434 lines
16 KiB
C#
434 lines
16 KiB
C#
using System.Numerics;
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using System.Runtime.InteropServices;
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using Hexa.NET.ImGui;
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using SDL3;
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namespace SDL3_TestingSuite.SDL3;
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/// <summary>
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/// Implementation of ImGui for SDL3 Renderer backend.
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/// https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_sdlrenderer3.h
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/// </summary>
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public unsafe static class ImGuiSDL3Renderer
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{
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private sealed class TextureState
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{
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public ImTextureDataPtr Source;
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public readonly Dictionary<nint, nint> RendererTextures = new();
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}
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public class RendererData
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{
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public nint Renderer; // Main viewport's renderer
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public ImVector<SDL.FColor> ColorBuffer;
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// Render State
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public SDL.ScaleMode CurrentScaleMode;
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}
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private struct BackupSDLRendererState
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{
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public SDL.Rect Viewport;
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public bool ViewportEnabled;
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public bool ClipEnabled;
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public SDL.Rect ClipRect;
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}
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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private delegate void RendererCreateWindowFn(ImGuiViewportPtr viewport);
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private static readonly RendererCreateWindowFn RendererCreateWindowDelegate = RendererCreateWindow;
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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private delegate void RendererDestroyWindowFn(ImGuiViewportPtr viewport);
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private static readonly RendererDestroyWindowFn RendererDestroyWindowDelegate = RendererDestroyWindow;
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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private delegate void RendererSetWindowSizeFn(ImGuiViewportPtr viewport, Vector2 size);
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private static readonly RendererSetWindowSizeFn RendererSetWindowSizeDelegate = RendererSetWindowSize;
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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private delegate void RendererRenderWindowFn(ImGuiViewportPtr viewport);
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private static readonly RendererRenderWindowFn RendererRenderWindowDelegate = RendererRenderWindow;
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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private delegate void RendererSwapBuffersFn(ImGuiViewportPtr viewport);
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private static readonly RendererSwapBuffersFn RendererSwapBuffersDelegate = RendererSwapBuffers;
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public static RendererData Data => ImGui.GetCurrentContext().Handle != null ? ImGuiUserData<RendererData>.Get(ImGui.GetIO().BackendRendererUserData)! : null!;
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public static bool Init(nint renderer)
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{
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ImGuiIOPtr io = ImGui.GetIO();
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RendererData bd = new RendererData();
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io.BackendRendererUserData = ImGuiUserData<RendererData>.Store(bd);
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io.BackendRendererName = (byte*)Marshal.StringToHGlobalAnsi("NepImGuiSDL3Renderer");
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io.BackendFlags |= ImGuiBackendFlags.RendererHasVtxOffset; // We can honor the ImDrawCmd.VtxOffset field, allowing for large meshes.
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io.BackendFlags |= ImGuiBackendFlags.RendererHasTextures; // We can honor ImGuiPlatformIO.Textures[] requests during render.
