[VideoOut] Scope the AMD integrated-GPU penalty to Windows (#339)

* [VideoOut] Prefer real integrated GPUs over software rasterizers (#325)

Penalize only AMD integrated GPUs (the #97 vkCreateGraphicsPipelines
crash) instead of all integrated devices, so Intel/Apple/Qualcomm iGPUs
outrank Cpu-type software rasterizers (Mesa lavapipe). Hoist
ScorePhysicalDevice to the outer class and add unit tests for the
ordering.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* [VideoOut] Scope AMD iGPU penalty to Windows via a penalty helper

Extract ComputeDevicePenalty (the value subtracted from a device's base
score) and gate the #97 AMD-integrated penalty on Windows only. Mesa RADV
on Linux (e.g. the Steam Deck's AMD APU) is a different, working driver
and should keep its full integrated score. Add a Steam Deck test case and
drop inline comments.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* [VideoOut] Move device-scoring helpers out of the const block

Relocate ScorePhysicalDevice and ComputeDevicePenalty below the leading
const cluster instead of splitting it, and trim the vendor-ID reference
comment to adapters an x86-64 host can realistically enumerate.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.cs

@@ -271,6 +271,10 @@ internal static unsafe class VulkanVideoPresenter
     private static bool _presenterCloseRequested;
     private const string DebugUtilsExtensionName = "VK_EXT_debug_utils";
     private const uint NvidiaVendorId = 0x10DE;
+    private const uint AmdVendorId = 0x1002;
+    // Other GPU PCI vendor IDs, for reference when adding future rules:
+    // Intel 0x8086, Apple 0x106B, Qualcomm 0x5143 (Windows-on-ARM), Microsoft software 0x1414.
+    private const int LastResortPenalty = 1000;
     private const string PortabilityEnumerationExtensionName = "VK_KHR_portability_enumeration";
     private const string PortabilitySubsetExtensionName = "VK_KHR_portability_subset";
     private const int GlfwPlatformHint = 0x00050003;
@@ -279,6 +283,50 @@ internal static unsafe class VulkanVideoPresenter
     private const int GlfwPlatformWayland = 0x00060003;
     private const int GlfwPlatformX11 = 0x00060004;
     private const int GlfwPlatformNull = 0x00060005;
+
+    internal static int ScorePhysicalDevice(
+        PhysicalDeviceProperties properties,
+        string name,
+        string? deviceOverride)
+    {
+        if (!string.IsNullOrWhiteSpace(deviceOverride))
+        {
+            return name.Contains(deviceOverride, StringComparison.OrdinalIgnoreCase) ? 1000 : -1000;
+        }
+
+        var score = properties.DeviceType switch
+        {
+            PhysicalDeviceType.DiscreteGpu => 300,
+            PhysicalDeviceType.VirtualGpu => 100,
+            PhysicalDeviceType.IntegratedGpu => 50,
+            PhysicalDeviceType.Cpu => 20,
+            _ => 10,
+        };
+
+        if (properties.VendorID == NvidiaVendorId)
+        {
+            score += 500;
+        }
+
+        score -= ComputeDevicePenalty(properties, OperatingSystem.IsWindows());
+
+        return score;
+    }
+
+    internal static int ComputeDevicePenalty(PhysicalDeviceProperties properties, bool isWindows)
+    {
+        var penalty = 0;
+
+        if (isWindows &&
+            properties.DeviceType == PhysicalDeviceType.IntegratedGpu &&
+            properties.VendorID == AmdVendorId)
+        {
+            penalty += LastResortPenalty;
+        }
+
+        return penalty;
+    }
+
     private static bool _splashHidden;
     private static long _enqueuedGuestWorkSequence;
     // Largest contiguous completed sequence, retained for compact diagnostics.
@@ -3200,33 +3248,6 @@ internal static unsafe class VulkanVideoPresenter
             _window.Title = VideoOutExports.GetWindowTitle();
         }
 
