n" + "    gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n" + "}\n";
+        const string fragSrc120 = "#ifdef GL_ES\n    precision mediump float;\n#endif\n" + "uniform sampler2D Texture;\n" + "varying vec2 Frag_UV;\n" + "varying vec4 Frag_Color;\n" + "void main() {\n" + "    gl_FragColor = Frag_Color * texture2D(Texture, Frag_UV.st);\n" + "}\n";
+        const string vertSrc130 = "uniform mat4 ProjMtx;\n" + "in vec2 Position;\nin vec2 UV;\nin vec4 Color;\n" + "out vec2 Frag_UV;\nout vec4 Frag_Color;\n" + "void main() {\n" + "    Frag_UV    = UV;\n" + "    Frag_Color = Color;\n" + "    gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n" + "}\n";
+        const string fragSrc130 = "uniform sampler2D Texture;\n" + "in vec2 Frag_UV;\nin vec4 Frag_Color;\n" + "out vec4 Out_Color;\n" + "void main() {\n" + "    Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n" + "}\n";
+        const string vertSrc300es = "precision highp float;\n" + "layout (location = 0) in vec2 Position;\n" + "layout (location = 1) in vec2 UV;\n" + "layout (location = 2) in vec4 Color;\n" + "uniform mat4 ProjMtx;\n" + "out vec2 Frag_UV;\nout vec4 Frag_Color;\n" + "void main() {\n" + "    Frag_UV    = UV;\n" + "    Frag_Color = Color;\n" + "    gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n" + "}\n";
+        const string fragSrc300es = "precision mediump float;\n" + "uniform sampler2D Texture;\n" + "in vec2 Frag_UV;\nin vec4 Frag_Color;\n" + "layout (location = 0) out vec4 Out_Color;\n" + "void main() {\n" + "    Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n" + "}\n";
+        const string vertSrc410 = "layout (location = 0) in vec2 Position;\n" + "layout (location = 1) in vec2 UV;\n" + "layout (location = 2) in vec4 Color;\n" + "uniform mat4 ProjMtx;\n" + "out vec2 Frag_UV;\nout vec4 Frag_Color;\n" + "void main() {\n" + "    Frag_UV    = UV;\n" + "    Frag_Color = Color;\n" + "    gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n" + "}\n";
+        const string fragSrc410 = "in vec2 Frag_UV;\nin vec4 Frag_Color;\n" + "uniform sampler2D Texture;\n" + "layout (location = 0) out vec4 Out_Color;\n" + "void main() {\n" + "    Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n" + "}\n";
+
+        (string vertSrc, string fragSrc) = glslVersion switch
+        {
+            < 130  => (vertSrc120, fragSrc120),
+            300    => (vertSrc300es, fragSrc300es),
+            >= 410 => (vertSrc410, fragSrc410),
+            _      => (vertSrc130, fragSrc130)
+        };
+
+        string fullVert = bd.GlslVersionString + vertSrc;
+        string fullFrag = bd.GlslVersionString + fragSrc;
+
+        uint vert = gl.CreateShader(GLShaderType.VertexShader);
+        gl.ShaderSource(vert, fullVert);
+        gl.CompileShader(vert);
+        if (!CheckShader(gl, vert, "vertex shader")) return false;
+
+        uint frag = gl.CreateShader(GLShaderType.FragmentShader);
+        gl.ShaderSource(frag, fullFrag);
+        gl.CompileShader(frag);
+        if (!CheckShader(gl, frag, "fragment shader")) return false;
+
+        bd.ShaderHandle = gl.CreateProgram();
+        gl.AttachShader(bd.ShaderHandle, vert);
+        gl.AttachShader(bd.ShaderHandle, frag);
+        gl.LinkProgram(bd.ShaderHandle);
+        if (!CheckProgram(gl, bd.ShaderHandle, "shader program")) return false;
+
+        gl.DetachShader(bd.ShaderHandle, vert);
+        gl.DetachShader(bd.ShaderHandle, frag);
+        gl.DeleteShader(vert);
+        gl.DeleteShader(frag);
+
+        bd.AttribLocationTex = gl.GetUniformLocation(bd.ShaderHandle, "Texture");
+        bd.AttribLocationProjMtx = gl.GetUniformLocation(bd.ShaderHandle, "ProjMtx");
+        bd.AttribLocationVtxPos = (uint)gl.GetAttribLocation(bd.ShaderHandle, "Position");
+        bd.AttribLocationVtxUV = (uint)gl.GetAttribLocation(bd.ShaderHandle, "UV");
+        bd.AttribLocationVtxColor = (uint)gl.GetAttribLocation(bd.ShaderHandle, "Color");
+
+        gl.GenBuffers(1, ref bd.VboHandle);
+        gl.GenBuffers(1, ref bd.ElementsHandle);
+
+        if (bd.HasBindSampler)
+        {
+            gl.GenSamplers(2, bd.TexSamplers);
+            for (int i = 0; i < 2; i++)
+            {
+                int filter = i == 0 ? (int)GLEnum.Linear : (int)GLEnum.Nearest;
+                gl.SamplerParameteri(bd.TexSamplers[i], GLSamplerParameterI.TextureMinFilter, filter);
+                gl.SamplerParameteri(bd.TexSamplers[i], GLSamplerParameterI.TextureMagFilter, filter);
+                gl.SamplerParameteri(bd.TexSamplers[i], GLSamplerParameterI.TextureWrapS, (int)GLEnum.ClampToEdge);
+                gl.SamplerParameteri(bd.TexSamplers[i], GLSamplerParameterI.TextureWrapT, (int)GLEnum.ClampToEdge);
+            }
+        }
+
+        gl.BindTexture(GLTextureTarget.Texture2D, (uint)lastTexture);
+        gl.BindBuffer(GLBufferTargetARB.ArrayBuffer, (uint)lastArrayBuffer);
+        gl.BindVertexArray((uint)lastVertexArray);
+
+        return true;
+    }
 
