377 lines
16 KiB
C#
377 lines
16 KiB
C#
using System.Diagnostics;
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using System.Numerics;
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using System.Runtime.CompilerServices;
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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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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 ClipEnabled;
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public SDL.Rect ClipRect;
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}
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public static RendererData GetRendererData() => ImGui.GetCurrentContext().Handle != null ? ImGuiUserData<RendererData>.Get(ImGui.GetIO().BackendRendererUserData)! : null!;
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public static SDL3Window? Parent;
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public static bool Init(nint renderer, SDL3Window? parentWindow = null)
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{
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Parent = parentWindow;
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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 = DelegateStorage.RendererCreateWindowDelegate.GetPtrForDelegate();
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platformIO.RendererDestroyWindow = DelegateStorage.RendererDestroyWindowDelegate.GetPtrForDelegate();
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platformIO.RendererRenderWindow = DelegateStorage.RendererRenderWindowDelegate.GetPtrForDelegate();
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platformIO.RendererSwapBuffers = DelegateStorage.RendererSwapBuffersDelegate.GetPtrForDelegate();
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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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ImGuiIOPtr io = ImGui.GetIO();
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ImGuiPlatformIOPtr platformIO = ImGui.GetPlatformIO();
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if (io.BackendRendererName != null)
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{
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Marshal.FreeHGlobal((nint)io.BackendRendererName);
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}
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ImGuiUserData<RendererData>.Free(io.BackendRendererUserData);
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io.BackendRendererName = null;
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io.BackendRendererUserData = null;
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io.BackendFlags &= ~(ImGuiBackendFlags.RendererHasVtxOffset | ImGuiBackendFlags.RendererHasTextures | ImGuiBackendFlags.RendererHasViewports);
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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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}
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public static void SetupRenderState(nint renderer)
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{
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// Clear out any viewports and cliprect set by the user
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// FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
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SDL.SetRenderViewport(renderer, nint.Zero);
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SDL.SetRenderClipRect(renderer, nint.Zero);
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}
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public static void NewFrame()
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{
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RendererData bd = GetRendererData();
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Debug.Assert(bd != null, "Context or backend not initialized! Did you call ImGuiSDL3Renderer.Init()?");
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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(renderScaleX == 1.0f ? drawData.FramebufferScale.X : 1.0f, 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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ImTextureDataPtr texture = drawData.Textures[i];
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if (texture.Handle != null)
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{
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UpdateTexture(texture, renderer);
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}
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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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ClipEnabled = SDL.RenderClipEnabled(renderer)
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};
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SDL.GetRenderViewport(renderer, out old.Viewport);
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SDL.GetRenderClipRect(renderer, out old.ClipRect);
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// Set up render state
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SetupRenderState(renderer);
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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 drawList = drawData.CmdLists[n];
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for (int cmdIndex = 0; cmdIndex < drawList.CmdBuffer.Size; cmdIndex++)
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{
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ImDrawCmd cmd = drawList.CmdBuffer[cmdIndex];
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if (cmd.UserCallback != null)
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{
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if (cmd.UserCallback == DelegateStorage.DrawCallbackResetRenderStateDelegate.GetPtrForDelegate())
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{
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SetupRenderState(renderer);
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}
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else
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{
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// this is cursed af and idk if it even works :)
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ImDrawCmdPtr cmdPtr = new ImDrawCmdPtr
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{
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Handle = (ImDrawCmd*)Unsafe.AsPointer(ref cmd)
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};
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((delegate* unmanaged[Cdecl]<ImDrawListPtr, ImDrawCmdPtr, void>)cmd.UserCallback)(drawList, cmdPtr);
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}
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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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// Convert ImGui vertices to SDL vertices
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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 colR = (byte)((col >> 0) & 0xFF);
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byte colG = (byte)((col >> 8) & 0xFF);
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byte colB = (byte)((col >> 16) & 0xFF);
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byte colA = (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 - clipOffset.X) * renderScale.X,
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Y = (srcVert.Pos.Y - clipOffset.Y) * renderScale.Y
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},
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Color = new SDL.FColor
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{
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R = colR / 255f,
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G = colG / 255f,
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B = colB / 255f,
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A = colA / 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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// Get texture
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ImTextureID texId = cmd.GetTexID();
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if (!SDL.RenderGeometry(renderer, texId, vertices, vertices.Length, indices, indices.Length))
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{
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Program.Logger.Log($"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.Viewport);
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SDL.SetRenderClipRect(renderer, old.ClipEnabled ? old.ClipRect : new SDL.Rect());
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}
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private static void UpdateTexture(ImTextureDataPtr tex, nint renderer)
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{
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if (tex.Status == ImTextureStatus.WantDestroy)
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{
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if (tex.TexID != ImTextureID.Null)
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SDL.DestroyTexture(tex.TexID);
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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 needsCreate = tex.TexID == ImTextureID.Null || SDL.GetRendererFromTexture(tex.TexID) != renderer;
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if (tex.Status == ImTextureStatus.WantCreate || needsCreate)
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{
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if (tex.TexID != ImTextureID.Null)
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SDL.DestroyTexture(tex.TexID);
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// Create texture on the renderer that is actually drawing this viewport.
