Update ID2D1Shader interface and generator

src/ComputeSharp.D2D1.SourceGenerators/ID2D1ShaderGenerator.CreateEffectDisplayNameProperty.Syntax.cs

@@ -16,18 +16,25 @@ partial class EffectDisplayName
         /// <summary>
         /// Creates a <see cref="PropertyDeclarationSyntax"/> instance for the <c>EffectDisplayName</c> property.
         /// </summary>
-        /// <param name="effectDisplayName">The input effect display name value.</param>
+        /// <param name="effectDisplayName">The input effect display name value, if available.</param>
         /// <returns>The resulting <see cref="PropertyDeclarationSyntax"/> instance for the <c>EffectDisplayName</c> property.</returns>
-        public static PropertyDeclarationSyntax GetSyntax(string effectDisplayName)
+        public static PropertyDeclarationSyntax GetSyntax(string? effectDisplayName)
         {
+            // Get the expression: either a string literal, or just null
+            ExpressionSyntax displayNameExpression = effectDisplayName switch
+            {
+                { } => LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(effectDisplayName)),
+                _ => LiteralExpression(SyntaxKind.NullLiteralExpression)
+            };
+
             // This code produces a method declaration as follows:
             //
-            // readonly string global::ComputeSharp.D2D1.__Internals.ID2D1Shader.EffectDisplayName => "<EFFECT_DISPLAY_NAME>";
+            // readonly string? global::ComputeSharp.D2D1.__Internals.ID2D1Shader.EffectDisplayName => <EFFECT_DISPLAY_NAME>;
             return
-                PropertyDeclaration(PredefinedType(Token(SyntaxKind.StringKeyword)), Identifier(nameof(EffectDisplayName)))
+                PropertyDeclaration(NullableType(PredefinedType(Token(SyntaxKind.StringKeyword))), Identifier(nameof(EffectDisplayName)))
                 .WithExplicitInterfaceSpecifier(ExplicitInterfaceSpecifier(IdentifierName($"global::ComputeSharp.D2D1.__Internals.{nameof(ID2D1Shader)}")))
                 .AddModifiers(Token(SyntaxKind.ReadOnlyKeyword))
-                .WithExpressionBody(ArrowExpressionClause(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(effectDisplayName))))
+                .WithExpressionBody(ArrowExpressionClause(displayNameExpression))
                 .WithSemicolonToken(Token(SyntaxKind.SemicolonToken));
         }
     }

src/ComputeSharp.D2D1.SourceGenerators/ID2D1ShaderGenerator.CreateEffectDisplayNameProperty.cs

@@ -1,6 +1,5 @@
 using System.Diagnostics.CodeAnalysis;
 using ComputeSharp.D2D1.SourceGenerators.Helpers;
-using ComputeSharp.SourceGeneration.Extensions;
 using Microsoft.CodeAnalysis;
 
 namespace ComputeSharp.D2D1.SourceGenerators;
@@ -18,15 +17,15 @@ private static partial class EffectDisplayName
         /// </summary>
         /// <param name="compilation">The input <see cref="Compilation"/> object currently in use.</param>
         /// <param name="structDeclarationSymbol">The <see cref="INamedTypeSymbol"/> for the shader type in use.</param>
-        /// <returns>The resulting effect display name.</returns>
-        public static string GetInfo(Compilation compilation, INamedTypeSymbol structDeclarationSymbol)
+        /// <returns>The resulting effect display name, if available.</returns>
+        public static string? GetInfo(Compilation compilation, INamedTypeSymbol structDeclarationSymbol)
         {
             if (TryGetDefinedEffectDisplayName(compilation, structDeclarationSymbol, out string? effectDisplayName))
             {
                 return effectDisplayName;
             }
 
-            return structDeclarationSymbol.GetFullyQualifiedMetadataName();
+            return null;
         }
 
         /// <summary>

src/ComputeSharp.D2D1.SourceGenerators/ID2D1ShaderGenerator.cs

@@ -58,7 +58,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                     token.ThrowIfCancellationRequested();
 
                     // EffectDisplayName info
-                    string effectDisplayName = EffectDisplayName.GetInfo(context.SemanticModel.Compilation, typeSymbol);
+                    string? effectDisplayName = EffectDisplayName.GetInfo(context.SemanticModel.Compilation, typeSymbol);
 
                     token.ThrowIfCancellationRequested();
 
@@ -149,7 +149,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             .Select(static (item, _) => item.Diagnostcs));
 