     public static void DestroyDeviceObjects()
     {
-        ImVector<ImTextureDataPtr> texures = ImGui.GetPlatformIO().Textures;
+        RendererData? bd = GetRendererData();
-        for (int i = 0; i < texures.Size; i++)
+        if (bd == null) return;
+        GL gl = bd.Gl;
+
+        if (bd.HasBindSampler && bd.TexSamplers[0] != 0)
         {
-            ImTextureDataPtr texture = texures[i];
+            gl.DeleteSamplers(2, bd.TexSamplers);
-            texture.Status = ImTextureStatus.WantDestroy;
+            bd.TexSamplers[0] = bd.TexSamplers[1] = 0;
-            UpdateTexture(texture, GetRendererData().Renderer);
+        }
+
+        if (bd.VboHandle != 0)
+        {
+            gl.DeleteBuffer(bd.VboHandle);
+            bd.VboHandle = 0;
+        }
+        if (bd.ElementsHandle != 0)
+        {
+            gl.DeleteBuffer(bd.ElementsHandle);
+            bd.ElementsHandle = 0;
+        }
+        if (bd.ShaderHandle != 0)
+        {
+            gl.DeleteProgram(bd.ShaderHandle);
+            bd.ShaderHandle = 0;
+        }
+
+        ImVector<ImTextureDataPtr> textures = ImGui.GetPlatformIO().Textures;
+        for (int i = 0; i < textures.Size; i++)
+        {
+            ImTextureDataPtr tex = textures[i];
+            if (tex.RefCount == 1)
+            {
+                tex.SetStatus(ImTextureStatus.WantDestroy);
+                UpdateTexture(tex);
+            }
         }
     }
 