-        private static int ScorePhysicalDevice(
-            PhysicalDeviceProperties properties,
-            string name,
-            string? deviceOverride)
-        {
-            if (!string.IsNullOrWhiteSpace(deviceOverride))
-            {
-                return name.Contains(deviceOverride, StringComparison.OrdinalIgnoreCase) ? 1000 : -1000;
-            }
-
-            var score = properties.DeviceType switch
-            {
-                PhysicalDeviceType.DiscreteGpu => 300,
-                PhysicalDeviceType.VirtualGpu => 100,
-                PhysicalDeviceType.Cpu => 50,
-                PhysicalDeviceType.IntegratedGpu => -100,
-                _ => 10,
-            };
-
-            if (properties.VendorID == NvidiaVendorId)
-            {
-                score += 500;
-            }
-
-            return score;
-        }
-
         private void LoadComputeDeviceLimits()
         {
             _vk.GetPhysicalDeviceProperties(_physicalDevice, out var properties);

tests/SharpEmu.Libs.Tests/VideoOut/VulkanPhysicalDeviceScoringTests.cs

@@ -0,0 +1,94 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Libs.VideoOut;
+using Silk.NET.Vulkan;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.VideoOut;
+
+public sealed class VulkanPhysicalDeviceScoringTests
+{
+    private const uint NvidiaVendorId = 0x10DE;
+    private const uint AmdVendorId = 0x1002;
+    private const uint IntelVendorId = 0x8086;
+    private const uint QualcommVendorId = 0x5143;
+
+    private static PhysicalDeviceProperties Device(PhysicalDeviceType type, uint vendorId = 0)
+        => new() { DeviceType = type, VendorID = vendorId };
+
+    private static int Score(PhysicalDeviceType type, uint vendorId = 0)
+        => VulkanVideoPresenter.ScorePhysicalDevice(Device(type, vendorId), name: string.Empty, deviceOverride: null);
+
+    [Fact]
+    public void RealIntegratedGpuOutranksSoftwareRasterizer()
+    {
+        Assert.True(Score(PhysicalDeviceType.IntegratedGpu) > Score(PhysicalDeviceType.Cpu));
+    }
+
+    [Theory]
+    [InlineData(IntelVendorId)]
+    [InlineData(QualcommVendorId)]
+    [InlineData(0u)]
+    public void NonAmdIntegratedGpuBeatsSoftware(uint vendorId)
+    {
+        Assert.True(Score(PhysicalDeviceType.IntegratedGpu, vendorId) > Score(PhysicalDeviceType.Cpu));
+    }
+
+    [Fact]
+    public void DiscreteGpuOutranksIntegratedGpu()
+    {
+        Assert.True(Score(PhysicalDeviceType.DiscreteGpu) > Score(PhysicalDeviceType.IntegratedGpu));
+    }
+
+    [Fact]
+    public void NvidiaDiscreteGpuScoresHighest()
+    {
+        var nvidia = Score(PhysicalDeviceType.DiscreteGpu, NvidiaVendorId);
+        Assert.True(nvidia > Score(PhysicalDeviceType.DiscreteGpu));
+        Assert.True(nvidia > Score(PhysicalDeviceType.IntegratedGpu));
+    }
+
+    [Fact]
+    public void DeviceOverridePinsMatchingAdapterAndExcludesOthers()
+    {
+        var properties = Device(PhysicalDeviceType.Cpu);
+        Assert.Equal(1000, VulkanVideoPresenter.ScorePhysicalDevice(properties, "Radeon Graphics", "radeon"));
+        Assert.Equal(-1000, VulkanVideoPresenter.ScorePhysicalDevice(properties, "Radeon Graphics", "nvidia"));
+    }
+
+    [Fact]
+    public void AmdIntegratedGpuIsLastResortOnWindows()
+    {
+        var penalty = VulkanVideoPresenter.ComputeDevicePenalty(
+            Device(PhysicalDeviceType.IntegratedGpu, AmdVendorId), isWindows: true);
+        Assert.True(penalty > 0);
+        Assert.True(50 - penalty < 10);
+    }
+
+    [Fact]
+    public void AmdApuIsNotPenalizedOffWindows()
+    {
+        var penalty = VulkanVideoPresenter.ComputeDevicePenalty(
+            Device(PhysicalDeviceType.IntegratedGpu, AmdVendorId), isWindows: false);
+        Assert.Equal(0, penalty);
+    }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void AmdDiscreteGpuIsNeverPenalized(bool isWindows)
+    {
+        Assert.Equal(0, VulkanVideoPresenter.ComputeDevicePenalty(
+            Device(PhysicalDeviceType.DiscreteGpu, AmdVendorId), isWindows));
+    }
+
+    [Theory]
+    [InlineData(IntelVendorId)]
+    [InlineData(QualcommVendorId)]
+    public void NonAmdIntegratedGpuIsNeverPenalized(uint vendorId)
+    {
+        Assert.Equal(0, VulkanVideoPresenter.ComputeDevicePenalty(
+            Device(PhysicalDeviceType.IntegratedGpu, vendorId), isWindows: true));
+    }
+}