[Metal] Add a real support check for Metal.

veldrid · Mar 20, 2018 · 8a7ccd3 · 8a7ccd3
1 parent 0058c68
commit 8a7ccd3
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Showing 4 changed files with 54 additions and 1 deletion.
diff --git a/src/Veldrid.MetalBindings/MTLDevice.cs b/src/Veldrid.MetalBindings/MTLDevice.cs
@@ -126,6 +126,9 @@ public Bool8 isDepth24Stencil8PixelFormatSupported
         [DllImport(MetalFramework)]
         public static extern MTLDevice MTLCreateSystemDefaultDevice();
 
+        [DllImport(MetalFramework)]
+        public static extern NSArray MTLCopyAllDevices();
+
         private static readonly Selector sel_name = "name";
         private static readonly Selector sel_maxThreadsPerThreadgroup = "maxThreadsPerThreadgroup";
         private static readonly Selector sel_newLibraryWithSource = "newLibraryWithSource:options:error:";

diff --git a/src/Veldrid.MetalBindings/NSArray.cs b/src/Veldrid.MetalBindings/NSArray.cs
@@ -0,0 +1,14 @@
+using System;
+using static Veldrid.MetalBindings.ObjectiveCRuntime;
+
+namespace Veldrid.MetalBindings
+{
+    public struct NSArray
+    {
+        public readonly IntPtr NativePtr;
+        public NSArray(IntPtr ptr) => NativePtr = ptr;
+
+        public UIntPtr count => UIntPtr_objc_msgSend(NativePtr, sel_count);
+        private static readonly Selector sel_count = "count";
+    }
+}
diff --git a/src/Veldrid/GraphicsDevice.cs b/src/Veldrid/GraphicsDevice.cs
@@ -595,7 +595,7 @@ public static bool IsBackendSupported(GraphicsBackend backend)
 #endif
                 case GraphicsBackend.Metal:
 #if !EXCLUDE_METAL_BACKEND
-                    return RuntimeInformation.IsOSPlatform(OSPlatform.OSX);
+                    return MTL.MTLGraphicsDevice.IsSupported();
 #else
                     return false;
 #endif

diff --git a/src/Veldrid/MTL/MTLGraphicsDevice.cs b/src/Veldrid/MTL/MTLGraphicsDevice.cs
@@ -11,6 +11,8 @@ namespace Veldrid.MTL
 {
     internal unsafe class MTLGraphicsDevice : GraphicsDevice
     {
+        private static readonly Lazy<bool> s_isSupported = new Lazy<bool>(GetIsSupported);
+
         private readonly MTLDevice _device;
         private readonly MTLCommandQueue _commandQueue;
         private readonly MTLSwapchain _mainSwapchain;
@@ -307,6 +309,40 @@ public override void ResetFence(Fence fence)
             Util.AssertSubtype<Fence, MTLFence>(fence).Reset();
         }
 
+        internal static bool IsSupported() => s_isSupported.Value;
+
+        private static bool GetIsSupported()
+        {
+            bool result = false;
+            try
+            {
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                {
+                    if (RuntimeInformation.OSDescription.Contains("Darwin"))
+                    {
+                        NSArray allDevices = MTLDevice.MTLCopyAllDevices();
+                        result |= (ulong)allDevices.count > 0;
+                        ObjectiveCRuntime.release(allDevices.NativePtr);
+                    }
+                    else
+                    {
+                        MTLDevice defaultDevice = MTLDevice.MTLCreateSystemDefaultDevice();
+                        if (defaultDevice.NativePtr != IntPtr.Zero)
+                        {
+                            result = true;
+                            ObjectiveCRuntime.release(defaultDevice.NativePtr);
+                        }
+                    }
+                }
+            }
+            catch
+            {
+                result = false;
+            }
+
+            return result;
+        }
+
         internal MTLComputePipelineState GetUnalignedBufferCopyPipeline()
         {
             lock (_unalignedBufferCopyPipelineLock)