-    // @formatter:off — disable formatter after this line
+
+    private static void InitMultiViewportSupport()
+    {
+        ImGuiPlatformIOPtr platformIO = ImGui.GetPlatformIO();
+        platformIO.RendererRenderWindow = DelegateStorage.RendererRenderWindowDelegate.GetPtrForDelegate();
+    }
+
+    private static void ShutdownMultiViewportSupport()
+    {
+        ImGui.DestroyPlatformWindows();
+    }
+
+    private static void ApplySamplerLinear(RendererData bd)
+    {
+        if (bd.HasBindSampler)
+        {
+            bd.Gl.BindSampler(0, bd.TexSamplers[0]);
+        }
+        else
+        {
+            bd.UseTexParameterToSetSampler = true;
+            bd.NextSampler = (int)GLEnum.Linear;
+        }
+    }
+
+    private static void ApplySamplerNearest(RendererData bd)
+    {
+        if (bd.HasBindSampler)
+        {
+            bd.Gl.BindSampler(0, bd.TexSamplers[1]);
+        }
+        else
+        {
+            bd.UseTexParameterToSetSampler = true;
+            bd.NextSampler = (int)GLEnum.Nearest;
+        }
+    }
+
+
+    private static bool CheckShader(GL gl, uint handle, string desc)
+    {
+        gl.GetShaderiv(handle, GLShaderParameterName.CompileStatus, out int status);
+        gl.GetShaderiv(handle, GLShaderParameterName.InfoLogLength, out int logLen);
+        if (status == 0)
+        {
+            string log = logLen > 1 ? gl.GetShaderInfoLog(handle) : "";
+            Console.Error.WriteLine($"[ImGui OpenGL3] Failed to compile {desc}:\n{log}");
+        }
+        return status != 0;
+    }
+
+    private static bool CheckProgram(GL gl, uint handle, string desc)
+    {
+        gl.GetProgramiv(handle, GLProgramPropertyARB.LinkStatus, out int status);
+        gl.GetProgramiv(handle, GLProgramPropertyARB.InfoLogLength, out int logLen);
+        if (status == 0)
+        {
+            string log = logLen > 1 ? gl.GetProgramInfoLog(handle) : "";
+            Console.Error.WriteLine($"[ImGui OpenGL3] Failed to link {desc}:\n{log}");
+        }
+        return status != 0;
+    }
+
+
+    private static void SetCap(GL gl, GLEnableCap cap, bool enabled)
+    {
+        if (enabled) gl.Enable(cap);
+        else gl.Disable(cap);
+    }
+
+
     public static class DelegateStorage
     {
         [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-        internal delegate void DrawCallbackResetRenderStateFn(ImDrawListPtr drawList, ImDrawCmdPtr cmd);
+        internal delegate void DrawCallbackFn(ImDrawListPtr drawList, ImDrawCmdPtr cmd);
-        internal static readonly DrawCallbackResetRenderStateFn DrawCallbackResetRenderStateDelegate = DrawCallbackResetRenderState;
-        private static void DrawCallbackResetRenderState(ImDrawListPtr drawList, ImDrawCmdPtr cmd) { } // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
 
-        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+        internal static readonly DrawCallbackFn DrawCallbackResetRenderStateDelegate = DrawCallbackResetRenderState;
-        internal delegate void RendererCreateWindowFn(ImGuiViewportPtr viewport);
+        private static void DrawCallbackResetRenderState(ImDrawListPtr _, ImDrawCmdPtr __) { } // Intentionally empty.
-        internal static readonly RendererCreateWindowFn RendererCreateWindowDelegate = RendererCreateWindow;
+
-        private static void RendererCreateWindow(ImGuiViewportPtr viewport)
+        internal static readonly DrawCallbackFn DrawCallbackSetSamplerLinearDelegate = DrawCallbackSetSamplerLinear;
+        private static void DrawCallbackSetSamplerLinear(ImDrawListPtr _, ImDrawCmdPtr __)
         {
-            ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
+            RendererData? bd = GetRendererData();
-            if (vd == null || vd.Window == nint.Zero)
+            if (bd != null) ApplySamplerLinear(bd);
-                return;
+        }
 
-            if (vd.Renderer == nint.Zero)
+        internal static readonly DrawCallbackFn DrawCallbackSetSamplerNearestDelegate = DrawCallbackSetSamplerNearest;
-            {
+        private static void DrawCallbackSetSamplerNearest(ImDrawListPtr _, ImDrawCmdPtr __)
-                vd.Renderer = SDL.CreateRenderer(vd.Window, null);
+        {
-                vd.RendererOwned = true;
+            RendererData? bd = GetRendererData();
-            }
+            if (bd != null) ApplySamplerNearest(bd);
         }
 
         [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-        internal delegate void RendererDestroyWindowFn(ImGuiViewportPtr viewport);
+        internal delegate void RendererRenderWindowFn(ImGuiViewportPtr viewport, void* renderArg);
-        internal static readonly RendererDestroyWindowFn RendererDestroyWindowDelegate = RendererDestroyWindow;
-        private static void RendererDestroyWindow(ImGuiViewportPtr viewport)
-        {
-            ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
-            if (vd == null)
-                return;
 
