gpu: add BindGroupLayout.Entry constructor helper APIs

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

gpu/src/bind_group_layout.zig

@@ -3,7 +3,9 @@ const ShaderStageFlags = @import("types.zig").ShaderStageFlags;
 const Buffer = @import("buffer.zig").Buffer;
 const Sampler = @import("sampler.zig").Sampler;
 const Texture = @import("texture.zig").Texture;
+const TextureView = @import("texture_view.zig").TextureView;
 const StorageTextureBindingLayout = @import("types.zig").StorageTextureBindingLayout;
+const StorageTextureAccess = @import("types.zig").StorageTextureAccess;
 const Impl = @import("interface.zig").Impl;
 
 pub const BindGroupLayout = opaque {
@@ -11,10 +13,80 @@ pub const BindGroupLayout = opaque {
         next_in_chain: ?*const ChainedStruct = null,
         binding: u32,
         visibility: ShaderStageFlags,
-        buffer: Buffer.BindingLayout,
-        sampler: Sampler.BindingLayout,
-        texture: Texture.BindingLayout,
-        storage_texture: StorageTextureBindingLayout,
+        buffer: Buffer.BindingLayout = .{},
+        sampler: Sampler.BindingLayout = .{},
+        texture: Texture.BindingLayout = .{},
+        storage_texture: StorageTextureBindingLayout = .{},
+
+    /// Helper to create a buffer BindGroupLayout.Entry.
+    pub fn buffer(
+        binding: u32,
+        visibility: ShaderStageFlags,
+        binding_type: Buffer.BindingType,
+        has_dynamic_offset: bool,
+        min_binding_size: u64,
+    ) Entry {
+        return .{
+            .binding = binding,
+            .visibility = visibility,
+            .buffer = .{
+                .type = binding_type,
+                .has_dynamic_offset = has_dynamic_offset,
+                .min_binding_size = min_binding_size,
+            },
+        };
+    }
+
+    /// Helper to create a sampler BindGroupLayout.Entry.
+    pub fn sampler(
+        binding: u32,
+        visibility: ShaderStageFlags,
+        binding_type: Sampler.BindingType,
+    ) Entry {
+        return .{
+            .binding = binding,
+            .visibility = visibility,
+            .sampler = .{ .type = binding_type },
+        };
+    }
+
+    /// Helper to create a texture BindGroupLayout.Entry.
+    pub fn texture(
+        binding: u32,
+        visibility: ShaderStageFlags,
+        sample_type: Texture.SampleType,
+        view_dimension: TextureView.Dimension,
+        multisampled: bool,
+    ) Entry {
+        return .{
+            .binding = binding,
+            .visibility = visibility,
+            .texture = .{
+                .sample_type = sample_type,
+                .view_dimension = view_dimension,
+                .multisampled = multisampled,
+            },
+        };
+    }
+
+    /// Helper to create a storage texture BindGroupLayout.Entry.
+    pub fn storageTexture(
+        binding: u32,
+        visibility: ShaderStageFlags,
+        access: StorageTextureAccess,
+        format: Texture.Format,
+        view_dimension: TextureView.Dimension,
+    ) Entry {
+        return .{
+            .binding = binding,
+            .visibility = visibility,
+            .storage_texture = .{
+                .access = access,
+                .format = format,
+                .view_dimension = view_dimension,
+            },
+        };
+    }
     };
 
     pub const Descriptor = extern struct {