graphics/autotesting: skip backbuffer-clamp-to-window under autotesting

ConfirmRenderingSettings clamps the requested back-buffer size to fit
Window.ClientBounds — fine for dev, wrong for headless CI capture (a
portrait 640x1136 sample gets clipped to 640x749 on a shorter desktop).

Adds SkipBackBufferClampToWindow on GraphicsDeviceManager (copied to
PresentationParameters in ChangeOrCreateDevice). ConfirmRenderingSettings
honours it; the Vulkan swap-chain creation also bypasses
surfaceCapabilities.currentExtent when set. The autotesting harness sets
the flag in OnGameStarted, before device creation.

Author: xen2

sources/engine/Stride.Engine/Engine/Game.cs

@@ -310,15 +310,15 @@ public override void ConfirmRenderingSettings(bool gameCreation)
 
             var deviceManager = (GraphicsDeviceManager)graphicsDeviceManager;
 
-            if (gameCreation)
+            if (gameCreation && !deviceManager.SkipBackBufferClampToWindow)
             {
                 //if our device width or height is actually smaller then requested we use the device one
                 deviceManager.PreferredBackBufferWidth = Context.RequestedWidth = Math.Min(deviceManager.PreferredBackBufferWidth, Window.ClientBounds.Width);
                 deviceManager.PreferredBackBufferHeight = Context.RequestedHeight = Math.Min(deviceManager.PreferredBackBufferHeight, Window.ClientBounds.Height);
             }
 
             //these might get triggered even during game runtime, resize, orientation change
-            if (renderingSettings != null && renderingSettings.AdaptBackBufferToScreen)
+            if (!deviceManager.SkipBackBufferClampToWindow && renderingSettings != null && renderingSettings.AdaptBackBufferToScreen)
             {
                 var deviceAr = Window.ClientBounds.Width / (float)Window.ClientBounds.Height;
 

sources/engine/Stride.Games/GraphicsDeviceManager.cs

@@ -191,6 +191,13 @@ private void GameOnWindowCreated(object sender, EventArgs eventArgs)
         /// </value>
         public string RequiredAdapterUid { get; set; }
 
+        /// <summary>
+        ///   When set, the requested back-buffer size is honoured as-is and any clamp to the host
+        ///   window's client area is skipped (both in <see cref="GameBase.ConfirmRenderingSettings"/>
+        ///   and in the <see cref="GraphicsPresenter"/>'s swap-chain creation).
+        /// </summary>
+        public bool SkipBackBufferClampToWindow { get; set; }
+
         /// <summary>
         ///   Gets or sets the preferred color space for the Back-Buffers.
         /// </summary>
@@ -1185,6 +1192,7 @@ void ChangeOrCreateDevice()
 
                     // Find the best device configuration based on the current settings
                     var graphicsDeviceInformation = FindBestDevice(forceCreate);
+                    graphicsDeviceInformation.PresentationParameters.SkipBackBufferClampToWindow = SkipBackBufferClampToWindow;
                     // Give a chance to the game to modify the device settings before the device is created or reset
                     OnPreparingDeviceSettings(this, new PreparingDeviceSettingsEventArgs(graphicsDeviceInformation));
 

sources/engine/Stride.Graphics/PresentationParameters.cs

@@ -194,6 +194,12 @@ public sealed class PresentationParameters : IEquatable<PresentationParameters>
     /// </remarks>
     public ColorSpace ColorSpace;
 
+    /// <summary>
+    ///   When set, the presenter honours <see cref="BackBufferWidth"/> / <see cref="BackBufferHeight"/>
+    ///   as-is and skips any clamp to the host window's client area.
+    /// </summary>
+    public bool SkipBackBufferClampToWindow;
+
     /// <summary>
     ///   The color space type used for the Graphics Presenter output.
     /// </summary>

sources/engine/Stride.Graphics/Vulkan/SwapChainGraphicsPresenter.Vulkan.cs

@@ -432,8 +432,11 @@ private unsafe void CreateSwapChain(int width, int height, PixelFormat desiredFo
             // Create swapchain
             GraphicsDevice.NativeInstanceApi.vkGetPhysicalDeviceSurfaceCapabilitiesKHR(GraphicsDevice.NativePhysicalDevice, surface, out var surfaceCapabilities);
 
-            Description.BackBufferWidth = (int)surfaceCapabilities.currentExtent.width;
-            Description.BackBufferHeight = (int)surfaceCapabilities.currentExtent.height;
+            if (!Description.SkipBackBufferClampToWindow)
+            {
+                Description.BackBufferWidth = (int)surfaceCapabilities.currentExtent.width;
+                Description.BackBufferHeight = (int)surfaceCapabilities.currentExtent.height;
+            }
 
             // Buffer count
             uint desiredImageCount = Math.Max(surfaceCapabilities.minImageCount, 2);