-            if (vd.RendererOwned && vd.Renderer != nint.Zero)
-            {
-                SDL.DestroyRenderer(vd.Renderer);
-            }
-
-            vd.Renderer = nint.Zero;
-            vd.RendererOwned = false;
-        }
-
-        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-        internal delegate void RendererRenderWindowFn(ImGuiViewportPtr viewport);
         internal static readonly RendererRenderWindowFn RendererRenderWindowDelegate = RendererRenderWindow;
-        private static void RendererRenderWindow(ImGuiViewportPtr viewport)
+        private static void RendererRenderWindow(ImGuiViewportPtr viewport, void* renderArg)
         {
-            ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
+            if ((viewport.Flags & ImGuiViewportFlags.NoRendererClear) == 0)
-            if (vd == null || vd.Renderer == nint.Zero)
             {
-                return;
+                RendererData? bd = GetRendererData();
+                if (bd != null)
+                {
+                    bd.Gl.ClearColor(0f, 0f, 0f, 1f);
+                    bd.Gl.Clear(GLClearBufferMask.ColorBufferBit);
+                }
             }
-
+            RenderDrawData(viewport.DrawData);
-            if (Parent != null)
-            {
-                SDL.SetRenderDrawColorFloat(vd.Renderer, Parent.ClearColor.X, Parent.ClearColor.Y, Parent.ClearColor.Z, 0f);
-                SDL.RenderClear(vd.Renderer);
-            }
-
-            RenderDrawData(viewport.DrawData, vd.Renderer);
-        }
-
-        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-        internal delegate void RendererSwapBuffersFn(ImGuiViewportPtr viewport);
-        internal static readonly RendererSwapBuffersFn RendererSwapBuffersDelegate = RendererSwapBuffers;
-        private static void RendererSwapBuffers(ImGuiViewportPtr viewport)
-        {
-            ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
-            if (vd == null || vd.Renderer == nint.Zero)
-                return;
-
-            SDL.RenderPresent(vd.Renderer);
         }
     }
-    // @formatter:on — enable formatter after this line
+
 }