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io.BackendFlags |= ImGuiBackendFlags.RendererHasViewports;
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bd.Renderer = renderer;
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ImGuiPlatformIOPtr platformIO = ImGui.GetPlatformIO();
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platformIO.RendererCreateWindow = (void*)Marshal.GetFunctionPointerForDelegate(RendererCreateWindowDelegate);
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platformIO.RendererDestroyWindow = (void*)Marshal.GetFunctionPointerForDelegate(RendererDestroyWindowDelegate);
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platformIO.RendererSetWindowSize = (void*)Marshal.GetFunctionPointerForDelegate(RendererSetWindowSizeDelegate);
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platformIO.RendererRenderWindow = (void*)Marshal.GetFunctionPointerForDelegate(RendererRenderWindowDelegate);
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platformIO.RendererSwapBuffers = (void*)Marshal.GetFunctionPointerForDelegate(RendererSwapBuffersDelegate);
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return true;
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}
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public static void Dispose()
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{
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var io = ImGui.GetIO();
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var platformIO = ImGui.GetPlatformIO();
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DestroyDeviceObjects();
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io.BackendRendererName = null;
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io.BackendRendererUserData = null;
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io.BackendFlags &= ~(ImGuiBackendFlags.RendererHasVtxOffset | ImGuiBackendFlags.RendererHasTextures);
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platformIO.RendererTextureMaxWidth = 0;
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platformIO.RendererTextureMaxHeight = 0;
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platformIO.RendererRenderState = null;
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platformIO.RendererCreateWindow = null;
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platformIO.RendererDestroyWindow = null;
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platformIO.RendererSetWindowSize = null;
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platformIO.RendererRenderWindow = null;
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platformIO.RendererSwapBuffers = null;
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}
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public static void NewFrame() { }
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private static void RendererCreateWindow(ImGuiViewportPtr viewport)
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{
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Program.Logger.Log(null);
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ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
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if (vd == null || vd.Window == nint.Zero)
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return;
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if (vd.Renderer == nint.Zero)
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{
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vd.Renderer = SDL.CreateRenderer(vd.Window, (string?)null);
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vd.RendererOwned = true;
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}
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Program.Logger.Log(null);
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}
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private static void RendererDestroyWindow(ImGuiViewportPtr viewport)
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{
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Program.Logger.Log(null);
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ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
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if (vd == null)
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return;
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if (vd.RendererOwned && vd.Renderer != nint.Zero)
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{
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SDL.DestroyRenderer(vd.Renderer);
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}
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vd.Renderer = nint.Zero;
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vd.RendererOwned = false;
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Program.Logger.Log(null);
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}
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private static void RendererSetWindowSize(ImGuiViewportPtr viewport, Vector2 size)
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{
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// SDL renderer windows track size through the platform window callback.
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Program.Logger.Log(null);
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}
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private static void RendererRenderWindow(ImGuiViewportPtr viewport)
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{
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Program.Logger.Log(null);
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ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
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if (vd == null || vd.Renderer == nint.Zero)
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{
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return;
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}
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RenderDrawData(viewport.DrawData, vd.Renderer);
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Program.Logger.Log(null);
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}
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private static void RendererSwapBuffers(ImGuiViewportPtr viewport)
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{
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Program.Logger.Log(null);
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ImGuiSDL3Platform.ViewPortData? vd = ImGuiUserData<ImGuiSDL3Platform.ViewPortData>.Get(viewport.PlatformUserData);
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if (vd == null || vd.Renderer == nint.Zero)
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return;
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SDL.RenderPresent(vd.Renderer);
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Program.Logger.Log(null);
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}
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public static void RenderDrawData(ImDrawDataPtr drawData, nint renderer)
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{
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// Skip if no data to render
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if (drawData.Handle == null || drawData.CmdListsCount == 0)
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return;
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SDL.GetRenderScale(renderer, out float renderScaleX, out float renderScaleY);
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Vector2 renderScale = new Vector2(
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renderScaleX == 1.0f ? drawData.FramebufferScale.X : 1.0f,
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renderScaleY == 1.0f ? drawData.FramebufferScale.Y : 1.0f);
