[video] added sdl window and host display plumbing

2026-07-31 06:59:45 +08:00 · 2026-07-28 01:05:42 +03:00
parent 5181df82c8
commit 8c0df4b371
17 changed files with 2925 additions and 1546 deletions
@@ -0,0 +1,129 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SDL;
+using static SDL.SDL3;
+
+namespace SharpEmu.Libs.VideoOut;
+
+public sealed record HostDisplayMode(int Width, int Height, int RefreshRate);
+
+public sealed record HostDisplayInfo(
+    int Index,
+    string Name,
+    IReadOnlyList<HostDisplayMode> Modes);
+
+public static unsafe class HostDisplayCatalog
+{
+    private const SDL_InitFlags VideoFlag = SDL_InitFlags.SDL_INIT_VIDEO;
+    private static int _queryFailureLogged;
+
+    public static IReadOnlyList<HostDisplayInfo> Query()
+    {
+        var initializedHere = false;
+        var videoReady = false;
+        try
+        {
+            initializedHere = (SDL_WasInit(VideoFlag) & VideoFlag) == 0;
+            if (initializedHere && !SDL_InitSubSystem(VideoFlag))
+            {
+                LogQueryFailure(SDL_GetError() ?? "unknown SDL error");
+                return CreateFallback();
+            }
+            videoReady = true;
+
+            using var displays = SDL_GetDisplays();
+            if (displays is null || displays.Count == 0)
+            {
+                LogQueryFailure("SDL reported no displays");
+                return CreateFallback();
+            }
+
+            var result = new List<HostDisplayInfo>(displays.Count);
+            for (var index = 0; index < displays.Count; index++)
+            {
+                var display = displays[index];
+                var name = SDL_GetDisplayName(display);
+                var modes = ReadModes(display);
+                result.Add(new HostDisplayInfo(
+                    index,
+                    string.IsNullOrWhiteSpace(name) ? $"Display {index + 1}" : name,
+                    modes));
+            }
+
+            return result;
+        }
+        catch (Exception exception)
+        {
+            LogQueryFailure(exception.Message);
+            return CreateFallback();
+        }
+        finally
+        {
+            if (initializedHere && videoReady)
+            {
+                SDL_QuitSubSystem(VideoFlag);
+            }
+        }
+    }
+
+    private static IReadOnlyList<HostDisplayMode> ReadModes(SDL_DisplayID display)
+    {
+        var modes = new HashSet<HostDisplayMode>();
+        using (var fullscreenModes = SDL_GetFullscreenDisplayModes(display))
+        {
+            if (fullscreenModes is not null)
+            {
+                for (var index = 0; index < fullscreenModes.Count; index++)
+                {
+                    var mode = fullscreenModes[index];
+                    AddMode(modes, &mode);
+                }
+            }
+        }
+
+        AddMode(modes, SDL_GetDesktopDisplayMode(display));
+        if (modes.Count == 0)
+        {
+            return CreateFallbackModes();
+        }
+
+        return modes
+            .OrderByDescending(mode => (long)mode.Width * mode.Height)
+            .ThenByDescending(mode => mode.Width)
+            .ThenByDescending(mode => mode.RefreshRate)
+            .ToArray();
+    }
+
+    private static void AddMode(HashSet<HostDisplayMode> modes, SDL_DisplayMode* mode)
+    {
+        if (mode is null || mode->w <= 0 || mode->h <= 0)
+        {
+            return;
+        }
+
+        var refreshRate = mode->refresh_rate > 0
+            ? Math.Max(1, (int)Math.Round(mode->refresh_rate, MidpointRounding.AwayFromZero))
+            : 0;
+        modes.Add(new HostDisplayMode(mode->w, mode->h, refreshRate));
+    }
+
+    private static IReadOnlyList<HostDisplayInfo> CreateFallback() =>
+        [new HostDisplayInfo(0, "Display 1", CreateFallbackModes())];
+
+    private static IReadOnlyList<HostDisplayMode> CreateFallbackModes() =>
+        [
+            new HostDisplayMode(3840, 2160, 60),
+            new HostDisplayMode(2560, 1440, 60),
+            new HostDisplayMode(1920, 1080, 60),
+            new HostDisplayMode(1280, 720, 60),
+        ];
+
+    private static void LogQueryFailure(string message)
+    {
+        if (Interlocked.Exchange(ref _queryFailureLogged, 1) == 0)
+        {
+            Console.Error.WriteLine($"[GUI][WARN] SDL display query failed: {message}");
+        }
+    }
+}