SDL3/OpenGLTexture.cs

@@ -0,0 +1,182 @@
+using System.Numerics;
+using Hexa.NET.ImGui;
+using Hexa.NET.OpenGL;
+using SDL3;
+
+namespace SDL3_TestingSuite.SDL3;
+
+public sealed unsafe class OpenGLTexture : IDisposable
+{
+    private readonly GL _gl;
+
+    public uint Handle { get; private set; }
+    public int Width { get; }
+    public int Height { get; }
+
+    public ImTextureRef ImGuiTexture => new ImTextureRef(null, (nint)Handle);
+    public Vector2 Size => new Vector2(Width, Height);
+
+    public string? FileName;
+    public string? FilePath;
+    public string? Extension;
+
+    private OpenGLTexture(GL gl, uint handle, int width, int height, string? path = null)
+    {
+        _gl = gl;
+        Handle = handle;
+        Width = width;
+        Height = height;
+        
+        if (path == null) return;
+        FileName = Path.GetFileName(path);
+        FilePath = path;
+        Extension = Path.GetExtension(path);
+    }
+
+    public static OpenGLTexture FromFile(GL gl, string path)
+    {
+        nint surface = string.Equals(Path.GetExtension(path), ".bmp", StringComparison.OrdinalIgnoreCase)
+            ? SDL.LoadBMP(path)
+            : Image.Load(path);
+
+        if (surface == nint.Zero)
+        {
+            throw new InvalidOperationException($"Failed to load image '{path}': {SDL.GetError()}");
+        }
+
+        try
+        {
+            return FromSurface(gl, surface, path);
+        }
+        finally
+        {
+            SDL.DestroySurface(surface);
+        }
+    }
+
+    public static OpenGLTexture FromSurface(GL gl, nint surface, string? path = null)
+    {
+        if (surface == nint.Zero)
+        {
+            throw new ArgumentException("Surface cannot be null.", nameof(surface));
+        }
+
+        SDL.PixelFormat uploadFormat = BitConverter.IsLittleEndian
+            ? SDL.PixelFormat.ABGR8888
+            : SDL.PixelFormat.RGBA8888;
+
+        nint converted = SDL.ConvertSurface(surface, uploadFormat);
+        if (converted == nint.Zero)
+        {
+            throw new InvalidOperationException($"Failed to convert image surface to RGBA32: {SDL.GetError()}");
+        }
+
+        try
+        {
+            SDL.Surface* convertedSurface = (SDL.Surface*)converted;
+            bool locked = false;
+
+            if (SDL.MustLock(*convertedSurface))
+            {
+                if (!SDL.LockSurface(converted))
+                {
+                    throw new InvalidOperationException($"Failed to lock image surface: {SDL.GetError()}");
+                }
+
+                locked = true;
+            }
+
+            try
+            {
+                uint texture = UploadRgba32(gl, convertedSurface);
+                return new OpenGLTexture(gl, texture, convertedSurface->Width, convertedSurface->Height, path);
+            }
+            finally
+            {
+                if (locked)
+                {
+                    SDL.UnlockSurface(converted);
+                }
+            }
+        }
+        finally
+        {
+            SDL.DestroySurface(converted);
+        }
+    }
+
+    private static uint UploadRgba32(GL gl, SDL.Surface* surface)
+    {
+        uint texture = 0;
+        gl.GenTextures(1, ref texture);
+
+        gl.GetIntegerv(GLGetPName.TextureBinding2D, out int previousTexture);
+        gl.BindTexture(GLTextureTarget.Texture2D, texture);
+
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.MinFilter, (int)GLTextureMinFilter.Linear);
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.MagFilter, (int)GLTextureMagFilter.Linear);
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.WrapS, (int)GLEnum.ClampToEdge);
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.WrapT, (int)GLEnum.ClampToEdge);
+
+        gl.PixelStorei(GLPixelStoreParameter.UnpackAlignment, 1);
+        gl.PixelStorei(GLPixelStoreParameter.UnpackRowLength, surface->Pitch / 4);
+        gl.TexImage2D(
+            GLTextureTarget.Texture2D,
+            0,
+            GLInternalFormat.Rgba,
+            surface->Width,
+            surface->Height,
+            0,
+            GLPixelFormat.Rgba,
+            GLPixelType.UnsignedByte,
+            surface->Pixels);
+        gl.PixelStorei(GLPixelStoreParameter.UnpackRowLength, 0);
+
+        gl.BindTexture(GLTextureTarget.Texture2D, (uint)previousTexture);
+        return texture;
+    }
+
+    private static uint UploadRgba32FromPixels(GL gl, byte[] pixels, int width, int height)
+    {
+        uint texture = 0;
+        gl.GenTextures(1, ref texture);
+
+        gl.GetIntegerv(GLGetPName.TextureBinding2D, out int previousTexture);
+        gl.BindTexture(GLTextureTarget.Texture2D, texture);
+
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.MinFilter, (int)GLTextureMinFilter.Linear);
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.MagFilter, (int)GLTextureMagFilter.Linear);
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.WrapS, (int)GLEnum.ClampToEdge);
+        gl.TexParameteri(GLTextureTarget.Texture2D, GLTextureParameterName.WrapT, (int)GLEnum.ClampToEdge);
+
+        gl.PixelStorei(GLPixelStoreParameter.UnpackAlignment, 1);
+
+        fixed (byte* ptr = &pixels[0])
+        {
+            gl.TexImage2D(
+                GLTextureTarget.Texture2D,
+                0,
+                GLInternalFormat.Rgba,
+                width,
+                height,
+                0,
+                GLPixelFormat.Rgba,
+                GLPixelType.UnsignedByte,
+                (nint)ptr);
+        }
+
+        gl.BindTexture(GLTextureTarget.Texture2D, (uint)previousTexture);
+        return texture;
+    }
+
+    public void Dispose()
+    {
+        if (Handle == 0)
+        {
+            return;
+        }
+
+        _gl.DeleteTexture(Handle);
+        Handle = 0;
+    }
+}

