Add WindowsMinVer config for minimum target Windows version switch

Source/Engine/Platform/Win32/IncludeWindowsHeaders.h

@@ -9,20 +9,13 @@
 #define WINVER 0x0601
 #endif
 #ifndef _WIN32_WINNT
-#define _WIN32_WINNT 0x0601
+#define _WIN32_WINNT WINVER
 #endif
 #ifndef _WIN32_WINDOWS
-#define _WIN32_WINDOWS 0x0601
+#define _WIN32_WINDOWS WINVER
 #endif
 
-// Override Win API for UWP
+// Override for Xbox
-#if PLATFORM_UWP
-#define WINVER 0x0A00
-#define _WIN32_WINNT 0x0A00
-#define _WIN32_WINDOWS 0x0A00
-#endif
-
-// Override for Xbox Scarlett
 #if PLATFORM_XBOX_SCARLETT || PLATFORM_XBOX_ONE
 #define NOBITMAP
 #define NOMCX

Source/Engine/Video/MF/VideoBackendMF.cpp

@@ -11,6 +11,15 @@
 #if USE_EDITOR
 #include "Editor/Editor.h"
 #endif
+#include <sdkddkver.h>
+#if WINVER >= _WIN32_WINNT_WINBLUE && WINVER < _WIN32_WINNT_WIN10
+// Fix compilation for Windows 8.1 on the latest Windows SDK
+typedef enum _MFVideoSphericalFormat { } MFVideoSphericalFormat;
+#endif
+#ifndef MF_SOURCE_READER_CURRENT_TYPE_INDEX
+// Fix compilation for Windows 7 on the latest Windows SDK
+#define MF_SOURCE_READER_CURRENT_TYPE_INDEX 0xFFFFFFFF
+#endif
 #include <mfapi.h>
 #include <mfidl.h>
 #include <mfreadwrite.h>

Source/Tools/Flax.Build/Platforms/UWP/UWPToolchain.cs

@@ -77,6 +77,7 @@ namespace Flax.Build.Platforms
             options.CompileEnv.PreprocessorDefinitions.Add("_WINRT_DLL");
             options.CompileEnv.PreprocessorDefinitions.Add("_WINDLL");
             options.CompileEnv.PreprocessorDefinitions.Add("__WRL_NO_DEFAULT_LIB__");
+            options.CompileEnv.PreprocessorDefinitions.Add("WINVER=0x0A00");
 
             options.LinkEnv.InputLibraries.Add("WindowsApp.lib");
         }

Source/Tools/Flax.Build/Platforms/Windows/WindowsToolchain.cs

@@ -1,10 +1,23 @@
 // Copyright (c) 2012-2024 Wojciech Figat. All rights reserved.
 
+using System;
 using System.Collections.Generic;
 using System.IO;
 using Flax.Build.Graph;
 using Flax.Build.NativeCpp;
 
+namespace Flax.Build
+{
+    partial class Configuration
+    {
+        /// <summary>
+        /// Specifies the minimum Windows version to use (eg. 10).
+        /// </summary>
+        [CommandLine("winMinVer", "<version>", "Specifies the minimum Windows version to use (eg. 10).")]
+        public static string WindowsMinVer = "7";
+    }
+}
+
 namespace Flax.Build.Platforms
 {
     /// <summary>
@@ -31,6 +44,25 @@ namespace Flax.Build.Platforms
 
             options.CompileEnv.PreprocessorDefinitions.Add("PLATFORM_WINDOWS");
 
+            // Select minimum Windows version
+            if (!Version.TryParse(Configuration.WindowsMinVer, out var winMinVer))
+            {
+                if (int.TryParse(Configuration.WindowsMinVer, out var winMinVerMajor))
+                    winMinVer = new Version(winMinVerMajor, 0);
+                else
+                    winMinVer = new Version(7, 0);
+            }
+            int winVer;
+            if (winMinVer.Major >= 10)
+                winVer = 0x0A00; // Windows 10
+            else if (winMinVer.Major == 8 && winMinVer.Minor >= 1)
+                winVer = 0x0603; // Windows 8.1
+            else if (winMinVer.Major == 8)
+                winVer = 0x0602; // Windows 8
+            else
+                winVer = 0x0601; // Windows 7
+            options.CompileEnv.PreprocessorDefinitions.Add($"WINVER=0x{winVer:X4}");
+
             options.LinkEnv.InputLibraries.Add("dwmapi.lib");
             options.LinkEnv.InputLibraries.Add("kernel32.lib");
             options.LinkEnv.InputLibraries.Add("user32.lib");