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// SDL textures are renderer-owned and cannot be shared across renderer instances.
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nint sdlTexture = SDL.CreateTexture(renderer, SDL.PixelFormat.ABGR8888, SDL.TextureAccess.Static, tex.Width, tex.Height);
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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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tex.SetTexID(sdlTexture);
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tex.SetStatus(ImTextureStatus.Ok);
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return;
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}
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if (tex.Status == ImTextureStatus.WantUpdates)
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{
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// Update selected blocks. We only ever write to textures regions which have never been used before!
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// This backend choose to use tex.Updates[] but you can use tex.UpdateRect to upload a single region.
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nint sdlTexture = tex.TexID;
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for (int i = 0; i < tex.Updates.Size; i++)
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{
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ImTextureRect r = tex.Updates[i];
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SDL.Rect sdlR = new SDL.Rect { X = r.X, Y = r.Y, W = r.W, H = r.H };
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SDL.UpdateTexture(sdlTexture, sdlR, (nint)tex.GetPixelsAt(r.X, r.Y), tex.GetPitch());
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}
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tex.SetStatus(ImTextureStatus.Ok);
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}
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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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ImVector<ImTextureDataPtr> texures = ImGui.GetPlatformIO().Textures;
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for (int i = 0; i < texures.Size; i++)
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{
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ImTextureDataPtr texture = texures[i];
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texture.Status = ImTextureStatus.WantDestroy;
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UpdateTexture(texture, GetRendererData().Renderer);
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}
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}
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// @formatter:off — disable formatter after this line
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public static class DelegateStorage
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{
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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internal delegate void DrawCallbackResetRenderStateFn(ImDrawListPtr drawList, ImDrawCmdPtr cmd);
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internal static readonly DrawCallbackResetRenderStateFn DrawCallbackResetRenderStateDelegate = DrawCallbackResetRenderState;
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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.
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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internal delegate void RendererCreateWindowFn(ImGuiViewportPtr viewport);
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internal static readonly RendererCreateWindowFn RendererCreateWindowDelegate = RendererCreateWindow;
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private static void RendererCreateWindow(ImGuiViewportPtr viewport)
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{
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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, null);
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vd.RendererOwned = true;
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}
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}
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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internal delegate void RendererDestroyWindowFn(ImGuiViewportPtr viewport);
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internal static readonly RendererDestroyWindowFn RendererDestroyWindowDelegate = RendererDestroyWindow;
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private static void RendererDestroyWindow(ImGuiViewportPtr viewport)
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{
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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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}
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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internal delegate void RendererRenderWindowFn(ImGuiViewportPtr viewport);
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internal static readonly RendererRenderWindowFn RendererRenderWindowDelegate = RendererRenderWindow;
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private static void RendererRenderWindow(ImGuiViewportPtr viewport)
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{
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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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if (Parent != null)
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{
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SDL.SetRenderDrawColorFloat(vd.Renderer, Parent.ClearColor.X, Parent.ClearColor.Y, Parent.ClearColor.Z, 0f);
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SDL.RenderClear(vd.Renderer);
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}
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RenderDrawData(viewport.DrawData, vd.Renderer);
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}
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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internal delegate void RendererSwapBuffersFn(ImGuiViewportPtr viewport);
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internal static readonly RendererSwapBuffersFn RendererSwapBuffersDelegate = RendererSwapBuffers;
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private static void RendererSwapBuffers(ImGuiViewportPtr viewport)
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{
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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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}
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}
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// @formatter:on — enable formatter after this line
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} |