         // Get the EffectDisplayName info (hierarchy and effect display name)
-        IncrementalValuesProvider<(HierarchyInfo Hierarchy, string EffectDisplayName)> effectDisplayNameInfo =
+        IncrementalValuesProvider<(HierarchyInfo Hierarchy, string? EffectDisplayName)> effectDisplayNameInfo =
             shaderInfoWithErrors
             .Select(static (item, _) => (item.Hierarchy, item.EffectDisplayName));
 

src/ComputeSharp.D2D1.SourceGenerators/Models/D2D1ShaderInfo.cs

@@ -8,7 +8,7 @@ namespace ComputeSharp.D2D1.SourceGenerators.Models;
 /// </summary>
 /// <param name="Hierarchy">The hierarchy info for the shader type.</param>
 /// <param name="EffectId">The effect id info for the shader type.</param>
-/// <param name="EffectDisplayName">The effect display name for the shader type.</param>
+/// <param name="EffectDisplayName">The effect display name for the shader type, if available.</param>
 /// <param name="DispatchData">The gathered shader dispatch data.</param>
 /// <param name="InputTypes">The gathered input types for the shader.</param>
 /// <param name="ResourceTextureDescriptions">The gathered resource texture descriptions for the shader.</param>
@@ -20,7 +20,7 @@ namespace ComputeSharp.D2D1.SourceGenerators.Models;
 internal sealed record D2D1ShaderInfo(
     HierarchyInfo Hierarchy,
     EffectIdInfo EffectId,
-    string EffectDisplayName,
+    string? EffectDisplayName,
     DispatchDataInfo DispatchData,
     InputTypesInfo InputTypes,
     ResourceTextureDescriptionsInfo ResourceTextureDescriptions,

src/ComputeSharp.D2D1/Interfaces/__Internals/ID2D1Shader.cs

@@ -20,12 +20,12 @@ public interface ID2D1Shader
     ref readonly Guid EffectId { get; }
 
     /// <summary>
-    /// Gets the display name of the D2D effect using this shader.
+    /// Gets the display name of the D2D effect using this shader, if specified.
     /// </summary>
     /// <remarks>
     /// This only applies to effects created from <see cref="Interop.D2D1PixelShaderEffect"/>.
     /// </remarks>
-    string EffectDisplayName { get; }
+    string? EffectDisplayName { get; }
 
     /// <summary>
     /// Initializes the current shader from a buffer with the serialized dispatch data.

src/ComputeSharp.D2D1/Shaders/Interop/D2D1PixelShaderEffect.cs

@@ -32,11 +32,11 @@ public static ref readonly Guid GetEffectId<T>()
     }
 
     /// <summary>
-    /// Gets the effect display name of the D2D effect using this shader.
+    /// Gets the effect display name of the D2D effect using this shader, if available.
     /// </summary>
     /// <typeparam name="T">The type of D2D1 pixel shader to get the effect id for.</typeparam>
-    /// <returns>The effect display name of the D2D effect using <typeparamref name="T"/> shaders.</returns>
-    public static string GetEffectDisplayName<T>()
+    /// <returns>The effect display name of the D2D effect using <typeparamref name="T"/> shaders, if available.</returns>
+    public static string? GetEffectDisplayName<T>()
         where T : unmanaged, ID2D1PixelShader
     {
         Unsafe.SkipInit(out T shader);
@@ -71,7 +71,7 @@ public static void RegisterForD2D1Factory1<T>(void* d2D1Factory1, out Guid effec
             <Effect>
                 <Property name='DisplayName' type='string' value='
             """);
-        writer.WriteRaw(GetEffectDisplayName<T>());
+        writer.WriteRaw(GetEffectDisplayName<T>().AsSpan());
         writer.WriteRaw("""
             '/>
                 <Property name='Author' type='string' value='ComputeSharp.D2D1'/>
@@ -311,7 +311,7 @@ public static ReadOnlyMemory<byte> GetRegistrationBlob<T>(out Guid effectId)
             <Effect>
                 <Property name='DisplayName' type='string' value='
             """u8);
-        writer.WriteAsUtf8(GetEffectDisplayName<T>());
+        writer.WriteAsUtf8(GetEffectDisplayName<T>() ?? "");
         writer.WriteRaw("""
             '/>
                 <Property name='Author' type='string' value='ComputeSharp.D2D1'/>

tests/ComputeSharp.D2D1.Tests/D2D1EffectRegistrationDataTests.cs

@@ -46,7 +46,7 @@ public unsafe void EffectRegistrationData_Validate()
         Assert.AreEqual("""
             <?xml version='1.0'?>
             <Effect>
-                <Property name='DisplayName' type='string' value='ComputeSharp.D2D1.Tests.D2D1EffectRegistrationDataTests+TestRegistrationBlobShader'/>
+                <Property name='DisplayName' type='string' value=''/>
                 <Property name='Author' type='string' value='ComputeSharp.D2D1'/>
                 <Property name='Category' type='string' value='Stylize'/>
                 <Property name='Description' type='string' value='A custom D2D1 effect using a pixel shader'/>

tests/ComputeSharp.D2D1.Tests/D2D1PixelShaderEffectTests.cs

@@ -223,7 +223,7 @@ public float4 Execute()
     [TestMethod]
     public unsafe void DefaultEffectDisplayName_MatchesValue()
     {
-        Assert.AreEqual(D2D1PixelShaderEffect.GetEffectDisplayName<ShaderWithDefaultEffectDisplayName>(), typeof(ShaderWithDefaultEffectDisplayName).FullName);
+        Assert.AreEqual(D2D1PixelShaderEffect.GetEffectDisplayName<ShaderWithDefaultEffectDisplayName>(), null);
     }
 
     [D2DInputCount(0)]