SDL3/SDL3Window.cs

@@ -2,6 +2,9 @@
 using Hexa.NET.ImGui;
 using Hexa.NET.ImGuizmo;
 using Hexa.NET.ImPlot;
+using Hexa.NET.ImNodes;
+using Hexa.NET.OpenGL;
+using HexaGen.Runtime;
 using SDL3;
 
 namespace SDL3_TestingSuite.SDL3;
@@ -9,8 +12,7 @@ namespace SDL3_TestingSuite.SDL3;
 public sealed unsafe class SDL3Window : IDisposable
 {
     public readonly nint Window;
-    public readonly nint Renderer;
+
-    
     public readonly Vector4 DefaultClearColor = new Vector4(0.06f, 0.06f, 0.06f, 1f);
 
     private Vector4? _clearColor;
@@ -21,34 +23,66 @@ public sealed unsafe class SDL3Window : IDisposable
     }
 
     public event Action? RenderCallback;
+    public event Action? Disposing;
+    public event Action<Vector4>? Resized;
+    public event Action<SDL.Event>? EventCallback;
 
     private ImGuiContextPtr _imGuiContext;
     private ImPlotContextPtr _imPlotContext;
-
+    private ImNodesContextPtr _imNodesContext;
+    // private ImPLot3DContextPtr _imPlot3DContext;
+    
     public bool Disposed => _disposed;
     private bool _disposed;
 
     private readonly FileSystemWatcher? _watcher;
 
+    public readonly GL GL;
+
     public SDL3Window(string name, int posX, int posY, int width, int height, SDL.WindowFlags flags = SDL.WindowFlags.Resizable | SDL.WindowFlags.HighPixelDensity)
     {
+        if (OperatingSystem.IsLinux())
+            SDL.SetHint(SDL.Hints.VideoDriver, "x11");
+
         if (!SDL.Init(SDL.InitFlags.Events | SDL.InitFlags.Video | SDL.InitFlags.Gamepad))
             throw new Exception($"SDL_Init failed: {SDL.GetError()}");
 
+        SDL.GLSetAttribute(SDL.GLAttr.ContextFlags, (int)SDL.GLContextFlag.ForwardCompatible);
+        SDL.GLSetAttribute(SDL.GLAttr.ContextProfileMask, (int)SDL.GLProfile.Core);
+        SDL.GLSetAttribute(SDL.GLAttr.ContextMajorVersion, 4);
+        SDL.GLSetAttribute(SDL.GLAttr.ContextMinorVersion, 6);
+
+        SDL.SetHint(SDL.Hints.IMEImplementedUI, "1");
+
         // Create window & renderer
-        if (!SDL.CreateWindowAndRenderer(name, width, height, flags, out Window, out Renderer))
+        SDL.GLSetAttribute(SDL.GLAttr.DoubleBuffer, 1);
+        SDL.GLSetAttribute(SDL.GLAttr.DepthSize, 24);
+        SDL.GLSetAttribute(SDL.GLAttr.StencilSize, 8);
+        Window = SDL.CreateWindow(name, width, height, flags | SDL.WindowFlags.OpenGL);
+        if (Window == nint.Zero)
             throw new Exception($"SDL_CreateWindowAndRenderer failed: {SDL.GetError()}");
 
+        nint glContext = SDL.GLCreateContext(Window);
+        if (glContext == nint.Zero)
+            throw new Exception($"SDL_GL_CreateContext failed: {SDL.GetError()}");
+
+        SDL.GLMakeCurrent(Window, glContext);
+        SDL.GLSetSwapInterval(1);
+
         SDL.SetWindowPosition(Window, posX, posY);
-        SDL.SetRenderVSync(Renderer, 1);
+        // SDL.SetRenderVSync(Renderer, 1);
         SDL.ShowWindow(Window);
 
