[Vulkan] Add support for VK_KHR_portability_enumeration

If this extension is not enabled, instance creation will fail when
using MoltenVK via the Vulkan loader. This is not necessary when
loading the MoltenVK library directly.

Author: hyazinthh

src/Aardvark.Rendering.Vulkan/Core/Platform/DeviceChooserAuto.fs

@@ -19,18 +19,24 @@ type DeviceChooserAuto =
         | VkPhysicalDeviceType.Cpu -> 2
         | _ -> 1
 
+    static let scorePortability (device: PhysicalDevice) =
+        if device.HasExtension KHRPortabilitySubset.Name then 0
+        else 100
+
     /// Selects the device with the highest score according to the given function.
     new (score: PhysicalDevice -> int) =
         { inherit DeviceChooser(); score = score }
 
     /// Prefers either dedicated or integrated GPUs.
+    /// Non-conformant devices are chosen last.
     new (preferDedicated: bool) =
-        let score = if preferDedicated then deviceTypeScoreDedicated else deviceTypeScoreIntegrated
-        DeviceChooserAuto(fun device -> score device.Type)
+        let typeScore = if preferDedicated then deviceTypeScoreDedicated else deviceTypeScoreIntegrated
+        DeviceChooserAuto(fun device -> scorePortability device + typeScore device.Type)
 
     /// Selects the first reported device.
+    /// Non-conformant devices are chosen last.
     new () =
-        DeviceChooserAuto(fun _ -> 0)
+        DeviceChooserAuto(scorePortability)
 
     override _.IgnoreCache = true
-    override this.Choose(devices) = devices |> Array.sortByDescending this.score |> Array.head
+    override this.Choose(devices) = devices |> Seq.sortByDescending this.score |> Seq.head

src/Aardvark.Rendering.Vulkan/Core/Platform/Extensions.fs

@@ -31,6 +31,8 @@ module Extensions =
 
     let MemoryPriority                  = EXTMemoryPriority.Name
 
+    let PortabilityEnumeration          = KHRPortabilityEnumeration.Name
+
     let Shader8Bit16Bit = [
         KHR8bitStorage.Name
         KHRShaderFloat16Int8.Name

src/Aardvark.Rendering.Vulkan/Core/Platform/Instance.fs

@@ -7,6 +7,7 @@ open Microsoft.FSharp.NativeInterop
 open Aardvark.Base
 open Aardvark.Rendering
 open EXTLayerSettings
+open KHRPortabilityEnumeration
 open Vulkan11
 
 #nowarn "9"
@@ -156,6 +157,12 @@ type Instance(apiVersion : Version, layers : string seq, extensions : string seq
                 let! pLayerSettingsCreateInfo =
                     VkLayerSettingsCreateInfoEXT(uint32 layerSettings.Count, layerSettings.Pointer)
 
+                let flags =
+                    if isExtensionEnabled KHRPortabilityEnumeration.Name then
+                        VkInstanceCreateFlags.EnumeratePortabilityBitKhr
+                    else
+                        VkInstanceCreateFlags.None
+
                 let pNext =
                     if layerSettings.Count > 0 then
                         pLayerSettingsCreateInfo.Address
@@ -165,20 +172,22 @@ type Instance(apiVersion : Version, layers : string seq, extensions : string seq
                 let! pInfo =
                     VkInstanceCreateInfo(
                         pNext,
-                        VkInstanceCreateFlags.None,
+                        flags,
                         pApplicationInfo,
                         uint32 layers.Length, pLayers,
                         uint32 extensions.Length, pExtensions
                     )
 
                 let! pInstance = VkInstance.Zero
+                let result = VkRaw.vkCreateInstance(pInfo, NativePtr.zero, pInstance)
+
+                if result = VkResult.Success then
+                    return Some (!!pInstance, apiVersion)
 
-                let res = VkRaw.vkCreateInstance(pInfo, NativePtr.zero, pInstance)
-                let instance = NativePtr.read pInstance
-                if res = VkResult.Success then
-                    return Some (instance, apiVersion)
                 elif apiVersion.Minor > 0 then
+                    Log.warn $"[Vulkan] Failed to create instance for version {apiVersion} ({result})"
                     return tryCreate (Version(apiVersion.Major, apiVersion.Minor - 1, apiVersion.Build))
+
                 else
                     return None
             }

src/Aardvark.Rendering.Vulkan/Runtime/Headless.fs

@@ -26,6 +26,7 @@ type HeadlessVulkanApplication(debug: IDebugConfig,
             yield Extensions.MemoryBudget
             yield Extensions.MemoryPriority
             yield Extensions.DeviceFault
+            yield Extensions.PortabilityEnumeration
 
             yield! Extensions.Maintenance
             yield! Extensions.Raytracing debug.RaytracingValidationEnabled