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int fbWidth = (int)(drawData.DisplaySize.X * renderScale.X);
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int fbHeight = (int)(drawData.DisplaySize.Y * renderScale.Y);
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if (fbWidth <= 0 || fbHeight <= 0)
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return;
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for (int i = 0; i < drawData.Textures.Size; i++)
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{
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var texture = drawData.Textures[i];
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UpdateTexture(texture, renderer);
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}
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// Backup SDL renderer state
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BackupSDLRendererState old = new BackupSDLRendererState
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{
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ViewportEnabled = SDL.RenderViewportSet(renderer),
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ClipEnabled = SDL.RenderClipEnabled(renderer)
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};
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SDL.GetRenderViewport(renderer, out var oldViewport);
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old.Viewport = oldViewport;
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SDL.GetRenderClipRect(renderer, out var oldClipRect);
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old.ClipRect = oldClipRect;
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// Set up render state
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SDL.SetRenderViewport(renderer, 0);
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SDL.SetRenderClipRect(renderer, nint.Zero);
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// Set render state in platform IO
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ImGuiPlatformIOPtr platformIo = ImGui.GetPlatformIO();
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platformIo.RendererRenderState = (void*)renderer;
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Vector2 clipOffset = drawData.DisplayPos;
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// Render command lists
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for (int n = 0; n < drawData.CmdListsCount; n++)
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{
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ImDrawListPtr cmdList = drawData.CmdLists[n];
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for (int cmdIndex = 0; cmdIndex < cmdList.CmdBuffer.Size; cmdIndex++)
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{
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ImDrawCmd cmd = cmdList.CmdBuffer[cmdIndex];
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if (cmd.UserCallback != null)
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{
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continue; // User callback not implemented
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}
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else
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{
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// Apply clipping rectangle
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Vector4 clipRect = cmd.ClipRect;
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Vector2 clipMin = new Vector2((clipRect.X - clipOffset.X) * renderScale.X, (clipRect.Y - clipOffset.Y) * renderScale.Y);
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Vector2 clipMax = new Vector2((clipRect.Z - clipOffset.X) * renderScale.X, (clipRect.W - clipOffset.Y) * renderScale.Y);
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clipMin.X = Math.Max(0, clipMin.X);
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clipMin.Y = Math.Max(0, clipMin.Y);
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clipMax.X = Math.Min(fbWidth, clipMax.X);
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clipMax.Y = Math.Min(fbHeight, clipMax.Y);
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if (clipMax.X <= clipMin.X || clipMax.Y <= clipMin.Y)
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continue;
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SDL.Rect r = new SDL.Rect
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{
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X = (int)clipMin.X,
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Y = (int)clipMin.Y,
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W = (int)(clipMax.X - clipMin.X),
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H = (int)(clipMax.Y - clipMin.Y)
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};
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SDL.SetRenderClipRect(renderer, r);
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// Get texture
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nint texId = ResolveTextureId(cmd.GetTexID(), renderer);
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// Convert ImGui vertices to SDL vertices
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if (!RenderDrawCommand(cmdList, cmd, renderer, texId, renderScale))
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{
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Console.WriteLine($"Failed to render ImGui draw command: {SDL.GetError()}");
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}
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}
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}
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}
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// Reset render state
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platformIo.RendererRenderState = null;
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// Restore renderer state
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SDL.SetRenderViewport(renderer, old.ViewportEnabled ? old.Viewport : new SDL.Rect());
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SDL.SetRenderClipRect(renderer, old.ClipEnabled ? old.ClipRect : new SDL.Rect());
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}
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private static nint ResolveTextureId(ImTextureID texId, nint renderer)
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{
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if (texId == ImTextureID.Null)
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return nint.Zero;
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TextureState? state = ImGuiUserData<TextureState>.Get((void*)(nint)texId);
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if (state == null)
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return (nint)texId;
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if (!state.RendererTextures.TryGetValue(renderer, out nint rendererTexture) || rendererTexture == nint.Zero)
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{
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rendererTexture = CreateRendererTexture(state, renderer);
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state.RendererTextures[renderer] = rendererTexture;
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}
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return rendererTexture;
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}
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private static nint CreateRendererTexture(TextureState state, nint renderer)
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{
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ImTextureDataPtr tex = state.Source;
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// We keep ARGB8888 here because this project already relies on that upload path.