         // Create ImGui context
         _imGuiContext = ImGui.CreateContext();
         _imPlotContext = ImPlot.CreateContext();
+        _imNodesContext = ImNodes.CreateContext();
+        // _imPlot3DContext = ImPlot3D.CreateContext();
         ImPlot.SetImGuiContext(_imGuiContext);
         ImGuizmo.SetImGuiContext(_imGuiContext);
-
+        ImNodes.SetImGuiContext(_imGuiContext);
+        // ImPlot3D.SetImGuiContext(_imGuiContext);
+        
         ImGuiIOPtr io = ImGui.GetIO();
         io.ConfigFlags |= ImGuiConfigFlags.NavEnableKeyboard | ImGuiConfigFlags.NavEnableGamepad | ImGuiConfigFlags.DockingEnable;
         io.ConfigFlags |= ImGuiConfigFlags.ViewportsEnable;
@@ -68,33 +102,64 @@ public sealed unsafe class SDL3Window : IDisposable
                 if (!File.Exists(b.FullPath)) return;
 
                 if (Path.GetExtension(b.FullPath) != ".ttf") return;
-
                 ImGui.GetIO().AddFont(b.FullPath);
             };
             _watcher.Deleted += (_, b) =>
             {
                 if (Path.GetExtension(b.FullPath) != ".ttf") return;
-
                 ImGui.GetIO().RemoveFont(b.Name);
             };
+            _watcher.Renamed += (_, b) =>
+            {
+                if (Path.GetExtension(b.OldFullPath) != ".ttf") return;
+                ImGui.GetIO().RemoveFont(b.OldName);
+
+                if (!File.Exists(b.FullPath)) return;
+                if (Path.GetExtension(b.FullPath) != ".ttf") return;
+                ImGui.GetIO().AddFont(b.FullPath);
+            };
 
             _watcher.IncludeSubdirectories = false;
             _watcher.EnableRaisingEvents = true;
 
-            string[] fonts = Directory.GetFiles(fontsPath, "*.ttf", SearchOption.AllDirectories);
+            List<string> fonts = Directory.GetFiles(fontsPath, "*.ttf", SearchOption.AllDirectories).ToList();
+            fonts.Sort();
+
+            List<string> mergeFonts = new List<string>();
+            for (int i = fonts.Count - 1; i >= 0; i--)
+            {
+                if (Path.GetFileName(fonts[i]).StartsWith("merge_", StringComparison.OrdinalIgnoreCase))
+                {
+                    mergeFonts.Add(fonts[i]);
+                    fonts.RemoveAt(i);
+                }
+            }
+            mergeFonts.Reverse();
+            
+            foreach (string merge in mergeFonts)
+            {
+                io.AddFont(merge, true);
+            }
+
             foreach (string font in fonts)
             {
                 io.AddFont(font);
+                foreach (string merge in mergeFonts)
+                {
+                    io.AddFont(merge, true);
+                }
             }
         }
         catch (Exception e)
         {
             Console.WriteLine(e);
         }
+        
+        GL = new GL(new BindingsContext(Window, glContext));
 
         // Init platform and renderer
-        ImGuiSDL3Platform.Init(Window, Renderer, this);
+        ImGuiSDL3Platform.Init(GL, Window, glContext);
-        ImGuiSDL3Renderer.Init(Renderer, this);
+        ImGuiSDL3Renderer.Init(GL, "#version 330");
     }
 
     public bool ShouldClose;
@@ -103,10 +168,7 @@ public sealed unsafe class SDL3Window : IDisposable
     {
         while (!_disposed)
         {
-            if (ImGui.GetIO().WantTextInput && !SDL.TextInputActive(Window))
+            SDL.PumpEvents();
-                SDL.StartTextInput(Window);
-            else if (!ImGui.GetIO().WantTextInput && SDL.TextInputActive(Window))
-                SDL.StopTextInput(Window);
 
             while (SDL.PollEvent(out SDL.Event ev))
             {
@@ -119,9 +181,27 @@ public sealed unsafe class SDL3Window : IDisposable
                     case SDL.EventType.Quit:
                         ShouldClose = true;
                         break;
+                    case SDL.EventType.WindowResized:
+                    case SDL.EventType.WindowMoved:
+                        SDL.GetWindowSize(Window, out int w, out int h);
+                        SDL.GetWindowPosition(Window, out int x, out int y);
+                        Resized?.Invoke(new Vector4(x, y, w, h));
+                        break;
                 }
+                
+                EventCallback?.Invoke(ev);
             }
 