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nint sdlTexture = SDL.CreateTexture(renderer, SDL.PixelFormat.ARGB8888, SDL.TextureAccess.Static, tex.Width, tex.Height);
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if (sdlTexture == nint.Zero)
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return nint.Zero;
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SDL.UpdateTexture(sdlTexture, nint.Zero, (nint)tex.GetPixels(), tex.GetPitch());
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SDL.SetTextureBlendMode(sdlTexture, SDL.BlendMode.Blend);
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SDL.SetTextureScaleMode(sdlTexture, SDL.ScaleMode.Linear);
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return sdlTexture;
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}
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private static void UploadRendererTexture(ImTextureDataPtr tex, nint renderer, nint sdlTexture)
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{
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if (tex.Status == ImTextureStatus.WantUpdates)
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{
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for (int i = 0; i < tex.Updates.Size; i++)
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{
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var r = tex.Updates[i];
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SDL.Rect rect = new SDL.Rect
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{
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X = r.X,
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Y = r.Y,
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W = r.W,
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H = r.H
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};
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SDL.UpdateTexture(sdlTexture, rect, (nint)tex.GetPixelsAt(r.X, r.Y), tex.GetPitch());
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}
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}
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else
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{
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SDL.UpdateTexture(sdlTexture, nint.Zero, (nint)tex.GetPixels(), tex.GetPitch());
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}
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}
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private static void UpdateTexture(ImTextureDataPtr tex, nint renderer)
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{
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TextureState? state = null;
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if ((nint)tex.BackendUserData != nint.Zero)
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state = ImGuiUserData<TextureState>.Get(tex.BackendUserData);
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if (state == null)
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{
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state = new TextureState();
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tex.BackendUserData = ImGuiUserData<TextureState>.Store(state);
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}
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state.Source = tex;
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tex.SetTexID((nint)tex.BackendUserData);
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if (tex.Status == ImTextureStatus.WantDestroy)
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{
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foreach (nint rendererTexture in state.RendererTextures.Values)
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{
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if (rendererTexture != nint.Zero)
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SDL.DestroyTexture(rendererTexture);
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}
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state.RendererTextures.Clear();
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ImGuiUserData<TextureState>.Free(tex.BackendUserData);
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tex.BackendUserData = (void*)nint.Zero;
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tex.SetTexID(ImTextureID.Null);
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tex.SetStatus(ImTextureStatus.Destroyed);
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return;
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}
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bool hasRendererTexture = state.RendererTextures.TryGetValue(renderer, out nint sdlTexture) && sdlTexture != nint.Zero;
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if (!hasRendererTexture)
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{
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sdlTexture = CreateRendererTexture(state, renderer);
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state.RendererTextures[renderer] = sdlTexture;
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}
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if (sdlTexture != nint.Zero && (tex.Status == ImTextureStatus.WantCreate || tex.Status == ImTextureStatus.WantUpdates || !hasRendererTexture))
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{
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UploadRendererTexture(tex, renderer, sdlTexture);
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tex.SetStatus(ImTextureStatus.Ok);
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}
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}
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private static bool RenderDrawCommand(ImDrawListPtr drawList, ImDrawCmd cmd, nint renderer, nint texId, Vector2 scale)
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{
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uint indexOffset = cmd.IdxOffset;
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uint vertexOffset = cmd.VtxOffset;
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uint elemCount = cmd.ElemCount;
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SDL.Vertex[] vertices = new SDL.Vertex[elemCount];
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int[] indices = new int[elemCount];
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for (int i = 0; i < elemCount; i++)
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{
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ushort idx = drawList.IdxBuffer[(int)indexOffset + i];
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int vertIdx = (int)(vertexOffset + idx);
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ImDrawVert srcVert = drawList.VtxBuffer[vertIdx];
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uint col = srcVert.Col;
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byte r = (byte)((col >> 0) & 0xFF);
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byte g = (byte)((col >> 8) & 0xFF);
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byte b = (byte)((col >> 16) & 0xFF);
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byte a = (byte)((col >> 24) & 0xFF);
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vertices[i] = new SDL.Vertex()
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{
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Position = new SDL.FPoint()
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{
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X = srcVert.Pos.X * scale.X,
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Y = srcVert.Pos.Y * scale.Y
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},
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Color = new SDL.FColor()
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{
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R = r / 255f,
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G = g / 255f,
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B = b / 255f,
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A = a / 255f
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},
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TexCoord = new SDL.FPoint()
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{
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X = srcVert.Uv.X,
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Y = srcVert.Uv.Y
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}
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};
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indices[i] = i;
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}
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return SDL.RenderGeometry(renderer, texId, vertices, vertices.Length, indices, indices.Length);
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}
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public static void CreateDeviceObjects() { }
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public static void DestroyDeviceObjects()
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{
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var texures = ImGui.GetPlatformIO().Textures;
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for (int i = 0; i < texures.Size; i++)
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{
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var texture = texures[i];
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texture.Status = ImTextureStatus.WantDestroy;
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UpdateTexture(texture, nint.Zero);
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}
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}
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}
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