+            if (SDL.GetWindowFlags(Window).HasFlag(SDL.WindowFlags.Minimized))
+            {
+                SDL.Delay(10);
+                continue;
+            }
+            
+            GL.MakeCurrent();
+            GL.ClearColor(ClearColor.X, ClearColor.Y, ClearColor.Z, ClearColor.W);
+            GL.Clear(GLClearBufferMask.ColorBufferBit);
+
             ImGuiSDL3Platform.NewFrame();
             ImGuiSDL3Renderer.NewFrame();
             ImGui.NewFrame();
@@ -132,19 +212,18 @@ public sealed unsafe class SDL3Window : IDisposable
 
             ImGui.Render();
 
-            SDL.SetRenderScale(Renderer, io.DisplayFramebufferScale.X, io.DisplayFramebufferScale.Y);
+            GL.MakeCurrent();
-            SDL.SetRenderDrawColorFloat(Renderer, ClearColor.X, ClearColor.Y, ClearColor.Z, ClearColor.W);
-            SDL.RenderClear(Renderer);
 
-            ImGuiSDL3Renderer.RenderDrawData(ImGui.GetDrawData(), Renderer);
+            ImGuiSDL3Renderer.RenderDrawData(ImGui.GetDrawData());
 
             if ((io.ConfigFlags & ImGuiConfigFlags.ViewportsEnable) != 0)
             {
                 ImGui.UpdatePlatformWindows();
                 ImGui.RenderPlatformWindowsDefault();
             }
-
+            
-            SDL.RenderPresent(Renderer);
+            GL.MakeCurrent();
+            GL.SwapBuffers();
 
             if (ShouldClose)
             {
@@ -184,10 +263,13 @@ public sealed unsafe class SDL3Window : IDisposable
                 ImPlot.SetCurrentContext(_imPlotContext);
             }
 
+            Disposing?.Invoke();
+
             ImGuiSDL3Renderer.Dispose();
             ImGuiSDL3Platform.Dispose();
 
             RenderCallback = null;
+            Disposing = null;
         }
 
         if (_imGuiContext.Handle != null)
@@ -202,11 +284,23 @@ public sealed unsafe class SDL3Window : IDisposable
             ImPlot.DestroyContext(_imPlotContext);
             _imPlotContext = null;
         }
-
+        if (_imNodesContext.Handle != null)
-        if (Renderer != nint.Zero)
         {
-            SDL.DestroyRenderer(Renderer);
+            ImNodes.SetCurrentContext(null);
+            ImNodes.DestroyContext(_imNodesContext);
+            _imNodesContext = null;
         }
+        // if (_imPlot3DContext.Handle != null)
+        // {
+        //     ImPlot3D.SetCurrentContext(null);
+        //     ImPlot3D.DestroyContext(_imPlot3DContext);
+        //     _imPlot3DContext = null;
+        // }
+
+        // if (Renderer != nint.Zero)
+        // {
+        //     SDL.DestroyRenderer(Renderer);
+        // }
 
         if (Window != nint.Zero)
         {
@@ -214,4 +308,53 @@ public sealed unsafe class SDL3Window : IDisposable
         }
     }
 
-}
+}
+
+public unsafe class BindingsContext : IGLContext
+{
+    private readonly nint window;
+    private readonly nint context;
+
+    public BindingsContext(nint window, nint context)
+    {
+        this.window = window;
+        this.context = context;
+    }
+
+    public nint Handle => window;
+
+    public bool IsCurrent => SDL.GLGetCurrentContext() == context;
+
+    public void Dispose() { }
+
+    public nint GetProcAddress(string procName)
+    {
+        return (nint)SDL.GLGetProcAddress(procName).GetPtrForDelegate();
+    }
+
+    public bool IsExtensionSupported(string extensionName)
+    {
+        return SDL.GLExtensionSupported(extensionName);
+    }
+
+    public void MakeCurrent()
+    {
+        SDL.GLMakeCurrent(window, context);
+    }
+
+    public void SwapBuffers()
+    {
+        SDL.GLSwapWindow(window);
+    }
+
+    public void SwapInterval(int interval)
+    {
+        SDL.GLSetSwapInterval(interval);
+    }
+
+    public bool TryGetProcAddress(string procName, out nint procAddress)
+    {
+        procAddress = (nint)SDL.GLGetProcAddress(procName).GetPtrForDelegate();
+        return procAddress != 0;
+    }
+}